Electronic poster

Tuesday 13:30-15:30 Computer 41

13:30 3761. Unenhanced ECG-Gated Fast Spin-Echo MR Digital Subtraction Angiography (MRDSA) Using SPACE with Constant Flip Angle Mode of Femoral Arteries

Satoru Morita¹, Shinya Kojima¹, Masami Hirata¹, Masaru Suzuki¹, Kazufumi Suzuki¹, Ai Masukawa¹, Eiko Ueno<sup>1

1</sup>Department of Radiology, Tokyo Women's Medical University Medical Center East, Arakawa-ku, Tokyo, Japan

Unenhanced electrocardiographically-gated fast spin-echo-based magnetic resonance digital subtraction angiography (MRDSA) can obtain hemodynamic information of pulse wave transmission. We prospectively compared the image quality of MRDSA using sampling perfection with application optimized contrasts using different flip angle evolutions (SPACE) with constant flip angle mode and conventional half-Fourier single-shot turbo spin-echo (HASTE) sequence of femoral arteries in 10 healthy volunteers at 1.5T MRI. All quantitative and qualitative analyses of the SPACE were significantly better than those of the HASTE. We show that unenhanced electrocardiographically-gated fast spin-echo MRDSA using SPACE with constant flip angle mode provides good visual hemodynamic information of arteries.

14:00 3762. Nonenhanced Time-Resolved MR Angiography for the Arteriovenous Malformation/Fistula of the Pelvis and the Lower Extremity.

Masaaki Akahane¹, Jiro Sato¹, Shuhei Komatsu¹, Yasushi Watanabe², Yoshiro Satake², Kuni Ohtomo<sup>1

1</sup>Radiology, University of Tokyo, Bunkyo-ku, Tokyo, Japan; ²Clinical Radiology, University of Tokyo, Bunkyo-ku, Tokyo, Japan

Nonenhanced MRA by spin-labeling technique with subtraction between labeled and non-labeled images was applied to the time-resolved study for better background suppression in any inversion time. Seven patients having arteriovenous malformations or fistulas of the pelvis or lower extremity underwent nonenhanced time-resolved MRA using respiratory-gated balanced steady state free precession (SSFP) sequence with 1.5-T scanner (Toshiba EXCELART Vantage, Japan). Inversion times (TI) were assigned as 300, 800, 1300 and 1800 ms. Nonenhanced time-resolved MRA was useful for the evaluation of hemodynamics of the arteriovenous malformation or fistula and the distinction of feeding arteries.

14:30 3763. Adapted Random 3D Sampling Patterns for CE-MRA

Florian Knoll¹, Christian Clason², Manuela Aschauer³, Franz Ebner³, Rudolf Stollberger<sup>1

1</sup>Institute of Medical Engineering, Graz University of Technology, Graz, Austria; ²Institute for Mathematics and Scientific Computing, University of Graz, Graz, Austria; ³Department of Radiology, Medical University Graz, Graz, Austria

Variable density 3D random sampling trajectories have great potential for subsampled CE-MR angiography techniques which deliver data sets with high contrast to noise ratio. The goal of this work was to present a parameter-free method to construct variable density sampling patterns which are tailored to angiography. Sampling patterns are generated with the use of a probability density function that is constructed by using measured k-space data as a reference, which automatically ensures an appropriate distribution of sample points.

15:00 3764. Imaging of Pulmonary Artery and Vein Using ASL Based Non-Contrast MRA Technique

Tomoyuki Okuaki^1,2, Takeshi Ishimoto³, Momoe Kawakami³, Masaru Ishihara⁴, Tetsuro Ogino¹, Ivan Zimine¹, Marc Van Cauteren⁵, Toshiaki Miyati<sup>6

1</sup>Clinical Science, Philips Electronics Japan, Minato-ku, Tokyo, Japan; ²Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan; ³Hyogo Brain and Heart Center, Japan; ⁴Kakogawa Medical Center, Japan; ⁵Philips Healthcare, Netherlands; ⁶Kanazawa University Graduate School of Medical Science, Kanazawa, Ishikawa, Japan

