Small lesions of the kidney: CT evaluation. Comparison with ultrasound. The main idea of this study is to demonstrate the usefulness, sensitivity and specificity of the CT method for the detection of small lesions of the kidneys. Simple cysts of kidneys were excluded from the study, which is a very frequent finding in patients examined with the new imaging methods of CT and US. Also the cases of small tumors which can add in establishment of diagnosis by CT are analysed. In this report 33 patients were examined with computed tomography (CT) and 36 small renal lesions (less than 4 cm) were found. Ten of these lesions were small angiomyolipomas (0.7-3.2 cm), 9 hemorrhagic renal cysts (0.8-3.5 cm), 5 adenomas of kidneys, 3 small Grawitz, 1 hydatid cyst, 1 lymphomatous deposit, 2 secondary tumors from the intestine, 2 oncocytomas, a small tumor 1.38 cm in size, who was not rendered a diagnosis, and 2 with false positive in ultrasound examination.