Improved aortic stiffness assessment in the elderly using a one-dimensional fluid displacement MR method.

Purpose: To assess the in vitro accuracy of two rapid projective MR wave velocity measurement sequences, and their relative performance for assessing aortic stiffness in adults of all ages.

Materials And Methods: In vitro testing was performed using latex tube phantoms with precisely-known flow wave velocities, both in the presence and absence of simulated static tissue. A total of 104 adults representing a large age range (21-83 years) underwent aortic wave velocity (AWV) measurements using multiple trials of each method in a single MR session. The relative agreement between the two AWV results in each tertile of subject age and the coefficient of variation of the AWV data were assessed.

Results: In vitro wave velocities did not differ significantly from the known values for either MR method, with or without simulated static tissue. In vivo, the mean AWVs for the young and middle-aged cohorts did not differ significantly between the two MR methods. However, in the elderly group, the two methods did not agree, and one sequence was found to be superior in this age cohort.

Conclusion: In elderly individuals, a one-dimensional MR method for evaluating aortic stiffness based on aortic blood displacement yields a smaller coefficient of variation and superior overall performance than a similar method based on aortic blood velocity. The two methods perform equivalently in young and middle-aged subjects.