ISMRM 25th Annual Meeting & Exhibition • 22-27 April 2017 • Honolulu, HI, USA

Traditional Poster Session: Acquisition, Reconstruction & Analysis
 1272 -1296 Motion Correction 1297 -1316 More Motion 1317 -1331 RF Pulse Design 1332 -1366 Multimodal & Multiparametric 1367 -1386 Elastography 1387 -1406 Artifacts 1407 -1429 Sparse & Low-Rank Reconstruction 1430 -1476 Post-Processing & Analysis 1477 -1511 Pulse Sequences 1512 -1531 Reconstruction

Motion Correction
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 1272-1296 08:15 - 10:15

More Motion
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

RF Pulse Design
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

Multimodal & Multiparametric
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

 1332 Water and Fat Based Partial Volume Correction for PET/MRI Hyungseok Jang, Alan McMillan In this study we propose to develop methods that improve the resolution of PET images by utilizing water and fat-based partial volume correction. These methods are expected to be particularly useful in simultaneous breast PET/MR imaging as white adipose tissue is known to be minimally FDG avid. 1333 Simultaneous Estimation of ADC, T2-relaxation, Perfusion and 11C-acetate PET Uptake in Prostate Cancer Mikael Skorpil, Patrik Brynolfsson, Axel Hartwig, Mathias Engström Multiparametric MRI is the standard to evaluate suspected prostate cancer. T2-weighted and DWI are essential, while DCE is less crucial. We here demonstrate that simultaneous quantification of ADC, T2-relaxation and perfusion fraction f, which was calculated from non-IVIM low b-value data, is feasible in combination with 11C-acetate PET/MR imaging. ADC and T2-values differed significantly between healthy tissue and cancer, while f was more inconsistent. An important benefit of simultaneous acquisition is the lack of image mismatch between T2-maps and DWI. This enables more objective tumor grading, decreased inter-rater variability and using mathematical/statistical approaches or computer-aided detection to estimate cancer probability. 1334 Zero-echo-time PET/MRI attenuation correction shows good correlation between 15O-water PET and simultaneously acquired ASL in standard regional flow territories Markus Fahlström, Karolina Lindskog, Lieuwe Appel, Mathias Engström, Johan Wikström, Gunnar Antoni, Eva Kumlien, Elna-Marie Larsson, Mark Lubberink Zero-Echo-Time (ZTE) MRI for attenuation correction (AC) in hybrid PET/MRI-systems is a promising method. This study aims to examine reproducibility between 15O-water PET and simultaneously acquired Arterial Spin Labelling (ASL) using ZTE-MRI AC and the reproducibility between to subsequent ASL measurements. Measurements were performed on six subjects on an integrated 3.0 T PET/MRI-system. Regional cerebral blood flow (CBF) values from standard flow territories were compared. ASL showed good correlation with 15O-water PET, presenting another advantage of ZTE-MRI AC. A significant decrease between ASL measurements was detected, which may be important to consider when designing PET/MRI-studies. 1335 Hybrid ZTE/Dixon MR-based Attenuation Correction for Knee PET/MR Sodium Fluoride Studies Andrew Leynes, Valentina Pedoia, Florian Wiesinger, Anand Venkatachari, Sharmila Majumdar, Peder Larson This study introduces a new hybrid ZTE/Dixon MR-based attenuation correction (MRAC) method including bone density estimation for PET/MRI and quantifies the effect of bone attenuation on sodium fluoride uptake in the knee. 1336 Impact of new attenuation correction methods on whole-body PET/MR Mark Oehmigen, Marcel Gratz, Verena Ruhlmann, Lale Umutlu, Matthias Fenchel, Jan Ole Blumhagen, Harald Quick Recent developments in MR-based whole-body PET/MR attenuation correction allow for adding bone information and for eliminating truncation artefacts along the patients’ arms using the HUGE technique. 43 patients underwent a PET/MR whole-body examination. The PET SUVmax of 57 active lesions were measured for PET data reconstructed with four different µmaps: standard, standard+bone, standard+HUGE, and standard+bone+HUGE. Compared to the standard-µmap, the mean SUVmax of all 57 lesions increases by 14%±12% when adding bone, by 17%±12% when adding HUGE, and by 24%±19% when adding bone+HUGE. These results are an important step towards improved MR-based attenuation correction in whole-body PET/MR hybrid imaging. 1337 Comparison of UTE-based Attenuation Correction Methods for Simultaneous PET/MR Imaging of the Children's Brain Chang Gao, Junshen Xu, Bowen Fan, Jiajin Liu, Kui Ying In simultaneous PET/MR imaging, PET attenuation correction is based on MRI, unlike PET/CT systems, which directly use CT measurements. Various approaches have been developed based on templates, atlas information, direct segmentation of T1-weighted MR images. In the present study, we introduced two approaches of UTE-based attenuation correction for simultaneous PET/MR imaging focusing on children’s brain, including segmentation-based method and Support Vector Machine (SVM) regression method. The results have been compared with Gaussian Mixture Regression (GMR) model method. 1338 A Non-invasive Method for Quantifying Cerebral Blood Flow by Hybrid PET/MR Tracy Ssali, Udunna Anazodo, Jonathan Thiessen, Frank Prato, Keith St Lawrence While PET with [15O]H2O is the gold standard for imaging CBF, quantification requires measuring the arterial input function (AIF), which is an invasive and noisy procedure. ASL is an attractive alternative, however, its accuracy is limited by low SNR. Considering these limitations, we propose a hybrid PET/MRI approach using global CBF measurements from phase contrast MRI to convert [15O]H2O PET data into CBF maps. To test this method, using a large animal model, CBF was measured by this hybrid approach and by PET only, where the AIF was measured. Good agreement was found over a CBF range (20-100 ml/100g/min). 1339 Effects of B1 Correction on the Accuracy of T1, T2 and ADC Values Measured with a Diffusion-Weighted Dual-Echo Steady-State (DW-DESS) Sequence Rachel Chan, Aaron Boyes, Masoom Haider Diffusion-weighted dual-echo steady-state (DW-DESS) imaging allows multiple MR parameters to be quantified without image distortion. In this work, we investigate the effects of B1 correction on the accuracy of T1, T2 and ADC parameters estimated from DW-DESS. We extend the quantification to species with ADC and T2 values that are similar human cancers by using a novel phantom mixture. The accuracy of parameter estimates measured with DW-DESS is improved after B1 correction, with correlation coefficients of 0.912, 0.997 and 0.778 without B1 correction to 0.993, 0.998 and 0.947 after B1 correction (for T1, T2 and ADC, respectively). 1340 Improved clinical workflow for simultaneous whole-body PET/MRI using high-resolution CAIPIRINHA-accelerated MR-based attenuation correction Martin Freitag, Matthias Fenchel, Philipp Bäumer, Thorsten Heußer, Christopher Rank, Marc Kachelrieß, Klaus Kopka, Antonia Dimitrakopoulou-Strauss, Frederik Giesel, Uwe Haberkorn, Klaus Maier-Hein, Ralf Floca, Mark Ladd, Heinz-Peter Schlemmer, Florian Maier The present study assesses the value and reproducibility of a novel CAIPIRINHA-accelerated T1-weighted Dixon-based prototype for whole-body PET/MRI in comparison to the clinical standard. This prototype allows the aquisition of an MR-based attenuation correction and a high-resolution T1w DIXON stack that may be used for diagnostic correlation of PET findings in one single step. Voxel-wise intra-individual differences, intermethod-agreement using regression and bland-altman plot analysis, inter-reader agreement for image quality and a repeated measurement experiment in a healthy volunteer without tracer injection were peformed. The novel prototype demonstrated a high reproducibility of standardized uptake value quantification compared to the standard and excellent image quality for all body regions. Smaller breathing artifacts in the lungs may transfer on the PET µmap and thus influence the attenuation correction. Therefore, physicians and the technicians need to assess the µmap to veriy artifact-free acquisition. The novel protoype is useful for clinical PET/MRI studies towards time-efficient protocols as a separate T1w-sequence may be omitted. 1341 Preliminary Clinical Experience with FDG-PET/MRI in Plasma Cell Dyscrasias Tyler Fraum, Daniel Ludwig, Ephraim Parent, Farrokh Dehdashti, Michelle Miller-Thomas, Monica Shokeen, Keith Stockerl-Goldstein, Ravi Vij, Kathryn Fowler Multiple myeloma (MM) is an attractive target for FDG-PET/MRI, given the inherent limitations of both MRI and FDG-PET/CT when obtained separately. We performed FDG-PET/MR in a total of 36 patients with clinical diagnoses of a plasma cell dyscrasia (PCD), including a subset that underwent PET/CT and PET/MRI on the same day as part of a research protocol. FDG-PET/MRI was feasible for both the initial staging and subsequent treatment response assessment of PCDs and provided additional useful information compared with PET/CT. Sagittal T1-weighted images of the spine should be incorporated into standard protocols to improve spinal lesion detection. 