Comparison of CT Urography and MRI in Bladder Cancer Detection

Abstract

A final diagnosis of bladder cancer is made based on a pathological assessment using cystoscopy and biopsy. Recently, computed tomography (CT) and magnetic resonance imaging (MRI) have become widely used as screening tests for hematuria, and there are scattered reports of new imaging modalities such as CT urography (CTU) and diffusion-weighted MRI being useful in the detection of bladder cancer. However, there are no reports comparing CTU and MRI in this context. In the present study, we compared the bladder cancer detection abilities of CTU and MRI. We analyzed 58 cases of bladder cancer that had been examined by both CTU and bladder MRI. The objects of comparison were T2-weighted images and diffusion-weighted images for MRI and contrast CT images of the renal parenchyma and excretory phases for CTU. Bladder cancer was confirmed histopathologically via either biopsy or surgery for all cases. For patients with multiple bladder cancer, up to three lesions per case were included in the analysis. Two independent readers assessed all cases. Out of 91 lesions from 58 cases, Reader 1 detected 72 (79.1%) and 65 cases (71.4%), and Reader 2 detected 69 (75.8%) and 70 (76.9%), using MRI and CTU, respectively. The κ-values for Reader 1 versus Reader 2 were 0.780 for MRI and 0.857 for CT, showing high diagnostic consistency. MRI showed a higher lesion detection rate than CTU, but this difference was not statistically significant. This study showed no significant difference in bladder cancer detection rate between CTU and MRI, confirming the value of MRI in the clinical diagnosis of bladder cancer.