Electronic Posters: Cardiovascular

Vessel Wall Imaging (Non-Coronary)

Hall B Monday 14:00-16:00 Computer 36

14:00 3680. 3D Contrast-Enhanced Flow-Insensitive Peripheral Vessel Wall Imaging

Jingsi Xie¹, Zhaoyang Fan¹, Debiao Li<sup>1

1</sup>Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, United States

Develop a 3D contrast-enhanced flow-insensitive vessel wall imaging technique

14:30 3681. Quantitative Analysis of DCE-MRI to Identify and Characterize Plaque at Early Stages (AHA I-III)

Zhuoli Zhang¹, Nicole Mascheri¹, Jose Agraz¹, Zhaoyang Fan¹, Richard Tang¹, Xiaoming Bi², Peter Weale², Debiao Li<sup>1

1</sup>Northwestern University, Chicago, IL, United States; ²Siemens Healthcare , Chicago, IL, United States

Atherosclerotic disease is thought to begin shortly after birth. Through the years, plaques grow slowly, with variable morphologic aspects and properties at different stages of development. The American Heart Association (AHA) has established criteria by which plaques are classified according to content and structure. It is important to differentiate young stable plaques with a low extracellular lipid content that are not dangerous (types I–III) from unstable more dangerous types (IV-Vc). However, the molecular mediators of atherosclerosis at type I-III are an area of great interest in basic science. Characterization of plaque using MRI at a very early stage is very important for understanding disease process, choosing appropriate prevention and treatment strategies. Dynamic contrast-enhanced MRI (DCE-MRI) may play an important role to identify and characterize plaque at type I-III.

15:00 3682. Contrast Kinetics of Gadolinium Uptake May Discriminate Stable from Vulnerable Atherosclerotic Plaque

Alkystis Phinikaridou¹, Christopher Sucato¹, Stephan Anderson², James A. Hamilton<sup>1

1</sup>Physiology & Biophysics, Boston University, Boston, MA, United States; ²Radiology, Boston University, Boston, MA, United States

We used a rabbit model of controlled atherothrombosis to test whether in vivo MRI can distinguish between plaques that disrupt after pharmacological triggering (vulnerable) and those that do not (stable). We employed in vivo dynamic contrast enhanced MRI to study the contrast kinetics of gadolinium (Gd-DTPA) in a quantitative manner, which could help to understand the mechanism of gadolinium uptake and derive standardized criteria that could permit a differentiation of stable from vulnerable atherosclerotic plaques.

15:30 3683. Carotid Plaque Burden Measurement Using Ultrafast 3D Black-Blood MRI

Niranjan Balu¹, Vasily Yarnykh¹, Baocheng Chu¹, Jinnan Wang², Thomas Hatsukami¹, Chun Yuan<sup>1

1</sup>University of Washington, Seattle, WA, United States; ²Philips Research North America

Black-blood MRI is an established tool for carotid atherosclerotic plaque burden measurement. Accuracy of measurement can be improved by moving to isotropic imaging but can be challenging for patient compliance due to long scan times. In this work plaque assessment by an ultrafast isotropic 3D black-blood sequence (3D-MERGE) covering the entire cervical carotid arteries within 2 minutes is validated on patients with significant carotid plaque. 3D-MERGE provides good blood suppression and comparable plaque burden measurements to existing MRI protocols. Thus it provides a promising new tool for fast and accurate plaque burden assessment in patients with atherosclerotic plaque.

Tuesday 13:30-15:30 Computer 36

13:30 3684. Carotid Plaque Imaging with an Eight-Channel Transmit/Receive RF Array at 7 Tesla: First Results in Patients with Atherosclerosis.

Tobias Breyer^1,2, Oliver Kraff^1,2, Stefan Maderwald^1,2, Andreas Bitz^1,2, Stephan Orzada^1,2, Mark E. Ladd^1,2, Elke R. Gizewski^1,2, Harald H. Quick, <sup>23

1</sup>Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Nordrhein-Westfalen, Germany; ²Erwin L. Hahn Institute for Magnetic Resonance Imaging, University of Duisburg-Essen, Essen, Germany; ³Institute of Medical Physics, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany

Atherosclerosis is one leading cause of morbidity. In this study we implemented and adapted a plaque imaging protocol from 1.5 to 7 Tesla with use of a custom-built eight-channel transmit/receive RF array for the first time in human patients with hemodynamically relevant atherosclerosis. This approach allows for MR angiographic imaging without administration of gadolinium contrast comparable to contrast-enhanced MR angiography at lower field strengths. Plaque imaging at 7 Tesla requires different sequences compared to lower field strengths but allows a qualitatively comparable depiction of different intraplaque components, calcifications, vessel wall thickness and the luminal surface compared to lower field strenghts.