1342 Application of MR-based truncation correction (HUGE) in whole-body PET/MR hybrid imaging Maike E. Lindemann, Mark Oehmigen, Jan Ole Blumhagen, Harald H. Quick In quantitative PET-imaging, it is essential to correct for the attenuation of photons in tissue. In combined PET/MR-imaging the attenuation correction (AC) is based on MR-data and subsequent tissue class segmentation. The MR-FOV is limited due to B0-inhomogeneities and gradient nonlinearities. Therefore, the AC-map is truncated and reconstructed PET-data are biased. HUGE (B0-Homogenization using gradient enhancement), which determines an optimal readout gradient to compensate gradient nonlinearities, was applied in whole-body PET/MR examinations of 24 oncologic patients. The extension of the MR-FOV for MR-based AC showed an improvement of PET-quantification in integrated PET/MR-imaging by reducing the truncated areas of the AC-map. 1343 3D Printed Phantom for PETMR Attenuation Correction Derrick Gillan, Thomas Hope, Peder Larson This experiment sought to explore PET/MRI attenuation correction with a 3D printed skull phantom used to mimic bone attenuation and MR characteristics. 1344 Optimal MRI sequences for 68Ga-PSMA-11 PET/MRI in evaluation of biochemically recurrent prostate cancer Spencer Lake, Kirsten Greene, Antonio Westphalen, Spencer Behr, Ronald Zagoria, Eric Small, Peter Carroll, Thomas Hope On 68Ga-PSMA-11 PET/MRI for biochemically recurrent prostate cancer, small PSMA-positive lesions are detected on some, but not all MRI sequences.  To determine the most effective sequences to obtain for a 68Ga-PSMA-11 PET/MRI protocol, the sensitivities of small FOV T2, T1 post-contrast, and diffusion-weighted sequences for identification of small abdominopelvic nodes were evaluated.  In addition, multiphasic contrast-enhanced Differential Subsampling with Cartesian Ordering (DISCO) images were evaluated for detection of prostate bed recurrence.  Examination of 48 consecutive patients indicates that small FOV T2 images are most sensitive for small abdominopelvic nodes and DISCO images are most sensitive for prostate bed recurrence. 1345 T1 and T2 mapping using highly accelerated radial data acquisition and alternating direction method of multipliers Zhiyang Fu, Zhitao Li, Mahesh Keerthivasan, Diego Martin, Maria Altbach, Ali Bilgin Quantitative MRI requires accurate parameter estimation but long acquisition time limits the use of conventional techniques in the clinic. Recently, several T1 and T2 mapping methods based on highly accelerated radial trajectories have been proposed. The reconstruction problems in these works are formulated as unconstrained optimizations and solved using the non-linear conjugate gradient method. We propose an alternative formulation based on the alternating direction method of multipliers which reduces reconstruction time without compromising reconstruction quality. 1346 Eye Tracking System for Prostate Cancer Diagnosis Using Multi-Parametric MRI Haydar Celik, Baris Turkbey, Peter Choyke, Ruida Cheng, Evan McCreedy, Matthew McAuliffe, Naji Khosravan, Ulas Bagci, Bradford Wood Medical images have been studied using eye tracker systems from visual search and perception perspectives since 1960’s. However number of studies for the multi slice imaging is very limited due to the technical challenges. We developed a software to overcome the difficulties, and enable visual search/perception studies using multi-parametric MRI of prostate cancer. Multiparametric MR images (T2w, DWI, ADC map, and DCE) were synchronized with the eye tracker system and visual-attention maps were successfully created for each image types using gaze information. This is the first multiparametric MR study using an eye tracker system. 1347 A Constrained Least Squares Approach to MR Image Fusion Nicholas Dwork, John Pauly, Jorge Balbas Fusing a lower resolution color image with a higher resolution monochrome image is a common practice in medical imaging. By incorporating spatial context and/or improving the Signal-to-Noise ratio, the fused image provides clinicians with a single frame of the most complete diagnostic information.  In this paper, image fusion is formulated as a convex optimization problem which avoids image decomposition and permits operations at the pixel level. This results in a highly efficient and embarrassingly parallelizable algorithm based on widely available robust and simple numerical methods that realizes the fused image as the global minimizer of the convex optimization problem. 1348 A Comparison of Optimised Single-Shot MR Fingerprinting Pulse Sequence Designs. Jack Allen, James Kennedy, Peter Jezzard The parameter mapping accuracy of MR Fingerprinting (MRF) relies on specific signal patterns for each set of parameters. Choice of sequence design and acquisition parameters are two aspects that affect this. We optimised the TR and Flip Angle (FA) of a selection of simulated single-shot MRF designs, based on Inversion-Recovery Gradient Echo (IR-GRE), GRE, Spin Echo (SE) and IR-SE sequences. We compared the parameter assignment accuracy of each optimised design. Our results suggest that GRE-based sequences should be used for single-shot MRF. 1349 First results from an MRI compatible small animal PET insert operating in a clinical 3T PET/MRI Matthew Fox, Vanessa Palmer, Graham Schellenberg, Jarod Matwiy, Scott King, Andrew Goertzen, Jonathan Thiessen Reaching sub-millimeter limits in spatial resolution and improved temporal resolution, simultaneous PET/MRI using a pre-clinical MR compatible PET insert enables new discoveries in science and medicine. We recently evaluated a versatile MR compatible small animal PET insert in collaboration with Cubresa. Presented here are the first simultaneous images obtained using both imaging modes within our clinical 3T MRI. 1350 Quality Factors for Efficient and Precise MRF Imaging Danielle Kara, Mingdong Fan, Jesse Hamilton, Nicole Seiberlich, Mark Griswold, Robert Brown With the invention of MRF imaging, there is considerable freedom in input parameter selection, but it is difficult to determine how each choice affects the resulting parameter maps. Quality factors are introduced as a means of comparing MRF sequences with various input parameters (FA, TR, TE, N) on their abilities to precisely quantify T1 and T2. Simulations, fully sampled, and undersampled experiments verified that sequences with higher quality factors result in lower standard deviations in R1 and R2. With quality factor analysis, researchers and clinicians can readily determine the appropriate MRF input parameters to image more efficiently and precisely. 1351 Cross-Modality MR Image Reconstruction: CT-Constrained Anisotropic Diffusion to Preserve Edge Information in MRI of an Ancient Mummified Hand Johannes Fischer, Ali Özen, Dmitry Kurzhunov, Marco Reisert, Agazi Tesfai, Frank Rühli, Ute Ludwing, Michael Bock Constrained reconstruction is making use of additional image information to improve the precision in the reconstruction of undersampled MR data. Here we use co-registered CT-data as an anisotropic diffusion constraint to improve sharpness in short T2* images reconstructed from undersampled 3D UTE data of a mummified human hand. The results are compared to other established reconstruction methods. 1352 Contrast matching of ultra-high resolution minimum deformation averaged MRI models to facilitate computation of a multi-modal model of the human brain Julie Munk, Nina Jacobsen, Maciej Plocharski, Lasse Østergaard, Markus Barth, Andrew Janke, Steffen Bollmann A contrast matching algorithm was developed to enable non-linear coregistration of multi-modal minimum deformation averaged MRI models using cross correlation. The registration results show that the contrast conversion enables non-linear multi-modal coregistration. 1353 Fast Analytical Solution for Extreme Unaliasing of MR Fingerprinting Image Series Eric Pierre, Mark Griswold, Alan Connelly A non-iterative analytical solution to the MRF image reconstruction problem is presented. The method performs a direct interpolation of the acquired k-space points based on a singular-vector basis of fingerprints from a first-pass MRF estimate. The method is shown to drastically reduce spatio-temporal aliasing, allowing accurate T1 and T2 measurements for a single slice with a 7.6s acquisition, without need for auto-calibration data, and with computational overhead an order of magnitude faster than previously reported iterative image-based methods. 1354 Removing the estimation bias due to the noise floor in multi-parameter maps Karsten Tabelow, Chiara D'Alonzo, Lars Ruthotto, Martina Callaghan, Nikolaus Weiskopf, Joerg Polzehl, Siawoosh Mohammadi We demonstrate the bias effect due to the low signal-to-noise ratio of ultra-high resolution (0.5μm isotropic) Multi-Parameter Mapping acquisitions of quantitative R1, R2* and PD maps and develop a method for improved parameter estimation. 