Hazem Hassan

Neural network analysis of dynamic sequences of EUS elastography used for the differential diagnosis of chronic pancreatitis and pancreatic cancer

BACKGROUND EUS elastography is a newly developed imaging procedure that characterizes the differences of hardness and strain between diseased and normal tissue. OBJECTIVE To assess the accuracy of real-time EUS elastography in pancreatic lesions. DESIGN Cross-sectional feasibility study. PATIENTS The study group included, in total, 68 patients with normal pancreas (N = 22), chronic pancreatitis (N = 11), pancreatic adenocarcinoma (N = 32), and pancreatic neuroendocrine tumors (N = 3). A subgroup analysis of 43 cases with focal pancreatic masses was also performed. INTERVENTIONS A postprocessing software analysis was used to examine the EUS elastography movies by calculating hue histograms of each individual image, data that were further subjected to an extended neural network analysis to differentiate benign from malignant patterns. MAIN OUTCOME MEASUREMENTS To differentiate normal pancreas, chronic pancreatitis, pancreatic cancer, and neuroendocrine tumors. RESULTS Based on a cutoff of 175 for the mean hue histogram values recorded on the region of interest, the sensitivity, specificity, and accuracy of differentiation of benign and malignant masses were 91.4%, 87.9%, and 89.7%, respectively. The positive and negative predictive values were 88.9% and 90.6%, respectively. Multilayer perceptron neural networks with both one and two hidden layers of neurons (3-layer perceptron and 4-layer perceptron) were trained to learn how to classify cases as benign or malignant, and yielded an excellent testing performance of 95% on average, together with a high training performance that equaled 97% on average. LIMITATION A lack of the surgical standard in all cases. CONCLUSIONS EUS elastography is a promising method that allows characterization and differentiation of normal pancreas, chronic pancreatitis, and pancreatic cancer. The currently developed methodology, based on artificial neural network processing of EUS elastography digitalized movies, enabled an optimal prediction of the types of pancreatic lesions. Future multicentric, randomized studies with adequate power will have to establish the clinical impact of this procedure for the differential diagnosis of focal pancreatic masses.

Randomized controlled trial of endoscopic ultrasound-guided fine-needle sampling with or without suction for better cytological diagnosis.

Objective. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a highly accurate method to obtain specific diagnosis in various diseases. The optimal method of EUS-guided sampling of material for pathologic diagnosis has not been clearly established. The aim of our study was to compare two different techniques of EUS-guided sampling of solid masses, using either non-suction or suction with a 10-ml syringe. Material and methods. Patients assessed during a 6-month period were randomized to three passes of EUS-guided sampling with suction (26 patients) or non-suction (26 patients). The samples were characterized for cellularity and bloodiness, with a final cytology diagnosis established blindly. The final diagnosis was reached either by EUS-FNA if malignancy was definite, or by surgery and/or clinical follow-up of a minimum of 6 months in the cases of non-specific benign lesions. Results. EUS-guided fine-needle sampling with suction of solid masses increased the number of pathology slides (17.8±7.1 slides for suction as compared with 10.2±5.5 for non-suction, p=0.0001), without increasing the overall bloodiness of each sample. Sensitivity and the negative predictive values were higher when suction was applied, as compared to the non-suction group (85.7% as compared with 66.7%, p=0.05). Conclusions. This prospective randomized study showed that EUS-guided fine-needle sampling of solid masses using suction yields a higher number of slides without increasing bloodiness. Although, the proportion of target cells was relatively similar between the suction and non-suction sampling techniques, the sensitivity and negative predictive values of the procedure were significantly higher when suction was added.

Impact of EUS-guided FNA on management of gastric carcinoma

BACKGROUND EUS is an integral part of the pretherapeutic evaluation program for patients with upper GI cancer. OBJECTIVE To evaluate the impact of EUS-guided FNA on the clinical management of patients with gastric cancer. DESIGN The study included patients with confirmed gastric carcinoma who were referred to the Department of Surgical Gastroenterology, Gentofte Hospital, Copenhagen University, Copenhagen, Denmark, during a 6-year period (2001-2007). SETTING The patients underwent standard pretherapeutic evaluation. If no signs of incurability were detected, the patients were offered EUS and EUS-guided FNA. EUS-guided FNA was performed when lymph nodes or lesions were considered to be distant metastases. A board of surgeons was asked to evaluate the management of the patients after the results obtained by EUS-guided FNA were revealed. PATIENTS This study involved 234 patients with gastric carcinoma. INTERVENTION EUS-guided FNA. MAIN OUTCOME MEASUREMENTS Number of patients with distant metastasis diagnosed by EUS-guided FNA, with the avoidance of unnecessary surgery. RESULTS A total of 81 consecutive patients underwent EUS-guided FNA. Ninety-nine lesions were targeted, and 61 (62%) of these lesions were found to be malignant. In 38 of 81 patients (42%) distant metastases were confirmed by EUS-guided FNA. As judged by the board of surgeons, EUS-guided FNA changed the management plan in 34 of 234 patients (15%). LIMITATION The positive EUS-guided FNA diagnoses were not surgically verified. CONCLUSION EUS-guided FNA is a very important modality and should be integrated as a routine procedure in the preoperative staging algorithm of gastric cancer.

Endoscopic ultrasound-guided needle-based confocal laser endomicroscopy: a pilot study for use in focal pancreatic masses.

Copyright emerged in recent years as a novel method that enables in vivo microscopic analysis during ongoing endoscopy. Recently, CLE has gone beyond the superficial luminal indications with the development of a newmicroprobe (nCLE) (Cellvizio;Mauna Kea Technology, Paris, France). The aim of the present case series was to study the feasibility of EUS-guided nCLE and to correlate the findings with microscopy.

The use of double-balloon enteroscopy in retrieving mucosal biopsies from the entire human gastrointestinal tract.

Abstract Objective. The aim of this explorative study was to evaluate double-balloon enteroscopy (DBE) as a new tool for collecting mucosal biopsies from well-defined parts of the entire small and large bowel in patients with type 2 diabetes and in matched healthy subjects. Material and methods. Twelve subjects with type 2 diabetes and 12 body mass index and age-matched healthy subjects underwent anterograde and retrograde DBE under nurse-administered propofol sedation on two separate days. We attempted to collect two mucosal biopsies from every 30 cm from pylorus to rectum. Results. A mean of 21 biopsy sites were sampled in the diabetic group versus 25 in the healthy group. In 4 out of 24 patients (2 [17%] from each group) sampling from the entire gastrointestinal system was possible. Mean depth of maximal insertion (anterograde) was 478 ± 32 cm in patients with type 2 diabetes versus 465 ± 44 cm in healthy subjects (p = 0.81) and with retrograde access 230 ± 36 cm (type 2 diabetes) versus 207 ± 26 cm (healthy subjects). Conclusions. DBE is a minimally invasive way of collecting fresh biopsies from the entire gastrointestinal tract and, thus provides research and clinical communities with a new possibility to access hitherto unexplored human anatomy and physiology.