14:00 3685. Targeted Multi-Contrast Vessel Wall Imaging of Bilateral Peripheral Artery Disease

Niranjan Balu¹, Jinnan Wang², Xihai Zhao¹, Thomas Hatsukami¹, Chun Yuan<sup>1

1</sup>University of Washington, Seattle, WA, United States; ²Philips Research North America

Assessment of vessel wall involvement in peripheral arteries and veins can significantly improve the management of peripheral arterial disease (PAD) and deep vein thrombosis (DVT). The diffuse and bilateral disease in PAD requires bilateral large coverage. Assessment of lesion composition additionally requires multi-contrast imaging. However scan times for current black-blood MRI techniques can be prohibitively long. To address this issue we demonstrate a targeted high resolution multi-contrast imaging protocol combining bilateral isotropic large coverage 3D black-blood MRI for screening and optimized high-resolution 2D black-blood MRI. One case of DVT was identified out of six subjects scanned and characterized by multi-contrast imaging within a 30 minute scan time.

14:30 3686. Sex Differences of High-Risk Carotid Atherosclerotic Plaque in Asymptomatic Patients with Varying Levels of Stenosis -In Vivo 3.0T MRI Study

Hideki Ota^1,2, Mathew J. Reeves³, David C. Zhu², Arshad Majid⁴, Alonso Collar⁵, Nikunj Chauhan, Chun Yuan⁶, J.Kevin DeMarco<sup>2

1</sup>Diagnostic Radiology, Tohoku University, Sendai, Miyagi, Japan; ²Radiology, Michigan State University, East Lansing, MI, United States; ³Epidemiology, Michigan State University, East Lansing, MI, United States; ⁴Neurology & Ophthalmology, Michigan State University, East Lansing, MI, United States; ⁵Ingham Cardiothoracic & Vascular Surgeons, Lansing, MI, United States; ⁶Radiology, University of Washington, Seattle, WA, United States

The purpose of this study was to evaluate prevalence of complicated, high-risk carotid plaque characteristics in both men and women with a broad range of carotid artery stenosis. A total of 230 arteries (51% men) in 132 patients having 0-99% carotid stenosis were included for the analysis. After adjusting for baseline demographic characteristics as possible confounders, presence of complicated AHA VI plaque, lipid-rich/necrotic core, intraplaque hemorrhage were significantly more common in men than women. Increasing MRA stenosis was also associated with these high-risk plaque features. The present results indicate that the development of atherosclerosis appears different between men and women.

15:00 3687. In Vivo Detection of Vulnerable Atherosclerotic Plaque by Magnetic Resonance Imaging

alkystis phinikaridou¹, Frederick L. Ruberg, Hallock J. Kevin, Ye Qiao², Ning Hua, Jason Viereck, James A. Hamilton

¹physiology and biophysics, boston university, boston, ma, United States; ²Johns Hopkins

We used a rabbit model of controlled atherothrombosis to test whether in vivo MRI can distinguish between plaques that disrupt after pharmacological triggering (vulnerable) and those that do not (stable). In vivo MRI revealed that stable and vulnerable plaques had similar percent of stenosis, but vulnerable plaques more frequently showed: (1) positive remodeling, in which the plaque remains hidden within the vessel wall; and (2) enhanced gadolinium uptake associated with histological features of neovascularization, inflammation, and necrosis. These findings suggest that in vivo MRI may be used for localization of plaques that are prone to disruption prior to acute events.

Wednesday 13:30-15:30 Computer 36

13:30 3688. 3D Flow-Insensitive Vessel Wall Imaging Using T2PREP PSIR with SSFP

Jingsi Xie¹, Xiaoming Bi², Zhaoyang Fan¹, Himanshu Bhat¹, Saurabh Shah², Sven Zuehlsdorff², Debiao Li<sup>1

1</sup>Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, United States; ²Siemens Healthcare, Chicago, IL, United States

This work develops a 3D flow-insensitive technique for peripheral vessel wall imaging.

