Combined MRI and fibreoptic colonoscopy: technical considerations and clinical feasibility

A method of fibre-optic colonoscopy with simultaneous high resolution MRI has been developed to obtain cross-sectional information of the intramural and extramural extent of lesions, for diagnostic and therapeutic purposes. An MR-compatible colonoscope with receiver coil was designed, developed and used in ex vivo studies to scan a section of large bowel in transverse and longitudinal planes with T1 and T2 weighted spin-echo sequences. In vivo five patients were followed-up after excision of large bowel cancer. The patients were three men and two women aged 50-77 years, (mean 65.6 years) who were studied on a 0.5 T scanner (Picker Asset, OH, USA). The coil and colonoscope were inserted into the rectum. After routine visual inspection of the colon, T1 weighted spin-echo images and radio-frequency spoiled gradient-echo images of the bowel wall were obtained. Ex vivo: three layers of bowel wall were identified: an intermediate to high signal-intense mucosa, a high signal intensity layer on T1 weighting which...