1355 Analyzing the Bayesian Approach to Partial Volume in Magnetic Resonance Fingerprinting Debra McGivney, Anagha Deshmane, Yun Jiang, Mark Griswold We present work to optimize the parameters used in the Bayesian approach to partial volume in MRF. Care needs to be taken when choosing parameter values to balance effects from noise and over regularization of the solution. MRF brain data from a normal volunteer is analyzed to determine the optimal parameters in separating white matter from gray matter and gray matter from CSF. Parameter choices are confirmed by examining the results from our algorithm in regions of pure white matter. 1356 Accelerated Magnetic Resonance Fingerprinting Reconstruction using Majorization-Minimization Yang Li, SHUAI Wang, Edward Hui, Di Cui, Hing-Chiu Chang, Yik-Chung Wu Magnetic resonance fingerprinting (MRF) is a novel and efficient method for the estimation of MR parameters, such as off-resonance (DB­0), proton density (PD), T1 and T2. Because of the highly undersampled readout that is conventionally used, large number of dynamics (e.g. <1000) are often acquired for maintaining the fidelity of MR parameter estimations (a.k.a. dictionary matching). In this study, we propose a new algorithm, MRF reconstruction using majorization-minimization (mmMRF), such that fidelity of dictionary matching can remain similar even when significantly less number of dynamics are available. 1357 Toward an Optimized Dictionary for Pattern Matching in Magnetic Resonance Fingerprinting Kun Yang, Yun Jiang, Mark Griswold, Vikas Gulani, Debra McGivney An important issue in magnetic resonance fingerprinting (MRF) is the precision of pattern matching.  The sensitivity of inner product between the signal and dictionary can be corrupted by closely spaced dictionary entries.  In order to make MRF more sensitive and precise, four modifications of the MRF dictionary are proposed. The performance of each method is tested and compared over 30 repetitions in a phantom scan.  Some of the methods demonstrate a significant reduction in the error over the original MRF dictionary. 1358 Proton Density Mapping and Receiver Bias Correction for Absolute Quantification with MR Fingerprinting Anagha Deshmane, Debra McGivney, Yun Jiang, Dan Ma, Mark Griswold MR Fingerprinting (MRF) can simultaneously map multiple parameters and can be used to compute estimates of tissue fractions.  However, MRF-derived M0 maps contain information about both proton density (PD) and the receiver sensitivity profile (RP).  Here we estimate relative PD and RP from MRF M0 and T1 maps.  Relative PD and tissue fractions are combined for absolute quantity mapping of CSF, gray matter, and white matter as a fraction of the voxel equilibrium magnetization. 1359 In vivo MR blood oximetry based on $$T_2$$$-prepared bSSFP Michael Langham, Ana Rodríguez-Soto, Hyunyeol Lee, Nadav Schwartz, Felix Wehrli To develop in vivo MR oximetry based on T2-prepared bSSFP constant refocusing-pulse interval ($$\tau_{180}$$$) T2-preparation, three-parameter signal fitting for T2 extraction and magnetization reset for shortened pulse sequence cycle were implemented and evaluated against a multi-spin echo sequence using static and flowing MnCl2 solutions with known T2 values. The whole-blood T2 was also quantified to investigate the effect of varying . The phantom results support three-parameter fitting, and <5% error incurred in T2 quantification with shortened T2-preparation cycle and presence of constant flow. Approximately 10% longer whole-blood T2 was observed with constant  relative to varying . 1360 Comparison of Renal R2* Analysis Methods Inge Kalis, Axel Krafft, Michael Bock BOLD MRI can be applied as an indirect measure of the oxygenation level changes in the kidneys while performing an experiment with a functional renal challenge. These changes are detected by the relaxation rate R2* in the renal cortex and medulla. For R2* analysis different methods are proposed, such as the conventional manual ROI method and a compartmental method. Here, these methods and two further compartmental methods are compared to each other by analyzing full time-resolved renal BOLD MR experiments in healthy volunteers. 1361 Development of contrast agents for simultaneous PET/MRI of murine tumor models Samuel Gilmore, Abbie Shepard, Christine Howison, Joshua Goldenberg, Julio Cárdenas-Rodríguez, Mark Pagel PET/MRI contrast agents represent a new field of molecular imaging that provide an outstanding opportunity to employ simultaneous PET/MRI instrumentation for quantitative imaging. Over 90 responsive MRI contrast agents have been reported that change their contrast based on a biomarker and agent concentration, limiting their utility in vivo because a change in signal could arise from the presence of the biomarker and/or a change in the concentration of the agent.  We propose to use PET to quantify the agent concentration, and a comparison of PET and MRI contrast can quantitatively evaluate the biomarker in a concentration-independent manner.  Herein we describe the synthesis and characterization of 18F-radiolabeled responsive MRI contrast agents that are designed to measure pH and redox state using simultaneous PET/MRI for small animal studies. 1362 STEAM-CPMG: A method for localized Pulsed-Field-Gradient-Stimulated-Echo CPMG acquisitions Ericky Caldas de Almeida Araujo, Olivier Scheidegger The CPMG method has been long applied for multi-component T2 studies which have been shown to reveal the micro-anatomical compartmentation of water in biological tissue. A new method for localized CPMG acquisitions that makes use of the Stimulated Echo Acquisition Mode technique is presented. Besides offering localized T2-relaxation data within less than 10 s, the method is suited for performing Diffusion-Relaxation-Correlation-Spectroscopy studies. Such studies allow evaluating the translational diffusion of the different T2-compartments observed in vivo and shall offer new insights on diffusion and relaxation processes in biological tissues. The method has been validated in vitro. 1363 Early changes of irradiated parotid glands evaluated by T1rho-weighted imaging: a pilot study Zhengyang Zhou, Jian He, Weibo Chen Twenty-six NPC patients underwent serial T1rho-weighted imaging to evaluate the dynamic changes of parotid glands in patients undergoing intensity-modulated radiation therapy. Parotid volumes, T1rho values, mean radiation doses, and xerostomia degrees were recorded. Change rates of T1rho values were correlated with atrophy rates, mean radiation doses and xerostomia degrees. During RT, parotid volume decreased and parotid T1rho values increased significantly. The change rate of T1rho value correlated with the atrophy rate significantly at post-RT. Intra- and interobserver reproducibility of T1rho measurements were excellent. Dynamic changes of radiation-induced parotid damage in NPC patients underwent IMRT could be evaluated by T1rho-weighted imaging. 1364 A short protocol for determining apparent kurtosis validated in a hybrid MR-PET clinical environment Ricardo Loucao*, Ana-Maria Oros-Peusquens*, Karl-Josef Langen, Hugo Ferreira, Nadim Jon Shah Mean kurtosis (MK) obtained from the kurtosis tensor is often associated with acquisition protocols that may be long for clinical demands. Apparent kurtosis (Kapp), obtained from the direct fit of the signal to an exponential decay, is faster to acquire and may provide with similar information. Directional averaging is required to preserve spherical invariance; however, in clinical applications the trace of diffusion tensor measured with 3 directions is often used as tissue marker with good results. In this study we investigate Kapp derived from trace data in forty brain tumour patients and compare it to mean kurtosis. Kapp was found to be underestimated but the two metrics show a significantly high degree of correlation. 1365 68Ga-PSMA dose reduction for imaging the pelvic region with simultaneous PET/MR Edwin ter Voert, Hannes Nagel, Gaspar Delso, Irene Burger When performing simultaneous single station PET and MR scans in the pelvic region, the PET acquisition time could be increased to match the usually more extensive MR protocol acquisition time. The gain in detected coincidences could be applied to decrease the PET tracer dose and thus the patient’s radiation burden, while maintaining the same image quality. In this study we investigate the minimal 68Ga-PSMA dose for a 15-minute single station PET(/MR) scan to match image quality of the standard 2 minutes scan at full dose. 1366 Comparison of Myelin Water Fractions from Multi-Echo Spin-Echo and Multi-Gradient Echo Techniques Eva Alonso Ortiz, Ives Levesque, G. Bruce Pike Myelin Water Fraction (MWF) imaging is typically achieved using a Multi-Echo Spin-Echo (MESE) sequence that has a long acquisition time. The Multi-Gradient Recalled Echo (MGRE) sequence on the other hand, is fast, has multi-slice and 3D imaging capabilities, high temporal sampling of the signal decay curve, and low SAR. In this study, we imaged 11 healthy volunteers using MESE and MGRE sequences to perform a method-comparison study for the MWF. Our results suggest that the MGRE approach to MWF imaging is highly promising.