14:00 3689. The Value of Carotid Plaque MRI in the Selection of Choosing Stent-Treatment for Carotid Atherosclerosis Patients

Yan Song¹, Cheng Zhou, Min Chen, Nan Luo, Jiachun Liu, Lijun Wang, Yuan Fu, Xiangyang Ma², Chun Yuan<sup>3

1</sup>Department of Radiology, Beijing Hospital, Beijing, China; ²Philips Global Clinical Research Board, Greater China Region; ³Department of radiology, University Washington, Seattle, United States

The purpose was to evaluate the efficiency of carotid plaque MRI in stent-treatment decision for patients with carotid atherosclerosis comparing with DSA. A total of 17 symptomatic and 37 asymptomatic carotid arteries were evaluated by MRI and DSA. Images were evaluated for luminal stenosis and fibrous cap (FC) rupture, and the stent treatment decision was based on these criterions. Intraplaque hemorrhage and calcification were also evaluated by MRI. The result was that MRI was superior to DSA in determining stent treatment, especially for asymptomatic patients with carotid artery narrowing of less than 70% for its ability to detect FC rupture.

14:30 3690. Comparison of Direct Thrombus Imaging to Multi-Contrast MRI for Assessment of Carotid Atheroma

Victoria Eleanor Louise Young¹, Umar Sadat¹, Andrew J. Patterson¹, Martin J. Graves^1,2, Tjun Y. Tang¹, Peter J. Kirkpatrick³, Jonathan H. Gillard<sup>1

1</sup>University Department of Radiology, Addenbrookes Hospital, Cambridge, Cambridgeshire, United Kingdom; ²Department of Medical Physics, Addenbrookes Hospital, Cambridge, Cambridgeshire, United Kingdom; ³Department of Neurosurgery, Addenbrookes Hospital, Cambridge, Cambridgeshire, United Kingdom

Multi-contrast MRI is used for detection of complex carotid plaque, however, it is time consuming. Direct thrombus imaging (DTI) has been used previously to detect intraplaque haemorrhage. The aim of this study was to assess whether DTI could be used independent of other sequences to demonstrate complex disease. 55 patients with carotid stenosis (>30%) were imaged at 1.5T using a 4 channel phased-array carotid coil. Independent observers reviewed the multi-contrast imaging and DTI separately. DTI was found to be highly sensitive/specific for detecting complex plaque. DTI can be used independent of other imaging to identify complex plaque.

15:00 3691. Large Field-Of-View Submillimeter Isotropic Resolution Bilateral Peripheral Vessel Wall MRI Using 3D Fast Spin Echo with Flow-Insensitive Blood Suppression at 3 Tesla

Thanh D. Nguyen¹, Keigo Kawaji², Pascal Spincemaille¹, Martin R. Prince¹, Yi Wang<sup>1,2

1</sup>Radiology, Weill Cornell Medical College, New York, NY, United States; ²Biomedical Engineering, Cornell University, Ithaca, NY, United States

Black blood (BB) MRI can be used to characterize vessel wall and quantify atheresclerotic plaque burden in patients with peripheral vascular disease. T2prep inversion recovery (T2IR) has been shown to provide flow-insensitive BB contrast for 2D peripheral vessel wall MRI at 1.5T at the cost of reduced wall SNR The aim of this study is to achieve a considerable increase in T2IR BB imaging efficiency to obtain large field-of-view bilateral peripheral coverage with sub-millimeter isotropic resolution in reasonable scan time using SNR-efficient volumetric 3D fast spin echo acquisition at 3T. The developed sequence was capable of providing large volumetric coverage, excellent arterial and venous blood suppression and fat suppression, as well as good vessel wall visualization in healthy volunteers.

