Comparison of different MRI techniques for measuring aortic compliance
- PDF / 1,218,581 Bytes
- 2 Pages / 610 x 792 pts Page_size
- 8 Downloads / 176 Views
BioMed Central
Open Access
Poster presentation
Comparison of different MRI techniques for measuring aortic compliance El-Sayed H Ibrahim*, Kevin R Johnson, Jean M Shaffer and Richard D White Address: Oxford University, Oxford, UK * Corresponding author
from 13th Annual SCMR Scientific Sessions Phoenix, AZ, USA. 21-24 January 2010 Published: 21 January 2010 Journal of Cardiovascular Magnetic Resonance 2010, 12(Suppl 1):P137
doi:10.1186/1532-429X-12-S1-P137
Abstracts of the 13th Annual SCMR Scientific Sessions - 2010
Meeting abstracts - A single PDF containing all abstracts in this Supplement is available here. http://www.biomedcentral.com/content/files/pdf/1532-429X-11-S1-infoThis abstract is available from: http://jcmr-online.com/content/12/S1/P137 © 2010 Ibrahim et al; licensee BioMed Central Ltd.
Introduction Maintenance of aortic visco-elastic properties is essential for proper physiology(1). Reduced aortic compliance has shown to correlate with different pathologies (e.g. dissection). Invasive techniques using pressure catheters are historically the gold standard for measuring aortic stiffness. Transit-time (TT) (2) and cross-correlation (XC) (3) are recently introduced as MRI techniques for measuring pulse wave velocity (PWV), which reflects the vessel compliance. However, the reproducibility and behavior of these techniques have not yet been studied, which is the purpose of this work.
analyzed the images to determine inter-observer variability. One of the experts analyzed the images twice to compute intra-observer variability. Paired t-tests and BlandAltman analysis were conducted to measure the difference significance between the results. P < 0.05 was considered statistically significant.
Results The measured PWV values ranged from 2-16 m/s. The inter-observer/intra-observer variabilities were low as indicated by the interclass correlation-coefficient r = 0.94/ 0.98 and 0.83/0.87 for the TT and XC methods, respectively. The scan-rescan results did not show significant dif-
Methods Thirty consecutive cardiac patients (22 males/8 females; age = 51 ± 15 years), along with five healthy volunteers, were scanned on a 3 T MRI system (Siemens TIM TRIO, Erlangen, Germany). Three velocity-encoded (venc) cine images of the descending aorta were acquired: one ("candy cane") series along the aortic path and two crosssection series separated by about 12 cm. The imaging parameters were: flash sequence; TR/TE = 40/2 ms; flipangle = 15º; slice-thickness = 8 mm; venc = 150 cm/s; #phases = 128; scan-time = 26 s/slice of shallow breathing. In-house software was created with Matlab for analyzing the images. Figs. 1 and 2 show images of the same person, where PWV was calculated with TT and XC methods, respectively. Five of the conducted MRI scans were repeated twice with different position markers and scouting to compute the scan-rescan variability. Two experts
Figure 1 method for calculating PWV Transit-time Transit-time method for calculating PWV. Velocity curves (left) are computed at two distant points a
Data Loading...