Elastography
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

Artifacts
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

Sparse & Low-Rank Reconstruction
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

 1407 Continuous domain compressed sensing (CD-CS): application to accelerated dynamic MRI Arvind Balachandrasekaran, Greg Ongie, Mathews Jacob We introduce a novel continuous domain compressed sensing (CD-CS) framework for the recovery of MRI data. We formulate the recovery of the high-resolution continuous domain Fourier coefficients of the image from few of its samples as a structured low-rank matrix completion problem. We also introduce novel algorithms to solve this matrix completion problem in run-times that are comparable with discrete CS formulations. The application of this algorithm to (2D+time) dynamic MRI problems is observed to yield significantly improved reconstructions compared to state of the art CS methods. 1408 Novel annihilation filter framework for accelerated parameter mapping Arvind Balachandrasekaran, Mathews Jacob Quantitative parameter maps offer valuable information about various tissue attributes, which are early markers for many neurological disorders. However the long acquisition time of the associated image time series puts a restriction on the achievable spatial resolution. In this work, we introduce a novel framework, which exploits the exponential nature of the time profiles at every pixel and spatial smoothness of the exponential parameters to recover the images from highly under-sampled measurements. Our preliminary results clearly demonstrate the potential of the proposed algorithm. 1409 Task-based Optimization of Regularization in Highly Accelerated Speech RT-MRI Jieshen Chen, Sajan Goud Lingala, Yongwan Lim, Asterios Toutios, Shrikanth Narayanan, Krishna Nayak Speech RT-MRI has recently experienced significant improvements in spatio-temporal resolution, through the use of sparse sampling and constrained reconstruction. The regularization parameters used for balancing data consistency and object model consistency were often chosen by visual assessment of image quality. Here, we perform task-based optimization of regularization in highly accelerated speech RT-MRI, focusing on the production of consonants and vowels, and analyzing the articulatory features, using both qualitative and quantitative methods. Results drawn from different methods help determine proper regularization parameters for the reconstruction of specific speaking tasks. 1410 Study on regularization paremeter tuning in compressed sensing using no-reference image quality assessment Kihun Bang, Jinseong Jang, Dosik Hwang In Magnetic Resonance Imaging system, acquiring fewer measurements is required to reduce scan time, but it leads the aliasing artifact. Compressed Sensing is exploited to reconstruct image from undersampled data without artifacts by solving the optimization problem. However, It has some difficulites in selecting regularization parameters and this abstract propose the way to select regularization parameters by evaluating image quality. The quality of reconstructed image from proposed method is much better than the image from manual parameters. This study also has potential to be helpful in fast MR imaging. 1411 Compressed Sensing MRI Using Bunched Phase Encoding Jingxin Zhang, Kazi Islam, Kai Zhu This abstract presents a novel method for compressed sensing (CS) MRI. This method combines the variable density random undersampling and iterative image reconstruction in CS-MRI with the regularly reduced bunched phase encoding (BPE) and linear equation based image reconstruction of BPE-MRI to further reduce data acquisition time and improve image quality of CS-MRI. Simulation results demonstrate the effectiveness and advantage of the presented method. 1412 A Novel Hybrid Total Variation Minimization Method to MRI Reconstruction from Highly Undersampled Data Hongyu Li, Yong Wang, Dong Liang, Leslie Ying This abstract presents a novel hybrid total variation minimization algorithm to reconstruct MR images from reduced measurements. The method combines the benefits of both L1 and homotopic L0 minimization algorithms for sparse signal reconstruction in the sense that substantially fewer measurements are needed for exact reconstruction. The algorithm minimizes the conventional total variation when the gradient is small, and minimizes the L0 of gradient when the gradient is large. An auto-adaptive threshold determines the transition between L1 and L0 of the gradients. The experimental results show the proposed algorithm outperforms either L1 or homotopic L0 minimization when the same reduction factor is used. 1413 High resolution 3D MRI reconstruction using 3DMDTV regularization Yue Hu, Xin Lu, Kuangshi Zhao, Mathews Jacob Three-dimensional (3D) MRI plays an important role in many clinical applications due to its ability to provide the full geometry of the targeted region of the body. However, speed limitation remains the key challenge to 3D MRI. Here, we present a compressed sensing reconstruction scheme using the 3DMDTV regularization. The experiments demonstrate that for high acceleration factors, the proposed method has better performance than other schemes by providing more accurately recovered images with more subtle details preserved. 1414 Accelerated 3D Arterial Spin Labeling using Cartesian Acquisition with Spiral Reordering and Compressed Sensing Huajun She, Joshua Greer, Xinzeng Wang, Elena Vinogradov, Ananth Madhuranthakam Arterial spin labeling (ASL) is a non-contrast perfusion imaging method for MRI. However, 2D ASL suffers from low signal to noise ratio. 3D ASL is favorable to overcome the limitation of 2D ASL, but 3D acquisition is time-consuming, so acceleration of 3D ASL is highly desired. The new compressed sensing (CS) theory allows perfect reconstruction far below Nyquist rate. We implemented a novel 3D TSE acquisition using Cartesian Acquisition with SPiral Reordering (CASPR), which can be undersampled and combined with CS. Preliminary results show improved image quality using 3D Sparse-BLIP reconstruction that is comparable to fully sampled acquisition. 1415 Accelerated MR Diffusion Tensor Imaging Using Partial Fourier Compressed Sensing Chia-Chu Chou, Frank Ye, Cecil Yen, Behtash Babadi, Rao Gullapalli, David Leopold, JiaChen Zhuo 3D-DTI are often used in ex vivo imaging to achieve superior spatial resolution and to map fine white matter structure. However, image acquisition time is long especially when many diffusion directions are used to better define orientation profiles and resolve crossing fibers. In this study we apply a new imaging acceleration technique – Partial Fourier Compressed Sensing (PFCS) on DTI acceleration. We demonstrated PFCS provide satisfactory reconstruction with only half of the raw data while retaining fine anatomical details on DTI parameter maps. 1416 Beyond Low-Rank and Sparsity: A Manifold driven Framework for Highly Accelerated Dynamic Magnetic Resonance Imaging Ukash Nakarmi, Konstantinos Slavakis, Jingyuan Lyu, Chaoyi Zhang, Leslie Ying The state-of-the-art methods in accelerating dynamic Magnetic Resonance (dMR) Imaging rely on sparse and/or low-rank priors. We propose a novel manifold driven framework that exploits the manifold smoothness priors to highly accelerate data acquisition in dMR. We postulate that images in dMR lie on or close to a smooth manifold and learn the manifold geometry from the navigator signals. Capitalizing on the learned manifold, we develop two regularization loss functions and subsequently build a framework to reconstruct dMR images from highly undersampled k-space data. The proposed method is shown to be superior than competitive methods in different data sets. 1417 Application of Iterative Reconstruction for MR Digital Subtraction Angiography: Toward Better Visualization of Small Vessels and Reduction of Gadolinium-Based Contrast Media. Yasutaka Fushimi, Tomohisa Okada, Akira Yamamoto, Tsutomu Okada, Aurelien Stalder, Christoph Forman, Michaela Schmidt, Kaori Togashi Improved signal and temporal footprint for dynamic MRA due to the retrospective iterative reconstruction may better visualize small peripheral vessels with reduced GBCA dose. CE-MRA-TWIST images were reconstructed twice from the same raw data, with the standard product reconstruction and with iterative reconstruction (IT) by using L1 wavelet regularization in space and time. CE-MRA-IT-TWIST nicely visualized hemodynamics in the brain even with 20% GBCA dose administration compared with CE-MRA-TWIST, especially in the arterial phase. Enhancement slope of CE-MRA-IT-TWIST was statistically higher than that of CE-MRA-TWIST. 1418 A low rank Hankel matrix reconstruction approach to recover hybrid time and frequency data in non-uniformly sampled magnetic resonance spectroscopy Hengfa Lu, Xinlin Zhang, Tianyu Qiu, Jian Yang, Di Guo, Zhong Chen, Xiaobo Qu Magnetic resonance spectroscopy has many important applications in bio-engineering while the acquisition of high dimensional spectroscopy is usually time consuming. Non-uniformly sampling can speed up the data acquisition but the missing data points have to be restored with proper signal models. In this work, a specific two dimensional magnetic resonance signal, of which the first dimension lies in time domain while the second dimension lies in frequency domain, is reconstructed with a proposed low rank enhanced Hankel matrix method. Results on realistic magnetic resonance spectroscopy shows that proposed method outperform the state-of-art compressed sensing method on recovering low intensities spectral peaks. 