Non-Contrast & Contrast-Enhanced MRA
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Monday May 9th
Room 511D-F  14:00 - 16:00 Moderators: Tim Leiner and Mitsue Miyazaki

14:00 84.   Introduction: Contrast-Enhanced MRA: Relic of the Past or Alive & Kicking?
Jeffrey H. Maki


14:12 85.   Simultaneous MR Angiography and Perfusion (MRAP): Application in Lower Extremity MRA and Skeletal Muscle Perfusion  
Katherine L Wright1,2, Nicole Seiberlich2,3, John A Jesberger2, Raymond F Muzic1,3, Mark A Griswold1,3, and Vikas Gulani2,3
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States, 2Case Center for Imaging Research, Case Western Reserve University, Cleveland, Ohio, United States, 3Department of Radiology, University Hospitals, Cleveland, Ohio, United States

Complete evaluation of both large and small vessel status would typically require two separate contrast enhanced acquisitions: MR angiography and dynamic contrast enhanced (DCE) perfusion. Both the MRA and quantitative DCE perfusion could be obtained simultaneously if a 3D time-resolved contrast enhanced data set could be acquired in a manner that the contrast and spatial/temporal resolution requirements for both exams could be met. This study demonstrates feasibility and repeatability of simultaneous MRA and perfusion (MRAP) with a time resolved MRA acquisition, and initial application for leg angiography and quantitative skeletal muscle perfusion at rest and following a physiological stimulus (exercise).

14:24 86.   4D PC MR of the portal venous system: Benefits of using a Blood Pool Contrast Agent 
Benjamin Landgraf1, Alex Frydrychowicz1, Kevin Johnson2, Alejandro Roldan1, Chris Francois1, Scott Reeder1,2, and Oliver Wieben2
1Radiology, University of Wisconsin - Madison, Madison, WI, United States, 2Medical Physics, University of Wisconsin - Madison, Madison, WI, United States

This study aims to determine the effects of intravascular contrast agent on radially encoded velocity mapping MRI on the quality of visualization of the portal venous vasculature. While imaging without a contrast agent provides good image quality, examination of vessel signal and diagnostic quality of vasculature in derived angiograms from human volunteer after contrast administration shows greatly improved image quality and visualization of distal branches of the portal vasculature.

14:36 87.   Comparison of CAPR MRA with CT Angiography for Evaluation of Below the Knee Runoff: Preliminary Results of Radiologist Confidence 
Phillip Young1, James F Glockner1, Terri R Vrtiska2, Thanila Macedo2, Petrice Mostardi2, and Stephen J Riederer2
1Radiology, Mayo Clinic, Rochester, MN, United States, 2Mayo Clinic

We describe initial results of a comparison of radiologist confidence in evaluating CAPR MRA and CTA for below the knee runoff in clinical patients. CAPR MRA demonstrates significantly higher radiologist confidence for distal vessels than CTA

14:48 88.   ECG-gated First-pass Contrast-enhanced Magnetic Resonance Angiography of the Thorax - Initial Experience in Healthy Volunteers and Patients  -permission withheld
Moritz Wagner1,2, Yutaka Natsuaki2,3, Bernd Hamm1, Gerhard Laub2,3, and Paul Finn2
1Radiology, Charite - University Hospital, Berlin, Germany, 2Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, United States, 3Siemens Healthcare, United States

Our study presents a novel ECG gated first-pass CEMRA sequence which reads out central k-space data during the cardiac resting phase while the overall center of k-space was made to coincide with peak arterial enhancement. The improved data acquisition efficiency of the ECG-gated first-pass CEMRA allowed for high resolution imaging of the entire thorax. We report initial data of ECG-gated first-pass CEMRA in healthy volunteers and patients.

15:00 89.   Incidental Venous Thrombosis as Detected by Magnetic Resonance Thrombus Imaging in 245 Patients with Suspected Peripheral Arterial Disease Using a Blood Pool Contrast Agent  -permission withheld
Dariusch Reza Hadizadeh1, Guido M Kukuk1, Ute L Fahlenkamp1, Jürgen Gieseke1,2, Frank Träber1, Josephine Pressacco3, Christian Schäfer4, Eberhard Rabe5, Arne Koscielny6, Frauke Verrel6, Hans H Schild1, and Winfried A Willinek1
1Radiology, University of Bonn, Bonn, NRW, Germany, 2Philips Healthcare, Best, Netherlands, 3Radiology, Montreal Heart Institute, Montreal, Quebec, Canada, 4Internal Medicine II, Division of Cardiology, Pneumology, and Angiology, University of Bonn, Bonn, NRW, Germany, 5Dermatology, Division of Phlebology, University of Bonn, Bonn, NRW, Germany, 6Vascular Surgery, University of Bonn, Bonn, NRW, Germany

