Quantitative Assessment of Arterial Stiffness by Multiphase Analysis in Retrospectively Electrocardiogram-Gated Multidetector Row Computed Tomography

PURPOSE: To determine the feasibility of assessment of arterial stiffness with multiphase analysis of data sets of retrospectively electrocardiogram (ECG)-gated multidetector row computed tomography (MDCT) coronary angiography by comparing wall stiffness of the descending aorta between patients under chronic hemodialysis and age-matched controls undergoing imaging for by-pass graft. MATERIALS AND METHODS: We retrospectively assessed 33 patients composed of 10 hemodialysis patients and 23 age-matched control subjects, who underwent MDCT to evaluate the coronary arterial lesions and pulse wave velocity (PWV) measurement. Scan data were reconstructed at 25 phases between 0% and 96% of the R-R intervals with an increment of 4%. Pixel-based measurements of arterial dimensions were performed at 1 cross-section of the descending aorta in a transaxial plane including the aortic valve at its widest. Aortic distensibility (AD) was calculated as follows: AD = (maximal dimension -- minimal dimension)/minimal dimension x pulse pressure. Comparison in the AD was performed between the hemodialysis patients and control subjects. Correlation between the AD and PWV were assessed separately in the patients under hemodialysis and age-matched controls. RESULTS: AD was significantly smaller in patients under hemodialysis than in age-matched controls. The square of PWV correlated better with the inverse of the AD in the control subjects compared to patients on hemodialysis. CONCLUSION: Multiphase analysis in ECG-gated MDCT enables us to assess stiffness of the descending aorta objectively and noninvasively.