Deep-learning-aided forward optical coherence tomography endoscope for percutaneous nephrostomy guidance.

Percutaneous renal access is the critical initial step in many medical settings. In order to obtain the best surgical outcome with minimum patient morbidity, an improved method for access to the renal calyx is needed. In our study, we built a forward-view optical coherence tomography (OCT) endoscopic system for percutaneous nephrostomy (PCN) guidance. Porcine kidneys were imaged in our experiment to demonstrate the feasibility of the imaging system. Three tissue types of porcine kidneys (renal cortex, medulla, and calyx) can be clearly distinguished due to the morphological and tissue differences from the OCT endoscopic images. To further improve the guidance efficacy and reduce the learning burden of the clinical doctors, a deep-learning-based computer aided diagnosis platform was developed to automatically classify the OCT images by the renal tissue types. Convolutional neural networks (CNN) were developed with labeled OCT images based on the ResNet34, MobileNetv2 and ResNet50 architectures. Nested cross-validation and testing was used to benchmark the classification performance with uncertainty quantification over 10 kidneys, which demonstrated robust performance over substantial biological variability among kidneys. ResNet50-based CNN models achieved an average classification accuracy of 82.6%±3.0%. The classification precisions were 79%±4% for cortex, 85%±6% for medulla, and 91%±5% for calyx and the classification recalls were 68%±11% for cortex, 91%±4% for medulla, and 89%±3% for calyx. Interpretation of the CNN predictions showed the discriminative characteristics in the OCT images of the three renal tissue types. The results validated the technical feasibility of using this novel imaging platform to automatically recognize the images of renal tissue structures ahead of the PCN needle in PCN surgery.

Precocious puberty in a 7-year-old boy: a novel case.

A 7-year-old boy was referred for evaluation of precocious puberty, evidenced by penile enlargement and pubic hair formation. His testicular size was prepubertal bilaterally. A comprehensive hormonal evaluation showed an elevated serum testosterone value (4.0 nmol/L) and a prepubertal gonadotropin value. A 0.9-cm heterogenous left testicular mass was detected on scrotal ultrasonography. Inguinal exploration was performed with ultrasound-guided open testicular biopsy and orchiectomy. Pathologic evaluation of the orchiectomy specimen showed the unclassified type of a mixed germ cell sex cord stromal tumor (MGCSCST), composed of neoplastic Sertoli cells and seminoma-like germ cells. Isolated previous reports of unclassified MGCSCSTs of the testis are now thought to be reports of sex cord stromal tumors with entrapped non-neoplastic germ cells. In our patient, the germ cells appeared to be neoplastic with aberrant expression of c-kit and placental alkaline phosphatase, a high proliferative rate, and DNA aneuploidy. Postoperatively, the patient's serum testosterone concentrations returned to prepubertal values (<0.2 nmol/L) and puberty was halted. This case represents a novel cause of precocious puberty.