Evaluation of renal and urinary tract abnormalities noted on scintiscans: a retrospective study of 1,711 radioisotope skeletal surveys performed in an 18-month period.

On 247 of the 1,711 scintiscans (15%), the appearance of renal or urinary tract areas differed sufficiently from normal to merit mention in interpretation. For 162 patients (195 surveys), the abnormalities noted were classified as "minor." For 39 patients (52 surveys), the abnormalities noted were classified as "major"--that is, confirmed by other means or considered of major importance to diagnosis and management. Of these, 9 were filling defects (2 each were renal cell carcinoma, simple cyst, and polycystic disease; 3 were a mass of undetermined nature) and 30 were unilateral or bilateral urinary tract obstruction indicated by hydroureter and massive retention in renal area(s). These obstructive manifestations were associated with primary pelvic or prostatic malignancy or extension of malignant disease; in nine patients, progression or remission of obstruction was noted on sequential imaging. These changes were compatible with changes in clinical status and may afford an added means of following response to therapy in appropriate patients.