LAS VEGASBuoyed by effective postprocessing techniques, modern multislice CT has swept away some of the modality's limitations in visualizing the complex pancreas and created new challenges for radiologists in assessing incidentally detected lesions.
At the Stanford International Symposium on Multidetector-Row CT, radiologists demonstrated how the latest scanners are propelling CT forward in the pancreas, pushed by the steam of sophisticated multiplanar reformations and minimum intensity projections (MinIPs), which are now considered crucial (see Figure 1).
Islet cell tumors
At the Stanford symposium, R. Brooke Jeffrey, MD, discussed the use of multislice CT to distinguish islet cell tumors from ductal adenocarcinoma.
"Islet cell tumors represent only a small percentage of pancreatic neoplasms, but they are important because they have a much better prognosis than the more common ductal adenocarcinoma," said Dr. Jeffrey, professor of radiology, Stanford University.
Unlike ductal adenocarcinoma, islet cell tumor cells are usually hypervascular and rarely cystic. Features typical of ductal adenocarcinoma, such as local invasion, vascular encasement, and pancreatic duct obstruction, are far less common in islet cell tumors. Calcifications are present in up to 15% of islet cell tumors, whereas they are extremely rare in ductal adenocarcinoma cases.
For smaller tumors and multiple tumors, intraoperative ultrasound should be combined with CT for maximum sensitivity. As lesions get larger, they tend to be much more heterogeneous and are able to obstruct veins but not encase the arteries. It's also important to bear in mind that not all hypervascular lesions are necessarily islet cell tumorsthey may actually be renal cell carcinoma metastases.