[MR imaging of bladder tumors using fluid attenuated inversion recovery (FLAIR) technique]

Magnetic resonance imaging (MRI) has been reported valuable for the diagnosis of bladder tumors, but does not provide adequate staging of these tumors. Therefore, we examined whether the FLAIR technique could be used to improve the diagnostic ability of MRI. FLAIR utilizes inversion recovery and can display a lesion as a heavy T2-WI by decreasing the signal intensity of water and thus altering the contrast at the bladder wall. The inversion time (TI), that gave urine a signal intensity of "zero", was determined by theoretical analysis. In addition, MRI by the FLAIR technique was performed on 29 patients with bladder tumors. With the FLAIR technique, MRI showed a sensitivity of 78.6% and a specificity of 91.7% for pT1 or smaller lesions, while the values were respectively 91.7% and 78.6% for pT2 or worse lesions.