1419 Accelerating 3D Head-and-Neck MR Imaging Using Compressed Sensing with Structure-Guided Total Variation for MR-Guided Multi-Fractional Radiotherapy Yihang Zhou, Jing Yuan, Oi Lei Wong, Winky Wing Ki Fung, George Chiu, Kin Yin Cheung, Siu Ki Yu MR image-guided radiotherapy (IGRT) holds potentials on outcome improvement in the head-and-neck (HN) radiotherapy. Patients receiving MR-guided multi-fractional HN IGRT are immobilized in each treatment fraction and set up to the exact position as of the treatment planning scan. Inter-fractional MR images are supposed to show highly correlated anatomy structure and edge information which can be incorporated into compressed sensing (CS) based MR reconstruction to shorten the scan time while preserve image quality in multiple fractions. In this study, we investigated the feasibility of accelerating high spatial resolution 3D MRI using CS with structure-guided total variation for multi-fractional HN radiotherapy. 1420 Accelerate multi-dimensional magnetic resonance spectroscopy with low rank tensor and Hankel structures Jiaxi Ying, Hengfa Lu, Qingtao Wei, Jiang-Feng Cai, Di Guo, Jihui Wu, Zhong Chen, Xiaobo Qu Non-uniformly sampling is an effective way to accelerate high-dimensional magnetic resonance spectroscopy (MRS). The spectrum is usually reconstructed with proper prior knowledge. In this work, we exploit the intrinsic N-D exponential signals  of multi-dimensional MRS to reconstruct the spectrum. A low rank tensor representation of multi-dimensional MRS and the exponential structure of the associated factors are simultaneously explored. Results on 3-D MRS data shows that the proposed method can faithfully reconstruct the spectrum from a small amount of measurements, allowing a significant reduction of acquiring time in real applications. 1421 A novel compressed sensing inspired approach for flow reconstruction Felipe Cortés, Carlos Sing-Long, Sergio Uribe High scan times are one of the most important drawbacks in 4D flow scans and multiple solutions have been proposed to solve this issue. We propose a novel method for undersampled flow reconstruction inspired on the ideas of compressed sensing. By considering the magnitude and complex phase as separate variables, we were able to impose independent properties on each, such as having a constant magnitude over all flow enconding acquisitions and enforcing low phase values on low magnitude areas, thus directly reducing the resulting images' noise. Our method was able to successfully reconstruct flow data with negligible error from undersampled data. 1422 Quantitative Susceptibility Map Reconstruction from MR Phase Data Using Morphology-Adaptive Total Variation Li Guo, Yihao Guo, Yingjie Mei, Jijing Guan, Wufan Chen, Yanqiu Feng MEDI reduces streaking artifacts in QSMs by minimizing total variation in smooth regions in the susceptibility map. However, MEDI still contains artifacts near image edges because this method does not impose any constraint on voxels near edges. We aim to improve the reconstruction of quantitative susceptibility map from MR phase data by introducing morphology-adaptive TV regularization which imposes the TV constraint on the whole susceptibility map but with different weights in smooth and non-smooth regions. The performance of the proposed method is demonstrated in both simulation and in vivo data sets. 1423 Multi-contrast image guided graph representation and its application in compressed sensing MRI reconstruction Zongying Lai, Xiaobo Qu, Jiaxi Ying, Hengfa Lu, Zhifang Zhan, Di Guo, Zhong Chen Under-sampling the k-space data and reconstructing images with sparsity constraint is one efficient way to accelerate magnetic resonance imaging However, achieving high acceleration factor is challenging since image structures may be lost or blurred when the sampled information is not sufficient. In this work, we propose a new approach to reconstruct magnetic resonance images by learning the prior knowledge from multi-contrast images with graph-based sparsifying transform. To incorporate extra information from multi-contrast image, registration is included in a bi-level optimization frame as well as the sparse reconstruction. Experiment results demonstrate that the proposed method outperforms the state-of-art with high accelerating factor. 1424 Image quality impact of randomized sampling trajectories: implications for compressed sensing Melissa Jones, Richard Frayne, Robert Lebel Compressed sensing (CS) has the potential to drastically reduce MR acquisition times, however image quality of prospectively implemented CS is not as good as predicted by retrospectively under-sampled data. This may be due to the sensitivity of appropriate (randomized) CS k-space sampling to eddy currents. We show the existence of these detrimental interactions in full but randomly-sampled k-space, and quantify these interactions in under-sampled CS image reconstruction. We demonstrate how sorting the acquisition order to minimize the total k-space trajectory length mitigates this issue and improves image quality. 1425 Optimization of Reconstruction Parameters of Compressed Sensing STIR SEMAC for Metal Artifact Reduction MRI of Hip, Knee and Ankle Arthroplasty Implants: How many Iterations and how much Regularization is needed? Gaurav Thawait, Dharmdev Joshi, Esther Raithel, Mathias Nittka, Wesley Gilson, Jan Fritz Compressed sensing-(CS)-based Slice Encoding for Metal Artifact Correction (SEMAC) turbo spin echo (TSE) pulse sequences achieve high–quality metal artifact reduction MRI around arthroplasty implants. Compressed sensing-based undersampling of k-space permits the time-neutral use of SEMAC, but requires iterative reconstruction algorithms, which are time consuming. We determined minimum number of iterations and regularization required for diagnostic image quality of STIR CS-SEMAC data sets of hip, knee and ankle arthroplasty implants. Our results show that 15-17 iterations and 0.0035 regularization results in optimal image quality of STIR CS-SEMAC images, which currently requires 4-5 minutes of reconstruction time. 1426 Flexible Prospective Compressed Sensing Acceleration of Prostate DCE-MRI with Quantized CIRCUS James Rioux, Nathan Murtha, Allister Mason, Chris Bowen, Sharon Clarke, Steven Beyea Improving the temporal resolution of dynamic contrast-enhanced (DCE) MRI sequences often requires a reduction in image spatial resolution or quality.  We propose an acquisition and reconstruction strategy, Quantized CIRCUS, which allows reconstruction of prospectively accelerated DCE-MRI data with desired spatial and temporal resolution, similar to golden-angle radial acquisition schemes but using Cartesian sampling.  We demonstrate that this approach allows improved temporal resolution compared to standard clinical methods, without significant degradation of image quality or resolution, which may provide more accurate information for diagnosis of diseases like prostate cancer. 1427 Flexible convex optimization with non-smooth regularizations for accelerated MRI reconstructions Renjie He, Ruobing He, Guobing Li, Nan Liu, Renkuan Zhai, Ding Yu, Qi Liu, Jian Xu, Weiguo Zhang Convex optimization with non-smooth regularizers has recently gained increased interest as it has shown excellent performance and the ability to facilitate most of reconstruction problems in MR convincible. While there are many approaches towards its fulfillment, a flexible yet easy and comprehensive to realize method is always beneficial.  One of the algorithms is proposed in this abstract. and we demonstrate that this algorithm can be easily adapted to many reconstruction problems in MRI with accelerated performance. 1428 Quantitative Evaluation of Temporal Sparse Regularizers for Compressed Sensing Breast DCE-MRI Dong Wang, Lori Arlinghaus, Thomas Yankeelov, David Smith We quantitatively evaluate temporal sparse regularizers for breast DCE-MRI data under standard compressed sensing schemes. We consider five temporal regularizers on 4.5x retrospectively undersampled Cartesian in vivo breast DCE-MRI data, namely Fourier transform (FT), Haar wavelet transform (WT), total variation (TV), second order total generalized variation (TGV$$_{\alpha}^{2}$$$) and nuclear norm (NN). Both signal-to-error ratio and concordance correlation coefficients of the derived pharmacokinetic parameters $$K^{\text{trans}}$$$ (volume transfer constant) and $$v_\mathrm{e}$$$(extravascular extracellular volume fraction) are estimated. Results show that NN produces the lowest image error while TV/TGV$$_{\alpha}^{2}$$$ produce the most accurate pharmacokinetic parameters. 1429 Assessing a radial multi-spin-echo sequence for robustness to motion artefacts in quantitative NMR imaging Bertrand Coppa, Benjamin Marty, Pierre-Yves Baudin, Noura Azzabou, Pierre Carlier Fast parametric NMR imaging such as T2 and fat fraction mapping can be performed with a multi-spin-echo (MSE) sequence and an EPG-based model. Here, we compared a radial MSE encoding scheme to a standard Cartesian acquisition to monitor these two parameters in area subject to respiratory motion artifacts. Results show that the radial sequence was less affected from motion than the cartesian one and then improved the confidence of parameters estimation at these locations.