For lung imaging, depiction of pulmonary artery (PA) and vein (PV) can be done using ASL based technique. However, visualization of PV using conventional ASL approach is challenging because tagged blood in the pulmonary artery requires several seconds to reach the vein. In this work we evaluated the possibility of simultaneous visualization of PA and PV using ASL based technique at multiple inversion times (TI). For PA, high scores were observed at TI=800ms and 1100ms respectively; For PV, highest score was observed at TI=300ms. Expected clinical application is imaging of patients with pulmonary infarction.

Wednesday 13:30-15:30 Computer 41

13:30 3765. Ultra Low Dose 4D Contrast Enhanced MRA Using HYBRID HYPR Technique

Yijing Wu¹, Kevin M. Johnson¹, Steven R. Kecskemeti¹, Charlse A. Mistretta², Patrick Alan Turski<sup>3

1</sup>Medical Physics, University of Wisconsin, Madison, Madison, WI, United States; ²Medical Physics and Radiologly, University of Wisconsin, Madison, Madison, WI, United States; ³Radiology, University of Wisconsin, Madison, Madison, WI, United States

Time resolved contrast-enhanced magnetic resonance angiography has been widely used to evaluate vascular hemodynamics. Due to recent concern of the NSF disease, eliminating or reducing Gadolinium-based contrast agent is desirable. HYBRID HYPR decouples the high spatial resolution and SNR, which require relative long scan time, from the high temporal resolution, which demands for fast data acquisitions. It used the HYPR constrained reconstruction to obtain high temporal resolution, high spatial resolution, and high SNR image series. The hypothesis of this work is that the contrast dose can be reduced using the HYBRID HYPR technique: the SNR of the HYPR images is primarily determined by the composite, which is generated using minimal mount of contrast agent (e.g. post contrast phase-contrast images) or can be acquired before contrast injection (e.g. Time-of-Flight images). High temporal and spatial resolution time resolved contrast-enhanced MRA can be obtained by using Low Dose HYBRID HYPR method with contrast dose as low as 1ml.

14:00 3766. Congenital Heart Disease: Role of Time-Resolved MR Angiography

kambiz nael¹, Michael Fenchel¹, Stefan G. Ruehm¹, J Paul Finn<sup>1

1</sup>Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States

Advances in fast imaging tools such as parallel acquisition and sparse k-space sampling methods such as time-resolved angiography with interleaved stochastic trajectories (TWIST), have the potential to improve the performance of time-resolved MR angiography (TR-MRA). In this study we evaluated the clinical usefulness of a 3D CE-MRA protocol that encompasses both high spatial and high temporal resolution acquisition in evaluation of patients with congenital heart disease (CHD). Our objective is to investigate whether TR-MRA can unravel complex functional vascular anatomy in patients with CHD and to assess the incremental diagnostic value of TR-MRA over conventional MRA in this population.

14:30 3767. Evaluation of Non-Contrast Time-Spatial Labeling Inversion Pulse for Abdominal Angiography Compared to Contrast-Enhanced Angiography

Erin Jane Kelly¹, Steve Saeger², David E. Neal<sup>2

1</sup>Toshiba America Medical Systems, Tustin, CA, United States; ²Radiology, Central Ohio Primary Care Physicians, Columbus, OH, United States

Non-contrast angiography techniques are becoming increasingly important in the clinical setting. 3D SSFP Time-SLIP has been developed to produce bright blood angiograms for abdominal angiography, including renal MRA exams. The purpose of this study was to evaluate image quality and diagnostic confidence for Time-SLIP compared to contrast-enhanced MRA in the same group of patients. Image quality scores were 2.6±0.7 and 2.4±0.7 for Time-SLIP and CE-MRA, and Diagnostic quality scores were 2.8±0.4 and 2.4±0.8 for Time-SLIP and CE-MRA, respectively. This study indicates that Time-SLIP is a safe and effective alternative for CE-MRA and may replace CE-MRA in the clinical setting.

