Mahmud Mossa-Basha¹, Haining Liu¹, Dan S. Hippe¹, Niranjan Balu¹, Jie Sun¹, Dean Shibata¹, and Chun Yuan^1
1Radiology, University of Washington Medical Center, Seattle, WA, United States

Intracranial arterial calcification evaluation has shown increasing importance in the literature based on associations with current and future stroke events, dementia and cognitive decline.  We hypothesize that the proton-density image, SNAP Ref, that is generated with Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) can more adequately assess calcifications compared to 3D TOF MRA relative to the reference standard, thin slice CTA.

Sagar Mandava¹, Mahesh Bharath Keerthivasan¹, Kevin Johnson², Diego R. Martin³, Ali Bilgin^1,3,4, and Maria I. Altbach^3
1Electrical and Computer Engineering, University of Arizona, Tucson, AZ, United States, ²Siemens Healthcare, Tucson, AZ, United States, ³Medical Imaging, University of Arizona, Tucson, AZ, United States, ⁴Biomedical Engineering, University of Arizona, Tucson, AZ, United States

The DIR-FSE sequence is popularly used to assess plaque build up but is known to be a single slice technique due to a non-selective inversion pulse used in the DIR module. In this work we present a technique to improve the SNR efficiency of DIR-FSE sequences by multi-band excitation. The proposed technique can generate multiple slices at the exact null point of blood and the acquired data can be used to create upto 16 TE images and T2 maps for all the acquired slices. 

Seong-Eun Kim¹, John A Roberts¹, J Scott McNally¹, Bradley D Bolster, Jr.², Gerald S Treimam^3,4, and Dennis L Parker ^1
1Department of Radiology, UCAIR, University of Utah, Salt Lake City, UT, United States, ²Siemens Healthcare, Salt Lake City, UT, United States, ³Department of Surgery, University of Utah, Salt Lake City, UT, United States, ⁴Department of Veterans Affairs, VASLCHCS, Salt Lake City, UT, United States

Contrast enhanced T1 imaging has been used to aid in the detection of the fibrous cap overlying the necrotic core. We have implemented 3D SOS with retrospective cardiac cycle gated compressed sensing reconstruction to minimize, characterize artifacts in post-contrast imaging. Radial based k-space trajectory may offer reduced motion sensitivity and more robust ciné-ROCS reconstructions due to its inherent oversampling of central k-space. Ciné-ROCS reconstruction from 3D SOS acquisition demonstrates improved demonstration of fine plaque structures and vessel wall movement due to cardiac motion to the regular reconstruction and may help provide information on symptomatic plaque development and response to treatment.

Seong-Eun Kim¹, J Scott McNally¹, Bradley D Bolster, Jr.², Gerald S Treimam^3,4, and Dennis L Parker ^1
1Department of Radiology, UCAIR, University of Utah, Salt Lake City, UT, United States, ²Siemens Healthcare, Salt Lake City, UT, United States, ³Department of Surgery, University of Utah, Salt Lake City, UT, United States, ⁴Department of Veterans Affairs, VASLCHCS, Salt Lake City, UT, United States

DWI might provide a tool for discriminating intraplaque hemorrhage and lipid core from other components. Motion insensitive 3D DW-DE SOS has been developed to acquire high resolution DWI to improve the accuracy of ADC measurements. This technique was able to yield high resolution ADC that could provide clear ROI selection for important plaque components. Increased spatial resolution in motion insensitive 3D DW-DE SOS can improve the sensitivity of ADC maps in plaque component identification. The results obtained indicate that an ADC map may be of substantial value in identifying lipid and hemorrhage within overall plaque burden.

Seong-Eun Kim¹, J Scott McNally¹, Bradley D Bolster, Jr.², Gerald S Treimam^3,4, and Dennis L Parker ^1
1Department of Radiology, UCAIR, University of Utah, Salt Lake City, UT, United States, ²Siemens Healthcare, Salt Lake City, UT, United States, ³Department of Surgery, University of Utah, Salt Lake City, UT, United States, ⁴Department of Veterans Affairs, VASLCHCS, Salt Lake City, UT, United States

DWI has the potential to provide complementary information that will allow better discrimination of plaque components such as lipid core. Iron has consistently been found in higher concentrations in atherosclerotic plaque compared to vessel tissue. In previous studies, intraplaque T2* distinguished symptomatic from asymptomatic plaques in patients with carotid atherosclerosis. In this work we introduce simultaneous measurement of ADC and T2* using a motion insensitive high resolution 3D multiple echo diffusion weighted driven equilibrium Stack of Stars sequence. This technique can provide high resolution T2* and ADC values simultaneously, which may provide important clinical information to detect plaque progression.

Yoshimitsu Ohgiya¹, Nobuyuki Ohike ², Naomi Yagi ¹, Hiroto Sasamori¹, Jiro Munechika ¹, Masanori Hirose ¹, and Takehiko Gokan ^1
1Showa University School of Medicine, Tokyo, Japan, ²Department of Pathology, Showa University Fujigaoka Hospital, Yokohama-shi, Japan

The purpose of this study was to investigate whether 3D turbo spin-echo (TSE) SPACE sequence can evaluate plaque characteristics of the carotid artery. Mann-Whitney test was used to examine differences in the contrast ratio (CR) between soft plaques and fibrous plaques on T1- and T2-weighted images. The mean CR of the soft plaques (1.54 ± 0.25) was significantly higher than that of the fibrous plaques (1.17 ± 0.13) (p < 0.001) on T1-weighted images. In conclusion, T1-weighted TSE SPACE sequence can evaluate main components of plaques in the carotid artery with high sensitivity and specificity.

Robert Frost¹, Aaron T. Hess², Linqing Li³, Matthew D. Robson², Luca Biasiolli², and Peter Jezzard^1
1FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, ²Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom, ³Section on Magnetic Resonance Spectroscopy, National Institute of Mental Health, Bethesda, MD, United States

Ghosting and blurring artifacts caused by swallowing or coughing can be a significant problem in quantitative T2 mapping of atherosclerotic plaque in the carotid artery. The method is based on a multi-slice multiple spin-echo sequence which acquires k-space lines sequentially with a 2 s gap between lines. A navigator echo was added at the end of the echo-train to identify and reacquire data corrupted by motion. The selective reacquisition reduced ghosting and blurring artifacts in healthy volunteer scans with intentional swallowing motion.