Synopsis: High-spatial resolution contrast-enhanced-MRA of the run-off vessels during the equilibrium phase of blood-pool contrast agents (SSMRA) has been shown to increase sensitivity and specificity in stenosis grading of the arterial vasculature. The simultaneous visualization of veins allows for diagnosis of important additional venous findings that may affect therapeutic regimen. Acute and chronic deep venous thrombosis was diagnosed in 26 of 245 patients of patients with peripheral arterial occlusive disease and was confirmed by duplex ultrasound.

15:12 90.   Acceleration Dependent Vascular Anatomy for Non-Contrast-Enhanced MRA (ADVANCE-MRA) 
Andew Nicholas Priest1, Martin J Graves1, and David J Lomas1
1Department of Radiology, Addenbrookes Hospital and University of Cambridge, Cambridge, United Kingdom

Recently demonstrated methods for non-contrast enhanced MR angiography use velocity-sensitised preparation to suppress the signal from flowing blood. Arterial images are generated by subtraction of bright- and dark-blood images, acquired with and without flow suppression. However, discrimination between arteries and veins is inadequate to allow reliable depiction of arteries without venous contamination. An alternative approach, using acceleration-dependent flow suppression, has been implemented, taking advantage of the pulsatility of arterial flow. It is demonstrated to give good arterial depiction with no venous contamination over a wide range of motion suppression gradient amplitudes, without substantial background signals, fluid contamination and other artifacts.

15:24 91.   Non-Enhanced Extracranial Carotid MR Angiography Using Pseudocontinuous ASL: Comparison with Pulsed ASL and Clinical Feasibility at 1.5T 
Ioannis Koktzoglou1,2, NavYash Gupta3, and Robert R Edelman1
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, 2Radiology, The University of Chicago, Chicago, IL, United States, 3Vascular Surgery, NorthShore University HealthSystem, Evanston, IL, United States

Compared with alternate nonenhanced approaches of time-of-flight magnetic resonance angiography (MRA), new nonenhanced techniques such as pulsed arterial spin labeling (PASL) may offer potential benefits. A more recent labeling approach, pseudocontinuous arterial spin labeling (PCASL), has been reported to improve the signal-to-noise ratio (SNR) of cerebral perfusion imaging compared with PASL. The purpose of this study was to investigate whether PCASL can improve the SNR of nonenhanced carotid MRA compared with pulsed methods.

15:36 92.   3D Angiography with Psuedo Continous Arterial Spin Labeling(PCASL) and Accelerated 3D Radial Acquisition 
Huimin Wu1, Walter F Block2, Patrick A Turski3, Charles A Mistretta1, and Kevin M Johnson1
1Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, 2Biomedical engineering, University of Wisconsin-Madison, Madison, WI, United States,3Radiology, University of Wisconsin-Madison, Madison, WI, United States

3D angiography with pseudo continuous Arterial Spin Labeling (PCASL) tagging scheme and accelerated radial sampling pattern has been implemented. Feasibility studies on intracranial vasculature have been done on healthy volunteer and images show large coverage, transparent background, isotropic resolution, high contrast and SNR. Comparison with standard 3D TOF demonstrate the advantage of 3D PCASL angiography on substantially improved visualization of vessels with slow filling.

15:48 93.   Highly-Accelerated Dynamic Non-Contrast MRA Using a Combination of Compressed Sensing and Parallel Imaging 
Ricardo Otazo1, Pippa Storey1, Daniel Kim1, Daniel K Sodickson1, and Vivian S Lee1
1Department of Radiology, NYU School of Medicine, New York, NY, United States

Non-gadolinium MRA with varying flow sensitivities can be performed by acquiring sets of FSE images in systole and diastole with different refocusing flip angles, so that the subtraction of systolic and diastolic images provides angiograms that resemble “time-resolved” MRA. In order to achieve feasible acquisition times and reduce sensitivity to subject motion, accelerated imaging is required. The inherent sparsity of the angiograms and the presence of correlations among the images acquired with different flip angles make the technique a good candidate for compressed sensing. We demonstrate feasibility of 16-fold accelerated dynamic non-contrast MRA using compressed sensing and parallel imaging.