A new staging criterion for bladder carcinoma using gadolinium-enhanced magnetic resonance imaging with an endorectal surface coil: a comparison with ultrasonography

Objective To evaluate the accuracy of a new staging criterion, submucosal linear enhancement (SLE) on gadolinium-diethylenetriamine-pentaacetic acid-enhanced T1-weighted magnetic resonance imaging (MRI) using an endorectal surface coil (endorectal enhanced MRI), and to compare the accuracy of this method with that of transurethral ultrasonography (TUUS). Patients and methods The study included 71 patients with bladder tumours (63 men and eight women, mean age 65.5 years, range 31-85). The SLE coincided with abundant submucosal vascular beds, as reported in a previous study. When the SLE beneath the tumour maintained continuity, the tumour was diagnosed as superficial (less than or equal to T1), but if the SLE was interrupted by the tumour, the disease was considered invasive (greater than or equal to T2a). Superficial muscle invasion (less than half the muscle layer) and deep muscle invasion (more than half the muscle layer) were classified as T2a and T2b, respectively. When the tumour formed an extravesical mass, the tumour was classified as T3b. Results The staging accuracy for bladder tumours using SLE on endorectal-enhanced MRI or TUUS was 83% and 60%, respectively (P<0.01). Using the SLE, muscle invasion of bladder tumour was diagnosed with an accuracy of 87%, a sensitivity of 91% and a specificity of 87%; this was significantly better than with TUUS (P<0.01). Conclusion The criterion of SLE on Gd-DTPA enhanced T1-weighted MRI using an endorectal surface coil is useful for staging bladder tumour, and the staging accuracy is significantly better than with TUUS.