ISMRM 24th Annual Meeting & Exhibition 07-13 May 2016 Singapore

Scientific Session: Abdominal Technique & Pulse Sequences

Wednesday, May 11, 2016
Summit 2
10:00 - 12:00
Moderator: Lorenzo Mannelli

Improving Respiratory Phase-resolved 3D Body Imaging Using Iterative Motion Correction and Average (MoCoAve)
Xiaoming Bi1, Jianing Pang2, Wensha Yang2, Matthias Fenchel3, Zixin Deng2, Yuhua Chen4, Richard Tuli2, Debiao Li2, Gerhard Laub1, and Zhaoyang Fan2
1Siemens Healthcare, Los Angeles, CA, United States, 2Cedars-Sinai Medical Center, Los Angeles, CA, United States, 3Siemens Healthcare GmbH, Erlangen, Germany, 4University of Pennsylvania, Philadelphia, PA, United States
4D (respiratory phase-resolved 3D) MRI has been increasingly used for the planning of radiotherapy and minimally invasive surgery. Recently developed self-gating methods showed great potential in 4D MRI by providing high imaging efficiency and isotropic spatial resolution. However, images of individual phases may suffer from decreased SNR and increased streaking artifact since only a subset of data were used for reconstruction. A motion correction and average (MoCoAve) framework was developed in this work to address such limitations. Preliminary results from patients showed that the proposed method can significantly improve SNR and image quality without compromising motion information.

Variable Density Compressed Sensing Single Shot Fast Spin Echo
Valentina Taviani1, Daniel V. Litwiller2, Jonathan I. Tamir3, Andreas M. Loening1, Brian A. Hargreaves1, and Shreyas S. Vasanawala1
1Stanford University, Stanford, CA, United States, 2Global MR Applications and Workflow, GE Healthcare, New York, NY, United States, 3University of California Berkeley, Berkeley, CA, United States
Variable density (VD) sampling was implemented into an extended echo train single shot fast spin echo (SSFSE) pulse sequence. Compressed sensing (CS) reconstuction was used. With respect to regular undersampling and ARC (Autocalibrated Reconstruction for Cartesian imaging), VD CS SSFSE allows higher acceleration factors, which translates in increased flexibility in the choice of echo times  for full-Fourier imaging (shorter minimum TEs) and faster acquisitions (shorter breath-holds). 

Free-breathing non-contrast enhanced 3D radial respiratory-motion resolved pancreatic MRI at 3T using sparse iterative reconstruction
Jessica AM Bastiaansen1, Jerome Yerly1,2, Jean-Baptiste Ledoux2, Ruud B van Heeswijk1,2, Davide Piccini3, and Matthias Stuber1,2
1Department of Radiology, University hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 2Center for Biomedical Imaging, Lausanne, Switzerland, 3Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland
Pancreatic MRI is commonly performed during breath-held or navigator-gated acquisitions. The long breath-holds needed for high spatial resolution are not always feasible in patients and residual respiratory motion may still occur. Additionally, in some implementations, the navigator leads to a local signal void that may obscure parts of the anatomy of interest. Here we used a free-breathing self-navigated 3D radial gradient-recalled-echo (GRE) imaging sequence, and compared the 1D motion correction as performed on the scanner versus a motion-resolved 4D sparse iterative reconstruction. We show that non-contrast enhanced pancreatic MRI can be performed at 3T during free-breathing, while motion-resolved sparse reconstruction can efficiently minimize the adverse effects of respiratory motion.

Radial Volumetric Interpolated Breath-hold Examination of the Liver: Clinical Impact of Self-gated 3D Isotropic Contrast-enhanced Late-Phase MR Imaging - Permission Withheld
Jakob Weiss1, Jana Taron1, Ahmed E. Othman1, Robert Grimm2, Petros Martirosian1, Christina Schraml1, Konstantin Nikolaou1, and Mike Notohamiprodjo1
1Diagnostic and Interventional Radiology, University of Tuebingen, Tuebingen, Germany, 2Siemens Healthcare, Erlangen, Germany
To evaluate clinical performance of contrast-enhanced 3D-isotropic radial volumetric interpolated breath-hold examination (VIBE) for late-phase MR imaging of the liver. A prototype retrospective self-gating algorithm for more motion-robust data acquisition was implemented and compared to standard Cartesian VIBE. Utilization of self-gating VIBE provides significantly improved image quality, especially in coronal reformations and Gd-EOB-DTPA-enhanced late-phase scans. Moreover, in 11% only radial VIBE provided diagnostic image quality, thus having a direct implication on patient care. Therefore, self-gated radial VIBE seems a valuable approach to improve diagnostic accuracy in late-phase MR imaging of the liver.

Improved detection of capsular enhancement in hepatocellular carcinoma using multiphasic hepatic arterial imaging and DIfferential Sub-sampling with Cartesian Ordering (DISCO) in gadoxetic acid-enhanced magnetic resonance imaging
Shintaro Ichikawa1, Utaroh Motosugi1, Tetsuya Wakayama2, Takashi Kakegawa1, Hiroshi Kumagai1, and Hiroshi Onishi1
1University of Yamanashi, Yamanashi, Japan, 2GE Healthcare Japan, Tokyo, Japan
DIfferential Subsampling with Cartesian Ordering (DISCO) is a new high spatiotemporal resolution, dynamic contrast-enhanced magnetic resonance imaging (MRI) technique. We evaluated the usefulness of multiple (n=6) hepatic arterial phases (HAPs) with DISCO in gadoxetic acid-enhanced dynamic MRI for detecting capsular enhancement in hepatocellular carcinoma (HCC). Such capsular enhancement is detected more frequently by combining portal venous phase (PVP) images and multiphasic hepatic arterial images with DISCO. Combining DISCO with PVP improved the liver imaging reporting and data system (LI-RADS) v2014 score from LR4 to LR5.

