RESUMO
OBJECTIVE: To comparatively evaluate CT scan and MRI in the preoperative staging of renal tumours. METHODS: 46 patients with a solid renal tumour were investigated preoperatively by CT scan (n = 43) and MRI (n = 46), the results of which were compared with pathological data. RESULTS: MRI assessed capsular effraction with a sensitivity of 95.6% and a specificity of 52.1%, versus 95.2 and 40%, respectively, for CT scan. Three cases of perirenal extension were detected by MRI. The sensitivity of MRI was higher than that of CT scan for the demonstration of adenopathy (71.4% versus 57.1%) with specificities of 92.3 and 88.8%, respectively. Fourteen cases were associated with tumour extension into the proximal renal vein, which extended into the distal segment of this vein in 12 cases, into the inferior vena cava in 6 cases and as far as the right atrium in 2 cases. The performance of MRI was always better than that of CT scan in relation to venous segments of surgical interest (respective sensitivities of 70% and 83.33% in the distal renal vein and 66.6% and 83.33% in the inferior vena cava: and respective specificities of 84.8% and 97% in the distal renal vein and 91.8% and 97.5% in the inferior vena cava), provided the results of T1-weighted spin echo sequences and FLASH gradient echo sequences were assessed conjointly. CONCLUSION: These results lead us to now prefer MRI to CT scan for the preoperative staging of renal cancer, in the presence of a contraindication to iodinated contrast agent injection, very large tumours, and whenever venous extension is suspected on ultrasonography.
