CMR real-time, free-breathing, phase contrast flow quantification: a novel approach to assess ventricular coupling in co
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CMR real-time, free-breathing, phase contrast flow quantification: a novel approach to assess ventricular coupling in constrictive pericarditis Paaladinesh Thavendiranathan*, David Verhaert, Michael Walls, Sanjay Rajagopalan, Chung Yiu-Cho, Orlando Simonetti, Subha V Raman From 2011 SCMR/Euro CMR Joint Scientific Sessions Nice, France. 3-6 February 2011 Background/objective Constrictive pericarditis (CP) is an important cause of heart failure; however, with accurate diagnosis and directed treatment it is potentially curable. Cardiac magnetic resonance imaging (CMR) has played a diagnostic role, primarily by allowing assessment of pericardial morphology but with limited depiction of physiological changes. We sought to examine the feasibility of a novel CMR approach that enables real-time phase contrast (RT-PC) assessment of discordant respirophasic changes in trans-mitral and tricuspid flow velocity - the signature findings in CP - due to enhanced ventricular interdependence.
Method Patients referred to the CMR lab pre-pericardectomy or for assessment of suspected CP were included. Following routine CMR examination for CP, transmitral (MV) and tricuspid valve (TV) flow velocities were simultaneously obtained by through-plane RT-PC imaging during unrestricted respiration using a slice position to include both valves (Figure 1) with the following parameters: TR/TE=13.7ms/2.5ms, water excitation pulse with flip angle=25 o , 10mm slice thickness, 160x120 matrix, EPI factor=15, TSENSE rate=2, slice thickness=10mm, and VENC=150cm/s. Shared velocity encoding was used to achieve an effective temporal
Figure 1 (A) Horizontal long axis cine image used for selection of RT-PC imaging plane. (B) Magnitude and (C) phase images obtained with RT-PC acquisition. Regions of interest for mitral inflow (red) and tricuspid inflow (green) are illustrated in both the magnitude and phase images.
The Ohio State University, Columbus, OH, USA © 2011 Thavendiranathan et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Thavendiranathan et al. Journal of Cardiovascular Magnetic Resonance 2011, 13(Suppl 1):O33 http://jcmr-online.com/content/13/S1/O33
resolution of 55ms and typically, 200-400 phases were obtained. The diagnosis of CP was confirmed using a combination of clinical history, diagnostic imaging, invasive hemodynamic measurements, intra-operative findings, and histopathology. Regions of interest at the mid-portion of the MV and TV were chosen on the PC images (Figure 1). Peak velocity data from average of 4 neighboring pixels for both valves were displayed simultaneously (Figure 2). The percentage change in velocity were calculated for MV as (MV expiratory E velocity -
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inspiratory E velocity)/(inspiratory E velocity) and for TV as (T
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