Cholangioscopy- versus fluoroscopy-guided transpapillary mapping biopsy for preoperative evaluation of extrahepatic cholangiocarcinoma: a prospective randomized crossover study

Multimodal convolutional neural network-based algorithm for real-time detection and differentiation of malignant and inflammatory biliary strictures in cholangioscopy: a proof-of-concept study (with video)

BACKGROUND AND AIMS

Deep learning algorithms gained attention for detection (computer-aided detection [CADe]) of biliary tract cancer in digital single-operator cholangioscopy (dSOC). We developed a multimodal convolutional neural network (CNN) for detection (CADe), characterization and discriminating (computer-aided diagnosis [CADx]) between malignant, inflammatory, and normal biliary tissue in raw dSOC videos. In addition, clinical metadata were included in the CNN algorithm to overcome limitations of image-only models.

METHODS

Based on dSOC videos and images of 111 patients (total of 15,158 still frames), a real-time CNN-based algorithm for CADe and CADx was developed and validated. We established an image-only model and metadata injection approach. In addition, frame-wise and case-based predictions on complete dSOC video sequences were validated. Model embeddings were visualized, and class activation maps highlighted relevant image regions.

RESULTS

The concatenation-based CADx approach achieved a per-frame area under the receiver-operating characteristic curve of .871, sensitivity of .809 (95% CI, .784-.832), specificity of .773 (95% CI, .761-.785), positive predictive value of .450 (95% CI, .423-.467), and negative predictive value of .946 (95% CI, .940-.954) with respect to malignancy on 5715 test frames from complete videos of 20 patients. For case-based diagnosis using average prediction scores, 6 of 8 malignant cases and all 12 benign cases were identified correctly.

CONCLUSIONS

Our algorithm distinguishes malignant and inflammatory bile duct lesions in dSOC videos, indicating the potential of CNN-based diagnostic support systems for both CADe and CADx. The integration of non-image data can improve CNN-based support systems, targeting current challenges in the assessment of biliary strictures.

A novel peroral digital cholangioscope with a large accessory channel: An experimental study

BACKGROUND/PURPOSE

A peroral cholangioscope (POCS) can allow direct visualization of the biliary mucosa and its use is becoming more widespread due to improvements in functionality, image quality, and operability, as well as the development of related devices. Recently, a novel mother-baby peroral cholangioscope (nMB-POCS) with a large (2-mm) accessory channel has been developed. In this study, we evaluated the feasibility of this novel POCS in a dry simulation and animal model.

METHODS

We evaluated the ease of insertion and maneuverability of the nMB-POCS, the image quality, and the passage of the devices into the accessory channel and into the common bile duct in a dry and live porcine model.

RESULTS

In both models, the nMB-POCS could be easily inserted into the duodenoscope and into the distal bile duct and hilum. The image quality was good, and it was possible to observe the surface structure and the vascular network of the bile duct mucosa in detail.

CONCLUSIONS

The nMB-POCS with its larger accessory channel is expected to improve the efficiency of diagnosis and  treatment, and reduce the procedure time. Clinical studies in patients are warranted.

Comparison of tube-assisted mapping biopsy with digital single-operator peroral cholangioscopy for preoperative evaluation of biliary tract cancer

Background/Aims

Digital single-operator cholangioscopy (DSOC)-guided mapping biopsy (DMB) and tube-assisted mapping biopsy (TMB) are two techniques used for preoperative evaluation of biliary tract cancer (BTC). However, data regarding the diagnostic performance of these techniques are limited.

Methods

We retrospectively examined consecutive patients with BTC who underwent either technique at our institution between 2018 and 2020. We evaluated the technical success rate, adequate tissue acquisition rate, and diagnostic performance of these techniques for the evaluation of lateral spread of BTC.

Results

A total of 54 patients were included in the study. The technical success rate of reaching the target sites was 95% for DMB and 100% for TMB. The adequate tissue acquisition rate was 61% for DMB and 69% for TMB. The adequate tissue acquisition rate was low, especially for target sites beyond the secondary biliary radicles. The sensitivity of DMB alone was 39%, which improved to 65% when combined with visual impression. Experts demonstrated a higher negative predictive value and diagnostic accuracy with respect to both DSOC visual impression and DMB for the evaluation of lateral spread of BTC compared to trainees.

Conclusions

Adequate tissue acquisition rates were similar between the two techniques. Since DMB requires expertise, TMB may be an acceptable option when DSOC is unavailable or when DSOC expertise is limited.

Choledochoscopy: An update

Choledochoscopy, or cholangioscopy, is an endoscopic procedure for direct visualization within the biliary tract for diagnostic or therapeutic purposes. Since its conception in 1879, many variations and improvements are made to ensure relevance in diagnosing and managing a range of intrahepatic and extrahepatic biliary pathologies. This ranges from improved visual impression and optical guided biopsies of indeterminate biliary strictures and clinically indistinguishable pathologies to therapeutic uses in stone fragmentation and other ablative therapies. Furthermore, with the evolving understanding of biliary disorders, there are significant innovative ideas and techniques to fill this void, such as nuanced instances of biliary stenting and retrieving migrated ductal stents. With this in mind, we present a review of the current advancements in choledo-choscopy with new supporting evidence that further delineates the role of choledochoscopy in various diagnostic and therapeutic interventions, complications, limitations and put forth areas for further study.