Reappraisal of endosonography of ampullary tumors: correlation with transabdominal sonography, CT, and MRI

Abstract

Purpose: To reappraise the accuracy of transabdominal sonography (US), CT, MRI, and endosonography (EUS) in the diagnosis and staging of ampullary tumors.

Method: We reviewed the medical records and the images of 41 consecutive patients with ampullary tumors. Tumor detection rate and accuracy of TNM (tumor-node-metastasis) staging of malignant tumors were determined. Imaging findings were correlated with histopathologic findings.

Results: The detection rates for ampullary tumors were 97.6% for EUS, 81.3% for MRI, 28.6% for CT, and 12.2% for US (p < 0.001 for EUS versus CT; p < 0.001 for EUS versus US; p > 0.05 for EUS versus MRI). The accuracy in T staging for ampullary carcinomas was 72.7% for EUS, 53.8% for MRI, and 26.1% for CT (p < 0.01 for EUS versus CT; p > 0.05 for EUS versus MRI). The accuracy in N staging for ampullary carcinomas was 66.7% for EUS, 76.9% for MRI, and 43.5% for CT with no statistically significant difference between the 3 modalities. The sensitivity in detecting malignant lymph nodes was 46.7% for EUS, 25.0% for MRI, and 0% for CT (p < 0.01 for EUS versus CT; p > 0.05 for EUS versus MRI; p > 0.05 for MRI versus CT). Transpapillary stenting, advanced tumor extension (>T2), large tumor size (>2 cm), tumor differentiation, and endoscopic appearance of tumor growth did not significantly influence EUS accuracy in T or N staging (p > 0.05).

Conclusion: EUS was superior to CT and was equivalent to MRI for tumor detection and T and N staging of ampullary tumors. Neither indwelling stents nor tumor size, differentiation, or endoscopic appearance affected the staging accuracy of EUS.