Clinical Application of Sonographic Elasticity Imaging for Aging of Deep Venous Thrombosis

Objective. Aging of deep venous thrombosis is an important and difficult clinical problem. Because it is known that thrombi harden as they mature, we have preliminarily tested sonographic elasticity imaging, a technique that estimates tissue hardness, to age venous thrombi. Methods. Two adult patients with lower extremity thrombi were studied. One had a clinically chronic thrombus (at least 3 years old), whereas the other patient's thrombus was clinically subacute (25 days old). We performed freehand compression sonographic scans using a 5‐MHz linear array transducer. Phase‐sensitive B‐scan frames were processed offline by a two‐dimensional complex correlation‐based adaptive speckle‐tracking technique. The distribution of internal strains in the wall of the vein, thrombus, and surrounding tissue was analyzed. Clot hardness was normalized to the venous wall. Results. The chronic clot was homogeneous, and the strain in the chronic clot was at least 10 times smaller than that in the vessel wall. The subacute clot was much more heterogeneous, and, on average, the strain magnitude in the clot was 3 to 4 times greater than that in the vessel wall. Conclusions. In this preliminary work, the 2 thrombi appeared very different, and these results suggest that elasticity imaging may be able to age deep venous thrombosis.