Alison N. Pruzan^1,2, Audrey Kaufman^1,2, Claudia Calcagno^1,2, Yu Zhou^1,2, Zahi A. Fayad^1,2, and Venkatesh Mani^1,2
1Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ²Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States

Evaluation of atherosclerosis in smaller arteries in the hand may be clinically useful in certain disease conditions such as Diabetes. We sought to demonstrate feasibility of vessel wall imaging of the superficial palmar arch using 7T and 3T MRI in comparison with very high frequency micro ultrasound. Results indicated that 7T imaging of the palmar arch was feasible and subjective image quality analysis was better than 3T and ultrasound.

Ziwu Zhou¹, Fei Han¹, Takegawa Yoshida¹, Kim-Lien Nguyen¹, Paul Finn¹, and Peng Hu^1
1Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States

A recent proposed technique called four dimensional, multiphase, steady-state imaging with contrast enhancement (MUSIC) enables detailed anatomical assessment of cardiovascular system. However, limited available cardiac phase prevents accurate functional assessment of the heart. In this study, we compared original MUSIC with an improved MUSIC technique that generates double cardiac phases. Initial results suggest a more accurate left ventricular volume measurement and better appreciation of cardiac wall motion can be achieved with more cardiac phases.

Eric G. Stinson¹, Joshua D. Trzasko¹, and Stephen J. Riederer^1
1Radiology, Mayo Clinic, Rochester, MN, United States

Single-echo Dixon imaging for contrast-enhanced MR angiography (CE-MRA) can provide the advantages of multi-echo Dixon without the tradeoff of longer acquisitions and reduced temporal resolution. Single-echo Dixon imaging assumes that both the water and fat signals are real and have known initial phase and phase due to field inhomogeneities. However, when a paramagnetic Gadolinium-based contrast agent is injected for CE-MRA, the field may be perturbed and render the a priori phase estimates invalid. The purpose of this study is to demonstrate the effect of Gd-induced field perturbations on first-pass single-echo Dixon CE-MRA and describe strategies to avoid or correct artifacts.

Davide Piccini^1,2, Peter J. Weale³, Saeed Mirsadraee⁴, Rachel O. Forsythe⁵, Annette S. Cooper⁶, and Scott Semple^5,6
1Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, ²Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland,³Siemens Healthcare Ltd, Camberley, United Kingdom, ⁴NHS Lothian & Clinical Research Imaging Centre Queen's Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom, ⁵Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom, ⁶Clinical Research Imaging Centre, University of Edinburgh, Edinburgh, United Kingdom

Respiratory self-navigated 3D-radial MRA is an efficient and robust method for the depiction of coronary luminal anatomy at 1.5T. Higher magnetic fields are more challenging, due to off-resonance artifacts. Contrast-enhanced imaging is usually beneficial. However, variable contrast during prolonged scans can deteriorate the self-navigation signal. Here we investigate the use of an ultra-small super-paramagnetic iron oxide particles (USPIO) contrast agent with longer half-life in combination with self-navigation at 3T. Systolic and diastolic datasets from 10 volunteers were acquired and analyzed. We show that USPIO contrast-enhanced self-navigated coronary MRA is feasible at 3T with good image quality and reliable motion correction.

Holger Eggers¹, Bernhard Schnackenburg², Marc Kouwenhoven³, Alan Huang³, Tim Leiner⁴, Rolf Gebker⁵, and Sebastian Kelle^5
1Philips Research, Hamburg, Germany, ²Philips Healthcare, Hamburg, Germany, ³Philips Healthcare, Best, Netherlands, ⁴Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ⁵German Heart Institute Berlin, Berlin, Germany

Chemical shift encoding-based water-fat imaging, or Dixon imaging, has recently been demonstrated to permit first-pass peripheral MRA without subtraction. While previous work focused on an evaluation at 1.5 T, this work explores the feasibility of this subtractionless method at 3 T. Results on the first six patients are presented and are compared with the established subtraction method. Substantial improvements in image quality are seen, and the use of three stations is, despite particular challenges at 3 T, preliminarily found to be practicable.

Jacob Agris¹, Neda Rastegar², Kelly Fabrega-Foster², Sheela Agarwal^1,3, Daniel Haverstock⁴, and Ihab Kamel^2
1Radiology, Bayer, Whippany, NJ, United States, ²Radiology, Johns Hopkins, Baltimore, MD, United States, ³Radiology, Massachusetts General Hospital, Boston, MA, United States, ⁴Statistics, Bayer, Whippany, NJ, United States

International, multicenter phase 3 blinded study comparing the performance of CE-MRA with Gadobutrol, a high relaxivity and highly stable macrocyclic contrast agent, to 2D Time-of-flight MRA (ToF) using CTA as the standard of reference (SoR). 317 patients suspected of renal artery disease were enrolled. There was almost no error in the Gadobutrol MRA vessel measurements (0.0mm Gadobutrol vs 0.5mm ToF for stenosis measurements) and superior assessability as well as superior specificity was demonstrated reducing the need for additional imaging studies by 50%. Gadobutrol enhanced MRA of the renal arteries has superior visualization, more accurate measurements and is a valuable alternative to CTA without any ionizing radiation.

Christopher S Johns¹, Smitha Rajaram², David Capener¹, David G Kiely³, Andrew J Swift^1,4, and Jim M Wild^1
1Academic Unit of Radiology, University of Sheffield, Sheffield, United Kingdom, ²Radiology Department, Sheffield Teaching Hospitals, Sheffield, United Kingdom, ³Sheffield Pulmonary Vascular Clinic, Sheffield Teaching Hospitals, Sheffield, United Kingdom, ⁴Institute of Insilico Medicine, The University of Sheffield, Sheffield, United Kingdom

A comparison of perfusion SPECT and MRI in screening for chronic thromboembolic disease. To assess the role of MRI perfusion in the clinical imaging pathway in this patient group. 

Farshid Faraji¹, Alastair Martin¹, and David Saloner^1
1Department of Radiology, UCSF, San Francisco, CA, United States

Intracranial aneurysms are localized dilations in blood vessels occurring in 1-6% of the population which can have devastating consequences in the event of rupture. Many aneurysms are asymptomatic, found incidentally, and fall below the surgical size threshold. For this reason, physicians choose to follow aneurysms with imaging rather than opting for surgical or endo-vascular intervention. Here we further our analysis of a previously presented image processing technique using contrast-enhanced MRA to follow intracranial aneurysms longitudinally. We investigate the measurement error of this post-processing technique in 100 intracranial aneurysms, and evaluate the differential effects of imaging at 1.5T and 3T.

