Figure 1From: Very different performance of the power Doppler modalities of several ultrasound machines ascertained by a microvessel flow phantomDifferent performance of the power Doppler ultrasound modality of two machines in one patient. (A) Machine B, presence of a positive power Doppler signal (arrow) within the region of synovial proliferation. (B) Machine A, this signal is absent. Arrowhead, vessel; *noise on cortical surface.Back to article page