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- Open Access
Comparison of different MRI techniques for measuring aortic compliance
© Ibrahim et al; licensee BioMed Central Ltd. 2010
Published: 21 January 2010
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.
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 cross-section series separated by about 12 cm. The imaging parameters were: flash sequence; TR/TE = 40/2 ms; flip-angle = 15º; slice-thickness = 8 mm; venc = 150 cm/s; #phases = 128; scan-time = 26 s/slice of shallow breathing.
Discussion and conclusion
The TT and XC methods provide reproducible means of estimating PWV in the aorta. The TT method produced the most reproducible measurements with minimal user interface. The XC method has the shortest processing time and requires only one series of MRI images. Both techniques require high temporal resolution for accurate measurements. In conclusion, either technique can be used for estimating aortic PWV with insignificant difference between the results.
This article is published under license to BioMed Central Ltd.