Contrast-enhanced harmonic endoscopic ultrasonography with time-intensity curve analysis for intraductal papillary mucinous neoplasms of the pancreas.

Abstract

Preoperative diagnosis of the pathological grade of intraductal papillary mucinous neoplasms (IPMNs) is difficult. This study aimed to evaluate the accuracy of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) with time - intensity curve analysis in differentiating between low or intermediate grade dysplasia (LGD/IGD) and high grade dysplasia or invasive carcinoma (HGD/invasive carcinoma) in IPMNs and to assess correlation between the time - intensity curve parameters and tumor microvessel density. Data from 30 patients with resected IPMNs (14 LGD/IGD, 16 HGD/invasive carcinoma) who underwent CH-EUS with time - intensity curve analysis were evaluated retrospectively. Time - intensity curve parameters and the microvessel density of the mural nodule were compared between the HGD/invasive carcinoma and LGD/IGD groups; the diagnostic accuracy of the time - intensity curve parameters was evaluated. The echo intensity change and echo intensity reduction rate of the mural nodule, and the nodule/pancreatic parenchyma contrast ratio were significantly higher in the HGD/invasive carcinoma group than in the LGD/IGD group (P < 0.05); the accuracies of these parameters were 80 %, 86.7 %, and 93.3 %, respectively. The microvessel density of the mural nodule was significantly higher in the HGD/invasive carcinoma group (P = 0.002). There was a strong positive, linear correlation between the echo intensity change of the mural nodule and the microvessel density (r = 0.803, P < 0.001). CH-EUS with time - intensity curve analysis is potentially useful for quantitatively evaluating the blood flow of IPMN microvasculature, and for differentiating between HGD/invasive carcinoma and LGD/IGD.