title: Effectiveness of contrast-enhanced endoscopic ultrasound for detecting mural nodules in intraductal papillary mucinous neoplasm of the pancreas and for making therapeutic decisions.
abstract: OBJECTIVE
  There have been few studies to date evaluating the effectiveness of contrast-enhanced endoscopic ultrasound (CE-EUS) for detecting mural nodules in patients with branch duct-type intraductal papillary mucinous neoplasm (BD-IPMN) of the pancreas. We aim to evaluate the effectiveness of CE-EUS for detecting mural nodules in BD-IPMN.
  
  
  METHODS
  Of the 427 BD-IPMN patients, 21 patients (4.9%) in whom the presence of mural nodules was suggested by CE computed tomography (CT) or magnetic resonance imaging (MRI), or in whom the presence of nodule-like lesions as shown by fundamental EUS, were examined by CE-EUS.
  
  
  RESULTS
  The mean diameter of cystic lesions was 29.8 ± 12.8 mm. The mean diameter of mural nodules was 9.5 ± 5.7 mm. BD-IPMN was detected in the pancreatic head in 16 cases, pancreatic body in 2 cases, and pancreatic tail in 3 cases. The mean follow-up period was 17.2 ± 11.9 months. The detection rates of mural nodule-like lesions in BD-IPMN patients on CT, MRI, and fundamental EUS were 36.8%, 63.2%, and 100%, respectively. The detection rates of true mural nodules in BD-IPMN patients on CT, MRI, and fundamental EUS were 85.7%, 71.4%, and 100%, respectively. The echo levels of mural nodule-like lesions on fundamental EUS were hyperechoic in 6 patients, isoechoic in 9 patients, and hypoechoic in 6 patients. The final diagnosis was mucus lumps in 14 patients and mural nodules in 7 patients. The contrast patterns observed were avascular, isovascular, and hypervascular in 14, 3, and 4 patients, respectively. No patients showed a hypovascular pattern. Fourteen patients showing an avascular pattern were diagnosed as having mucus lumps, and they were able to avoid surgical resection. Of the 7 patients who were diagnosed as having mural nodules, 5 underwent surgical resection. The pathological findings were adenocarcinoma in 2 patients and adenoma in 3 patients. Of the 3 adenoma patients, fundamental EUS demonstrated a hypoechoic area in 1 patient and an isoechoic area in 2 patients. Of the 2 adenocarcinoma patients, 1 each showed a hypoechoic area and a hyperechoic area. It was difficult to distinguish between patients with adenoma and patients with adenocarcinoma using the echo levels obtained from fundamental EUS.
  
  
  CONCLUSIONS
  CE-EUS may be useful for avoiding the overdiagnosis of BD-IPMN with mural nodule-like lesions. However, it has difficulty in distinguishing between clearly benign and malignant lesions in BD-IPMN.
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Fujita
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Itoi
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Ikeuchi
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sofuni
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Tsuchiya
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kamada
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Umeda
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Reina
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Tonozuka
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Honjo
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Shuntaro
authors.initials: S
authors.lastname: Mukai
authors.affiliation: Department of Gastroenterology and Hepatology, Tokyo Medical University, Shinjuku-ku, Tokyo 160-0023, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Moriyasu