Dariusch Reza Hadizadeh¹, Vera Catharina Keil¹, Gregor Jost², Hubertus Pietsch², Martin Weibrecht³, Bishr Agha¹, Christian Marx¹, Michael Perkuhn³, Hans Heinz Schild¹, and Winfried Albert Willinek^4
1Radiology, University of Bonn, Bonn, Germany, ²MR and CT Contrast Media Research, Bayer Healthcare, Berlin, Germany, ³Innovative Technologies, Research Laboratories, Philips Technologie GmbH, Aachen, Germany, ⁴Department of Radiology, Neuroradiology, Sonography and Nuclear Medicine, Brüderkrankenhaus Trier, Trier, Germany

In an animal model bolus kinetics and image quality after injection of 1M gadobutrol (standard and half-dose) and 0.5M gadopentetate dimeglumine (standard-dose) had been investigated in 4D-MRA at 3T and dynamic CTA. The first pass arterial peak Gd-concentrations (quantified by CTA) were higher for standard-dose compared to half-dose gadobutrol. In 4D-MRA the first pass arterial peak enhancement was comparable for both gadobutrol doses and gadopentetate dimeglumine due to peak cut-off effects at high vascular Gd concentrations. Markedly higher venous bolus peaks were found for standard-dose gadobutrol. Image quality of 4D-MRA was rated significantly higher for both doses of gadobutrol.

Pin-Chen Chen¹, Hsin-Hui Chiu², Wen-Yih Isaac Tseng³, and Hsu-Hsia Peng^4
1Institute of Systems Neuroscience, Hsinchu, Taiwan, ²Department of Pediatrics, Taipei, Taiwan, ³Center for Optoelectronic Biomedicine, Taipei, Taiwan, ⁴Department of Biomedical Engineering and Environmental Sciences, Hsinchu, Taiwan

We aim to evaluate relative helicity of aortic flow for patients with Marfan syndrome (MFS) by 4D flow phase-contrast MRI. An individual helicity_AED mapping was composed to provide the information of the spatiotemporal distribution of relative helicity. The E sign represents the relative helicity cores shown in the early diastole whereas D sign represents the relative helicity core shown time-delayed and downstream. The A sign represents an additional relative helicity core other than D, E, or the normal single cores. MFS patients showed abnormal relative helicity core in helicity_AED mapping, which provided promising approaches for patient managements in the future.

Beth Ripley¹, Gregory J Wilson¹, and Jeffrey H Maki^1
1Department of Radiology, University of Washington Medical Center, Seattle, WA, United States

A new method of lymphatic channel mapping was evaluated in a retrospective review of pre-surgical lymphedema MR exams. Dual Agent Relaxation Contrast MR Lymphangiography (DARC-MRL) uses intracutaneous injection of a Gd contrast agent for enhancement of lymphatic channels and concomitant intravenous injection of USPIO (ferumoxytol) for suppression of (otherwise lymphatic-obscuring) veins. 43 MR exams using DARC-MRL were compared to 43 matched exams using conventional (no USPIO) MR lymphangiography. Exams were graded for degree of venous contamination, and DARC-MRL exams exhibited dramatically less obscuring venous contamination than the conventional method.

Giulia Ginami¹, Simone Coppo¹, Li Feng², Davide Piccini^1,3, Tobias Rutz⁴, Ricardo Otazo², Daniel Sodickson², Matthias Stuber^1,5, and Jerome Yerly^1,5
1University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, ²Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, United States, ³Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, ⁴Division of Cardiology and Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland, ⁵Center for Biomedical Imaging (CIBM), Lausanne, Switzerland

Free-running self-navigated techniques have been introduced in order to allow for time resolved three-dimensional whole-heart MR acquisitions. A more recently proposed free-running 5D (x-y-z-cardiac-respiration) XD-GRASP (eXtra-Dimensional Golden-angle RAdial Sparse Parallel MRI) approach enables acquisition and reconstruction of cardiac- and respiratory-motion resolved 3D volumes. In this study, we investigated the potential of 5D XD-GRASP in a clinical setting.

Marcos Paulo Botelho¹, Shivraman Giri², Ioannis Koktzoglou^1,3, Alto Stemmer⁴, and Robert R. Edelman^1,5
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²Siemens Healthcare, Chicago, IL, United States, ³Radiology, University of Chicago Pritzker School of Medicine, Chicago, IL, United States, ⁴Siemens Healthcare GmbH, Erlangen, Germany, ⁵Radiology, Feinberg School of Medicine, Northwestern Univesity, Chicago, IL, United States

We evaluated a novel approach for visualizing and quantifying peripheral arterial calcifications using a stack-of-stars 3D FLASH pulse sequence.  The technique permitted isotropic 1mm3 spatial resolution and displayed dark calcifications against a relatively uniform bright background.  Banding artifacts relating to chemical shift were minimized by the use of radial in-plane spatial encoding and an in-phase echo time, while vascular signal was enhanced by the use of a low flip angle near the Ernst angle of blood. In patients with peripheral arterial disease, there was excellent correlation using CT angiography as the standard of reference.  

Nobuyuki Toyonari¹, Masami Yoneyama², Seiichiro Noda¹, Yukari Horino¹, and Kazuhiro Katahira^1
1Kumamoto Chuo Hospital, Kumamoto, Japan, ²Philips Electronics Japan, Tokyo, Japan

Non-contrast MR angiography (MRA) is a promising method to diagnose and follow-up of vascular diseases such as dissecting aortic aneurysm. Conventionally, 3D gated balanced steady-state free precession (bSSFP) is used for the aorta, but it has several limitations. To overcome bSSFP’s limitations , we propose a new technique based on gradient echo DIXON sequence with flow-independent relaxation-enhanced non-contrast MRA technique (Relaxation-Enhanced Angiography without Contrast and Triggering: REACT). We showed that REACT could provide more robust and stable MRA without any artifacts and failed fat suppression compared with conventional bSSFP. 

Michael O. Zenge¹, Justin Ream², Ankur Doshi², Mary Bruno², Christopher Stroehlein³, Peter Speier³, Hersh Chandarana², and Harald H. Quick^4,5
1Siemens Healthcare, Malvern, PA, United States, ²Radiology, NYU Langone Medical Center, New York, NY, United States, ³Siemens Healthcare, Erlangen, Germany, ⁴Erwin L. Hahn Institute for MR Imaging, University Duisburg-Essen, Essen, Germany, ⁵High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany

Although unenhanced MR angiography eliminates the need for contrast injection, it would use ECG triggering which adds extra time and complexity to patient preparation. In the current work, time-of-flight (TOF) unlimited introduces self-gated rapid, radial MR imaging with continuous table movement for seamless coverage of the peripheral vasculature. In-vivo experiments in five healthy volunteers and two patients were performed. Initial results are more than promising and TOF unlimited demonstrates similar image quality compared to conventional ECG triggered TOF despite sevenfold accelerated data acquisition. Thus, novel TOF unlimited may be a time efficient screening tool for peripheral arterial disease.

