Simultaneous quantitative evaluation of both iliac arteries and veins via accelerated four-dimensional flow in healthy controls and patients with deep vein thrombosis: a pilot study

Background: Understanding iliac hemodynamics in both healthy individuals and patients with vascular diseases is important from both physiological and pathological perspectives, and the four-dimensional (4D) flow technique is a valuable tool for the accurate quantification of hemodynamics. However, conventional 4D flow acquisition is time-consuming. Therefore, this study aimed to evaluate the hemodynamics of the iliac arteries and veins using both conventional single-velocity encoding (VENC) and compressed sensing (CS)-accelerated dual-VENC 4D flow sequences in healthy controls (HCs) and patients with deep vein thrombosis (DVT). Methods: This study included HCs and patients with DVT between December 2024 and April 2025. Two conventional single-VENC 4D flow sequences with high and low VENCs and a dual-VENC CS-accelerated sequence were performed and postprocessed by two experienced readers. Quality control, including test-retest reliability, agreement between techniques, and intra- and inter-reader agreement, was performed, and the correlation between age and flow parameters was also calculated. Results: The acquisition time for conventional high-VENC, low-VENC, and CS dual-VENC 4D flow was 10.6, 10.7, and 8.8 min, respectively. In the quality control analysis, the intraclass correlation coefficients (ICCs) for test-retest reliability, intraobserver, and interobserver agreements were all >0.85 (P≤0.001). In arterial segments, both velocity and wall shear stress (WSS) measured by the CS methods were lower than those obtained by conventional methods, with the underestimation percent ranging from 2.8% to 11.8% in HCs and from 1.9% to 14.8% in patients with DVT. For venous segments, CS-based measurements underestimated velocity and WSS by 1.1-12.0% in HCs and 1.3-14.2% in patients with DVT. Negative correlations were found between age and arterial velocity (R=-0.33), arterial WSS (R=-0.34), and venous velocity (R=-0.29) (all P values