Ultrasonic and radionuclide scanning in pancreatic disease.

Ultrasonic examination of the pancreas is rendered difficult by the echogenic characteristics of the organ, by its depth, by the overlying gas, and by bony structures and anatomic variations. The reintroduction of gray-scale imaging promises to simplify the technique and expand its usefulness. The 75Se-/-selenomethionine scan is a reliable test when performed after effective pancreatic stimulation with a scintillation camera that permits the angulation required to separate pancreas from liver. Gallium-67-citrate may be important for both mapping inflammatory processes and imaging some tumors. Retrograde pancreatography has developed into a rather reliable and sensitive method of visualizing pancreatic duct abnormalities. Angiography remains the most reliable technique for finding small lesions, while computerized axial tomography appears a promising modality in the near future. In acute pancreatitis, gallium scanning may find a place alongside plain films, GI series, and echography. Chronic pancreatitis appears best studied by pancreatography, possibly with selenomethionine scanning as a function study and echography to find associated mass lesions. Pseudocysts are most easily located by ultrasound examination. Screening for pancreatic carcinoma is done most effectively with selenomethionine scanning when the index of suspicion is low and with pancreatography or arteriography when it is high. Echography is useful for localization for aspiration biopsy and for sequential evaluation of therapeutic response. Islet-cell tumors are best found by angiographic studies.