Taehoon Shin¹, Qin Qin², Jang-Yeon Park^3,4, Robert S. Crawford⁵, and Sanjay Rajagopalan^6
1Diagnostic radioloy and nuclear medicine, University of Maryland, Baltimore, MD, United States, ²Radiology, Johns Hopkins University, Baltimore, MD, United States, ³Biomedical Engineering, Sungkyunkwan University, Suwon, Korea, Republic of, ⁴Center for neuroscience imaging research, Insititute for Basic Science, Suwon, Korea, Republic of, ⁵Vascular and endovascular surgery, University of Maryland, Baltimore, MD, United States, ⁶Cardiovascular Medicine, University of Maryland, Baltimore, MD, United States

Velocity-selective (VS) magnetization-prepared non-contrast-enhanced MR angiography has advantages of large 3D FOV, arbitrary 3D spatial resolution and need for single acquisition only. Peripheral VS-MRA has shown great potential at 1.5T but might be challenging at 3T due to large B0 and B1 inhomogeneity in the pelvis and legs. In this study, we show that the effects of B0 and B1 offsets are manifested as arterial signal loss, stripe artifact and background signal variation. We develop multiple-refocused VS excitation pulses and propose successive applications of two VS preparation pulses with shifted excitation profiles to suppress these artifacts.

Markus Henningsson¹ and Rene Botnar^1
1Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom

Image-based navigation (iNAV) is a promising respiratory motion correction approach for coronary MR angiography (CMRA). However, for dual-phase CMRA the technique may fail due to the different cardiac motion states of the systolic and diastolic acquisition. Here we propose the use of separate independent systolic and diastolic iNAV acquisitions to address this issue. We compared iNAV to the conventional diaphragmatic one-dimensional navigator (1D NAV) in 8 healthy subjects. The proposed technique achieves similar or improved coronary vessel sharpness compared to 1D NAV while reducing dual-phase CMRA acquisition time.

Ruth P Lim^1,2,3, Emma Hornsey¹, Dinesh Ranatunga^1,2, Huming Hao⁴, Lucy McKenna¹, Julie Smith¹, Tim Spelman⁵, Jason Chuen^3,4, and Mark Goodwin^1,2
1Radiology, Austin Health, Melbourne, Australia, ²Radiology, The University of Melbourne, Melbourne, Australia, ³Surgery, The University of Melbourne, Melbourne, Australia, ⁴Surgery, Austin Health, Melbourne, Australia, ⁵Centre for Population Health, Burnet Institute, Melbourne, Australia

Venous mapping is important in end stage renal disease patients requiring vascular access for hemodialysis. We compare image quality (IQ) and measured vessel caliber of FSE based non-contrast MRV  (NC-MRV) to contrast-enhanced MRV (CE-MRV) and US in available segments in 10 healthy volunteers.  Central and arm vein IQ was diagnostic, but forearm vein IQ was suboptimal, inferior to CE-MRV. No difference in vessel caliber between sequences was demonstrated for most segments between NC-MRV and CE-MRV, but both MRV techniques yielded significantly larger caliber measurements than US, raising concern regarding application of MRV-derived measurements to clinical practice.

Xiangyu Yang¹, Michael Miller², and Michael V Knopp^1
1Radiology, The Ohio State University, Columbus, OH, United States, ²Plastic Surgery, The Ohio State University, Columbus, OH, United States

Currently, MRA is not considered the optimal technique for preoperative imaging of perforators before flap reconstructive plastic surgeries. In this prospective study, we demonstrate that the quality of perforator MRA can be greatly enhanced by using the phase contrast technique. Perforator imaging with PC-MRA not only generates images with better quality and contrast than X-ray and iodinated contrast based CTA, the current clinical gold-standard, but also offers unique features, such as the capability to visualize venous flow and differentiate perforator arteries and veins, that are highly relevant to the design, planning, and execution of DIEP flap reconstructive surgery.  

Eleanor S K Berry¹, Peter Jezzard¹, and Thomas W Okell^1
1FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom

Vessel-encoded pseudo-continuous arterial spin labeling (VEPCASL) can be used to obtain vessel-selective time-resolved angiograms. Here we compare accelerated Cartesian and radial readouts to demonstrate the feasibility of speeding up their acquisition, enabling better prospects for use of the method in a clinical setting. It was possible to acquire 2D vessel-selective angiograms in less than one minute. Accelerated (undersampled) radial acquisition consistently led to angiograms with higher signal-to-noise ratio and better quality peripheral artery imaging versus accelerated Cartesian imaging.

Marc D Lindley^1,2, Daniel Kim², Kristi Carlston², Leif Jensen², Daniel Sommers², Ganesh Adluru², Edward VR DiBella², Christopher J Hanrahan², and Vivian S Lee^2
1Physics, University of Utah, Salt Lake City, UT, United States, ²Radiology, UCAIR, University of Utah, Salt Lake City, UT, United States

As an alternative to contrast-enhanced (CE) MRA, we developed an accelerated non-contrast MRA of thoracic aorta using a combination of T2-prepared and fat saturation preparations, b-SSFP readout, 3D radial stack of stars sampling with tiny golden angles, and compressed sensing. This NC-MRA was compared with standard ECG-gated CE-MRA in 8 patients. Normalized signal difference and aortic diameters were not significantly different between CE- and NC-MRA methods.

Amber Pokorney¹, Niccolo Stefani², Zhiqiang Li³, Jonathan M. Chia², John Condie⁴, Houchun Harry Hu¹, and Jeffrey H. Miller^1
1Radiology, Phoenix Children's Hospital, Phoenix, AZ, United States, ²Philips, North America, Cleveland, OH, United States, ³Barrow Neurological Institute, Phoenix, AZ, United States, ⁴Neurology, Phoenix Children's Hospital, Phoenix, AZ, United States

This pilot clinical study evaluates the diagnostic utility of a 3D spiral pCASL approach and a 3D dynamic PASL pulse sequence (i.e., CINEMA) in evaluating the neurovasculature in pediatric patients.  With increasing recent concerns over the possible deposition of Gadolinium in the brain, a viable clinical protocol that can supplant traditional contrast-enhanced MR angiography is particularly relevant to the pediatric population.  Our clinical results in patients ranging from 1 year of age to adolescents demonstrate that both 3D spiral pCASL and dynamic PASL are robust approaches and yield diagnostically useful information that supports clinical findings from conventional TOF angiography.      

