[Computed tomographic diagnosis of renal tumors without using contrast media]

The question whether contrast medium is necessary for diagnosis of renal tumour in CT is studied on the basis of 80 histologically proven cases of hypernephroma. More than 97% of the tumours were diagnosed on plain scan. The presence of structural inhomogeneities was decisive for recognising tumours 2 cm and larger without the use of c.m. In disagreement with current opinion injection of c.m. is not necessary for exclusion of hypernephroma. Injection of c.m. is useful however for differentiating between physiological variations and tumours less than 3 cm in size, and for diagnosis of tumour thrombosis of the renal vein.