Diagnostic Utility of Magnetic Resonance Imaging for Plantar Vein Thrombosis.

Background: Plantar vein thrombosis (PVT) is a rare cause of unilateral plantar foot pain not commonly assessed during sonographic scans for venous thromboembolic evaluation. The present study aims to increase awareness of PVT when evaluating musculoskeletal conditions and to discuss the utility and characteristic imaging findings of PVT on magnetic resonance imaging (MRI).

Methods: This is a retrospective chart review identifying patients with suspected PVT via search of a single institution's radiology reports. Twelve patients had an available lower extremity MRI. These 12 MRIs were independently reviewed by 2 fellowship-trained musculoskeletal radiologists for common imaging characteristics. Of note, only 7 of the 12 available imaging studies contained MRI findings consistent with PVT as determined by the radiology reviewers. For these 7 patients, clinical characteristics were also recorded.

Results: Between both radiology reviewers, there was 100% agreement confirming, localizing, and describing the findings of PVT. Of the 7 cases of MRI-confirmed PVT, 6 of 7 studies were performed without contrast and 1 of 7 was performed with and without contrast. The lateral plantar vein was the predominant vein involved in 85.7% (6/7). All 7 cases showed signs of intraluminal signal change, venous enlargement, and muscle edema. Two cases (28.6%, 2/7) displayed collateralization and/or enlargement of surrounding veins. In the only MRI performed with contrast, perivascular enhancement and a filling defect were noted.

Conclusion: In the evaluation of a painful foot, an MRI can be used to diagnose PVT reliably and may have several advantages over compression ultrasonography (US) because of its ability to identify other unsuspected etiologies of a painful foot and elimination of technical limitations of compression US in the plantar foot region.