Quantitative two-dimensional phase-contrast magnetic resonance imaging characterization of lower extremity venous disease: venous reflux versus venous obstruction.

Background: Lower extremity venous disease (LEVD) is a complex disorder, and determining the etiology of LEVD is paramount for treatment selection. Two-dimensional phase-contrast magnetic resonance imaging (2D PC-MRI) can provide an objective measure of hemodynamic status and may help differentiate between different etiologies of LEVD. A total of 271 participants, including 256 symptomatic patients with venous lower extremity disease and 15 healthy volunteers, were collected in this cohort study. Methods: It is a single-center prospective observational study using 2D PC-MRI analysis to assess the hemodynamic characteristics of patients with LEVD among participants recruited between April 2017 and October 2021 at a tertiary hospital. The approval institutional review board number for this study were 201802137B0, 201901058B0, 202100938B0, and 202102344B0. Participants were classified as venous reflux (VR) and venous obstruction (VO) by standard ultrasonography. 2D PC-MRI by 1.5 T scanner revealed stroke volume (SV), forward flow volume (FFV), absolute stroke volume (ASV), mean flux (MF), velocity time integral (VTI), and mean velocity (MV) for each selected venous segments. Results: 2D PC-MRI assessed 167 diseased legs from the 116 VR patients [mean age ± standard deviation (SD): 57.9±12.8 years; 39 males] and 113 diseased legs from the 95 VO patients (mean age ± SD: 66.4±12.8 years; 42 males). 2D PC-MRI analysis demonstrated discrimination ability to differentiate from VR to VO [SV, FFV, ASV, MF, VTI, and MV in the various venous segments, respectively, P≤0.001; area under the curve (AUC) =62-68.8%, P≤0.001 by Mann-Whitney U test]. The ratio data (morbid limb to normal limb) in the same individual with single-leg disease revealed differences between VR and VO (SV, FFV, ASV, and MF in the various venous segments, respectively; P<0.05; AUC =60.2-68.7%, P≤0.05 by Mann-Whitney U test). The most favorable differentiating variables of ratios were FFV in the great saphenous veins [AUC =68.7%, 95% confidence interval (CI): 59.8-77.6%] and ASV in the external iliac veins (AUC =67.4%, 95% CI: 58.7-76.2%). Conclusions: Quantitative 2D PC-MRI analysis is capable of differentiating VR from VO. It also provides an important diagnostic capability for preoperative evaluation.