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

Scientific Session: MR Angiography

Friday, May 13, 2016
Room 300-302
08:00 - 10:00
Moderator: Dariusch Hadizadeh

Time-Resolved Non-Contrast-Enhanced MR Angiography with Static Tissue Suppression using Velocity-Selective Pulse Trains - Permission Withheld
Qin Qin1,2, Guanshu Liu1,2, Ye Qiao1, and Dexiang Liu1,2,3
1Radiology, Johns Hopkins University, Baltimore, MD, United States, 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 3Radiology, Panyu District Central Hospital, Guangzhou, China, People's Republic of
Time-resolved non-contrast-enhanced MR angiography (NCE-MRA), by providing hemodynamic flow patterns, is promising for many vascular disorders. Conventional techniques remove tissue background using various arterial spin labeling (ASL) approaches with paired subtraction of control and label scans. Here a new multi-phase MRA method is introduced that achieves background suppresstion by applying a tissue mask, which is derived from thresholding a velocity-selective MRA (VSMRA) obtained at the end of the cycle. The feasibility of this new single-scan dynamic approach was demonstrated on extracranial and intracranial vasculatures of healthy volunteers at 3T. 

Nonenhanced hybridized arterial spin-labeled magnetic resonance angiography of the extracranial carotid arteries at 3 Tesla using a fast low-angle shot readout
Ioannis Koktzoglou1,2, Matthew T Walker1,2, Joel R Meyer1,2, Ian G Murphy1,3, and Robert R Edelman1,3
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
Nonenhanced hybridized arterial spin labeling (hASL) magnetic resonance angiography (MRA) using a fast low-angle shot (FLASH) readout was used to image the extracranial carotid arteries at 3 Tesla. Comparisons were made with 2D time-of-flight (TOF) MRA and contrast-enhanced MRA. Image quality obtained hASL FLASH MRA was found to be superior to that 2D TOF, with the method also providing improved inter-rater agreement, quantification of arterial cross-sectional area, and vessel sharpness.

Isotropic 3D Black Blood MRI of Abdominal Aortic Aneurysm: Comparison with CT Anigography
Chengcheng Zhu1, Bing Tian2, Florent Seguro1, Joe Leach1, Qi Liu2, Jianping Lu2, Luguang Chen2, Michael Hope1, and David Saloner1
1Radiology, University of California, San Francisco, San Francisco, CA, United States, 2Radiology, Changhai Hospital, Shanghai, China, People's Republic of
Computed Tomography angiography (CTA) is the gold standard for abdominal aortic aneurysm (AAA) imaging, but requires radiation and iodinated contrast. We previously developed an isotropic 3D black blood technique (DANTE-SPACE) for AAA imaging. In this study we validated 3D MRI against CTA for AAA diameter and volume measurement, and found excellent accuracy and reproducibility. Features of intra-luminal thrombus (ILT) composition that are possibly related to faster AAA growth can be identified on 3D MRI but not on CTA. 3D black blood MRI can be used as a non-invasive tool for AAA serial monitoring and ILT evaluation and has the potential to improve patient risk stratification. 

High Resolution MRI for Characterization of Inflammation within Abdominal Aortic Aneurysm
Chengcheng Zhu1, Thomas Hope1, Henrik Haraldsson1, Farshid Faraji1, David Saloner1, and Michael Hope1
1Radiology, University of California, San Francisco, San Francisco, CA, United States
Abdominal aortic aneurysms (AAAs) with focal inflammation (identified by USPIO uptake) have been reported to predict faster growth. Previous 2D T2* mapping method is limited by spatial resolution. This study evaluated 3D high-resolution techniques (up to 1.3mm isotropic) for inflammation imaging of AAAs. Experiments were preformed using both USPIO phantoms and in vivo patient studies. We found the signal characteristics of 3D DANTE-SPACE images had good agreement with T2* value drop, and it provided higher resolution and possible information on USPIO concentration. Therefore, 3D high resolution methods may help risk stratify patients with AAA disease by characterizing and quantifying inflammation.

Robust large-volume fat suppression in whole-heart free-breathing self-navigated coronary MR angiography at 3T using lipid insensitive binomial off-resonant excitation (LIBRE) pulses
Jessica AM Bastiaansen1, Davide Piccini1,2, Ruud B van Heeswijk1,3, and Matthias Stuber1,3
1Department of Radiology, University hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 2Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, 3Center for Biomedical Imaging, Lausanne, Switzerland
Large volume fat suppression is increasingly challenging at high magnetic field strengths due to B0 and B1 inhomogeneities. In this study, we developed a novel lipid-insensitive binomial off-resonant (LIBRE) radiofrequency excitation pulse to achieve near-complete fat suppression in large 3D volumes and applied it to whole-heart coronary imaging at 3T. In 6 healthy volunteers, we performed free-breathing self-navigated whole-heart 3D radial coronary MRA, and quantitatively compared the results to more commonly used methods for lipid nulling. We show that LIBRE significantly improves the signal nulling of lipid resonances resulting in both improved blood pool delineation for self-navigation and increased vessel conspicuity in the final images.