15:00 3768. Non-Contrast-Enhanced Renal MRA Using Inflow-Enhanced, Inversion-Recovery at 3T

Thorsten Alexander Bley^1,2, Scott Brian Reeder², Mark Schiebler², Naoyuki Takei³, Jean H. Brittain⁴, Thomas Grist², Christopher J. Francois<sup>2

1</sup>Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; ²Radiology, University of Wisconsin-Madison, Madison, WI, United States; ³Japan Applied Science Laboratory, GE Healthcare, Tokyo, Japan; ⁴Applied Science Laboratory, GE Healthcare, Waukesha, WI, United States

This work presents validation of an inflow-enhanced, inversion-recovery (IR) balanced steady state free precession (bSSFP) based non-contrast-enhanced MRA (NCE-MRA) for assessment of renal arteries at 3T in patients with suspected renal artery stenosis or with a history of renal artery transplant. NCE-MRA with inflow-enhanced IR bSSFP produced consistent results and demonstrated moderate agreement with CE-MRA for both readers and strong inter-observer agreement for grading renal artery stenosis >50%.

Thursday 13:30-15:30 Computer 41

13:30 3769. Time-SLIP Versus DSA in Patients with Renal Artery Stenosis

Isabelle Parienty¹, Faiza Admiraal-Behloul², Francis Jouniaux¹, Michel Piotin³, Guy Rostoker<sup>3

1</sup>Centre d'Imagerie du Bois de Verrière, Antony, France; ²MRI, Toshiba Medical Systems Europe, Zoetermeer, Netherlands; ³Nephrology, Centre Hospitalier Claude Galien, Paris, France

The purpose of this study was to compare the findings in non-contrast enhanced MRA using the Time Spatial Labeling Inversion Pulse (Time-SLIP) technique to those of Digital Subtraction Angiography (DSA) in patients with significant renal artery stenosis (>60%, or >50% with post stenotic dilation).

14:00 3770. Respiratory Rate Regulation for Optimal Time-SLIP Imaging of Renal Arteries

Francis Jouniaux¹, Isabelle Parienty¹, Faiza Admiraal-Behloul<sup>2

1</sup>Centre d'Imagerie du Bois de Verrière, Antony, France; ²MRI, Toshiba Medical Systems Europe, Zoetermeer, Netherlands

Respiratory gated non contrast enhanced MR angiography using Time-Spatial inversion labeling pulse (Time-SLIP) is a well established technique at our institution for the exploration of renal arteries. Since 2007, we scanned more than 450 patients with age ranging for 18 to 92 year old. Patients with fast and/or irregular respiration rates (RR) can be very challenging to image. Most of the difficult patients are old (80+), or have a cardiac disease and/or a respiratory disease. A breath hold of more than 16s is intolerable for most of these patients. We describe how regulating the respiratory rate can significantly improve the image quality and the success rate of Time-SLIP.

14:30 3771. Assessment of Non-Contrast Angiography in Diabetic Patients

Erin Jane Kelly¹, JoEllyn L. L. Stolinski², James Jelinek<sup>2

1</sup>Magnetic Resonance, Toshiba America Medical Systems, Tustin, CA, United States; ²Radiology, Washington Hospital Center, Washington, D.C., United States

Diabetes is highly associated with renal failure and peripheral artery disease. In light of the association between MRI contrast media and the onset of NSF/NSD, it is increasingly important to replace CE-MRA with non-contrast angiographic imaging techniques, such as Fresh Blood Imaging and Time-SLIP. In this study, diabetic patients referred for and MRA were imaged with FBI and Time-SLIP for peripheral run-offs and renal angiography. Image Quality and Diagnostic Confidence scores indicate that FBI and Time-SLIP are both safe and effective alternatives to CE-MRA in this patient group.

