Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

The bleeding complication risk of surgery or percutaneous transhepatic gallbladder drainage (PTGBD) may increase in patients with acute cholecystitis receiving antithrombotic therapy (ATT). Endoscopic gallbladder drainage (EGBD) may be recommended for such patients. English articles published between 1991 and 2018 in peer-reviewed journals that discuss cholecystectomy, PTGBD, and EGBD in patients with ATT or coagulopathy were reviewed to assess the safety of the procedures, especially in terms of the bleeding complication. There were 8 studies on cholecystectomy, 3 on PTGBD, and 1 on endoscopic transpapillary gallbladder drainage (ETGBD) in patients receiving ATT. With respect to EGBD, 28 studies on ETGBD (including 1 study already mentioned above) and 26 studies on endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) were also analyzed. The overall bleeding complication rate in patients with ATT who underwent cholecystectomy was significantly higher than that in patients without ATT (6.5% [23/354] vs. 1.2% [26/2,224], p<0.001). However, the bleeding risk of cholecystectomy and PTGBD in patients receiving ATT was controversial. The overall technical success, clinical success, and bleeding complication rates of ETGBD vs. EUS-GBD were 84% vs. 96% (p<0.001), 92% vs. 97% (p<0.001), and 0.65% vs. 2.1% (p=0.005), respectively. One patient treated with ETGBD experienced bleeding complication among 191 patients with bleeding tendency. ETGBD may be an ideal drainage procedure for patients receiving ATT from the viewpoint of bleeding, although EUS-GBD is also efficacious.

Early detection of pancreatic ductal adenocarcinoma (PDAC) in the general population is difficult due to unknown clinical characteristics. This study was conducted to clarify the factors associated with early stage PDAC. Well-known symptoms and factors associated with PDAC were classified into clinical indicators, risk factors, and imaging findings concomitant with early stage PDAC. To analyze these factors for the detection of patients with early stage PDAC compared to patients without PDAC, we constructed new diagnostic strategies. The factors of 35 patients with early stage PDAC (stage 0 and IA) and 801 patients without PDAC were compared retrospectively. Clinical indicators; presence and number of indicators, elevated pancreatic enzyme level, tumor biomarker level, acute pancreatitis history, risk factors; familial pancreatic cancer, diabetes mellitus, smoking history, imaging findings; presence and number of findings, and main pancreatic duct dilation were significant factors for early stage PDAC detection. A new screening strategy to select patients who should be examined by imaging modalities from evaluating clinical indicators and risk factors and approaching a definitive diagnosis by evaluating imaging findings had a relatively high sensitivity, specificity, and areas under the curve of 80.0%, 80.8%, and 0.80, respectively. Diagnosis based on the new category and strategy may be reasonable for early stage PDAC detection.

Background/Aims: Residual common bile duct (CBD) stones occasionally become symptomatic after stone removal with endoscopic retrograde cholangiopancreatography (ERCP) upon removal of the endoscopic biliary stent (EBS). An accurate evaluation of residual stones before stent removal is necessary. This study evaluated a new two-step check method using endoscopic ultrasound (EUS) for the detection of residual stones after ERCP stone removal. Methods: Fifty-six patients who underwent CBD stone removal and EBS placement were prospectively enrolled. Residual stones were evaluated by the check method. EBS was removed at the time of the check method or at a later time of residual stone removal. The primary outcome was to evaluate the efficacy of this check method. Results: Residual CBD stone/sludge was detected in 20 of 56 patients (35.7%; stones: 28.6%, sludge: 7.1%) by the check method and removed by the ERCP procedure at a later time. After stent and final stone removal, patients were followed for an average of 211 days; cholangitis recurred in only 1.8% of patients. There were no adverse events associated with the check method. Temporary EBS prevented the recurrence of cholangitis by residual stone and caused no adverse events in the pancreatobiliary tract until the two-step check method (median, 113 days; range, 17–232 days). Conclusion: The new check method may be ideal and feasible for EBS removal because recurrences are very rare when a clear CBD has been verified, and an additional ERCP procedure is also possibly avoided.