Differentiation of non-ampullary duodenal carcinoma from intestinal-type ampullary carcinoma by tailored multidetector CT: utility of four imaging criteria.

OBJECTIVE

To evaluate the diagnostic accuracy of four imaging criteria obtained with a tailored duodenal MDCT to differentiate non-ampullary duodenal carcinoma (NADC) and intestinal-type ampullary carcinoma (ITAC).

MATERIALS AND METHODS

In this retrospective single-center study, patients with resected ITAC and NADC who underwent preoperative contrast-enhanced MDCT using a tailored duodenal protocol were included. Three radiologists independently reviewed each MDCT, using four imaging criteria to differentiate the two cancer types: lesion shape, ductal cutoff, duodenopancreatic groove fixation and pancreatico-duodenal artery infiltration. Sensitivity, specificity, positive and negative predictive values of the imaging criteria were calculated using histopathologic analysis as the reference standard. Interobserver agreements were assessed using kappa statistics.

RESULTS

57 patients (mean age 55 years ± 18.2 (standard deviation); 25 women) were included in the study. ITAC was significantly different in terms of lesion shape (p < 0.0001) and duodenopancreatic groove fixation (p < 0.0007). Sensitivity and specificity of the lesion shape for the three readers were 47-66%, 83-92% (κ = 0.72); of the ductal cutoff were 24-52%, 61-71% (κ = 0.52); of the duodenopancreatic groove fixation were 54-73%, 86-93% (κ = 0.81); of the pancreatico-duodenal artery infiltration were 19-28%, 48-52% (κ = 0.44). When all features were taken into account, sensitivity and specificity in differentiating between ITAC vs NADC were 85.7% and 83.3%.

CONCLUSION

The lesion shape and duodenopancreatic groove fixation have high specificity and moderate/strong interreader agreement for preoperative differentiation of ITAC and NADC on tailored duodenal MDCT.

KEY POINTS

Question Preoperative differentiation of non-ampullary duodenal carcinoma and intestinal-type ampullary carcinoma has potential implications on patients' management. Findings Two imaging criteria acquired on a tailored duodenal CT allowed to differentiate between intestinal-type ampullary carcinoma non-ampullary duodenal carcinoma with > 80% sensitivity and specificity. Clinical relevance A tailored duodenal CT is a reliable tool to differentiate between intestinal-type ampullary carcinoma and non-ampullary duodenal carcinoma, with potential treatment implications.