Ioannis Koktzoglou^1,2, Marcos P Botelho^1,3, Shivraman Giri⁴, Amit Pursnani⁵, and Robert R Edelman^1,3
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²University of Chicago Pritzker School of Medicine, Chicago, IL, United States, ³Northwestern University Feinberg School of Medicine, Chicago, IL, United States, ⁴Siemens Healthcare, Chicago, IL, United States, ⁵Medicine, NorthShore University HealthSystem, Evanston, IL, United States

To describe a pseudocontinuous arterial spin-labeled quiescent-interval slice-selective (pCASL QISS) pulse sequence for vessel-selective nonenhanced MR angiography. 

Marc D Lindley^1,2, Daniel Kim², Kristi Carlston², Leif Jensen², Daniel Sommers², Ganesh Adluru², Edward VR DiBella², Christopher J Hanrahan², and Vivian S Lee^2
1Physics, University of Utah, Salt Lake City, UT, United States, ²Radiology, UCAIR, University of Utah, Salt Lake City, UT, United States

Quadruple inversion-recovery (QIR), non-contrast (NC) MRA was developed as an alternative to contrast-enhanced MRA, and it performance was evaluated in patients with peripheral arterial disease.  The scan time for QIR with respiratory gating, however, is on the order of 10-15 minutes. We sought to accelerate QIR using a combination of 3D radial stack-of-stars sampling with tiny golden angles and compressed sensing (CS). This study shows that 5.3-fold accelerated QIR with radial k-space sampling and CS produces images that are comparable to those produced by original QIR (e.g., 2.7-fold acceleration using GRAPPA). In 10 human subjects, normalized signal difference and vessel dimensions were not significantly different between original QIR and 5.3-fold accelerated QIR with radial k-space sampling and CS.

John Bisges¹, Scott K. Nagle¹, Christopher J. François¹, Peter Bannas², Michael D. Hope³, J. Paul Finn⁴, Karl Vigen¹, Thomas M. Grist¹, Scott B. Reeder¹, and Mark L. Schiebler^1
1Radiology, UW-Madison, Madison, WI, United States, ²Radiology, University of Hamburg-Eppendorf, Hamburg, Germany, ³Radiology, University of California at San Francisco, San Francisco, CA, United States, ⁴Radiology, University of California at Los Angeles, Los Angeles, CA, United States

The use of pulmonary magnetic resonance angiography (MRA) is playing an increasingly important role for the primary diagnosis of pulmonary  embolism (PE) and other causes of acute chest pain. We will define appropriate imaging  scenarios  for the clinical use of this test.  Then, using a pictorial essay approach, we will demonstrate the various imaging features that: (A)  directly indicates  the presence of PE; (2) indirectly suggests the presence of PE; (3) findings that directly show right heart strain; (4) indirect findings suggesting elevated central venous pressure and most importantly; (5) those findings that can mimic PE. After review of these teaching cases, imaging  physicians will be able to confidently make the diagnosis of PE on pulmonary MRA examinations.

Ana Beatriz Solana¹, Erin A. Paul², Ek Tsoon Tan³, Amee M. Shah², Wyman W. Lai², Christopher J. Hardy³, and Anjali Chelliah^2
1GE Global Research, Garching bei Muenchen, Germany, ²Dept of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital of New York, New York, NY, United States, ³GE Global Research, Niskayuna, NY, United States

Phase contrast (PC) MR flow measurements are affected by multiple sources of error, including background phase offsets.  The gold-standard approach to correct these offsets involves repeating PC measurements on a static phantom, prolonging each CMR study and impeding exam workflow. Here, we compared the performance of a self-calibrated correction to static-phantom corrected PC data obtained from a pediatric and congenital heart disease population. Self-calibrated correction results showed strong agreement with phantom-corrected data for all vessel types and differed from static-phantom correction by a mean difference in Qp/Qs values of only 0.069. 

Rene Bastkowski¹, Kilian Weiss^1,2, David Maintz¹, and Daniel Giese^1
1Department of Radiology, University Hospital of Cologne, Cologne, Germany, ²Philips Healthcare, Hamburg, Germany

A novel method based on single-voxel-spectroscopy (PRESS) for the analysis and correction of eddy-current induced artefacts in spiral phase-contrast MRI is presented. It is demonstrated, that 0th and 1st order corrections result in residual background offsets of less than 0.5cm/s, inherently correcting for geometrical misalignments between flow acquisitions as well as 2nd order spatial phase offsets. The method does not require special hardware and can be applied as a pre-scan.

Fatih Suleyman Hafalir^1,2, Ana Beatriz Solana², Peng Lai³, Malek Makki⁴, Anja C.S. Brau⁵, Axel Haase¹, and Martin A. Janich^2
1Technischen Universität München, Munich, Germany, ²GE Global Research, Munich, Germany, ³GE Healthcare, Menlo Park, CA, United States, ⁴MRI Research Center, University Children Hospital, Zurich, Switzerland, ⁵GE Healthcare, Munich, Germany

4D flow MRI is a powerful tool for visualization and quantification of blood flow. Repeated acquisition of 4 echoes with different velocity encoding is needed to measure flow in 3D. In this study, we propose a new ktv-ARC reconstruction by incorporating correlations between velocity encoded echoes (v) to the spatiotemporal correlations (kt). The error behavior of the method was analyzed on retrospectively undersampled in vivo cardiac data and resulted in more accurate velocity images with ktv-ARC compared to kt-ARC. 

Jesús Urbina^1,2, Julio Sotelo^1,3, Cristian Montalba¹, Felipe Valenzuela^1,3, Cristián Tejos^1,3, Pablo Irarrázaval^1,3, Marcelo Andia^1,4, Israel Valverde^5,6, and Sergio Uribe^1,4
1Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ²School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, ³Electrical Engineering Department, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁴Radiology Department, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁵Pediatric Cardiology Unit, Hospital Virgen del Rocio, Seville, Spain, ⁶Institute of Biomedicine of Seville, Universidad de Sevilla, Seville, Spain

The aim of this work was to evaluate the accuracy of relative pressures obtained from 3D PC-MRI in a realistic aortic phantom with different grades of aortic coarctations at rest and stress conditions. We also evaluated the accuracy of the relative pressures when subjected to different aortic segmentation and spatial resolutions. The accuracy of the 3D PC-MRI is excellent compared with catheterization values with mild to moderate AoCo at rest and stress conditions. Also, relative pressures were in excellent accuracy with catheterization values when the aortic segmentation only included laminar flow and with higher spatial resolution at rest and stress conditions. However, its accuracy decreases for severe AoCo cases.

