Free-breathing non-contrast-enhanced flow-independent MR angiography using magnetization-prepared 3D non-balanced dual-echo Dixon method: A feasibility study at 3 Tesla.

In this work we aimed to investigate the feasibility of using a new pulse sequence called Relaxation-Enhanced Angiography without Contrast and Triggering (REACT) for free-breathing non-contrast-enhanced MR angiography (NCE-MRA) for multiple anatomies on 3T. Two magnetization-preparation pulses were incorporated with a three-dimensional dual-echo Dixon sequence. A T2-prep pulse, followed by a non-selective inversion pulse with a short inversion time, together suppressed tissue with short T1 and T2, while enhancing the signal of native blood with long T1 and T2. A two-point non-balanced gradient-echo Dixon method, based on dual-echo acquisition with semi-flexible echo times for water-fat separation, was used for improved fat suppression over a large field of view. General image quality, vasculature visibility, and clinical indications of the proposed method were investigated in healthy subjects and patients in both torso and extremities based on visual inspection. Preliminary results from REACT obtained in free-breathing with no cardiac triggering showed uniform suppression of background tissue over the field of view and robust blood-to-tissue contrast over multiple anatomies. Future clinical studies are warranted for further investigation of its diagnostic performance and limitations.
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