Measurement of vessel wall strain using cine phase contrast MRI.

PURPOSE To determine the feasibility of using magnetic resonance imaging (MRI) to non-invasively measure strain in the aortic wall. MATERIALS AND METHODS Cine phase contrast MRI was used to measure the velocity of the aortic wall and calculate changes in circumferential strain over the cardiac cycle. A deformable vessel phantom was used for initial testing and in vitro validation. Ultrasonic sonomicrometer crystals were attached to the vessel wall and used as a gold standard. RESULTS In the in vitro validation, MRI-calculated wall displacements were within 0.02 mm of the sonomicrometer measurements when maximal displacement was 0.28 mm. The measured maximum strain in vitro was 0.02. The in vivo results were on the same order as prior results using ultrasound echo-tracking. CONCLUSION Results of in vivo studies and measurement of cyclic strain in human thoracic and abdominal aortas demonstrate the feasibility of the technique.