A 62-year-old woman underwent a series of urologic procedures for nephrolithiasis and was diagnosed with a pyeloduodenal fistula (PDF) on computed tomography urography. After the placement of a metallic ureteral stent and nephrostomy tube, an esophagogastroduodenoscopy was performed to evaluate for PDF resolution. Two areas of mucosal defects within the anterior duodenal sweep were closed using the over-the-scope clip system and hemostasis clips. We review the literature and discuss the etiologies, presentation, diagnosis, and treatment of PDF. This is the second documented case of endoscopic PDF closure using the over-the-scope clip system and the third case of endoscopically treated PDF.

Objectives

Reliable in situ diagnosis of diminutive (≤5 mm) colorectal polyps could allow for "resect and discard" and "diagnose and leave" strategies, resulting in $1 billion cost savings per year in the United States alone. Current methodologies have failed to consistently meet the Preservation and Incorporation of Valuable endoscopic Innovations (PIVIs) initiative thresholds. Convolutional neural networks (CNNs) have the potential to predict polyp pathology and achieve PIVI thresholds in real time.

Methods

We developed a CNN-based optical pathology (OP) model using Tensorflow and pretrained on ImageNet, capable of operating at 77 frames per second. A total of 6,223 images of unique colorectal polyps of known pathology, location, size, and light source (white light or narrow band imaging [NBI]) underwent 5-fold cross-training (80%) and validation (20%). Separate fresh validation was performed on 634 polyp images. Surveillance intervals were calculated, comparing OP with true pathology.

Results

In the original validation set, the negative predictive value for adenomas was 97% among diminutive rectum/rectosigmoid polyps. Results were independent of use of NBI or white light. Surveillance interval concordance comparing OP and true pathology was 93%. In the fresh validation set, the negative predictive value was 97% among diminutive polyps in the rectum and rectosigmoid and surveillance concordance was 94%.

Discussion

This study demonstrates the feasibility of in situ diagnosis of colorectal polyps using CNN. Our model exceeds PIVI thresholds for both "resect and discard" and "diagnose and leave" strategies independent of NBI use. Point-of-care adenoma detection rate and surveillance recommendations are potential added benefits.