An Iterative Approach to Respiratory Self-Navigation Allows for Improved Image Quality and 100% Scan Efficiency in Contrast-Enhanced Inversion-Recovery Whole-Heart Coronary MRA at 3T; a First Patient Study
Giulia Ginami1, Davide Piccini1,2, Pierre Monney3, Pier Giorgio Masci3, and Matthias Stuber1,4
1University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland, 2Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, 3Division of Cardiology and Cardiac MR Center, University Hospital of Lausanne (CHUV), Lausanne, Switzerland, 4Center for Biomedical Imaging (CIBM), Lausanne, Switzerland
The performance of Self-Navigation (SN) for respiratory motion compensation in 3T whole-heart coronary MRA may be compromised by contrast variations secondary to slow-infusion of a contrast agent. In this study, we quantitatively and successfully tested the hypothesis that an Iterative approach to SN (IT-SN) leads to improved performance during slow infusion.

Six month clinical outcomes following pulmonary contrast enhanced magnetic resonance angiography for the primary workup of pulmonary embolism
Mark L. Schiebler1, Michael D. Repplinger2, Christopher Lindholm3, John Harringa2, Christopher J. François1, Karl K. Vigen1, Azita G. Hamedani2, Thomas M. Grist1,4,5, Scott B. Reeder1,2,4,6, and Scott K. Nagle1,5,7
1Radiology, UW-Madison, Madison, WI, United States, 2Emergency Medicine, UW-Madison, Madison, WI, United States, 3UW Madison School of Medicine, UW-Madison, Madison, WI, United States, 4Biomedical Engineering, UW-Madison, Madison, WI, United States, 5Medical Physics, UW-Madison, Madison, WI, United States, 6Medicine, UW-Madison, Madison, WI, United States, 7Pediatrics, UW-Madison, Madison, WI, United States
The aim of this study was to determine the effectiveness of pulmonary magnetic resonance angiography (PE-MRA) for the primary diagnosis of pulmonary embolism (PE). We retrospectively reviewed the electronic medical records of 675 consecutive patients who underwent PE-MRA. Adverse events (venous thromboembolism (VTE), bleeding or death) that were potentially related either to  over or under treatment of PE during the subsequent 6 months  were extracted from the electronic medical record. The negative predictive value for this test was found to be 97%. Based upon these outcomes, PE-MRA performs similarly to CTA as a primary test to exclude clinically significant pulmonary embolism in patients presenting acutely with dyspnea.

Model-based characterization of the transpulmonary circulation by DCE-MRI
Salvatore Saporito1, Ingeborg H.F. Herold 1,2, Patrick Houthuizen3, Jacques A. den Boer1, Harrie C.M. van den Bosch4, Hendrikus H.M. Korsten 1,2, Hans C. van Assen1, and Massimo Mischi1
1Department of Electrical Engineering, Eindhoven University of technology, Eindhoven, Netherlands, 2Department of Anesthesiology and Intensive Care, Catharina Hospital Eindhoven, Eindhoven, Netherlands,3Department of Cardiology, Catharina Hospital Eindhoven, Eindhoven, Netherlands, 4Department of Radiology, Catharina Hospital Eindhoven, Eindhoven, Netherlands
Objective measures to assess pulmonary circulation status would improve heart failure patient care. We propose a method for the characterization of the transpulmonary circulation by DCE-MRI. Parametric deconvolution was performed between contrast agent first passage time-enhancement curves derived from the right and left ventricular blood pool. The transpulmonary circulation was characterized as a linear system with impulse response modelled as local density random walk model. We tested the method on 32 heart failure patients and 19 healthy volunteers; patients presented longer transpulmonary transit times and more skewed transpulmonary impulse responses.

Predictive Bolus Tailoring of Gd-Based Contrast Agents for Optimized Contrast-Enhanced MRA
Jeffrey H Maki1 and Gregory J Wilson1
1Radiology, University of Washington, Seattle, WA, United States
Gadolinium contrast for CE-MRA is typically injected at a fixed, relatively fast (1.5 – 2.0 mL/s) rate.  This results in a peaked bolus profile such that vascular signal intensity (SI) decays during latter k-space acquisition, leading to blurring and ringing artifacts.  A “tailored” test bolus-based predictive algorithm was developed to determine a patient-individualized multi-phase injection to achieve any arbitrary arterial SI “plateau” duration.  This technique was tested on 10 patients and compared to 10 patients receiving a fixed 1.6 mL/s contrast injection.  The tailored bolus plateau duration was 24 vs. 9 s (p < 0.01) with only a 20% SI loss.

Cardiac and Respiratory Self-Gated 4D Multi-Phase Steady-State Imaging with Ferumoxytol Contrast (MUSIC)
Fei Han1, Ziwu Zhou1, Takegawa Yoshida1, Kim-Lien Nguyen1,2, Paul J Finn1, and Peng Hu1
1Radiology, University of California, Los Angeles, Los Angeles, CA, United States, 2Division of Cardiology, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, CA, United States
We proposed a cardiac and respiratory self-gated, 4D multi-phase steady-state imaging with contrast (MUSIC) technique for detailed evaluation of cardiovascular anatomies. A rotating cartesian k-space sampling pattern was designed that integrates frequently sampled k-space centerline as self-gating signal and allows retrospective data-binning based on derived motion signal. Phantom and in-vivo results on 7 clinical indicated pediatric CHD patients show that the proposed self-gated MUSIC could potentially eliminates the need of external physiological signal for motion gating, has increased scan efficiency while maintaining or exceeding the image quality of the original MUSIC.

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