Abstract
We investigated the reliability of contrast-enhanced ultrasound (CEUS) in assessing calf muscle microvascular perfusion in health and disease. Response to a post-occlusive reactive hyperaemia test was repeated on two occasions >48 h apart in healthy young (28 +/- 7 y) and elderly controls (70 +/- 5 y), and in peripheral arterial disease patients (PAD, 69 +/- 7 y; n = 10, 9 and 8 respectively). Overall, within-individual reliability was poor (coefficient of variation [CV] range: 15-87%); the most reliable parameter was time to peak (TTP, 15-48% CV). Nevertheless, TTP was twice as long in elderly controls and PAD compared to young (19.3 +/- 10.4 and 22.0 +/- 8.6 vs. 8.9 +/- 6.2 s respectively; p < 0.01), and area under the curve for contrast intensity post-occlusion (a reflection of blood volume) was similar to 50% lower in elderly controls (p < 0.01 versus PAD and young). Thus, CEUS assessment of muscle perfusion during reactive hyperaemia demonstrated poor reliability, yet still distinguished differences between PAD patients, elderly and young controls. (C) 2015 World Federation for Ultrasound in Medicine & Biology.