Dynamic Contrast-Enhanced MRA of the aorta using a Golden-Angle Radial Sparse Parallel (GRASP) sequence: comparison with conventional time-resolved Cartesian MRA (TWIST)

Abstract Purpose: to compare the application of two contrast-enhanced time-resolved magnetic resonance angiography sequences on an aortic diseases patient cohort: the conventional Cartesian-sampling-based, TWIST sequence, and the radial-sampling-based GRASP sequence. Radial-sampling-based techniques are less sensitive to motion than cartesian sampling and consequently are expected to improve the image quality in body parts subjected to motion. Methods: 1.5T magnetic resonance angiography data from thirty patients (60.9±16.1y.o.) were assessed to investigate image quality as well as spatial and temporal blurring in the ascending aorta (AA), descending aorta (DA) and abdominal aorta (AbA). Results: GRASP offered superior depiction of vascular structures in terms of vascular contrast for qualitative analysis (TWIST, reader 1: 1.6±0.5; reader 2: 1.9±0.4; reader 3: 1.1±0.4; GRASP, reader 1: 1.5±0.5; reader 2: 1.4±0.5; reader 3: 1.0±0.2) and vessel sharpness for qualitative (TWIST, reader 1: 1.9±0.6; reader 2: 1.6±0.6; reader 3: 2.0±0.3; GRASP, reader 1: 1.4±0.6; reader 2: 1.2±0.4; reader 3: 1.3±0.6) and quantitative analysis (TWIST, AA=0.12±0.04, DA=0.12±0.03, AbA=0.11±0.03; GRASP, AA=0.20±0.05, DA=0.22±0.06, AbA₌0.20±0.05). Streaking artefacts of GRASP were stronger visible compared to TWIST (TWIST, reader 1: 2.2±0.6; reader 2: 1.9±0.3; reader 3: 2.0±0.5; GRASP, reader 1: 2.6±0.6; reader 2: 2.3±0.5; reader 3: 2.8±0.6). Conclusion: GRASP outperformed TWIST in SNR, vessel sharpness and reduction in image blurring; streaking artifacts were stronger visible with GRASP, but did not affect diagnostic image quality.