Skeletal muscle perfusion in peripheral arterial disease a novel end point for cardiovascular imaging

Abstract

Peripheral arterial disease (PAD) is characterized by lower limb arterial obstruction due to atherosclerosis. There are over 8 million people with PAD in the U.S at present (1). As a consequence of impaired tissue perfusion, PAD patients can experience pain, diminished exercise capacity, and tissue loss, with some ultimately requiring amputation (2). The presence of PAD is a high risk marker of additional cardiovascular disease as the annual rate of events including myocardial infarction, stroke, and cardiovascular death is 5% to 7% (3). Presently used diagnostic methods include the ankle-brachial index (ABI), pulse volume recordings, duplex ultrasonography, venous plethysmography and angiography by X-ray, computed tomography, or magnetic resonance imaging, all of which have limitations.

Figures

Figure 1. Contrast-Enhanced Inversion Recovery MR Image of the Calf at Peak Exercise

This is a cross-sectional inversion recovery magnetic resonance (MR) image of the right calf of a normal subject obtained immediately after cessation of plantar-flexion exercise to exhaustion while in a 1.5-T MR scanner and after infusion of 0.1 mM/kg of a gadolinium chelate contrast agent. Note that in this subject, work was performed by the anterior tibialis and soleus muscles (arrows), which appear bright due to the rapid arrival of contrast. There is much less signal and thus less perfusion noted in the gastrocnemius (in the posterior portion of the calf).