Optimized 3D bright blood MRI of aortic plaque at 3 T

Purpose: To evaluate the feasibility of an optimized bright blood MRI protocol at 3 T in combination with contrast agent administration for the detection and characterization of aortic high-risk plaques for the improved workup of acute stroke patients. Materials and Methods: ECG synchronized T1-weighted 3D gradient echo MRI was performed in 45 acute stroke patients. Data were acquired with high near isotropic spatial resolution (∼1 mm³) covering the entire thoracic aorta. To compensate for breathing and vessel motion artifacts, images were collected using respiratory navigator gating in combination with short diastolic data acquisition windows adjusted on a patient-by-patient basis. In patients with aortic plaques ≥3 mm in thickness, gadolinium contrast agent was administered and both pre- and post-contrast T1-weighted 3D measurements with identical vessel coverage were performed. Results: Bright blood 3D MRI detected 33 high-risk plaques with an average maximum plaque thickness of 4.2±1.0 mm in 23 of 45 acute stroke patients. The availability of pre- and post-contrast images acquired within the same session enhanced the identification of calcified plaque components in 77% of all analyzed plaques: post-contrast MRI clearly improved the delineation of hypointense plaque cores in 23 of 30 cases and assisted in the classification of core shape and of core fraction. Conclusion: 3D bright blood MRI at 3 T was feasible for the detection of aortic high-risk sources and may help to improve the detection of causes of cerebral embolism in acute stroke patients.