Pim van Ooij¹, Merih Cibis², Wouter V. Potters¹, Oscar H Franco³, Meike Vernooij⁴, Aad van der Lugt⁴, Frank J Gijsen², Jolanda J Wentzel², and Aart J Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Biomedical Engineering, Erasmus MC, Rotterdam, Netherlands, ³Epidemiology, Erasmus MC, Rotterdam, Netherlands, ⁴Radiology, Erasmus MC, Rotterdam, Netherlands

The purpose of this study is to investigate if, already in early disease, a correlation exists between wall thickness (WT) and wall shear stress (WSS) in the carotid bifurcation. Eleven subjects with plaques in the left carotid arteries underwent 3D-flow-MRI and proton-density-weighted-EPI for WSS and WT quantification, respectively. Relationships between WT and WSS were investigated on an individual basis and using cohort-averaged maps (atlases). Spearman’s ρ averaged over all subjects was -0.28, which was significantly different from 0 (p<0.001). For the atlases, ρ was -0.66 (p<0.001). The atlas approach facilitates more statistical power to show that wall thickening occurs in low WSS regions.

Dahan Kim^1,2, Carson Hoffman¹, Oliver Wieben^1,3, and Kevin M. Johnson^1
1Department of Medical Physics, University of Wisconsin, Madison, WI, United States, ²Department of Physics, University of Wisconsin, Madison, WI, United States, ³Department of Radiology, University of Wisconsin, Madison, WI, United States

In this work, we examined the feasibility of registering 4D-flow MRI scans with different scan sequences, and demonstrate how the incorporation of complementary, registered data can enhance characterization of hemodynamic information. Black blood (BB) and 4D-flow magnitude images demonstrated excellent registration between the pre- and post-rotation data sets, with high values of correlation and good overlap of the vessels between head rotation. Joint visualization of aneurysm 4D flow and BB shows accurate lesion depiction only after registration and is a promising technique for the comprehensive evaluation of vascular pathology.

Aiqi Sun¹, Bo Zhao², Yunduo Li¹, Qiong He¹, Zechen Zhou¹, Shuo Chen¹, Rui Li¹, and Chun Yuan^1,3
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua Universiy, Beijing, China, People's Republic of, ²Martinos Center for Biomedical Imaging, Harvard Medical School, Chalestown, MA, United States, ³Department of Radiology, University of Washington, Seattle, WA, United States

Conventional phase-contrast (PC) MRI method relies on ECG-synchronized cine acquisition to acquire data over multiple cardiac cycles. The underlying spatiotemporal averaging limits this method to studying pathological irregularities. Real-time PC-MRI is a promising approach to overcome these limitations. Although several techniques have been developed to real-time PC-MRI, few have been fully validated due to the difficulty of acquiring a reference data set as gold standard. This study aims at validating the accuracy of a novel real-time PC-MRI technique through both flow phantom experiments and in vivo experiments. 

Eva S. Peper¹, Wouter V. Potters¹, Bram F. Coolen¹, Henk A. Marquering¹, Gustav J. Strijkers¹, Pim van Ooij¹, and Aart J. Nederveen^1
1Radiology, Academic Medical Center (AMC), Amsterdam, Netherlands

Flow MRI of the carotid arteries has emerged as an important imaging field during the last decade and has been shown valuable for the assessment of hemodynamics in the context of atherosclerosis. In this study a 2D flow acquisition was accelerated using random undersampling and compressed sensing reconstruction. For validation of the reconstructed flow a phantom experiment was performed at different acceleration factors followed by an in vivo scan of the carotid arteries.

Christopher J Francois¹, Zachary Borden¹, Sylvana Garcia-Rodriguez¹, Jon Wrobel¹, and Alejandro Roldan-Alzate^1
1Radiology, University of Wisconsin - Madison, Madison, WI, United States

This study investigated the effects of 3D printing technology on flow rates in patient-specific total cavo-pulmonary connection models. 4D flow MRI was used to quantify flow through the Fontan, Glenn, left pulmonary artery and right pulmonary artery in three models at four different flow rates. No statistically significant differences in flow in any of the regions of interest were observed.

Hideki Ota¹, Koichiro Sugimura², Haruka Sato², Yuta Urushibata³, Yoshiaki Komori³, Hiroaki Shimokawa², and Kei Takase^1
1Diagnostic Radiology, Tohoku University Hosipital, Sendai, Japan, ²Cardiovascular Medicine, Tohoku University Hosipital, Sendai, Japan, ³Research&Collaborations, Siemens Japan KK, Tokyo, Japan

Etiologies of pre-capillary pulmonary hypertension may be associated with pulmonary arterial hemodynamics. This study included 64 patients (pulmonary arterial hypertension [PAH], 25, chronic thromboembolic pulmonary hypertension [CTEPH], 39) who underwent 4D flow and cardiac MR imaging. Backward flow ratio and forward flow eccentricity in the pulmonary trunk as assessed by 4D flow MR and several cardiac MR parameters were different between two diseases. After controlling for age and mean pulmonary arterial pressure, backward flow ratio was the strongest differentiator of PAH from CTEPH.  4D flow has a potential to visualize different pulmonary arterial hemodynamics according to etiologies in pulmonary hypertension.

Sylvana García-Rodríguez¹, Jon Wrobel¹, Alejandro Roldán-Alzate^1,2, and Christopher J. François^1
1Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, United States

The effects of MRI-derived three-directional velocity profiles implemented at the inlet of aortic dissection (AD) computational fluid dynamics (CFD) simulations were investigated. Two AD models were generated from in vivo MRA data using 3D printing. In vitro 4D Flow MRI was performed on the AD phantoms at two flow rates. Normal and multidirectional blood flow vectors at the AD inlet was measured from 4D Flow MRI data and used in CFD simulations. Significant differences were found in pressure distribution in response to inlet boundary condition definitions. Peak velocity and wall shear stress were also affected by inlet condition definition.

