Fully self-gated dual-venc five-dimensional flow magnetic resonance imaging for simultaneous imaging of the cardiovascular and portal venous systems: A feasibility study.

PURPOSE: To develop and evaluate a fully self-gated dual-venc five-dimensional (5D) flow cardiovascular magnetic resonance (CMR) technique for joint assessment of cardiovascular and portal venous hemodynamics under free breathing.

METHODS

A dual-venc 5D flow sequence using a spiral-in Cartesian sampling trajectory was implemented. Cardiac and respiratory motion were retrospectively resolved using principal component analysis of self-gating signals, followed by total variation regularized reconstruction. The technique was first tested in a custom-built phantom with steady flow and stationary parts, and compared with conventional four-dimensional (4D) flow. It was then evaluated in healthy volunteers and in patients with cirrhosis or portal hypertension, including post-transjugular intrahepatic portosystemic shunt (TIPS) cases. No contrast agent was administered for either the phantom or in vivo scans, with an in vivo 5D flow scan time of approximately 15 min per subject. Hemodynamic parameters in both the cardiovascular and portal venous systems were quantified and compared with conventional breath-held, ECG-triggered two-dimensional (2D) phase-contrast (PC) MRI. For each subject, flow internal consistency (IC) across vessel planes and respiration-resolved flow variations were also computed.

RESULTS

Phantom experiments demonstrated an average 67% improvement in velocity-to-noise ratio (VNR) and similar flow quantification compared with fully sampled 4D flow MRI. In vivo evaluation included 12 healthy volunteers, 8 cirrhosis patients, and 9 post-TIPS patients. Across all cohorts, dual-venc 5D flow achieved substantial VNR enhancement (approximately 200% on average), high flow IC (>82%), and strong agreement with 2D PC MRI for both peak and net flow (bias <10%). Respiration-resolved analysis revealed a consistent increase in net flow in the main pulmonary artery (MPA), right pulmonary artery (RPA), and superior vena cava (SVC) during inspiration, along with elevated SVC peak flow.

CONCLUSIONS

Fully self-gated dual-venc 5D flow MRI enables simultaneous, respiration-resolved quantification of cardiovascular and portal venous hemodynamics within a clinically feasible scan time and with high VNR. This technique provides a promising tool for characterizing systemic hemodynamics in cirrhosis and for evaluating portal-systemic circulatory interactions following TIPS.