[Computed tomography of pancreatic tumors]

Computed tomography (CT) and in particular multi-detector row computed tomography (MDCT), also known as multislice CT (MSCT), is ideally suited for detecting pancreatic tumors because of the high spatial resolution.The method of choice is hydro-CT which involves distension of the stomach and duodenum by administration of 1-1.5 l water as a negative contrast medium under medically induced hypotension by administration of buscopan. The patient is laid on the right side at an angle of 30-45 degrees in order to obtain an artefact-free image of the close anatomical relationship around the pancreas head. In addition, curved MPRs or in rare cases 3D reconstructions could be very helpful in identifying the critical anatomic tumor site in the neighbourhood of the visceral vessel system. After the correct diagnosis of an adenocarcinoma has been made only 20% of all patients are shown to have a surgically resectable disease, but the overall survival rate is significantly higher after resection in combination with a multimodal tumor therapy strategy. The reason is that the correct diagnosis of the resectability of the tumor is one of the main criteria for overall survival of these patients. Currently practically all pancreatic tumors can be detected using MDCT and the detection rate varies between 70% and 100% (most recent literature references give a sensitivity of 89% and specificity up to 99%). In some rare cases the differentiation between focal necrotizing pancreatitis and pancreatic carcinoma can be difficult even with sophisticated protocols. Resectability can be correctly diagnosed with MDCT with a sensitivity of 94% and a specificity of 89%. MDCT is an ideal tool for the detection of neuroendocrine tumors, metastases and for the differentiation of cystic pancreatic lesions such as pseudocysts, microcystic adenomas or intraductal papillary mucinous neoplasms (IPMN). Particularly, the differentiation of the latter into benign, borderline or malignant transformation is not always possible, but indirect signs, such as small nodules adjacent to the ductal wall, the diameter of the pancreatic duct, or a direct communication between cystic lesions and duct can be detected because of the high spatial resolution and is comparable to the findings in MRI. Moreover MD-CT is an ideal procedure for the differentiation of local tumor stages in patients under neoadjuvant or adjuvant chemotherapy.