Post-Processing & Analysis
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

 1430 Evaluating effect of B1 field Inhomogeneity on DCE-MRI Data Analysis of Brain Tumor Patients at 3T ANIRBAN SENGUPTA, RAKSHIT DADARWAL , RAKESH GUPTA, ANUP SINGH In the current study, transmit B1 field inhomogeneity(B1FI) distribution and propagation of flip-angle(FA) related errors to Dynamic-contrast-enhanced(DCE) MRI data analysis in brain tumors of human subjects at 3T MRI were studied. Experimental and simulation studies were performed to evaluate the propagation of these errors to DCE-MRI data analysis and its correction were performed during signal intensity(S(t)) to concentration-time-curve(C(t)) conversion. This study show that B1FI introduced substantial errors in DCE-MRI data analysis(tracer-kinetic and hemodynamic parameters) and these errors were mitigated by correcting FA using B1 map. B1FI related error also showed dependence on concentration of contrast agent and length of concentration-time-curve. 1431 Brain Network Atlas Estimation using Centered Graph Shrinkage with Application to Developing and Aging Brains Islem Rekik, Gang Li, Minjeong Kim, Weili Lin, Dinggang Shen Learning how to average brain networks (i.e., build a brain network atlas) constitutes a key step in creating a reliable ‘mean’ representation of a set of normal brains, which can be used to spot deviations from the normal network atlas (i.e., abnormal cases). However, this topic remains largely unexplored in neuroimaging field. In this work, we propose a network atlas estimation framework through a non-linear diffusion along the local neighbors of each node (network) in a graph. Our evaluation on both developing and aging datasets showed a better ‘centeredness’ of our atlas in comparison with the state-of-the-art network fusion method. 1432 Robust and fast phase unwrapping strategy to improve SWI quality Yongquan Ye, Jinguang Zong, Weiguo Zhang A robust and fast phase unwrapping strategy was developed for multi-echo SWI, to improve image quality where classic SWI fails, such as cavity vicinity regions, as well as to provide pristine field map for subsequent QSM applications. A smoothing and a seed prioritizing method were proposed, which was demonstrated to provide very robust unwrapping on phase difference map between neighboring echoes. And with a high quality unwrapped phase difference map, the phase of all echoes can be robustly unwrapped in seconds. 1433 A Fast Adaptive Multispectral Nonlocal Denoising Filter Michael Maring, Mustapha Bouhrara, Richard Spencer We introduce a new high-performance nonlocal filter, NESMA, for noise reduction in multispectral (MS) MR imaging.  Through extensive analysis, we show that the NESMA filter demonstrates a high degree of overall image denoising while preserving edges and small structures. We compared the performance of the NESMA filter to the multispectral nonlocal maximum likelihood (MS-NLML) filter.  Although the MS-NLML filter is highly efficient, it requires extensive computational time. NESMA markedly decreases computation time while maintaining comparable levels of noise reduction and feature preservation.  Finally, we show that adaptive selection of similar voxels further improves filtering quality. 1434 Inversion quality independent robust $$T_1$$$-quantification of MOLLI sequence data Thomas Kampf, Theresa Reiter, Wolfgang Bauer Quantitative mapping of the longitudinal relaxation time has gained increasing interest as it allows monitoring of important structural and functional information of the myocardium. The MOLLI sequence commonly used in clinical research requires a high quality of the inversion pulses for unbiased quantification which is non-trivial especially at high fields. In this work we present a simple modification of the MOLLI sequence which in combination with the recently introduced IGF post processing solves the problem of insufficient inversion quality as demonstrated in phantom experiments. 1435 Improved Infant MRI Brain Extraction utilizing Clustering and Morphological Approaches Yao Wu, Sonia Dahdouh, Marine Bouyssi-Kobar, Manoj Kumar, Josepheen Cruz, Wonsang You, Catherine Limperopoulos Accurate brain extraction is a key procedure in neuroimage analyses. This paper aims to solve the intracranial cavity overestimation issue inherent to existing brain extraction methods when applied to infant brains. We applied k-means clustering method and morphological approaches to improve the accuracy of previously published brain extraction techniques. Evaluation of our proposed method on 28 preterm MR images showed more robust and effective infant brain extraction compared to previous methods. 1436 SNR-Weighted Regularization of ADC Estimates using Double-Echo in Steady-State Bragi Sveinsson, Garry Gold, Brian Hargreaves, Daehyun Yoon Double-echo in steady-state (DESS) is a 3D sequence which offers both morphological images and quantitative parameter maps (SNR-efficient 3D maps of T2 and apparent diffusion coefficient (ADC)) in various applications, such as breast imaging or knee cartilage imaging. The sequence has less sensitivity to ADC than to T2, sometimes leading to noisy ADC maps. Here, we investigate the effects of using regularized fitting of the signals, with a penalty in ADC variability, to produce less noisy ADC maps. The method is designed to apply less regularization to regions with high SNR. The approach makes use of a recent analytical expression for a ratio between DESS signals. 1437 Optimal contrast enhancement of blockface images for MRI guided reconstruction of mouse brain volumes Christoffer Gothgen, Catharina Holland, Christos Zoupis Schoinas, Karine Mardon, Maciej Plocharski, Lasse Østergaard, Andrew Janke Blockface imaging can improve atlases of the rodent brain by supplying high resolution images. This study compares three different contrast stretching methods for enhancing the information in blockface images together with a registration to a 16.4 T atlas of the mouse brain. Contrast enhancement technique used was histogram equalization, adjusting the image intensity values by stretching them between the bottom 1% and the top 1% and CLAHE with a clip limit of 0.01 and a uniform histogram. Registrations was rigid, affine and SyN. By using CLAHE as contrast stretching method a high similarity to the MRI was found. 1438 B0 Field Inhomogeneity Corrected Quantitative Susceptibility Mapping Young-joong Yang, Jong-Hyun Yoon, Hyeon-Man Baek, Chang-Beom Ahn QSM is a method that generates internal susceptibility distribution of subject using material’s intrinsic magnetic susceptibility property. Bo inhomogeneity affects magnitude and phase images. In this study, QSM with B0 field inhomogeneity correction is proposed. Using numerical simulation and in-vivo experiment, proposed method is verified. In simulation, improved susceptibility map is obtained with less root mean square error. In in-vivo experiment, signal loss and non-uniformity at frontal lobe are reduced. As field inhomogeneity increases according to the increase of main field strength, this method would be a more important element for QSM. 1439 Real-time large-scale anatomical landmark detection with limited medical images Jun Zhang, Mingxia Liu, Dinggang Shen Landmark detection based on deep neural networks has achieved state-of-the-art performance in natural image analysis. However, it is challenging to detect anatomical landmarks from medical images, due to limited data. Here, we propose a real-time large-scale landmark detection method with limited training data. We train our model with image patches and test it with the entire image, inspired by fully convolutional networks. Also, we develop a weighted loss function in our model to increase the correlations between image patches and their nearby landmarks. The experimental results of detecting 1741 landmarks from brain MR images demonstrate the effectiveness of our method. 1440 A fully automatic prostate segmentation method for both DWI and T2WI Yi Zhu, Rong Wei, Ge Gao, Yajing Zhang, Xiaoying Wang, Jue Zhang, Jing Fang Automatic prostate segmentation in MR images is a meaningful work, not only can be used in the first step of the Prostate Imaging Reporting and Data System, but also helps to predict pathologic stage of disease by determining the prostate volume. Here we show a novel new method can get the prostate contour for both T2WI and DWI fast and accurately without any manual intervention. The segmentation accuracies for 60 images are 83.7% (T2WI) and 87.1% (DWI). Even in some cases, such as prostate hyperplasia, our method shows good robustness. 1441 Fast fitting method for simultaneously quantifying multiple MR parameters using local optimization method with predetermined initial values Suguru Yokosawa, Yo Taniguchi, Tomoki Amemiya, Toru Shirai, Ryota Sato, Yoshihisa Soutome, Hisaaki Ochi A fast fitting method for quantifying multiple MR parameters using local optimization method with predetermined initial values is proposed. In the proposed method, an optimal neighborhood solution is extracted as predetermined initial values. A difference in MR parameters between the proposed method and the conventional method was less than 5 %. On the other hand, a computing time of the proposed method was approximately 15 times faster compared with the conventional method. We concluded that the proposed method can provide fast fitting process while maintaining calculation accuracy. 1442 Improved image texture features by Gaussian mixture models of grey-level co-occurrence matrices Tommy Löfstedt, Patrik Brynolfsson, Tufve Nyholm, Anders Garpebring Image texture features based on gray-level co-occurence matrices (GLCMs) are useful in e.g. the analysis of MR images of tumours. However, the features can be quite sensitive to the number of grey-levels in the analysed image, in particular if the region of interest is small. In this work we propose a new method for computing the GLCM, based on Gaussian mixture models. The results show that the new method improves the estimation of the GLCM and at the same time eliminates the difficult task of selecting the number of grey-levels. 1443 Optimization of 2D registration using minctracc on myelin stained brain slices Max Prihoda, Simon Hametner, Andreas Deistung, Verena Endmayr, Andrew Janke, Claude Lepage, Thomas Haider, Simon Robinson, Xiang Feng, Hans Lassmann, Jürgen Reichenbach, Evelin Haimburger, Christian Menard, Hannes Traxler, Siegfried Trattnig, Günther Grabner Histological analyses are important for a wide spectrum of in vivo and in vitro imaging projects. But unlike MRI or CT, histological analyses are typically performed in two dimensions. Nonlinear tissue deformation and ruptures of brain tissue are often common, making analysis in slice direction more difficult. In this work, we optimized a hierarchical, nonlinear fitting pipeline on the basis of two high resolution, myelin stained brain sections using mintracc. 1444 Comparison of MP2RAGE-based morphometry methods for anorexia nervosa Bénédicte Maréchal, José Baiao Boto, Gkinis Georgios, Nadia Ortiz, Karl-Olof Lövblad, François Lazeyras, Maria Isabel Vargas, Alexis Roche, Tobias Kober We explore the sensitivity of a morphometry tool to detect anorexia-related brain atrophy in MP2RAGE images. We compare volumetry resulting from two previously reported morphometry strategies on 16 patients with clinical suspicion of anorexia and identify both similarities and differences in brain atrophy evaluation. 