Diffusion-weighted Imaging Versus Doppler Ultrasound in the Diagnosis of Calf Deep Vein Thrombosis

Abstract

Objectives: Doppler ultrasound (DUS) is the primary diagnostic tool used in lower extremity deep vein thrombosis (DVT). However, its accuracy may decrease in the calf-located DVT. This study aims to examine the contribution of diffusion-weighted imaging (DWI) to the diagnosis of acute calf DVT (CDVT). Materials and Methods: Consecutive patients with clinical suspicion of acute onset CDVT, referred to our department between January 1, 2018 and September 1, 2018, were recruited. Patients were initially evaluated with DUS. Same day magnetic resonance imaging (MRI) [axial T1 and T2-weighted, gradient echo, diffusion, and apparent diffusion coefficient (ADC) sequences with 1.5 T MRI] were performed for comparison. The ADC value was measured independently by two radiologists. Second-look DUS was performed as a confirmatory diagnostic method for patients with incompatible MRI and initial DUS findings. Results: Thirty-four patients were recruited during the study period. Restricted diffusion was defined significantly more often in patients with acute DVT (11/13 vs. 2/21, p<0.001). ADC value was 1.08x10-3 mm2 /s ±0.575 and 2.7x10-3 mm2 /s ±0.639 in patients with and without thrombus (p<0.001). Twelve patients had inconsistent results requiring a second look DUS (ultimately 7 false positive, 4 false-negative cases due to initial DUS), and MRI had a false-positive result in 1 patient. Conclusion: DWI could detect acute DVT with ADC mapping. Diffusion MRI of the lower extremity may contribute to the diagnosis of thrombi isolated to the deep veins of the calf, especially in selected patients with inconclusive or sub optimal DUS findings