COMPUTED-TOMOGRAPHY AND ULTRASONOGRAPHY - A COMPARATIVE-STUDY IN THE DIAGNOSIS OF ANALGESIC NEPHROPATHY

Computed tomography (CT) and ultrasonography (US) were performed in 40 patients who had consumed excessive quantities of analgesics (>1 kg) to compare their value in the diagnosis of analgesic nephropathy (AN). The computed tomography and sonographic features were renal papillary calcifications. Penal papillary necrosis (RPN) was documented in 20 o f 40 patients by US and in 14 of 40 patients by CT. In 11 patients, bo th US and CT were positive. In 9 patients, US was positive whilst CT w as negative. In 3 patients, CT was positive whilst US was negative. Pr evalence of RPN was 50% using US and 35% using CT. Using US as a gold standard, sensitivity of CT was 55%, specificity 85%, positive predict ive value 78.6% and negative predictive value 34.6%. Percent agreement with CT and US was 70%. Cohen's kappa statistic adjusting for chance agreement was 40%. Based on these results, it is found that US yielded a higher percentage of positive cases of RPN.