1445 Bias and SNR of $$T_1$$$ estimates derived from joint fitting of actual flip-angle and FLASH imaging data with variable flip angles M. Dylan Tisdall Previous work has suggested fitting joint AFI/FLASH data for T1 and B1+ by minimizing the 2-norm of the difference between the signal model and measurements will produce unbiased estimates of T1. We demonstrate that, contrary to previous results, the estimator has a substantial bias that varies with both the true T1 and B1+, and the receive channel count. We also demonstrate that the correct ML estimator removes the effect of channel count, and that the choice of AFI protocol has a larger impact of the quality of estimates than the addition of an extra FLASH scan. 1446 Quantification of iron liver with clinical MRI protocols Redouane Ternifi, Philippe Pouletaut, Magalie Sasso, Véronique Miette, Fabrice Charleux, Sabine Bensamoun Iron quantification has been assessed through the development of magnetic resonance sequences. The purpose is to improve the existing MRI iron protocols to better diagnose the degree of hemochromatosis. Five volunteers with healthy livers underwent four protocols for the quantification of iron overloads concentration (IOC). The results have demonstrated that existing clinical protocols could be improved to provide spatial distribution of iron within one slice and all over the entire liver volume. IDEAL-IQ® could be the best protocol to have IOC volume representation with a short time of acquisition and standard deviation values associated to mean IOC data. 1447 Harmonization for cortical thickness across sites in multi-center MRI study Lin Zhao, Tuo Zhang, Xianjun Li, Chao Jin, Miaomiao Wang, Xiaocheng Wei, Hong Yin, Zengjun Zhang, Xiaoqun Yao, Xiaoling Zhang, Jian Yang Cerebral cortex encodes crucial information of brain development, cytoarchitecture and function. However, varying data acquisition conditions at different centers could hamper group-wisely statistical analysis. This study aims to test the consistency of cortical thickness in the human brain across four sites and harmonize the deviations. Our results showed that variation of cortical thickness across sites were regionally independent, and deviation across centers could be reduced by linear regression method at a global scale, while the variations across subjects were well preserved. Those results suggest that our method has the promise in harmonizing cortical thickness measures in multi-center study. 1448 QEMDIM : Quality Evaluation using Multi-DIrectional Filter for no-reference MR image Jinseong Jang, Kihun Bang, Hanbyeol Jang, Dosik Hwang This paper proposes a new image quality assessment (IQA) for no-reference MRI, Quality Evaluation using Multi-DIrectional filters for MRI (QEMDIM), that is obtained from difference of statistical features between test images and numerous pre-scanned images in Mean Subtracted Contrast Normalization (MSCN) coefficient and Multi-Directional Filtered Coefficients (MDFC). the proposed method is capable of detecting various types of artifact and can be applied to clinical applications as well as being used to evaluate the performance of MRI hardware and software 1449 Diagnostic performance of texture analysis on MRI in differentiated degree of head and neck carcinoma Yu Chen, Yuan Li, Yuanli Zhu, Huadan Xue, Zhuhua Zhang, Hailong Zhou, Zhengyu Jin The aim of this study was to determine the diagnostic accuracy of pathological differentiated degree of head and neck squamous cell carcinoma (HNSCC) using MRI texture analysis.  The following texture analysis parameters were derived from the T1WI, T2WI , T2fs and Post-Gad T1WI based on different scale: entropy , mean pixel intensity, standard deviation(SD), skewness, and kurtosis. ROC curves and AUC of each parameter was determined, respectively. We conclude that the entropy at fine texture scale on Post-Gad T1WI had the best ability . 1450 Regional variations in cerebral venous contrast using susceptibility-based MRI Phillip Ward, Nicholas Ferris, Parnesh Raniga, Amanda Ng, David Dowe, David Barnes, Gary Egan In this study we compared the image contrast properties of susceptibility-weighted imaging (SWI) and quantitative susceptibility mapping (QSM) for cerebral venous identification and visualisation. SWI and QSM are minimally invasive techniques to image cerebral veins with distinct contrast properties. We hypothesised that these techniques would provide complementary vein contrast in different brain regions. Contrast was measured using 1072 manually traced vein images from ten volunteers. We found regional variations in the predictive power of vein contrast and computed maps of contrast profiles that may inform which technique is best for a given application. 1451 Quantitative and qualitative evaluation of bias field correction methods Falk Luesebrink, Hendrik Mattern, Alessandro Sciarra, Oliver Speck Bias field correction is an essential prerequisite for image analysis, especially at high field strength. In this study multiple correction methods, based on acquisition of a reference image and computational approaches with varied input parameters, are compared. The results indicate that acquisition of a conventional MPRAGE corrected by SPM yields quantitatively and qualitatively comparable results to acquiring a reference image (e.g. MP2RAGE), however, scan time is up to halfed. 1452 Rapid registration of EPI to high-resolution structural images David Manners, Claudia Testa, Stefania Evangelisti, Stefano Zanigni, Caterina Tonon, Raffaele Lodi Post-processing methods that can non-linearly register diffusion-weighted EPI data to high-resolution images are useful in the context of clinical protocols. The current research attempts to apply currently available registration methods to rapidly perform such registration. Investigations on healthy subjects show that an appropriately generated target image allows good quality registration to be performed even with freely available software. This is useful for example to provide cortical seeds for diffusion tractography. 1453 A graphical programming environment for creating and executing adaptive MRI protocols Refaat Gabr, Getaneh Tefera, William Allen, Amol Pednekar, Ponnada Narayana Inline processing of magnetic resonance images allows fast feedback of analysis and immediate access to quantitative information. It further allows the development of adaptive MRI protocols. Here, we present GRAPE, a development platform for graphical programming to facilitate the development of adaptive magnetic resonance imaging (MRI) protocols. This platform provides tools to enable graphical creation, execution, and debugging of image analysis algorithms integrated with the MRI scanner, all within a graphical environment. GRAPE is demonstrated with the implementation of patient-specific optimization of the scan parameters of 3D fluid-attenuated inversion recovery (FLAIR) protocol to enhance the contrast of brain lesions in multiple sclerosis, performed on a 3.0 Tesla MRI scanner. 1454 Validation of CSF based calibration for accurate and robust quantification of water content. Zaheer Abbas, Dominik Ridder, Krzysztof Dzieciol, Nadim Jon Shah Estimating tissue water content is challenging. Reliable quantification of the water content requires significant number of corrections and calibration to a reference. In this work, we proposed to use a region in cerebrospinal fluid for robust calibration; this is further validated in a cohort of healthy volunteers and compared to existing methods. 1455 Automatic nonlinear transformation of 7T MRI brain image to Talairach stereotaxic space Mingyi Li, Jian Lin, Katherine Koenig, Mark Lowe Transforming MRI brain images into Talairach space will greatly facilitate the comparison of neuroimaging research results across subjects and applications of atlas to research subjects and clinical patients. We developed an automatic processing pipeline based on nonlinear registration to transform 7T MRI brain images to Talairach space. The pipeline utilized matching scores derived from brain parcellation for quality assurance (QA). The pipeline was tested on subjects including five controls, three MS patients and three ALS patients. The results showed that the method generated better results than the automatic Talairach transformation provided by AFNI. The QA scores were also comparable to those computed from 3T MRI brain images in our previous study. 1456 Epilepsy Surgery Followup: Resected Tissue Analysis and Classification Fabrício Simozo, Tonicarlo Velasco, Luiz Murta Jr. Focal cortical dysplasia (FCD) is one of the main causes of refractory epilepsy. There is no self-sufficient method in order to evidence the presence and location of FCD, making complete diagnosis very difficult. Although some studies have addressed FCD identification, image texture is poorly explored. This study evaluated pre and post-surgical magnetic resonance images (MRI) of epilepsy patients in order to test Machine Learning classifiers and their ability to identify dysplasia using texture features and cortical thickness. Precision and recall scores suggest the capabilities of the proposed methodology in responding to the presence of FCD tissue. 1457 Optimization of multiple orientation QSM for building a clinically feasible protocol Harshan Ravi, Wen-Tung Wang, Dzung Pham, John Butman   Quantitative Susceptibility Mapping (QSM) offers unique, quantitative information about tissue magnetic susceptibility. A multi-orientation method, calculation of susceptibility through multi-orientation sampling (COSMOS), enables the dipole inversion by acquiring data at multiple orientations. In practical imaging settings, however, it is a challenge to image the subject multiple orientations.  Although small angle COSMOS  has been shown to generate reasonable QSM images, the selection of orientations within a practical acquisition protocol remains an open question. In this work, we investigated the influence of the number and direction of orientations on the outcome of small angle COSMOS for in vivo imaging. 1458 Differences in parameter sensitivities of GESFIDE MR signals generated on realistic angiograms and on idealized cylinders Philippe Pouliot, Louis Gagnon, David Boas, Frederic Lesage Idealized models of cylinders for the vasculature are used in several quantitative MRI techniques such as for perfusion, CBV, vessel size and vascular MR fingerprinting. While limitations of these models are recognized, a direct comparison of the predicted MR signal between different cylinder models and those using a real vasculature as substrate has not been done to our knowledge. Here we compare the sensitivity of the MR signal for the GESFIDE sequence for 4 sets of , models of cylinders and 6 realistic angiograms from mouse somatosensory cortex. In general, simulation results are all different between the different angiograms and the different models of cylinders. This suggests that much care should be used in interpreting literature results based on models of cylinders, or as well with models on angiograms, to account for the possibility of biases in the absolute results. Correlations and differences in absolute values, for some parameters, may perhaps be less subject to bias. 1459 Adaptive Magnetic Resonance Image signal enhancement using squared eigenfunctions of the Schrodinger operator Abderrazak Chahid, Hacene Serrai, Eric Achten, Taous-Meriem Laleg-Kirati The main of challenge of Magnetic Resonance Imaging (MRI) is dealing with high levels of noise which may corrupt the image especially since the noise is almost correlated with the image details. In this regard, we propose a new MRI enhancement method to overcome this limitation. The proposed MRI enhancement method relies on square sub-images enhancement depending on the noise level in each position using spatial adaptation of the Semi-Classical Signal Analysis (SCSA) method, where an enhancement parameter h is subject to a Gaussian distribution. The results show significant improvement in noise removal and preserving small details in the image. 1460 Obtaining accurate and fast unwrapped phase images Riccardo Metere, Harald Möller The unwrapping of phase data is a common problem in MRI. However, its solution is non-trivial for 2D or 3D images, and there has been some general research in this direction, notably in the field of optics. The two most pupular algorithms for MRI applications are: (i) a Laplacian-based method that is fast but inaccurate; (ii) a region-merging optimization method that is accurate but very slow. Here, we propose the adoption of a recently developed and freely available unwrap algorithm that significantly outperforms the other considered methods, allowing for both fast and accurate calculation of unwrapped phase images. 1461 Spatial resolution properties of QSM images using MEDI algorithm Se Young Chun We investigated the spatial resolution of the MEDI reconstructed QSM images by deriving an analytical expression of the estimator in terms of the true QSM image. The implication of this expression is that no regularization will be applied to some part of the QSM images if the corresponding magnitude image area contains strong edges and relatively strong regularization will be applied to some part of the QSM images if the corresponding magnitude image area contains low magnitude values. Our simulations with a phantom and a in-vivo QSM image confirm this analysis; Impulse perturbations were suppressed on the area where the magnitude image has low contrasts and impulses were preserved on the area where the magnitude image has high contrast or edges. 