Thursday 13:30-15:30 Computer 36

13:30 3692. Improved Human Carotid Intraplaque Hemorrhage Imaging Using a Slab-Selective Phase-Sensitive Inversion-Recovery (SPI) Sequence

Jinnan Wang¹, Marina S. Ferguson², Niranjan Balu², Chun Yuan², Thomas S. Hatsukami², Peter Boernert<sup>3

1</sup>Clinical Sites Research Program, Philips Research North America, Seattle, WA, United States; ²University of Washington; ³Philips Research Europe

Intraplaque hemorrhage (IPH) plays a critical role in the evolution of carotid atherosclerotic disease. In this study, a Slab-selective Phase-sensitive Inversion-recovery (SPI) technique, which combines both phase sensitive (PS) imaging and a specially designed IR turbo field echo (TFE) sequence, is proposed to improve the IPH contrast and blood suppression efficiency in human carotid IPH imaging. Significantly improved IPH contrast and blood suppression were found in the in vivo atherosclerotic patient scanning.

14:00 3693. DWI of Carotid Atheroma - Detection of Lipid Rich Necrotic Core

Victoria Eleanor Louise Young¹, Andrew J. Patterson¹, Umar Sadat¹, David J. Bowden¹, Martin J. Graves^1,2, Andrew N. Priest^1,2, Tjun Y. Tang¹, Jeremy N. Skepper³, Peter J. Kirkpatrick⁴, Jonathan H. Gillard<sup>1

1</sup>University Department of Radiology, Addenbrookes Hospital, Cambridge, Cambridgeshire, United Kingdom; ²Department of Medical Physics, Addenbrookes Hospital, Cambridge, Cambridgeshire, United Kingdom; ³Multi-imaging Centre, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom; ⁴Department of Neurosurgery, Addenbrookes Hospital, Cambridge, Cambridgeshire, United Kingdom

Lipid-rich necrotic core (LR/NC), which is difficult to identify on MRI, has importance in predicting risk of clinical events. Previous studies using diffusion-weighted imaging (DWI) for ex-vivo imaging have demonstrated a potential role for DWI. The aim of this study was to examine if DWI can be applied in vivo to differentiate LR/NC from fibrous cap. 28 patients with confirmed carotid atheroma were imaged at 1.5T using a dedicated 4 channel phased-array carotid coil and ADC maps produced. A significant difference was found between the ADC values for LR/NC and fibrous cap. DWI may provide addition information for plaque classification.

14:30 3694. Signal Evolution of Intraplaque Hemorrhage in Asymptomatic and Symptomatic Carotid Plaque: A Long-Term in Vivo High-Resolution Magnetic Resonance Imaging Follow-Up Study

Jianming Cai¹, Qingjun Wang¹, Yong Wang¹, Youquan Cai¹, Lin Ma¹, Chun Yuan<sup>2

1</sup>Radiology, Chinese PLA General Hospital, Beijing, China; ²Radiology, University of Washington, Seattle, WA, United States

By using in vivo multi-contrast high-resolution MRI, we performed a long-term follow-up study on asymptomatic and symptomatic carotid intraplaque hemorrhage (IPH) to observe difference in signal evolution within each group and between the two groups. In the present study, each patient with eligible IPH was given a carotid MRI examination on a 3.0-T MRI scanner every 6 months during a total 3 years period. Our findings show that asymptomatic and symptomatic carotid IPH demonstrated a different MRI signal evolution. The repeated IPH may be more common in the symptomatic plaque than in the asymptomatic plaque.

15:00 3695. Prospective Self-Gating to Eliminate Motion Artifacts in 3D Carotid Artery Wall Imaging

Zhaoyang Fan^1,2, Sven Zuehlsdorff³, Peng Lai⁴, YiuCho Chung³, Jose Agraz^1,2, Debiao Li<sup>1,2

1</sup>Radiology, Northwestern University, Chicago, IL, United States; ²Biomedical Engineering, Northwestern University, Evanston, IL, United States; ³Cardiac MR R&D, Siemens Healthcare, Chicago, IL, United States; ⁴Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States

Self-gating technique has recently been used in a 3D variable-flip-angle TSE sequence to exclude data acquired during swallowing, yet two shortcomings remain. First, a single self-gating (SG) line acquired immediately before readout in each TR may not be adequate to detect motion if the readout duration is considerably long. Second, real-time update of the reference line used for the cross-correlation analysis is necessary given potentially involuntary “drift” during 3D imaging. This work demonstrated that two SG lines, acquired immediately before and after readout during each TR, in combination with real-time update of the reference line make swallowing-motion gating more robust.

