NORMAL BLADDER WALL MORPHOLOGY IN GD-DTPA-ENHANCED CLINICAL MR-IMAGING USING AN ENDORECTAL SURFACE COIL AND HISTOLOGICAL ASSESSMENT OF SUBMUCOSAL LINEAR ENHANCEMENT USING [C-14]GD-DOTA AUTORADIOGRAPHY IN AN ANIMAL-MODEL

Objective: The purpose of this study was to investigate normal bladder wall morphology in gadolinium-diethylenetriaminepentaacetic acid (Gd- DTPA)-enhanced magnetic resonance (MR) imaging using an endorectal sur face coil and to perform histological assessment of submucosal linear enhancement with experimental C-14]-gadolinium-tetraazacyclododecane-t etraacetic acid (Gd-DOTA) autoradiography. Methods and material: MR im aging of the bladder was performed using an endorectal coil in 13 cons ecutive patients with bladder carcinoma and T1-, T2-, and Gd-DTPA-enha nced spin-echo images of the bladder wall were compared. After injecti on of [C-14]Gd-DOTA into a hamster, autoradiograms of the bladder wall were obtained and compared with serial histological sections. Results : The normal bladder wall appeared as a homogeneous layer of intermedi ate intensity on T1-weighted images. After administration of Gd-DTPA, the bladder wall was visualized as three layers: an inner thin layer o f low intensity, a middle layer of marked enhancement, and a thick out er layer of intermediate intensity. The autoradiograms demonstrated de nse accumulation of [C-14]Gd-DOTA in the submucosal layer. Thus, the i nner, middle, and outer layers corresponded to the mucosa, submucosa, and muscularis propria, respectively. The thickness of the bladder wal l demonstrated on T2-weighted images was almost equal to that of the o uter layer on enhanced T1-weighted images. Thus, T2-weighted images re vealed only the muscle layer as an intermediate-intensity band. In the preliminary clinical study, MR imaging invariably showed accurate sta ges of the bladder carcinoma in 13 patients. Conclusion: In MR imaging of the normal bladder wall, the submucosa was strikingly enhanced aft er Gd-DTPA administration, separating the bladder wall into three laye rs. This may have a potential role in the staging of bladder tumors. ( C) 1998 Elsevier Science Ireland Ltd. All rights reserved.