15:00 3772. An MRI Examination for Evaluation of Aortic Dissection Using a Blood Pool Agent

Rachel Clough¹, Tarique Hussain¹, Sergio Uribe¹, Peter Taylor², Reza Razavi¹, Tobias Schaeffter¹, Matthew Waltham<sup>2

1</sup>Division of Imaging Sciences, King's College London, London, United Kingdom; ²Guy’s and St Thomas’ NHS Foundation Trust, St Thomas' Hospital, London, United Kingdom

An MRI examination for evaluation of aortic dissection using a blood-pool agent is presented. The aims of this study were to investigate the use of direct thrombus MRI and quantitative flow analysis for the determination of false lumen thrombus volumes in patients with Type B aortic dissection. It is shown that blood-pool imaging together with direct thrombus MRI allows assessment of aortic anatomy and more accurate quantification of false lumen thrombosis compared with CT. Current clinical trials using false lumen thrombosis as a primary endpoint should consider multi-parametric MRI as the preferred diagnostic tool.

MRA: Preclinical Technical Developments

Hall B Monday 14:00-16:00 Computer 42

14:00 3773. Magnetic Resonance Venography with a Blood Pool Contrast Medium

Teik Choon See¹, Andrew Winterbottom¹, Edmund Soh², Ilse Joubert¹, Martin Graves¹, David Lomas<sup>1

1</sup>Radiology, University of Cambridge and Addenbrooke's Hospital, Cambridge, Cambridgeshire, United Kingdom; ²Singapore General Hospital, Singapore

Our prospective clinical trial authorised study aims to assess MR venography of the neck and thoracic central veinous system using Vasovist® (gadofosveset trisodium, Schering), a blood pool contrast agent, for first pass (FP) and steady state (SS) imaging. Images are assessed independently for image quality, artefacts, stenosis, and thrombosis. Sixteen participants recruited to date and 144 venous segments assessed. The result shows very favourable SS imaging quality compared to FP (although not quite statistically significant) with potential for improving diagnostic accuracy. Mild artefacts are seen in 50% of both techniques. No significant differences noted in detection of stenosis or thrombosis.

14:30 3774. Group-Encoded Ungated Inversion Nulling for Non-Contrast Enhancement in the Steady State (GUINNESS): A Balanced SSFP-Dixon Technique for Breath-Held Non-Contrast MRA

Manojkumar Saranathan¹, Ersin Bayram², James F. Glockner<sup>3

1</sup>Applied Science Lab, GE Healthcare, Rochester, MN, United States; ²GE Healthcare, Waukesha, WI, United States; ³Radiology, Mayo Clinic, Rochester, MN, United States

While contrast-enhanced MR Angiography (CEMRA) is widely used for evaluation of vascular pathology, recent nephrogenic systemic fibrosis (NSF) concerns following administration of Gadolinium based contrast agents have spurred interest in non-contrast MRA methods. Balanced steady state free precession (b-SSFP) imaging has shown great promise due to its high SNR and short scan times. We propose a balanced SSFP-Dixon technique with a novel group-encoded k-space segmentation scheme for breath-held non-contrast MRA.

15:00 3775. Optimization of Gradient Moment Nulling for Hybrid of Opposite-Contrast MRA Sequence

Tokunori Kimura¹, Masato Ikedo<sup>2

1</sup>MRI Systems Development Department, Toshiba Medical Systems , Otawara, Tochigi, Japan; ²MRI Systems Development Department, Toshiba Medical Systems, Otawara, Tochigi, Japan

We have proposed a new MR angiography technique named Hybrid of Opposite-Contrast MRA (HOP-MRA) with 3D dual-echo gradient-echo sequence combining Time-of-Flight (TOF) with a Flow-Sensitive Black-Blood (FSBB) employing flow dephasing gradients. In this study, for the purpose of decreasing flow-void appeared in major arteries, two types of gradient moment nulling (GMN) for the TOF part were compared between 1st order full 3-axis GMN and partial 2-axis GMN. We demonstrated that flow-void artifacts were decreased by using the 2-axis GMN in the TOF part and vessel misregistration due to phase-encode displacement in the TOF part was minor. The HOP technique is suitable for decreasing both flow-void and PED artifacts in MRA compared to TOF alone.

