SMALL SOLID RENAL LESIONS - USEFULNESS OF POWER DOPPLER US

Purpose: To evaluate whether the vascular pattern at power Doppler ult rasonography (US) improves diagnostic accuracy in small solid renal le sions over that at gray-scale U.S. Materials and methods: Gray-scale a nd power Doppler US were performed prospectively in 64 small (1.5-3.0- cm-diameter) solid renal lesions (26 renal cell carcinomas [RCCs], 34 angiomyolipomas, two oncocytomas, two pseudotumors). At gray-scale US, echogenicity and homogeneity of the lesion, an anechoic rim, intratum oral cysts, shadowing, or a central scar were sought. At power Doppler US, the vascular distribution was divided into four patterns. Results : Findings at gray-scale US included an anechoic rim or intratumoral c ysts in 20 of 26 RCCs (71%) and the two oncocytomas. Shadowing was see n in seven of 34 angiomyolipomas (21%). Echogenicity, homogeneity, and a central scar were not pathognomonic. At power Doppler US, pattern 3 (peripheral) or 4 (mixed penetrating and peripheral) was seen in all RCCs, seven of 34 angiomyolipomas, and the two oncocytomas. Pattern 1 (intratumoral focal) or 2 penetrating) was seen in 27 angiomyolipomas. Pattern 1 or 2 was characteristic of angiomyolipoma. The rate of corr ect diagnosis was significantly increased with combined US (78%) as co mpared to that with gray-scale (42%) or power Doppler (45%) US alone. Conclusion: The vascular distribution at power Doppler US could add im portant information to gray-scale US findings for differential diagnos is of small solid renal lesions.