B-mode nephrosonography in renal masses. Its use and some limitations.

One hundred B-mode nephrosonograms were reviewed, and 41 percent of these had a diagnosis proved by either arteriography, cyst puncture or tissue examination. There were 8 proved normal sonograms with one error, an upper pole renal cell carcinoma in a kidney badly distorted by chronic pyelonephritis and ureteral obstruction. Overlying ribs and anatomic distortion contributed to the misinterpretation. Sonic diagnosis of solid tumor was correct in all proved cases. Cysts were diagnosed in 23 patients; six were in error. Four were called cysts less than 3 cm. in diameter. If the lower limit of sonographic resolution is considered 3 cm., the accuracy for diagnosed simple cysts becomes 90 per cent.