Power Doppler analysis of tendon vascularization

Forty-nine patients with tendonitis (patellar in 16, quadriceps in two, Achilles in 12, rotator cuff disease in 19) and 47 patients with tenosynovitis (acute tenosynovitis in 25, stenosing tenosynovitis in 22) underwent ultrasound (US) and Power Doppler (PD)-US examination. Spectral analysis of flow signals was performed in all patients. Ten patients (six with tendonitis, four with tenosynovitis) were rewired after medical therapy. Six healthy volunteers were also examined for control purposes. Three different patterns of flow distribution were found in patients with tendonitis and active tenosynovitis. The vessels of tendons without tendon sheaths began with great peduncles at the level of the peritendinous soft tissues and were then distributed inside the tendon (pattern I). A clear peritendinous hypervascular pattern was found in all active tenosynovitis, but no vessels were found inside the tendons (pattern II). In some cases of intratendinous or partial lesions PD-US revealed some vessels located near or inside the lesion (pattern II). On spectral analysis these vessels corresponded to arteries with a low resistance index or small venules. PD-US revealed a significant reduction of flow signals in patients rewired after medical therapy. No pathological flow signals were found either in patients with stenosing tenosynovitis or in the control group. PD-US gives us an in vivo confirmation of tendon vascularity. Spectral analysis adds further information to gray-scale US.