PRELIMINARY ASSESSMENT OF 3-DIMENSIONAL MAGNETIC-RESONANCE-IMAGING FOR VARIOUS COLONIC DISORDERS

Background Improvements in magnetic resonance imaging (MRI) technology have enabled the acquisition oi three-dimensional MRI datasets in a s ingle breath hold. We adopted this technique to make a three-dimension al intraluminal and extraluminal assessment of the colon in three pati ents with various colonic disorders. Methods One patient was studied a fter having a double-contrast barium enema. Two patients had MRI scans after colonoscopy, which showed three colonic tumours in one and mult iple polyps in the ascending colon of the other. The process of rectal filling with 1.5-2.0 L water mixed with 15-20 mt 0.5 mol/L gadolinium -diethylenetriaminepentaacetic acid (Gd-DTPA) was monitored with MR fl uoroscopic sequence. Three-dimensional datasets of the contrast-filled colon were taken with patients in prone (before and after intravenous administration of 0.1 mmol/kg bodyweight Gd-DTPA) and supine position s. 64 sections with a voxel-resolution of 2.0X2.0x1.25 mm(3)-were take n during a 28 s breath hold. Three-dimensional maximum intensity proje ction, multiplanar reconstruction, and virtual colonoscopic images of the colon were created from these. Findings Analysis of the coronal so urce images in conjunction with multiplanar reconstructions revealed a ll relevant abnormalities, including diverticula, carcinomas, and poly ps. Three dimensional maximum-intensity projections gave a morphologic al overview of the whole colon. Targeted projections, made up of a lim ited number of coronal source images, showed diverticula and smaller p olyps more clearly. After patients were given intravenous contrast all colonic mass lesions were enhanced. Datasets obtained in prone patien ts gave the best intraluminal views of the colon. Virtual magnetic res onance colonoscopy showed colonic haustra as well as the ileocaecal va lve, but did not show clearly the diverticula. All intraluminal mass l esions, on the other hand, were easy to see. Interpretation The potent ial of three-dimensional colonic MRI to provide accurate, minimally in vasive, cost-effective polyp screening, as well as comprehensive colon ic tumour staging, warrants further investigation.