Staging of Pancreatic Adenocarcinoma by Imaging Studies

Abstract

Imaging studies play a crucial role in the diagnosis and management of patients with pancreatic adenocarcinoma. Computed tomography (CT) is the most widely available and best-validated modality for imaging patients with pancreatic adenocarcinoma. To maximize the diagnostic efficacy of CT, use of a pancreas protocol is mandatory. The sensitivity of CT for diagnosis of pancreatic adenocarcinoma (89%-97%) and its positive predictive value for predicting unresectability (89%-100%) are high. The positive predictive value of CT for predicting resectability (45%-79%) is low because the diagnostic criteria for diagnosing vascular invasion by tumor favors specificity over sensitivity to avoid denying surgery to patients with potentially resectable tumor. Furthermore, the sensitivity of CT for small hepatic and peritoneal metastases is limited. Magnetic resonance imaging has not been shown to perform better than CT for the diagnosis and staging of pancreatic adenocarcinoma, but can be helpful as an adjunct to CT, particularly for evaluation of small hepatic lesions that cannot be fully characterized by CT. Ultrasound is often the first study obtained in patients with obstructive jaundice or unexplained abdominal pain, but its utility for diagnosis and staging of patients with pancreatic adenocarcinoma is limited. Positron emission tomography/CT combines the functional information provided by positron emission tomography with the anatomic information provided by CT and is a promising modality for imaging of patients with pancreatic adenocarcinoma, but its utility has not been established. Endoscopic ultrasound is generally considered superior to CT for the diagnosis and local staging of pancreatic cancer, but is limited by availability and inability to assess for distant metastases.