Multi-detector CT (MDCT) is useful for distinguishing among adenoma, noninvasive carcinoma, and invasive carcinoma in patients with intraductal papillary mucinous neoplasm (IPMN), according to a study in the September issue of Radiology.
Hiroshi Ogawa, MD, from the department of radiology at the Nagoya University Graduate School of Medicine in Nagoya, Japan, and colleagues evaluated the capabilities of MDCT in determining the likelihood of invasiveness of IPMN.
Two radiologists blinded to the pathologic assessment of malignancy or parenchymal invasion of IPMN retrospectively evaluated CT images of 61 consecutive surgically resected tumors (26 adenomas, 15 noninvasive carcinomas, and 20 invasive carcinomas) in patients who underwent multiphase contrast material–enhanced CT with 0.5- or 1-mm collimation, according to the researchers.
The investigators statistically analyzed the findings by using univariate and multivariate analyses with the optimal cut-off levels of each continuous parameter determined by generating receiver operating characteristic curves.
The researchers said that following findings showed significant differences among the three groups: maximum diameter of the main pancreatic duct (MPD), size (length of major axis) of the largest mural nodule in the MPD or in any associated cystic lesion, abnormal attenuating area in the surrounding parenchyma, calcification in the lesion, protrusion of the MPD into the ampulla of Vater and bile duct dilatation.
According to Ogawa and colleagues, an MPD diameter of 6 mm or larger, a mural nodule of 3 mm or larger, and an abnormal attenuating area were independently predictive of malignancy. A mural nodule of 6.3 mm or larger in the MPD and an abnormal attenuating area were independently predictive of parenchymal invasion.
The researchers found that the sensitivity, specificity and accuracy for identifying malignancy were 83 percent, 81 percent and 82 percent and for identifying parenchymal invasion were 90 percent, 88 percent and 89 percent, respectively.