Multispectral Body Diffusion-Weighted Imaging
Valentina Taviani1, Shreyas S. Vasanawala1, and Brian A. Hargreaves1
1Stanford University, Stanford, CA, United States
A diffusion-weighted (DW) imaging method was developed to mitigate off-resonance-induced distortion and signal loss, which are problematic for body applications. A 2D RF pulse is used in place of the conventional spectral-spatial excitation used for DW spin echo echo-planar imaging. In the presence of off-resonance, a narrow band of frequencies is excited due to the different bandwidths between excitation and refocusing pulses. By progressively shifting the center frequency, the whole range of off-resonance can be excited and a composite image, corrected for off-resonance-induced distortion, can be reconstructed by estimating the field map from the spectral information. 

3D whole liver black blood imaging: a 3 min solution consisting of respiratory triggering and free breathing imaging techniques
Li Jiang1, Chenguang Zhao1, Andy Jiang1, Ming Yang1, Wengu Su1, Allan Jin1, Ping Yang1, Stephon Xu1, and Feng Huang1
1Philips Healthcare (Suzhou), Suzhou, Jiangsu, China, People's Republic of
Liver black blood imaging helps to detect and characterize focal liver lesions and thus is highly desirable clinically. The commonly used low b-value DWI sequence is limited due to inherent limitations of EPI, such as low spatial resolution and motion artifacts including blurring and ghosting. We proposed a 3D whole liver black blood imaging solution within 3 min. By combining with existing black blood preparation, a respiratory triggered VISTA sequence and a free breathing imaging technique utilizing GROWL reconstruction were proposed. Six healthy volunteers with stable and irregular respiration were scanned to further validate the feasibility of our proposed solution.

Potential Improvement in Apparent Diffusion Coefficient (ADC) Measurement by Respiratory Correlated Four Dimensional Diffusion-Weighted MRI (4D-DWI): Initial Investigation on Digital Phantoms and Human Subjects
Yilin Liu1, Fang-Fang Yin2, Brian Gary Czito2, Mustafa R. Bashir 3, Manisha Palta 2, Xiaodong Zhong 4, Brian M. Dale 5, and Jing Cai2
1Medical Physics Graduate Program, Duke University Medical Center, Durham, NC, United States, 2Radiation Oncology, Duke University Medical Center, Durham, NC, United States, 3Department of Radiology, Center for Advanced Magnetic Resonance Development, Duke University Medical Center, Durham, NC, United States, 4MR R&D Collaborations, Siemens Healthcare, Atlanta, GA, United States, 5MR R&D Collaborations, Siemens Healthcare, Cary, NC, United States
Diffusion-weighted imaging (DWI) has been shown to have superior tumor-to-tissue contrast for cancer detection in abdominal region. However, the respiratory motion may induce severe imaging errors or artifacts for DWI images. This study aims at developing and evaluating a respiratory correlated 4D-DWI technique using a retrospective sorting method for imaging respiratory motion on human subjects. Comparing to free breathing DWI, 4D-DWI can lead to more accurate measurement of ADC. This has a great potential to improve the visualization and delineation of cancer tumors for radiotherapy.

Simultaneous multislice accelerated diffusion-weighted imaging of the liver: comparison of different breathing schemes with standard sequences as reference
Christina Schraml1, Jana Taron1, Nina F Schwenzer1, Holger Schmidt1, Thomas Kuestner2, Michael Erb3, Mike Notohamiprodjo1, Konstantin Nikolaou1, Fritz Schick4, and Petros Martirosian4
1Diagnostic and Interventional Radiology, Department of Radiology, University Hospital Tuebingen, Tuebingen, Germany, 2Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, 3Department of Biomedical Magnetic Resonance, University Hospital Tuebingen, Tuebingen, Germany, 4Section on Experimental Radiology, Department of Radiology, University Hospital Tuebingen, Tuebingen, Germany
SMS-acceleration allows for considerable scan time reduction in hepatic DWI without substantial drawbacks in image quality both using respiratory-triggering and free-breathing acquisitions. In the present study set-up, ADC measured in SMS-DWI were lower than in standard DWI which should be considered when using absolute ADC for clinical reading. The demonstrated high image quality of SMS-DWI obtained in FB indicates great potential for scan time reduction in DWI for abdominal and whole-body applications.

Intravoxel incoherent motion diffusion-weighted imaging of hepatocellular carcinoma: is there a correlation with flow and perfusion metrics obtained with dynamic contrast-enhanced MRI?
Stefanie Hectors1, Mathilde Wagner1, Cecilia Besa1, Hadrien Dyvorne1, Octavia Bane1, M. Isabel Fiel2, Hongfa Zhu2, and Bachir Taouli1,3
1Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 3Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
We assessed the correlation between intravoxel incoherent diffusion-weighted imaging (IVIM-DWI) and dynamic contrast-enhanced MRI (DCE-MRI) in hepatocellular carcinoma (HCC) and liver parenchyma. DCE-MRI-derived arterial fraction and arterial flow were significantly negatively correlated with IVIM-DWI-derived perfusion fraction and pseudodiffusion in the liver, while IVIM-DWI parameters did not correlate with DCE-MRI parameters in HCC. These results indicate that IVIM-DWI and DCE-MRI provide non-redundant information in HCC.

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