Pneumatosis intestinalis. Appearance on MR examination.

We describe the magnetic resonance (MR) appearance of pneumatosis intestinalis in two patients. Pneumatosis is suggested by the finding of circumferential collections of air adherent or within the bowel wall. This air is more apparent on gradient-echo images due to "blooming" associated with magnetic field inhomogeneities at air-tissue interfaces. While MR is not routinely indicated as a diagnostic tool for the detection of pneumatosis, the radiologist should nevertheless be familiar with its appearance on MR examination.