Inflammatory pancreatic masses: Differentiation from ductal carcinomas with contrast-enhanced sonography using carbon dioxide microbubbles

OBJECTIVE. The aim of this study was to evaluate the clinical efficacy of contrast-enhanced sonography using carbon dioxide microbubbles to differentiate inflammatory pancreatic masses from ductal carcinomas of the pancreas. SUBJECTS AND METHODS. Fifty-five patients, including 35 patients with ductal carcinomas and 20 with inflammatory pancreatic masses, underwent contrast-enhanced sonography, CT, and digital subtraction angiography (DSA). Carbon dioxide microbubbles were prepared by mixing 10 ml of carbon dioxide and the same amount of 25% soybean oil vigorously. Carbon dioxide microbubbles were injected through an angiographic catheter that was placed in the celiac axis. Vascularity of the tumors as determined by those three techniques was interpreted by three physicians who had no knowledge of the pathologic results. RESULTS. Contrast-enhanced sonography was best at revealing tumor vascularity among the three techniques. On contrast-enhanced sonography, 19 (95%) of the 20 inflammatory pancreatic masses were isovascular and 32 (91%) of the 35 ductal carcinomas were hypovascular. In contrast, the isovascularity of inflammatory masses was five (25%) on CT, and two (10%) on DSA, respectively. The sensitivity and accuracy rate of differentiating both diseases on contrast-enhanced sonography were 98% and 95%, respectively; on CT, they were both 73%; and on DSA they were both 67%. From our results, an isovascular mass is probably an inflammatory mass, whereas a hypovascular mass is most likely a ductal carcinoma on contrast-enhanced sonography. CONCLUSION. Contrast-enhanced sonography can help differentiate an inflammatory pancreatic mass from a ductal carcinoma.