Local staging of rectal cancer using fused high resolution diffusion weighted imaging and modified MR rectography

Rectal cancer (RC) is a common malignant tumor with high mortality. MR imaging plays an important role in treatment decision making of RC. Unfortunately, the contents (gas and feces) in the rectum often induce artifacts and thus negatively affect the depicting and staging of RC. We developed a new protocol for MR rectography using oral administration of iso-osmotic mannitol to distend lumen after bowel cleansing preparation. Fused MR rectography and high resolution diffusion weighted imaging (DWI) is then performed to facilitate detection and staging of RC. Our present technique can eliminate the effect of gas and feces on image quality, especially on DWI, and can achieve satisfactory bowel distention, lesion depicture and visualization of surgical planes. Fused high resolution DWI and MR rectography can be a promising technique to improve the accuracy of RC local staging.