膀胱腫瘍におけるFluid attenuated inversion recovery(FLAIR)法によるMR像の検討

Abstract

膀胱腫瘍におけるMRIの有用性, 特に膀胱腫瘍におけるfluid attenuated inversion recovery(FLAIR)法の検討を行った. 1)FLAIR法は, 反転回復法(IR法)を応用し, 水の信号を抑制することにより膀胱壁の病変をheavy T2-WIとして描出する方法である. 2)本法は特別なMRシステムや造影剤は必要とせず, TR, TI等の撮像条件を変えるだけで可能な方法である. 3)pT1以下の症例では正診率84.6%, 敏感度78.6%, 特異度91.7%であり, pT2以上ではそれぞれ84.6%, 91.7%, 78.6%であった.SE法MRIと比較しても良好な結果であった

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.