Pim van Ooij¹, Alex J Barker², Henk A Marquering³, Gustav J Strijkers³, James C Carr², Michael Markl^2,4, and Aart J Nederveen^5
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Radiology, Northwestern University, Chicago, IL, United States, ³Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands, ⁴Biomedical Engineering, Northwestern University, Chicago, IL, United States, ⁵Academic Medical Center, Amsterdam, Netherlands

Altered hemodynamics in the left ventricle (LV) may contribute to heart failure in hypertrophic cardiomyopathy (HCM). The aim of this was study was to employ 4D flow MRI to identify regions with altered velocity in HCM patients based on the concept of 'LV flow heat maps' comparing velocity fields in HCM patients with an atlas derived from healthy controls. In the ejection phase, abnormally elevated velocity was found in the LV outflow tract, whereas the filling phase showed elevated velocity in the LV apex.

Alex S Hong¹, Emilie Bollache¹, Pim van Ooij¹, James C Carr¹, Alex J Barker¹, Jeremy D Collins¹, and Michael Markl^2
1Department of Radiology, Northwestern University, Chicago, IL, United States, ²Department of Radiology, Department of Biomedical Engineering, Northwestern University, Chicago, IL, United States

Aortic valve replacement (AVR) is an effective surgical approach to treating aortic valvular disease, but it is unclear if and what type of prosthesis can fully reproduce physiologically normal flow characteristic of a native aortic valve. We utilized 4D flow MRI to systematically compare blood flow in the thoracic aorta in post-AVR (bioprosthetic vs. mechanical) patients and healthy controls. Both bioprosthetic and mechanical valves were found to produce higher peak systolic flow velocities and peak wall shear stress in the ascending aorta than native valves, demonstrating the presence of significant changes in aortic blood flow in AVR patients.

Zixin Deng^1,2, Sangeun Lee³, Zhaoyang Fan¹, Christopher Nguyen¹, Iksung Cho³, Qi Yang¹, Xiaoming Bi⁴, Byoung-Wook Choi⁵, Jung-Sun Kim³, Daniel Berman¹, Hyuk-Jae Chang³, and Debiao Li^1
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States, ³Cardiology, Severance Hospital, Yonsei Univeristy College of Medicine, Seoul, Korea, Republic of, ⁴R&D, Siemens Healthcare, Los Angeles, CA, United States, ⁵Radiology, Severance Hospital, Yonsei Univeristy College of Medicine, Seoul, Korea, Republic of

Fractional flow reserve is an invasive diagnostic tool to evaluate the functional significance of a coronary stenosis by quantifyin­g the pressure gradient (ΔP) across the stenosis. We proposed a non-invasive technique to derive ΔP using Phase-contrast (PC)-MRI in conjunction with the Navier-Stokes equations (ΔP_MR). Excellent correlation was observed between derived ΔP_MR and measure ΔP from a pressure transducer in a small caliber phantom model. A significant increase in ΔP_MR was seen in the patient group vs. healthy controls. Preliminary results suggested that noninvasive quantification of ΔP_MR in coronary arteries is feasible. 

David A Feinberg^1,2, Alexander Beckett¹, An T Vu^1,2, and Liyong Chen^2
1Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States, ²Advanced MRI Technologies, Sebastopol, CA, United States

The purpose was to develop and evaluate a novel approach to MR phase imaging of blood flow and CSF flow by combining cine phase contrast (cine-PC) with simultaneous multi-slice (SMS) technique to measure velocity in several slice planes simultaneously. Comparisons were made between SMS 2-4 and conventional single-slice 2D cine-PC GE imaging. The velocity curves measured in internal carotid (ICA) and vertebral arteries and jugular veins and aqueductal CSF were similar between SMS and conventional single-slice cine-PC. In ICA correlations (R=0.92-0.98) in 6 subjects. This new ability for simultaneous cross-sectional hemodynamic quantification may be useful for medical diagnoses.  

Johannes Töger^1,2, Mikael Kanski¹, Per M Arvidsson¹, Marcus Carlsson¹, Sándor J Kovács³, Rasmus Borgquist⁴, Johan Revstedt⁵, Gustaf Söderlind², Håkan Arheden¹, and Einar Heiberg^1,2,6
1Department of Clinical Physiology, Lund University Hospital, Lund University, Lund, Sweden, ²Department of Numerical Analysis, Centre for Mathematical Sciences, Lund University, Lund, Sweden, ³Department of Internal Medicine, Washington University School of Medicine, St Louis, MO, United States, ⁴Department of Arrhythmias, Lund University Hospital, Lund University, Lund, Sweden, ⁵Department of Energy Sciences, Lund University, Faculty of Engineering, Lund, Sweden, ⁶Department of Biomedical Engineering, Lund University, Faculty of Engineering, Lund, Sweden

Diastolic dysfunction of the left ventricle (LV) of the heart is a severe condition associated with poor prognosis. However, objective and reproducible assessment of diastolic function remains a challenge. We propose a new method using 4D flow MR by quantification of blood mixing within the LV diastolic vortex-ring. Phantom validation showed fair agreement between 4D flow MR and planar laser-induced fluorescence (PLIF). Quantitative vortex-ring mixing differs between healthy controls and patients with heart failure, which demonstrates its potential as a marker of diastolic dysfunction.

