Magnetic resonance and CT of the normal and diseased pancreas: a comparative study.

Nineteen patients with proven pancreatic disease and 50 control subjects were examined by magnetic resonance (MR) using a variety of spin echo and inversion recovery techniques. The MR results were then compared with CT scans. The normal pancreatic head, body, and tail were identified by MR in approximately 60% of patients. Pancreatic adenocarcinoma and retroperitoneal lymphoma were detected using morphologic criteria similar to those used in CT. Differentiating bowel from pancreas was difficult on MR in patients with little retroperitoneal fat, and tissue relaxation times were usually not helpful in differentiating adenocarcinoma or lymphoma from normal pancreatic tissue. However, MR intensity, T1, and T2 were useful in differentiating pancreatic islet cell tumors from normal pancreatic tissue. MR accurately identified retroperitoneal invasion, vascular involvement, and liver metastases. In pancreatitis, tissue T1 and T2 relaxation times were prolonged and complications such as ductal dilatation, pseudocyst, phlegmon, and ascites were identified. Small pancreatic calcifications were not detected by MR. Pancreatic iron overload was seen in patients with hemochromatosis. Although respiratory motion and spatial resolution are currently limiting factors, MR is a versatile and unique modality for the evaluation of pancreatic disease.