Joshua Daniel Robinson^1,2, Cynthia K Rigsby^3,4, Michael Rose³, Susanne Schnell⁴, Alex J Barker⁴, and Michael Markl^4,5
1Pediatric Cardiology, Ann & Robert H Lurie Children's Hospital, Chicago, IL, United States, ²Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, United States, ³Medical Imaging, Ann & Robert H Lurie Children's Hospital, Chicago, IL, United States, ⁴Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States, ⁵McCormick School of Engineering, Northwestern University, Evanston, IL, United States

Tetralogy of Fallot (TOF) is the most common form of cyanotic heart disease. As life expectancy continues to increase, MRI plays a central role in evaluation for post-operative complications and reintervention. Current assessment is based on simplified parameters that measure late expression of underlying physiologic changes, with poor outcome prediction. In this study, we explore quantitative 4D flow metrics which may be important measures of hemodynamic efficiency. We found that energetic metrics are abnormal in TOF compared to healthy controls. While these metrics correlated only modestly with routine measurements of ventricular efficiency, they may represent earlier biomarkers of disease progression.

Jing Liu¹, Yan Wang¹, Farshid Faraji¹, Sarah Kefayati¹, Henrik Haraldsson¹, and David Saloner^1,2
1University of California San Francisco, San Francisco, CA, United States, ²VA Medical Center, San Francisco, CA, United States

A highly accelerated 4D flow MRI method with a high tempospatial resolution has been validated in healthy volunteers by comparing to the conventional method. The proposed method been demonstrated to be very promising for imaging the patients with intracranial aneurysms, by achieving an isotropic resolution of 1.3mm and a temporal resolution of 26ms within a 5-minute scan time (R=12). 

Peng Lai¹, Ann Shimakawa¹, Joseph Yitan Cheng², Marcus T Alley², Shreyas S Vasanawala², and Anja C.S Brau^3
1Global MR Applications and Workflow, GE Healthcare, Menlo Park, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States, ³Global MR Applications and Workflow, GE Healthcare, Munich, Germany

Cardiac 4D Flow suffers from blood signal saturation due to whole-volume imaging and limited accuracy if acquired without contrast agents. This work developed and investigated a new multiple thin slab scheme for non-contrast whole-chest 4D Flow. With in-flow enhancement and bright blood, the new sequence provides higher SNR and motion robustness than conventional 4D Flow. The proposed radial golden angle view order ensures smooth slab merging that is insensitive to cardiac and respiratory variations during the scan.

SEAN KUMAR SETHI¹, Giacomo Gadda², Ana M. Daugherty³, David T. Utriainen¹, Jing Jiang¹, Naftali Raz³, and Ewart Mark Haacke^4
1The MRI Institute of Biomedical Research, Detroit, MI, United States, ²Physics, University of Ferrara, Ferrara, Italy, ³Department of Gerontology, Wayne State University, Detroit, MI, United States,⁴Biomedical Engineering, Wayne State University, Detroit, MI, United States

We have established in previous works that a subset of multiple sclerosis (MS) patients show abnormal structure and flow in the internal jugular veins (IJV) when measured with MRI. In this retrospective analysis, we classified and compared extracranial venous collateral flow in MS and normal control samples using MR venography and Phase-contrast flow quantification with a large, standardized dataset. Over 50% of the MS cohort shows a jugular anomaly. The stenotic-MS group shows reduced Type I venous flow compared to healthy controls and non-stenotic MS, while having elevated Type II and Type III flows.

Patrick Magrath^1,2, Eric Aliotta^1,3, Shams Rashid¹, Yutaka Natsuaki⁴, Xiaoming Bi⁴, Zhe Wang^1,2, Kyung Sung^1,2,3, Peng Hu^1,2,3, Holden Wu^1,2,3, and Daniel B Ennis^1,2,3
1Department of Radiological Sciences, University of California, Los Angeles, CA, United States, ²Department of Bioengineering, University of California, Los Angeles, CA, United States, ³Physics and Biology in Medicine IDP, University of California, Los Angeles, CA, United States, ⁴Siemens Healthcare, Los Angeles, CA, United States

4D-flow MRI is used to quantify blood flow in a variety of neurovascular pathologies including intracranial aneurysms [1], but is limited by long scan times as well as moderate spatial and temporal resolution. Conventional RF pulses have poor slab profiles that contribute to low sequence efficiency by increasing the field-of-view needed to avoid aliasing in the slab direction. Our objectives were to design a minimum time, high Time Bandwith Product (TBW) VERSE pulse for 4D flow and to validate the improvement in sequence efficiency, confirm flow accuracy, and evaluate total SAR deposition for VERSE+4D-flow compared to our clinical 4D flow imaging protocol.

Joseph Y. Cheng¹, Tao Zhang¹, Adam B. Kerr², Michael Lustig³, John M. Pauly², and Shreyas S. Vasanawala^1
1Radiology, Stanford University, Stanford, CA, United States, ²Electrical Engineering, Stanford University, Stanford, CA, United States, ³Electrical Engineering & Computer Sciences, University of California, Berkeley, CA, United States

Volumetric time-resolved velocity imaging (4D flow) can be used as a single comprehensive sequence to quantify blood flow, evaluate cardiac function, and assess anatomy. However, fat signal can reduce tissue contrast, introduce high-signal-intensity artifacts from motion, and cause errors in velocity quantification. Two approaches are presented for reducing fat signal in contrast-enhanced 4D flow imaging with minimal time penalty. The first approach is a short spectral-spatial RF pulse that reduces fat signal below the level of contrast-enhanced blood pool. The second approach is the introduction of one additional echo with a different TE to separate fat/water for all flow encoding echoes. The performance of these approaches are evaluated in a static phantom study and in patient volunteer studies. 

Pim van Ooij¹, Matthan Caan¹, Bart M. W. Cornelissen², Henk A Marquering², Pieter Buur³, Gustav J Strijkers², Jeroen Hendrikse⁴, and Aart J Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands, ³Spinoza Center for Neuroimaging, Amsterdam, Netherlands, ⁴Radiology, University Medical Center Utrecht, Utrecht, Netherlands

In this study it was investigated if the communicating arteries redistribute blood flow in the circle of Willis (coW) with hypoplastic arteries. For this purpose, 4D flow MRI at 7 Tesla was used in ten healthy volunteers. 50% of the participants had a full coW, whereas 50% had hypoplastic or missing segments. Significant correlations were found for time-averaged blood flow (mL/s) between the left /right posterior communicating artery and the left/right posterior cerebral artery and between the anterior communicating artery and the right anterior cerebral artery. This finding illustrates that flow is redistributed through the communicating arteries in the coW.

