Abstract

Magnetic resonance direct thrombus imaging (MRDTI) is the first technique that directly visualizes thrombus in humans in vivo. Thrombus is associated with a substantial reduction in T1 caused by the paramagnetic properties of methaemoglobin, and this produces high signal intensity (bright) on T1-weighted images against a background of suppressed blood and fat (dark). This displays a positive image of thrombus without having to use intravenous contrast. Furthermore, direct visualization of thrombus rather than its indirect detection as a filling defect in flowing blood, or by surrogate markers such as changes in venous flow dynamics, overcomes many of the pitfalls of conventional imaging techniques and should provide an immediate definitive answer as to the presence or absence of clot. Moreover, simultaneous imaging of the legs and chest allows a comprehensive ascertainment of thrombus load.

Preliminary studies have shown that MRDTI is highly accurate for the diagnosis of both deep venous thrombosis