Pancreas and Biliary Tract

Malignant Disease

Because of the difficulty in obtaining accurate imaging of the pancreas with other methods, EUS may have its greatest impact in the evaluation of this organ [77,78]. Studies show that EUS is more accurate than any other test, including ultrasound, CT, MRI, ERCP, and angiography, for detection and staging of pancreatic tumors. EUS is also more accurate than CT or other tests for predicting resectability of a pancreatic mass. The high resolution images of EUS make it possible to visualize very small lesions, ductal abnormalities, and calcifications not seen with other methods. The accuracy of T staging is consistently good for both pancreatic and ampullary neoplasms (Table 9). T stage also correlates to presence of lymph nodes (see Table 5) and survival (Table 10).

The high accuracy of real-time EUS of the pancreas is primarily due to both its unsurpassed resolution of the parenchyma of the pancreas and its capability of evaluating and integrating (during the same examination)mucosal, vascular, ductal, and parenchymal abnormalities caused by disease. To obtain information about these 4 types of abnormalities, 4 separate tests would otherwise be required: (1) endoscopy for mucosa, (2) venogram or arteriogram for veins and arteries, (3) ERCP for pancreatic and bile ducts, and (4) CT or standard sonography for the parenchyma and the surrounding lymph nodes. Indications for EUS of the pancreas now include (1) staging potentially resectable tumors, (2) detection of endocrine tumors, and (3) evaluation of equivocal abnormalities in the pancreas present on other studies.

Table 5
Correlation of EUS T Stage with the Presence of Malignant Lymph Nodes ^a

^a Values are median estimates in percent from references in text.

Table 9
EUS Accuracy of T Staging for Pancreatic Carcinoma

Table 10
Correlation of T and N Stage to Survival For Pancreatic Carcinoma

Continued »