Roel LF van der Palen^1,2, Alex J Barker², Emilie Bollache², Michael J Rose³, Pim van Ooij⁴, Julio Garcia², Luciana Young⁵, Arno AW Roest¹, Michael Markl^2,6, Cynthia K Rigsby³, and Joshua D Robinson^5,7
1Department of Pediatric Cardiology, Willem-Alexander Children and Youth Center, Leiden University Medical Center, Leiden, Netherlands, ²Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States, ³Department of Medical Imaging, Ann & Robert Lurie Children’s Hospital of Chicago, Chicago, IL, United States, ⁴Department of Radiology, Academic Medical Center, Amsterdam, Netherlands, ⁵Division of Pediatric Cardiology, Ann & Robert Lurie Children’s Hospital of Chicago, Chicago, IL, United States, ⁶Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, IL, United States, ⁷Department of Pediatrics, Ann & Robert Lurie Children’s Hospital of Chicago, Chicago, IL, United States

Marfan syndrome (MFS) is a connective tissue disease with high risk of aortic dissection/rupture. Two-thirds of dissections occur in the ascending aorta, one-third in the descending aorta. Diameter plays an important role in risk stratification. However, recent literature has shown diameter only accounts for 50% of the dissections in the descending aortic region. It is not well known how aortic hemodynamics interact with the altered vascular structure of these aortas and how it may impact dilatation. A cohort of MFS children and an age appropriate control group were evaluated with 4D flow MRI: already distinct abnormalities are present in childhood.

Prem Venugopal¹, Ek Tsoon Tan¹, Peter Lamb¹, Christopher J Hardy¹, and Thomas K Foo^1
1GE Global Research, Niskayuna, NY, United States

Pulse wave velocity (PWV) is a commonly used surrogate for arterial stiffness. This abstract describes a new method to estimate arterial PWV by using MRI phase-contrast data to tune a 1D blood flow model describing the hemodynamics and propagation of the arterial pulse wave. Results obtained in a single volunteer indicate that the proposed approach could be used with low time resolution methods such as 4D Flow MRI to obtain PWV in the aorta with much lower variability than the foot-to-foot method.

Eva S. Peper¹, Qinwei Zhang¹, Bram F. Coolen², Wouter V. Potters¹, Pim van Ooij¹, Dennis W.J. Klomp³, and Aart J. Nederveen^1
1Radiology, AMC, Amsterdam, Netherlands, ²Biomedical Engineering and Physics, AMC, Amsterdam, Netherlands, ³Radiology, UMCU, Utrecht, Netherlands

Using a novel 15 channel coil for carotid artery imaging we could prove that the g-factor loss at higher acceleration factors is limited. This permits the use of higher parallel imaging factors than commonly exploited in carotid MRI. A 4D flow scan at high spatiotemporal resolution was accelerated 10 fold (SENSE 4 x 2.5), resulting in high quality images and consistent flow values acquired in a scantime as short as 7 min.

Masataka Sugiyama¹, Yasuo Takehara², Hatsuko Nasu¹, Shuhei Yamashita¹, Mika Kamiya¹, Nobuko Yoshizawa¹, Yuki Hirai¹, Takasuke Ushio¹, Naoko Hyodo¹, Yohei Ito¹, Naoki Oishi², Marcus Alley³, Tetsuya Wakayama⁴, and Harumi Sakahara^1
1Radiology, Hamamatsu University School of Medicine, Hamamatsu, Japan, ²Radiology, Hamamatsu University Hospital, Hamamatsu, Japan, ³Department of Radiology, Stanford University School of Medicine, Stanford, CA, United States, ⁴Applied Science Laboratory Asia Pacific, GE Healthcare Japan, Hino, Japan

3D cine PC MRI (4D-flow) study of abdominal aorta was conducted to measure wall shear stress (WSS) and to characterize aortic blood flow dynamics within saccular and fusiform abdominal aortic aneurysm and non-dilated aorta.  Peak systolic WSS was significantly lower within saccular aneurysm, and stream line analysis depicted  separated vortex flow within the saccular aneurysm.  The abnormal vortex flow and consequent low WSS of saccular aneurysmal wall may be reflecting the continuing risk of atherogenic changes of the saccular aneurysm in contrast to fusiform aneurysm.

Rouzbeh R Ahmadian¹, Austin P Boyd², Jeremy D Collins¹, James C Carr¹, Alex J Barker¹, and Michael Markl^3
1Radiology, Northwestern University, Chicago, IL, United States, ²Northwestern University, Chicago, IL, United States, ³Radiology & Biomedical Engineering, Northwestern University, Chicago, IL, United States

The advent of 3D printing has opened exciting possibilities for biomedical applications. One of the most intriguing of these possibilities is the ability to use images obtained from radiology scanners (CT or MR) to create 3D models of patient anatomy followed by 3D printing. These models will have all the same geometries of patient anatomy to very high detail. In order to have practical applications, however, these 3D models need to behave similarly to human tissue under standard conditions. Our research utilizes patient-specific 3D printed models in an in vitro fluid dynamic circuit to compare 4D Flow MRI data to that of the patient (in vivo). This direct comparison will allow for validation of the 3D printed model for further biomedical application. 

Julio Garcia¹, Silvia Hidalgo Tobon^2,3, Guadalupe Sagaon Rojas⁴, Benito de Celis Alonso⁵, Manuel Obregon², Porfirio Ibanez², Julio Erdmenger⁶, and Pilar Dies-Suarez^2
1Radiology, Northwestern University, Chicago, IL, United States, ²Investigacion en Imagen y Resonancia Magnetica Nuclear, Hospital Infantil de Mexico Federico Gomez, Mexico City, Mexico, ³Physics, Universidad Autonoma Metropolitana, Mexico, Mexico, ⁴Physics, Universidad Autonoma Metropolitana, Mexico City, Mexico, ⁵Faculty of Physics and Mathematics, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico, ⁶Pediatric Cardiology, Hospital Infantil de Mexico Federico Gomez, Mexico City, Mexico

Flow alterations in the pulmonary artery (PA) of patients with repaired tetralogy of Fallot (rTOF) may be link with elevated kinetic energy (KE). 4D flow MRI allows for the non-invasive volumetric assessment of flow hemodynamics, vorticity, and KE in patients with rTOF in the pulmonary (PA). Thus, the aim was to investigate the impact of flow alterations in the PA and its association with KE and vorticity.