Figure 17b. Lymphoma in a 37-year-old man. (a) Upper gastrointestinal radiograph reveals severe jejunal obstruction due to lymphoma (arrow). Note also the presence of a cardiac pacemaker device in the upper abdomen, which also serves to record an intramyocardial electrocardiogram. The electrocardiogram is transmitted to the transplant center via telephone on a daily basis for early detection of rejection. This procedure has made routine myocardial biopsy obsolete at our center but usually obviates the use of magnetic resonance (MR) imaging in heart transplant recipients. (b) CT scan helps confirm severe intestinal obstruction due to wall thickening (arrow). The lesion was surgically confirmed as an intestinal lymphoma. (c) CT scan shows multiple hepatic areas of hypoattenuation (arrow) that also proved to be due to lymphoma.