15:30 3776. Dynamically Changing Field-Of-View in the Comprehensive Neurovascular Exam

Petrice M. Mostardi¹, Clifton R. Haider¹, Norbert G. Campeau¹, John Huston¹, Stephen J. Riederer<sup>1

1</sup>Radiology, Mayo Clinic, Rochester, MN, United States

We define a comprehensive neurovascular exam (CNVE) as the high quality imaging of the aortic arch through the intracranial veins. The goal of this work is to image these territories by dynamically changing (scaling/shifting) the FOV during a contrast-enhanced acquisition. Volunteer studies were performed with an imaging protocol consisting of: (i) a large FOV, low dose (2 ml) time-resolved acquisition to provide overall diagnostic information and serve as a timing bolus and (ii) a high spatial resolution contrast-enhanced exam implementing dynamic change of the FOV to image the carotid arteries and the intracranial venous system.

Tuesday 13:30-15:30 Computer 42

13:30 3777. Direct Imaging and Quantification of Carotid Plaque Calcification (CPC) Using Ultrashort TE Pulse Sequences

Jiang Du¹, Jacqueline Corbeil¹, Richard Znamirowski¹, Michael Peterson², Niren Angle³, Graeme Bydder¹, Andrew Kahn<sup>4

1</sup>Radiology, University of California, San Diego, CA, United States; ²Pathology, University of California, San Diego, CA, United States; ³Surgery, University of California, San Diego, CA, United States; ⁴Medicine, University of California, San Diego, CA, United States

Carotid plaque vulnerability is dependent upon its tissue constituents, which may include fibrous tissue, lipid core, intra-plaque plaque hemorrhage as well as calcification. Clinical MR sequences have been employed to characterize the long T2 plaque components. Carotid plaque calcification (CPC) is undetectable with conventional clinical MR sequences. Here we describe the use of a 2D ultrashort TE (UTE) sequence combined with efficient long T2 suppression to image and characterize CPC (T2, T2* and water content) using a clinical 3T scanner. High spatial resolution micro-CT images were also acquired for comparison and validation.

14:00 3778. A New PVA-Based Dynamic Cardiac Phantom for Evaluation of Functional MR Imaging Methods at 3T

Robert Manzke¹, Anja Lutz², Marcel Schenderlein³, Axel Bornstedt², Raymond C. Chan⁴, Klaus Dietmeyer³, Volker Rasche<sup>5

1</sup>Tomographic Imaging, Philips Research Europe, Hamburg, Germany; ²Dept. of Internal Medicine II, University Hospital Ulm, Germany; ³Inst. Measurement, Control, and Microtechnology, University Ulm, Germany; ⁴Philips Research North America, Briarcliff Manor, NY, United States; ⁵Dept. of Internal Medicine II, University Hospital Ulm, Germany

A new PVA-based dynamic cardiac MR phantom is introduced, aiming to enable cross validation of novel tagged and phase contrast MR methods specifically at 3T, aiding the development of clinically relevant functional MR techniques. Examples of phase contrast and tagged images using a 3T system with a 6 element cardiac coil are given.

14:30 3779. Balanced SSFP Spin-Labeled Angiography Using Sparse Data: Optimization and Application to Supraaortic Vessels

Ioannis Koktzoglou¹, Philip Hodnett, ^1,2, Erik Offerman¹, Robert Edelman<sup>1

1</sup>Radiology, NorthShore University HealthSystem, Evanston, IL, United States; ²Northwestern University, Chicago, IL, United States

Arterial spin-labeled MRA using a balanced steady-state free precession is limited by flow artifacts in the setting of luminal narrowing. In a stenotic flow phantom, we show that these artifacts can be minimized with the use of abbreviated echo trains made possible with the use of parallel imaging acceleration and partial Fourier acquisition, and subsequently apply the technique in volunteers and patients.