Flow Quantification & Vessel Function

Hall B Monday 14:00-16:00 Computer 37

14:00 3696. 3D Flow Characteristics in Ventricular Assist Devices: Impact of Valve Geometry and Operating Conditions

Christoph Benk¹, Ramona Lorenz², Jürgen Hennig^2,3, Friedhelm Beyersdorf¹, Jan G. Korvink, ^3,4, Michael Markl<sup>2

1</sup>Dept. of Cardiovascular Surgery, University Hospital, Freiburg, Germany; ²Dept. of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany; ³FRIAS, Freiburg Institute for Advanced Studies, Freiburg, Germany; ⁴Laboratory for Simulation, IMTEK - Institute of Microsystem Technology, Freiburg, Germany

The use of paracorporeal ventricular assist devices (PVAD) has become a well-established procedure for patients with cardiogenic shock or who need biventricular support. However, implantation of Ventricular assist devices (VADs) is often associated with severe complications such as thrombosis inside the VAD and subsequent embolic events. It was therefore the purpose of this study to use flow sensitive 4D MRI for a detailed analysis of local and global 3D flow dynamics in a clinical routine VAD to study the effect of different system adjustments and valve designs on flow patterns.

14:30 3697. Time-Resolved Spin-Labeled Balanced SSFP Cineangiography for Visualizing Intracardiac Shunt

Federico E. Mordini¹, Ioannis Koktzoglou¹, Robert R. Edelman<sup>1

1</sup>Radiology, NorthShore University HealthSystem, Evanston, IL, United States

Existing methods for intracardiac shunt evaluation have important technical limitations. We developed a time-resolved spin-labeled cineangiographic technique (SLC) to image tagged blood within the heart for visualization of intracardiac shunt. Ten subjects with known atrial septal defects (ASD) were evaluated. Tagged inflowing blood was depicted with high signal intensity (SI) while non-tagged blood was suppressed. Flow was visualized crossing the atrial septum both inplane and throughplane. In conclusion, SLC is a non-contrast, non-velocity dependent method for visualizing RF-tagged blood flowing through cardiac chambers. SLC successfully depicted intracardiac shunting in all patients. SLC has potential use in the detection and pre-procedural assessment of ASD.

15:00 3698. Evaluation of Diastolic Function with Flow Quantification Phase Contrast Cardiac Magnetic Resonance Imaging

Jeremy Douglas Collins¹, Philip Anthony Hodnett¹, Timothy Anthony Scanlon¹, Amir H. Davarpanah¹, Aya Kino¹, Karin Dill¹, Sven C. Zuehlsdorff², James C. Carr<sup>1

1</sup>Radiology, Northwestern University, Chicago, IL, United States; ²Radiology, Siemens Healthcare, MR Research and Development, Chicago, IL, United States

Cardiac magnetic resonance is the reference standard for assessment of infiltrative heart disease and systolic function. The ability to assess diastolic dysfunction would enable comprehensive assessment of cardiac function. We evaluated 36 patients and 4 volunteers with flow quantification phase contrast imaging, comparing to Doppler echocardiography. Phase contrast imaging correctly classified all patients with grade I diastolic dysfunction. Differentiating patients with grade II dysfunction from normal diastolic function was not possible, although stratification based on E wave deceleration time was promising. A dedicated acquisition to assess the E’ lateral annulus velocity may be useful in this regard.

15:30 3699. Highly Accelerated Cine Phase-Contrast Flow Measurements Using k-T PCA with Spatial Compartments

Daniel Giese^1,2, Verena Knobloch¹, Henrik Pedersen³, Tobias Schaeffter², Sebastian Kozerke<sup>1,2

1</sup>Institute for Biomedical Engineering, Univeristy and ETH Zurich, Zurich, Switzerland; ²Division of Imaging Sciences, King's College London, London, United Kingdom; ³Functional Imaging Unit, Glostrup Hospital, Glostrup, Denmark

In this work, we present an extension of k-t PCA taking into account temporal correlations in spatial compartments. The compartment method is shown to significantly outperform conventional k-t PCA at high reduction factors. Using the approach up to 10- fold net acceleration of single-directional phase-contrast velocity mapping in the ascending and descending aorta is demonstrated with excellent agreement relative to fully sampled data even if only a single receive coil is available.