Automatic classification of endoscopic images for premalignant conditions of the esophagus

Barrett’s esophagus (BE) is a precancerous complication of gastroesophageal reflux disease in which normal stratified squamous epithelium lining the esophagus is replaced by intestinal metaplastic columnar epithelium. Repeated endoscopies and multiple biopsies are often necessary to establish the presence of intestinal metaplasia. Narrow Band Imaging (NBI) is an imaging technique commonly used with endoscopies that enhances the contrast of vascular pattern on the mucosa. We present a computer-based method for the automatic normal/metaplastic classification of endoscopic NBI images. Superpixel segmentation is used to identify and cluster pixels belonging to uniform regions. From each uniform clustered region of pixels, eight features maximizing differences among normal and metaplastic epithelium are extracted for the classification step. For each superpixel, the three mean intensities of each color channel are firstly selected as features. Three added features are the mean intensities for each superpixel after separately applying to the red-channel image three different morphological filters (top-hatfiltering, entropy filtering and range filtering). The last two features require the computation of the Grey-Level Co-Occurrence Matrix (GLCM), and are re ective of the contrast and the homogeneity of each superpixel. The classification step is performed using an ensemble of 50 classification trees, with a 10-fold cross-validation scheme by training the classifier at each step on a random 70% of the images and testing on the remaining 30% of the dataset. Sensitivity and Specificity are respectively of 79.2% and 87.3%, with an overall accuracy of 83.9%. © 2016 SPIE

Diagnostic accuracy and interobserver variability of CO-RADS in patients with suspected coronavirus disease-2019: a multireader validation study

Objective: To conduct a multireader validation study to evaluate the interobserver variability and the diagnostic accuracy for the lung involvement by COVID-19 of COVID-19 Reporting and Data System (CO-RADS) score. Methods: This retrospective study included consecutive symptomatic patients who underwent chest CT and reverse transcriptase-polymerase chain reaction (RT-PCR) from March 2020 to May 2020 for suspected COVID-19. Twelve readers with different levels of expertise independently scored each CT using the CO-RADS scheme for detecting pulmonary involvement by COVID-19. Receiver operating characteristic (ROC) curves were computed to investigate diagnostic yield. Fleiss’ kappa statistics was used to evaluate interreader agreement. Results: A total of 572 patients (mean age, 63 ± 20 [standard deviation]; 329 men; 142 patients with COVID-19 and 430 patients without COVID-19) were evaluated. There was a moderate agreement for CO-RADS rating among all readers (Fleiss’ K = 0.43 [95% CI 0.42–0.44]) with a substantial agreement for CO-RADS 1 category (Fleiss’ K = 0.61 [95% CI 0.60–0.62]) and moderate agreement for CO-RADS 5 category (Fleiss’ K = 0.60 [95% CI 0.58–0.61]). ROC analysis showed the CO-RADS score ≥ 4 as the optimal threshold, with a cumulative area under the curve of 0.72 (95% CI 66–78%), sensitivity 61% (95% CI 52–69%), and specificity 81% (95% CI 77–84%). Conclusion: CO-RADS showed high diagnostic accuracy and moderate interrater agreement across readers with different levels of expertise. Specificity is higher than previously thought and that could lead to reconsider the role of CT in this clinical setting. Key Points: • COVID-19 Reporting and Data System (CO-RADS) demonstrated a good diagnostic accuracy for lung involvement by COVID-19 with an average AUC of 0.72 (95% CI 67–75%). • When a threshold of ≥ 4 was used, sensitivity and specificity were 61% (95% CI 52–69%) and 81% (95% CI 76–84%), respectively. • There was an overall moderate agreement for CO-RADS rating across readers with different levels of expertise (Fleiss’ K = 0.43 [95% CI 0.42–0.44])

PROCESS FOR THE PREPARATION OF HYDROFLUOROALKANES

Process for the preparation of hydro(halo)fluoroalkanes by direct fluorination in liquid phase with elemental fluorine at low temperature (under 0 DEG C.) of the corresponding hydro(halo)=alkenes

Correlation between yield and operating conditions in the electrochemical fluorination of tripropylamine

Electrochemical fluorination of tripropylamine in anhydrous hydrogen fluoride was studied in order to verify the correlation between the operating conditions and the yield of the corresponding perfluoroamine. The parameters tested were: temperature, voltage, initial concentration of amine in the bath, constant concentration of amine in the bath and stirring effect. Experimental data show that temperature is the parameter exerting the most remarkable influence over perfluoroamine yield and by-products formation

Bianco come il sangue: il sangue artificiale

E' una lontana aspirazione dell'uomo quella di poter sostituire il sangue naturale con prodotti sintetici in grado di esplicare le stesse funzioni. La soluzione \ue8 stata trovata dalla chimica dei prodotti flururati per le loro propriet\ue0 caratteristiche di sciogliere i gas in forti proporzioni, di essere chimicamente inerti e di essere metabolizzati

Determinazione dei calori di formazione e di nitrazione del 3-nitro-4-clorobenzotrifluoruro e del 3,5dinitro4-clorobenzotrifluoruro.

I calori dii nitrazione di mono e dinitrazione del p-clorobenzotrifluoruro sono determinati conducendo le reazioni di nitrazione e confrontati con quelli ottenuti dai calori di combustione in calorimetro di Mahler