Compliance of the normal-sized aorta in adolescents with Marfan syndrome:: Comparison of MR measurements of aortic distensibility and pulse wave velocity

Purpose: To compare the aortic compliance of the normal-sized aorta of adolescents with Marfan syndrome and healthy controls using MR measurements of the aortic distensibility and pulse wave velocity. Materials and Methods: Fourteen patients (median age: 15 (9-21] years) and 11 healthy subjects (23 [12-32] years) were examined at 1.5 T. The MR protocol included 2D steady-state free precession (SSFP)-CINE MRI of the aortic distensibility and PC-MRI of the pulse wave velocity. All measurements were positioned perpendicular to the descending,aorta at the level of the diaphragm for assessing the changes in the aortic cross-sectional areas and additionally above and below this plane for assessing the pulse wave velocity. In addition contrast-enhanced 3D-MR angiography was performed in adolescents with Marfan syndrome to exclude morphologic changes and to prove normal-sized aorta. Results: Compared with control subjects, adolescents with Marfan syndrome had significantly decreased distensibility and significantly increased pulse wave velocity (chi(2)-test, p = 0.0002) using an age-related non-linear regression analysis. The related aortic compliance was significantly decreased (chi(2)-test, p = 0.0002). There was a good correlation between the two methods (r = 0.86). A low intraobserver variability was found for both methods (<= 2 %). Conclusions: MRI allows detecting abnormal elastic aortic wall properties already in the normal-sized aorta of adolescents with Marfan syndrome. Monitoring of these properties could be relevant for evaluating disease onset and progression. MRI has the potential value of compliance measurements for the follow-up and to guide therapy indications.