Fig. 4.

Example of contrast-enhanced ultrasound perfusion imaging in PAD. The top images illustrate background-subtracted color-coded images and corresponding time-intensity data at rest and during plantar flexion exercise from the calf muscles of a normal control subject. The bottom images show similar data from a patient with PAD and moderate claudication. Flow reserve from time-intensity data are at the top of each graph. Reproduced with permission.38) PAD: peripheral artery disease, BG: background image obtained immediately after microbubble destruction, s: seconds.