Efficacy of diagnosing intraductal papillary mucinous neoplasm with mural nodules by contrast-enhanced endoscopic ultrasound using time-intensity curve analysis with a new support program: A multicenter retrospective study (with video).

Background/objectives: Preoperative diagnosis of the pathological grade of intraductal papillary mucinous neoplasms (IPMN) is challenging. This study aimed to evaluate the accuracy of contrast-enhanced endoscopic ultrasound (CE-EUS) using time-intensity curve (TIC) analysis with a newly developed support program to differentiate between low-grade dysplasia (LGD) and high-grade dysplasia (HGD)/invasive carcinoma (IC) in IPMN.

Methods: This study retrospectively analyzed 32 patients who underwent CE-EUS using the support program for TIC analysis and IPMN resection (LGD: 17, HGD/IC: 15) at two medical centers. The TIC parameters of mural nodules (MN) were compared between the LGD and HGD/IC groups, and the diagnostic accuracies of the TIC parameters were evaluated.

Results: The MN/pancreatic parenchyma contrast ratio was significantly higher in the HGD/IC group than in the LGD group (1.53 vs. 0.99; P < 0.0001), and the diagnostic abilities of the contrast ratio were as follows: sensitivity, 67 %; specificity, 100 %; and accuracy, 84 %. There were no differences in the echo intensity reduction rate of the MNs between the two groups (HGD/IC, 61.6 vs. 61.2, 0.99; P = 0.421), and the diagnostic abilities of the reduction rate were as follows: sensitivity, 93 %; specificity, 41 %; and accuracy, 66 %.

Conclusions: The contrast ratio calculated using TIC analysis with the support program is potentially useful for differentiating between IPMNs with LGD and those with HGD/IC.