Virtual indigo carmine chromoendoscopy images: A novel modality for peroral cholangioscopy using artificial intelligence technology (with video).

BACKGROUND AND AIMS: Accurately diagnosing biliary strictures is crucial for surgical decisions, and although peroral cholangioscopy (POCS) aids in visual diagnosis, diagnosing malignancies or determining lesion margins via this route remains challenging. Indigo carmine is commonly used to evaluate lesions during gastrointestinal endoscopy. We aimed to establish the utility of virtual indigo carmine chromoendoscopy (VICI) converted from POCS images using artificial intelligence. METHODS: This single-center, retrospective study analyzed 40 patients with biliary strictures who underwent POCS using white light imaging (WLI) and narrow-band imaging (NBI). A "cycle-consistent adversarial network" (CycleGAN) was used to convert the WLI into VICI of POCS images. Three experienced endoscopists evaluated WLI, NBI, and VICI via POCS in all patients. The primary outcome was the visualization quality of surface structures, surface microvessels, and lesion margins. The secondary outcome was diagnostic accuracy. RESULTS: VICI showed superior visualization of the surface structures and lesion margins compared with WLI (P<0.001) and NBI (P<0.001). The diagnostic accuracies were 72.5%, 87.5%, and 90.0% in WLI alone, WLI and VICI simultaneously, and WLI and NBI simultaneously, respectively. WLI and VICI simultaneously tended to result in higher accuracy than WLI alone (P=0.083) and the results were not significantly different from WLI and NBI simultaneously (P=0.65). CONCLUSIONS: VICI in POCS proved valuable for visualizing surface structures and lesion margins and contributed to higher diagnostic accuracy comparable to NBI. In addition to NBI, VICI may be a novel supportive modality for POCS.

Detection of residual stones by peroral direct cholangioscopy in patients with intrahepatic stones after hepaticojejunostomy: A prospective study (with video).

BACKGROUND AND AIMS: The difficulty of radiographic confirmation of the presence of stones remains a challenge in the treatment of intrahepatic bile duct (IHBD) stones in patients after hepaticojejunostomy (HJ). Peroral direct cholangioscopy (PDCS) enables direct observation of the bile duct and is useful for detecting and removing residual stones; however, its effectiveness is not clearly established in this clinical context. METHODS: This single-center, single-arm, prospective study included 44 patients with IHBD who underwent bowel reconstruction with HJ during the study period. Stone removal was performed by short-type double-balloon enteroscopy (DBE). Following balloon-occluded cholangiography, the DBE was exchanged for an ultraslim endoscope through the balloon overtube for PDCS. The primary endpoint was the rate of residual stones detected by PDCS. Secondary endpoints were success rate of PDCS, residual stone removal with PDCS, procedure time for PDCS, procedure-related adverse events, and stone recurrence rate. RESULTS: PDCS was successful in 39/44 patients (89%), among whom residual stones were detected in 16 (41%) (95% CI: 28%-54%). Twelve patients (75%) had residual stones <5 mm. Stone removal was successful in 15 (94%) patients and median procedure time for PDCS was 16 (IQR: 10-26) min. The rate of procedure-related adverse events was 7% (3/44), all of which improved with conservative treatment. During median follow-up of 2.1 years (IQR: 1.4-3.3), the overall probability of recurrence-free status at 1, 2, and 3 years was 100%, 92%, and 86%, respectively. CONCLUSIONS: PDCS is a safe and effective procedure for complete stone removal in patients with IHBD stones after HJ.

Gastrointestinal stromal tumors in the duodenum show increased contrast enhancement compared with those in the stomach on computed tomography.

Duodenal gastrointestinal stromal tumors (D-GISTs) are a rare and relatively small subset of GISTs whose imaging features are not well known. The present study aimed to evaluate the enhancement pattern of D-GISTs compared with that of gastric GISTs (G-GISTs) using dynamic computed tomography. This single-center, retrospective, clinicopathological analysis was conducted on 10 patients with D-GISTs who underwent surgery between June 2006 and October 2018. In the same period, 25 patients with G-GISTs underwent surgery and were enrolled. The contrast ratio was defined as the ratio between Hounsfield units in contrast enhanced and unenhanced images in different phases, and these ratios were compared between the D-GIST and G-GIST groups. Furthermore, microvessel density, analyzed by immunohistochemical staining for CD31, was compared between the D-GIST and G-GIST groups. The contrast ratio of D-GIST was significantly higher than that of G-GIST in the arterial, portal and delayed phases (P<0.01, P<0.01 and P=0.02, respectively). The microvessel density of the D-GISTs was significantly higher than that of the G-GISTs (P<0.0001). D-GISTs were more hypervascular than G-GISTs on both imaging and pathological analyses.

Prevention of Post-Endoscopic Retrograde Cholangiopancreatography Pancreatitis by Endoscopic Pancreatic Stenting after Insertion of Self-Expandable Metal Stent for Malignant Distal Biliary Stricture.

The insertion of a self-expandable metal stent (SEMS) for nonpancreatic cancer is a factor predicting the risk of post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP). We evaluated the efficacy of endo-scopic pancreatic stenting (EPS) to prevent PEP after SEMS insertion in patients with malignant distal biliary stricture and without main pancreatic duct (MPD) obstruction. We performed a single-center, retrospective, historically controlled investigation to assess the outcomes of 33 consecutive patients who underwent SEMS insertion. From March 2013 to June 2015, 13 patients did not undergo EPS (Non-EPS group). The other 20 patients underwent EPS (EPS group) between July 2015 and August 2018. The background data demonstrated no significant differences. Except for one patient in the Non-EPS group, all patients underwent biliary sphinc-terotomy. The EPS group's PEP incidence was significantly lower (n = 1, 5%) than that of the Non-EPS group (n = 4, 31%) (p = 0.04). The median serum amylase and lipase levels after the procedure were significantly lower in the EPS group than in the Non-EPS group (amylase: 104 vs. 262 U/L; p < 0.01, lipase: 102 vs. 666 U/L; p = 0.01). The use of EPS decreased the incidence of PEP after SEMS insertion in individuals with malignant distal biliary stricture and without MPD obstruction.