Shuang Leng¹, Shuo Zhang², Xiaodan Zhao¹, Baoru Leong¹, Yiying Han¹, Yasutomo Katsumata³, Stuart Cook^1,4, Ru San Tan^1,4, and Liang Zhong^1,4
1National Heart Centre Singapore, Singapore, Singapore, ²Philips Healthcare Singapore, Singapore, Singapore, ³Philips Healthcare Japan, Tokyo, Japan, ⁴Duke-NUS Graduate Medical School Singapore, Singapore, Singapore

We have developed a semi-automatic tracking system of atrioventricular junction (AVJ) deformation with two-, three-, and four-chamber cardiovascular magnetic resonance (CMR) long-axis images ¹. In this study, we applied the feature-tracking technique in 18 radial rotational long-axis cine CMR planes and evaluated the motion of 36 evenly located AVJ points. Results have shown that 1) the obtained average AVJ velocities (Sm, Em and Am) and maximal displacements are independent of the number of AVJ points selected, and 2) the routinely acquired CMR imaging generated in clinical practice are sufficient enough for dynamic assessment of AVJ deformation.

Julio Garcia¹, Roel L.F. van der Palen², Alex J. Barker¹, Jeremy D. Collins¹, James C. Carr¹, Joshua Robinson³, Cynthia Rigsby³, and Michael Markl^1,4
1Radiology, Northwestern University, Chicago, IL, United States, ²Pediatric Cardiology, Leiden University Medical Center, Leiden, Netherlands, ³Department of Medical Imaging, Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL, United States, ⁴Biomedical Engineering, Northwestern University, Evanston, IL, United States

The systematic characterization of effects in aortic disease patients and healthy controls is important to improve disease diagnosis. 4D flow MRI can be applied for the analysis of altered hemodynamics in cardiovascular disease. However, data analysis can be time consuming and often data are not fully utilized by analysis based on 2D planes. This study aimed to systematically apply flow distribution analysis in the entire volume of the aorta to establish normative reference values across a wide age range from pediatric to adult subjects.

Moritz Braig¹, Jochen Leupold¹, Ko Cheng-Wen², Marius Menza¹, Juergen Hennig¹, Jan Korvink³, and Dominik von Elverfeldt^1
1University Medical Center Freiburg, Freiburg, Germany, ²Dept. Computer Science and Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan, ³Institute of Microstructure Technology, Karlsruhe Institute of Technology, Karlsruhe, Germany

So far preclinical 4D-Flow MRI has not been able to deliver an analysis of complex flow due to low resolution. The presented framework and improvements allow high quality data acquisitions with a reduced measurement time and the possibility to visualize regional flow abnormalities. An automatic magnitude segmentation in every timeframe combines anatomic information with the underlying blood flow showing even small vessels. It will draw new conclusions in mouse models of cardiovascular diseases as a valuable tool for preclinical researchers.

Joseph Y. Cheng¹, Tao Zhang¹, Marcus T. Alley¹, Michael Lustig², John M. Pauly³, and Shreyas S. Vasanawala^1
1Radiology, Stanford University, Stanford, CA, United States, ²Electrical Engineering & Computer Sciences, University of California, Berkeley, CA, United States, ³Electrical Engineering, Stanford University, Stanford, CA, United States

Volumetric cardiac-resolved flow imaging (4D flow) can enable the assessment of flow, function, and anatomy from a single sequence. Here, 4D flow is extended to higher dimensional space as N-D flow. By resolving different dynamics such as respiration or contrast enhancement, more diagnostic information can be extracted for a single-sequence protocol. Furthermore, this potentially improves image quality and quantification accuracy. N-D flow is enabled by a compressed-sensing and parallel imaging based acquisition and reconstruction. The feasibility of this approach is demonstrated for pediatric imaging. 

Zachary Borden¹, Peng Lai², Ann Shimakawa², Alejandro Roldan-Alzate^1,3, and Christopher J Francois^1
1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²GE Healthcare, Menlo Park, CA, United States, ³Department of Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, United States

Congenital heart disease is a common disease process which benefits from MRI 4D flow analysis. In a total cavo-pulmonary connection model, Cartesion 4D Flow mapping using k-t acceleration and variable density signal averaging correlates well with US flow probe data and 2D PC measurements. The improved post processing efficiency of Cartesian acquisition may allow more widespread adoption of 4D flow technology for analyzing congenital heart disease.