Small solid renal lesions: usefulness of power Doppler US.
OBJECTIVE
To evaluate whether the vascular pattern at power Doppler ultrasonography (US) improves diagnostic accuracy in small solid renal lesions over that at gray-scale US.


METHODS
Gray-scale and 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, intratumoral 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 cysts in 20 of 26 RCCs (77%) and the two oncocytomas. Shadowing was seen 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 correct diagnosis was significantly increased with combined US (78%) as compared to that with gray-scale (42%) or power Doppler (45%) US alone.


CONCLUSIONS
The vascular distribution at power Doppler US could add important information to gray-scale US findings for differential diagnosis of small solid renal lesions.
Jinzaki
M
M
Department of Diagnostic Radiology, Keio University School of Medicine, Tokyo, Japan.
Ohkuma
K
K
Tanimoto
A
A
Mukai
M
M
Hiramatsu
K
K
Murai
M
M
Hata
J
J
D018249:Adenoma, Oxyphilic / Q000098:blood supply / Q000000981:diagnostic imaging; D018207:Angiomyolipoma / Q000098:blood supply / Q000000981:diagnostic imaging; D002292:Carcinoma, Renal Cell / Q000098:blood supply / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018615:Ultrasonography, Doppler, Color