15:00 3780. Magnetic Resonance Imaging Measurements Predict Need for Intervention in Patients Post Ross Procedure

Anna Lakoma¹, James C. Carr<sup>1

1</sup>Department of Radiology, Northwestern University, Chicago, IL, United States

MRI derived pulmonary circulation parameters best predict need for future intervention in patients post Ross procedure.

Wednesday 13:30-15:30 Computer 42

13:30 3781. Accelerated Time Resolved Inflow with 3D Multi-Echo Radial Trajectories

Kevin M . Johnson¹, Oliver Wieben^1,2, Patrick Turski², Charles Mistretta<sup>1

1</sup>Medical Physics, University of Wisconsin - Madison, Madison, WI, United States; ²Radiology, University of Wisconsin - Madison, Madison, WI, United States

Arterial spin labeling (ASL) sequences which utilize tagging schemes to images the flow of blood have emerged as effective techniques for the non-contrast angiography; however, these techniques typically suffer from long acquisition times, sensitivity to tag delay parameters, and uncertain performance in cases of complex flow . To mitigate these errors, we investigate the utilization of highly accelerated, dynamic inflow imaging utilizing efficient, short TR 3D radial bSSFP sequences.

14:00 3782. Non-Contrast Enhanced Pulmonary Vein MRA with Compressed Sensing

Mehmet Akçakaya^1,2, Peng Hu², Vahid Tarokh¹, Warren J. Manning², Reza Nezafat<sup>2

1</sup>Harvard University, Cambridge, MA, United States; ²Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States

Non-contrast pulmonary vein (PV) MR angiography (MRA) is an alternative to the clinical contrast-enhanced technique. We have recently developed a non-contrast PV MRA technique using a sagittal selective inversion pulse. However, the resulting acquisition time is significantly longer than breath-hold contrast-enhanced technique. In this study, we investigate the feasibility of using compressed sensing for accelerating data acquisition in non-contrast PV MRA. We use a distributed compressed sensing technique to reconstruct separate coil images simultaneously. We show that this reconstruction yields good results even at high rates (x10).

14:30 3783. Non-Contrast Inversion Recovery Balanced Ssfp Mra of the Abdominal Aorta at 3T: Predicting Optimal Inversion Times by Blood Velocity Measurement

Iliyana Plamenova Atanasova^1,2, Ruth P. Lim¹, Hua Guo¹, Daniel Kim¹, Pippa Storey¹, Kellyanne McGorty¹, Andrew Laine², Vivian S. Lee<sup>1

1</sup>Department of Radiology, New York University, New York, United States; ²Columbia University, New York, United States

3D non-enhanced balanced steady-state free precession MRA with a slab-selective inversion (IR SSFP) has demonstrated promise for renal artery evaluation at 1.5T. With proper selection of inversion times (TI), the technique can be adopted for coronal imaging of the abdominal aorta with comprehensive superior-inferior coverage at 3T. We propose a method for subject-specific calculation of TI based on arterial blood velocities. Our results illustrate that visualization of the aortoiliac vessels using IR SSFP varies considerably across subjects depending on flow velocities. Thus, measuring aortic velocities prior to MRA enables an examination tailored to the patient’s physiology for improved arterial visualization.

15:00 3784. MRI Determined Carotid Artery Flow Velocities and Wall Shear Stress in a Mouse Model of Vulnerable and Stable Atherosclerotic Plaque

Gustav Jacob Strijkers¹, Glenda S. van Bochove¹, Roel Straathof¹, Rob Krams², Klaas Nicolay<sup>1

1</sup>Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; ²Department of Bioengineering, London Imperial College, London, United Kingdom

We report here on the pre-clinical MRI characterization of an apoE-/- mouse model of stable and vulnerable carotid artery atherosclerotic plaques, which were induced by a tapered restriction (cast) around the artery. Specific focus was on the quantification of flow velocities and wall shear stress (WSS), which are considered key players in the development of the plaque phenotype.