3D cine PCA enables rapid and comprehensive hemodynamic assessment of the abdominal aorta

Transcription

1 3D cine PCA enables rapid and comprehensive hemodynamic assessment of the abdominal aorta Poster No.: C-1138 Congress: ECR 2013 Type: Scientific Exhibit Authors: M. Takahashi 1, Y. Takehara 2, H. Isoda 3, T. Okuaki 4, Y. Fukuma 4, Keywords: DOI: T. Shimizu 2, N. Tooyama 1, K. Ichijo 1, H. Sakahara 2 ; 1 Hamamatsu, Select/JP, 2 Hamamatsu/JP, 3 Nagoya/JP, 4 Tokyo/JP Hemodynamics / Flow dynamics, Arteriosclerosis, Aneurysms, Audit and standards, MR-Angiography, Cardiovascular system /ecr2013/C-1138 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 9

2 Purpose Recently, there is increasing evidence that hemodynamic flow pattern is highly related to formation of atherosclerotic plaque. However, there have been no reliable databases concerning the flow dynamics of the normal and diseased aorta. The phase-resolved 3D phase contrast angiography (3D cine PC) allows measurements of the flow velocities within the entire vascular geometry throughout the cardiac cycle in-vivo. The purpose of this feasibility study is to test whether 3D cine PC with the latest 3.0T MR scanner can provide information concerning the flow dynamics of the normal abdominal aorta within a brief imaging time without using any contrast media. Methods and Materials Written informed consent was provided in all cases for this IRB approved study. Six normal volunteers were examined on a wide bore 3.0T MR scanner (Ingenia 3.0T, Phillips Electronics Japan, Ltd.) with use of phased array multicoil. 3D cine PC of the whole abdominal aorta and 2D cine PC (one axial slice at the infrarenal aorta) for reference were performed. Coronal 3D cine PC of the infrarenal abdominal aorta was performed using following parameters; TR(ms)/TE(ms)/FA(degree)/ of 4/2/10, Matrix of 256 x 195, reduction factor of 3.5, 20 slices, 12 phases/cardiac cycle and PPU gating. The value of velocity encoding was determined by the flow velocimetry performed with axial 2D cine PC. Acquired data were post-processed with flow analysis software. The average flow velocities during entire cardiac cycle in the same section as the 2D PC MRA were calculated and they were compared. Streamlines and calculated WSS were depicted in color coded 3D models. The composite images with information of flow combined from all 3 directions (PCA-M), automatically calculated from 3D cine PC, in mid-systole were used for segmenting arterial wall boundary. Results 3D cine PC data were successfully acquired in all subjects with brief imaging time of about 3 minutes. Reasonable quality of 3D MRA (average CNR of 190 +/- 39) was successfully post processed using PCA-M, which was used for segmenting abdominal aorta, in all cases. The average flow velocities calculated from 3D cine PC and 2D cine PC showed near values throughout entire cardiac cycle (Table 1). Page 2 of 9

3 Table 1: The average flow velocities calculated from 3D cine PC and 2D cine PC showed near values during entire cardiac cycle. References: Radiology, Seirei Mikatahara General Hospital - Hamamatsu/JP The average flow velocity at mid-systole at infrarenal transverse plane acquired by 3D cine PC and 2D cine PC MRA were / cm / s and / cm / s, respectively, with correlation coefficient of 0.66 (p<0.05),and those at mid-diastole were 2.9 +/- 0.9 cm / s and 2.8 +/- 1.0 cm / s, respectively, with correlation coefficient of 0.97 (p<0.05). Streamline analysis showed the flow patterns were laminar during the entire systole (Fig. 1). Page 3 of 9

4 Fig. 1: Representative color coded 3D maps post-processed for the assessment of hemodynamic patterns and WSS of 40 y.o. male volunteer. Streamline at end-systole delineates laminar flow throughout the whole geometry of the abdominal aorta. The streamline at end-diastole shows the brief period of turbulent flow. The values of WSS were high in most part of aortic wall at end-systole. References: Radiology, Seirei Mikatahara General Hospital - Hamamatsu/JP This undisturbed flow patterns and distributions of high WSS (Fig. 1) were different from those previously reported in ASO or AAA (Fig. 2). Page 4 of 9

5 Fig. 2: In the abdominal aorta suffering from aneurysm, vortices and turbulences are dominant and the WSS of the aneurysm is low even during systole. These images were post-processed from the data obtained with the same method as the current study. References: Radiology, Seirei Mikatahara General Hospital - Hamamatsu/JP Images for this section: Page 5 of 9

6 Table 1: The average flow velocities calculated from 3D cine PC and 2D cine PC showed near values during entire cardiac cycle. Page 6 of 9

7 Fig. 1: Representative color coded 3D maps post-processed for the assessment of hemodynamic patterns and WSS of 40 y.o. male volunteer. Streamline at end-systole delineates laminar flow throughout the whole geometry of the abdominal aorta. The streamline at end-diastole shows the brief period of turbulent flow. The values of WSS were high in most part of aortic wall at end-systole. Page 7 of 9

8 Fig. 2: In the abdominal aorta suffering from aneurysm, vortices and turbulences are dominant and the WSS of the aneurysm is low even during systole. These images were post-processed from the data obtained with the same method as the current study. Page 8 of 9

9 Conclusion With use of 3T and 3D cine PC MRA, hemodynamic assessment for the abdominal aorta was feasible in normal volunteers without administering any contrast media. Hemodynamic assessment of the abdominal aorta was feasible with rapid 3D cine PC. Its brief imaging time allows it to be included in a routine examination schedule and may help building a database concerning flow dynamics in normal and diseased aorta, which will be essential in research to disclose the link between flow disturbance and atherosclerosis. References none Personal Information Page 9 of 9