Objective: Evaluate the image quality and diagnostic performance of a free-breathing 3D-gradient-echo sequence with radial acquisition (rGRE) compared with a Cartesian breath-hold 3D-GRE (cGRE) sequence on hepatobiliary phase MRI in patients with breath-holding difficulties.
Methods: Twenty-eight consecutive patients (15 males; mean age 61 ± 11.9 years) were analysed in this retrospective IRB-approved study. Breath-holding difficulties during gadoxetate-disodium-enhanced liver MRI manifested as breathing artefacts during dynamic-phase imaging. MRI included axial and coronal cGRE and a radially sampled rGRE sequence during the hepatobiliary phase. Two radiologists independently evaluated cGRE and rGRE images for image quality, liver lesion detection and conspicuity, and bile duct conspicuity on a four-point scale.
Results: Liver edge sharpness was significantly higher on rGRE images (P < 0.001). Overall image quality was slightly but significantly higher for rGRE than for cGRE (P < 0.001 and P = 0.039). Bile duct conspicuity scores of rGRE and cGRE were not significantly different. Sensitivity for detection of the 26 liver lesions was similar for rGRE and cGRE (81-77 % and 73-77 %, P = 0.5 and 1.0). Lesion conspicuity scores were significantly higher for rGRE for one reader (P = 0.012).
Conclusion: In patients with breath-holding difficulties, overall image quality and liver lesion conspicuity on hepatobiliary phase MRI can be improved using the rGRE sequence.
Key points: • Patients with diminished breath-holding capacities present a major challenge in abdominal MRI. • A free-breathing sequence for hepatobiliary-phase MRI can improve image quality. • Further advances are needed to reduce acquisition time of the free-breathing gradient-echo sequence.