RESUMO
OBJECTIVE: To determine the frequency of perirenal hyperintensity on heavily T2-weighted images and to evaluate its relationship with serum creatinine levels. SUBJECTS AND METHODS: Axial and coronal single-shot fast spin-echo images which have been originally obtained for MR cholangiopancreatography in 150 subjects were examined by two observers individually for the presence of perirenal hyperintensity. The morphologic properties of perirenal hyperintensity (peripheral rim-like, discontinuous, polar) were recorded. Chi square test was used to test whether the frequencies of bilateral perirenal hyperintensity differ significantly in subjects with high serum creatinine levels and those with normal creatinine levels. This test was also used to compare the frequencies of perirenal hyperintensity in patients with and without renal cysts and in patients with and without corticomedullary differentiation. A p value of less than 0.05 was considered to be statistically significant. RESULTS: The perirenal hyperintensity was identified in 40 of 150 cases (26.6%) on heavily T2-weighted image. Serum creatinine levels were high in 18 of 150 cases (12%). The perirenal hyperintensity was present in 11 of 18 subjects (61%) with high serum creatinine levels and 26 of 132 subjects (19.7%) with normal creatinine levels. The difference of rates in two groups was statistically significant. Odds ratio was 6407 (95% confidence interval 2264 -18,129) . The frequency of perirenal hyperintensity was also significantly higher in subjects with renal cyst or cysts in whom serum creatinine levels were normal (p<0.05) (37.5% vs. 11.8%). CONCLUSION: Perirenal hyperintensities are more frequent in patients with high serum creatinine levels. They are also more common in patients with simple renal cysts.