Introduction: To analyze whether computed tomography (CT) or magnetic resonance imaging (MRI) reports are consistent for diagnosis of the same renal mass. Methods: We retrospectively reviewed 1,216 patients between January 2017 and December 2021 in our institute. Patients who had both CT and MRI reports prior to surgery were included. We compared the diagnostic accuracy of the CT and MRI results with the final pathological outcome. The patients were divided into two groups according to the consistency of reports: the consistent group and the inconsistent group. The inconsistent group was further divided into two subgroups: Group 1 included patients with benign findings on CT but malignant findings on MRI. Group 2 included cases with malignant findings on CT but benign findings on MRI. Results: Among 410 patients, 68 cases (16.6%) were benign. The sensitivity, specificity, and accuracy of the MRI and CT scans were 91.2%, 36.8%, and 82.2%, and 84.8%, 41.2%, and 77.6%, respectively. The consistent group included 335 patients (81.7%), whereas the inconsistent group was 75 cases (18.3%). The mean renal mass size was significantly smaller in the inconsistent group than in the consistent group (1.84±0.75 cm vs. 2.31±0.84 cm, respectively, p<0.001). For a renal mass size of 2–4 cm, group 1 showed more predictive of malignancy than that for patients in group 2. Conclusions: A smaller renal mass size affects the discrepancy of findings from CT and MRI reports. MRI showed better diagnostic accuracy in discrepant findings between CT and MRI reports for the detection of malignancy. SOURCE OF Funding: None