1462 AWESOME-Based De-Noising of Complex-Valued fMRI Time Series Henrik Marschner, Laurentius Huber, André Pampel, Harald Möller In this study we investigate possible benefits of an application of ‘AWESOME’ de-noising on fMRI. The application in a high-SNR finger tapping experiment showed a reduction of the already low thermal noise contribution and therefore improvement of tSNR and reduction of false positives; no adverse effects in the form of smoothing or suppression of ‘true’ activation was observed. A second investigation of the scalability of tSNR improvement on a resting state experiment with variable slice thickness / SNR showed that thermal noise can be reliably reduced and the tSNR proportionally improved without visible reduction of detail sharpness / resolution. 1463 Assessment of interplatform reproducibility of T1 quantification methods used for DCE-MRI: results from a multicenter phantom study Octavia Bane, Stefanie Hectors, Mathilde Wagner, Lori Arlinghaus, Madhava Aryal, Michael Boss, Yue Cao, Thomas Chenevert, Fiona Fennessy, Wei Huang, Nola Hylton, Jayashree Kalpathy-Cramer, Kathryn Keenan, Dariya Malyarenko, Robert Mulkern, David Newitt, Karl Stupic, Lisa Wilmes, Thomas Yankeelov, Yi-Fen Yen, Stephen Russek, Bachir Taouli Our multicenter study examined variability in T1 quantification by testing common inversion-recovery spin echo and variable flip angle (VFA) protocols, as well as T1 mapping methods used by participating sites, using a phantom with known T1 values. We found field strength dependence of the accuracy, and platform dependence of the repeatability of T1 measurements with the common VFA protocol. Accuracy for site-specific protocols was influenced by site, while repeatability, by type of protocol. Our findings suggest modified IR methods and VFA protocols with multiple flip angles and B1 correction as good methods for repeatable T1 measurement. 1464 Bio-inspired optimization of technical fiber-reinforced ramifications using high-resolution MRI of Dracaena marginata branchings as concept generators Linnea Hesse, Tom Masselter, Nils Spengler, Jan Gerrit Korvink, Jochen Leupold, Thomas Speck MRT is still a little-known and highly underestimated imaging method within the field of functional morphology and biomechanics of plants and biomimetics. Its non-invasive and non-destructive character in combination with a large variety of applicable imaging sequences, gives this method a strong potential to shed light to various unanswered scientific questions concerning both the plant structure and function as well as on physiology. Using a Bruker Biospec 94/20 9.4T and a 3D FLASH sequence we could gain new insights into the biomechanics and development of dragon tree ramifications as a source of inspiration for the optimization of technical fiber-reinforced ramifications. 1465 Fast Bloch-Torrey simulation of 3D RF spoiled gradient echo sequences using a number of subvoxels and molecular diffusion effect Ryoichi Kose, Katsumi Kose RF spoiled gradient echo sequences were studied both with experiments and  Bloch-Torrey simulation. The Bloch simulation of the 256×256×32 voxel images clarified that adequate number of subvoxels  were required for artifact-free images. The Bloch-Torrey simulation for one voxel magnetization clarified that adequate number of subvoxels were required for image intensity reproduction by diffusion effect. In conclusion, molecular diffusion effects are indispensable to reproduce the image contrast in SPGR. 1466 Analysis of error in Fat-Water Quantifications Originated from Models Xiaoqi Wang, Xiaoguang Cheng, Li Xu, Li Baoqing Fat-water separation imaging methods with multi-echo acquisition require specific fat spectrum model. The optimal spectrum model to be applied relies on the fat chemical properties as well as the acquisition scheme regarding to, for example, TR and TE. Herein we exam the consequence if inaccurate fat spectrum is used in the fat quantification processing, and analyze the related errors. 1467 Liver Biopsy Analysis to Determine Fat Droplet Distribution Benjamin Ratliff, Diego Hernando, Curtis Wiens, Changqing Wang, Rao Watson, Rashmi Agni, Claude Sirlin, Scott Reeder The purpose of this work was to quantify the size and clustering of fat droplets using liver biopsy, as part of a long-term effort to characterize the relationship between tissue microstructure and quantitative MRI signals in fat-containing tissue. Three H&E stained liver core biopsies with varying fat-fractions were analyzed using segmentation software in order to generate probability density functions for fat droplet size and location. This work demonstrates that fat droplet distribution in the liver can be modeled statistically to determine the size and location distribution of fat droplets, potentially enabling characterization of the MR signal observed from fatty liver. 1468 Diffusion effects on T2 relaxometry with triple echo steady-state free precession sequence Yangzi Qiao, Chao Zou, Xin Liu, Hairong Zheng In this study, the underestimation of T2 by TESS was revealed through simulation and phantom study. The bias becomes significant in high resolution TESS imaging with larger unbalanced gradient moment, as the diffusion effect can not be neglected. A possible correction scheme was also proposed, the results validated the diffusion effect on T2 estimation. However, the correction method relies on T1/T2/D as priori to calculate the signal change ratio through EPG algorithm. A possible solution might be simultaneous estimation on apparent diffusion coefficient and T2. 1469 Brain activity alteration during the training period of the Hybrid Assistive Limb® (HAL) for chronic spinal cord injuries: a task-based fMRI case report Kousaku Saotome, Akira Matsushita, Aiki Marushima, Hiroaki Kawamoto, Hideo Tsurushima, Tomohiko Masumoto, Masashi Yamazaki, Akira Matsumura, Yoshiyuki Sankai We previously developed the novel brain phantom showing image contrast and construction similar to those of in vivo MRI. This phantom has the potential to quantitatively assess the capability of the motion-corrected PROPELLER technique, which has been never approached. In the current study, we investigated the rotational frequency dependencies of the different two motion-corrected PROPELLER techniques by using our brain phantom. Our findings allow to quantitatively assess the capability of the Motion-Correction in PROPELLER. 1470 Determining the Time Efficiency of Quantitative MRI Methods using Bloch Simulations Willem van Valenberg, Frans Vos, Stefan Klein, Lucas van Vliet, Dirk Poot When measuring $$T_1, T_2, T_2^*, PD$$$, or $$B_1^+$$$, we prefer the MRI sequence that provides the best precision in the allowed scan time (i.e. having optimal time efficiency). However, experimentally determining the time efficiency is impractical when comparing many sequences, each possibly with varying settings, and multiple tissue types of interest. Here, we derive time efficiency through Bloch simulations which is applicable to any MRI sequence and tissue type. A specific strength of our framework is that it does not require an explicit fitting procedure which may not yet exist when designing novel MR sequences. 1471 Quantitative DCE-MRI Accuracy Evaluation Using Dynamic Physical vs. Digital Phantom: a Cross-Validation Yuan Le, Yuxiang Zhou, Eric Stinson, Stephen Riederer, Joel Felmlee To study the image accuracy of quantitative DCE-MRI a digital phantom and computer simulation were usually used. To validate the digital phantom method, we conducted a cross-validation study comparing the image accuracy estimation from simulation with that from a dynamic physical phantom with contrast infusion. Results showed that the estimated errors were usually higher with the physical phantom, likely due to the difference in reproducibility. Consistency was found in the measurement error comparison between imaging techniques when the temporal resolution was high. 1472 Early enhancement in breast DCE-MRI is sparse and can be imaged with a reduced FOV to increase temporal resolution Federico Pineda, Ty Easley, Gregory Karczmar Early enhancement in breast DCE-MRI is very sparse, if the FOV is reduced in these images and aliasing occurs, the likelihood that two significantly enhancing voxels overlap is low. We present a method for ‘unfolding’ of aliased DCE-MRI acquisitions that closely approximates fully-sampled acquisitions. This method could be used to increase the temporal resolution of DCE-MRI at very early times when enhancement is rapidly changing, allowing for the accurate measurement of early lesion kinetics. 1473 Simulation of Sound Pressure Level of MRI Scan Considering Eddy Currents Yukari Yamamoto, Yo Taniguchi, Hisaaki Ochi, Yoshihisa Soutome Since optimal waveforms should be chosen for each gradient pulse in order to reduce sound pressure levels (SPLs) in MRI scans, the simulation accuracy of the SPL must be improved. Assuming that the eddy current component is a cause of the disagreement between the measured and the simulated SPLs, we compared the simulation results with and without the eddy current component in this study. By including the eddy current component in the simulation, the magnitude of the SPL decreased, which reflects the decrease in the peak amplitude of the frequency component of the gradient waveform. However, the eddy current component did not affect the change trends of the SPLs depending on the change of waveforms. On the other hand, a slight change in the peak position of the frequency response functions appears to cause a significant change in the SPL, and the error of the FRF was also thought to cause disagreement between the measured and simulated SPLs. 1474 The effect of MR noise and resolution on textural features in simulated and real textures: implications for clinical practice. Joshua Shur, Matthew Orton, Simon Doran, James D'Arcy, David Collins, Maria Bali, Martin Leach, Dow-Mu Koh Sensitivity of textural features to acquisition parameters has important clinical implications. The aim of this study is to investigate the effect of noise and resolution on textural features. We compared textural features from a uniform and simulated texture, varied with noise, with experiment in a uniform phantom and organic texture. Our data demonstrate that a uniform texture behaves as if it has inherent texture, due to presence of artefact, and this in turn will influence textural features as noise and acquisition parameters are varied. We note that certain textural features used in clinical practice vary widely with image noise, whereas others appear to be robust. 1475 Quantification of contrast agent-induced enhancement of brain lesions in multiple sclerosis Jung-Jiin Hsu, William Stern, Jung-Yu Hsu, Roland Henry Contrast agents are routinely used in MRI to detect and evaluate tissue lesions. Conventional clinical protocols use T1-weighted sequences to visualize Gd contrast agent enhancement. Because T1-weighted MRI does not produce quantitative measurements, it is difficult to describe the lesion enhancement in quantitative terms and to infer the degree of the underlining disease activities of the lesions. A fast, whole-brain high-resolution T1 mapping method was developed to address this problem and applied to multiple sclerosis. 1476 LEI-ALOHA – Magnetic Resonance Imaging in the Tropical Island Setting Christopher Wiggins, Benedikt Poser While there are exceptions, most major MRI research centers are located in urban areas where a sizeable population is served by a large medical infrastructure and/or university. For researchers and technical staff alike, this often precludes the possibility of combining their research program with a remote, island-based lifestyle. Here we propose a set of theoretical techniques that form a framework for a purely philosophical research program.

Pulse Sequences
Acquisition, Reconstruction & Analysis

Monday, 24 April 2017
 Exhibition Hall 08:15 - 10:15

Reconstruction