Contrast ultrasound perfusion imaging of lower extremities in peripheral arterial disease: a novel diagnostic method

The purpose of this study was to establish contrast-enhanced ultrasound perfusion imaging (CUPI) of the lower extremities as a novel non-invasive diagnostic tool for patients with peripheral arterial disease (PAD).

Ultrasound contrast agent (SonoVue) was injected into a peripheral vein of 16 control subjects and 16 PAD patients and its appearance in the calf muscle was detected by low-energy harmonic ultrasound. Analysis of the wash-in curves revealed that PAD patients had a significantly longer time to peak intensity (TTP), i.e. duration of maximum contrast perfusion [37 s (19-79 s) in control subjects vs. 56 s (32-104 s) in PAD patients at rest, age-adjusted P=0.002]. Exercise stress test of the calf muscle resulted in a decrease of the TTP, maintaining the significant difference in TTP between the groups [19 s (8-37 s) in control subjects vs. 32 s (18-48 s) in PAD patients after exercise, age-adjusted P=0.004]. Neither ankle-brachial index and TTP nor age and TTP showed a significant correlation.

CUPI reflects the regional blood circulation of the calf muscle. In this pilot study, PAD patients show a significantly longer TTP than control subjects. The clinical relevance of CUPI is topic of ongoing studies.