ROLE OF MAGNETIC RESONANCE VENOGRAPHY IN EVALUATION OF LOWER LIMB VENOUS PATHOLOGIES

Abstract

Background: Lower-limb venous disorders encompass a wide spectrum of conditions, including deep vein thrombosis, chronic venous insufficiency, varicose veins and venous malformations. Doppler ultrasonography is commonly used for initial evaluation; however, assessment of proximal veins, disease extent and complex venous anatomy may be limited. Magnetic resonance venography (MRV) provides comprehensive non-invasive visualization of the lower-limb venous system and may provide additional anatomical information. Aim: To evaluate the role of magnetic resonance venography in the assessment of lower-limb venous pathologies and to compare its findings with Doppler ultrasonography. Methods: This hospital-based cross-sectional observational study included 50 patients with suspected lower-limb venous pathology who underwent Doppler ultrasonography followed by MRV. Patients were evaluated for suspected deep vein thrombosis, chronic venous insufficiency, varicose veins and venous malformations. MRV was performed using a 3-Tesla MRI system with non-contrast time-of-flight and phase-contrast sequences, covering the venous system from the pelvis to the ankles. The iliac, femoral, popliteal and calf veins were assessed for thrombosis, reflux, obstruction, collateral formation, anatomical variations, chronic venous changes and venous malformations. MRV findings were compared with Doppler ultrasonography. Diagnostic performance was assessed using sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy. Interobserver agreement was evaluated using Cohen's kappa. Results: The mean age of the study population was 46.2 ± 12.8 years, with males comprising 56%. Limb swelling (82%) and pain (76%) were the predominant clinical presentations. Suspected deep vein thrombosis was the commonest indication (48%). MRV demonstrated acute thrombosis in 36%, chronic thrombosis in 18%, venous reflux/chronic venous insufficiency in 28%, venous malformations in 8%, and no abnormality in 10% of patients. MRV achieved 100% anatomical coverage of the iliac, femoral, popliteal and calf veins and detected more thrombotic segments than Doppler at all levels. Overall, venous abnormalities were detected in 90% by MRV compared with 74% by Doppler, with 8 additional cases identified by MRV. MRV detected venous reflux in 14 versus 10, collateral veins in 12 versus 4, and venous wall thickening in 11 versus 3 patients compared with Doppler. All four venous malformations were detected by MRV compared with two by Doppler. MRV demonstrated 95.6% sensitivity, 88.9% specificity, 93.5% PPV, 91.7% NPV and 92% overall accuracy. Interobserver agreement was high for thrombosis (κ=0.86), extent of disease (κ=0.82) and venous malformations (κ=0.90). Additional findings included pelvic venous compression in 12%, collateral venous channels in 28%, and musculoskeletal abnormalities in 10%. MRV findings resulted in treatment modification in 34%, assisted surgical planning in 24%, and reduced the need for invasive procedures in 58% of patients. Conclusion: MRV demonstrated high diagnostic performance and provided more comprehensive anatomical assessment of lower-limb venous pathology than Doppler ultrasonography in the study population. Its ability to demonstrate additional thrombotic segments, chronic venous changes, collateral pathways, proximal venous compression and venous malformations highlights its value as a complementary problem-solving modality, particularly in patients with extensive, proximal or anatomically complex venous disease.