Neural network based detection of pulmonary nodules on chest radiographs

PURPOSE: We investigated the capabilities of an artificial neural network-based Computer-Aided Diagnosis (CAD) system in improving early detection of pulmonary nodules on chest radiographs. MATERIAL AND METHODS: We used a data-set of 145 digitized chest films. Two different radiologists read the radiographs to detect the sites of possible nodules. The system uses two neural networks trained on a training-set of 100 radiographs selected from the data-set. The first network is used to focus attention on the sites of potential nodules while the second calculates the likeliness of nodule presence in ROIs. The clinical test was performed on 45 more radiographs from the training-set, but different from those in the data-set, which were positive for both benign and malignant nodules. These latter plain films showed 65 nodular lesions which differed by shape and acquisition technique. RESULTS: Sensitivity was 89% in all radiographs while specificity, evaluated by ROI, and accuracy, were 98%. CONCLUSIONS: There are potential limitations in nodule detection on plain radiographs. Some of them are operator-dependent, such as nonsystematic investigation, lesion underestimation, and poor reading, and some are technique-dependent, such as X-ray beam/tube, low voltage, patient positioning, focus-film distance and development process. CADs may contribute to improving detection of pulmonary nodules because the false-negative rate is decreased and sensitivity consequently increased. The high sensitivity and specificity rates of neural networks encourage further trials on wider data-sets to help the radiologist in the early detection of pulmonary nodules.     

Value of hepatic arterial phase CT versus lipiodol ultrafluid CT in the detection of hepatocellular carcinoma

OBJECTIVE: To evaluate the role of hepatic arterial phase (HAP) spiral computed tomography (CT), as compared with iodized oil (Lipiodol ultrafluid [LUF]) CT for revealing nodular hepatocellular carcinomas (HCC). METHODS: Twenty-four cirrhotic patients underwent two-phase HCT examination: HAP 25 seconds and portal phase 70 seconds after injection of 1.5 mL/Kg contrast medium. All patients also underwent hepatic angiography and intraarterial infusion of iodized oil; LUF CT was performed 3-4 weeks after infusion. HCT images were compared with LUF CT images for detection of hepatic nodules. RESULTS: We found no significant difference between the sensitivity of HAP CT and LUF CT for nodules >10 mm, while HAP CT was more sensitive than LUF CT in revealing nodules <10 mm (47 vs. 27, p < 0.001). CONCLUSIONS: HCT should be considered as the first method for the detection of HCC, whereas LUF CT should be used only for therapy.     

Relief of methacholine-induced bronchospasm with extrafine beclomethasone dipropionate/formoterol in comparison with salbutamol in asthma

BackgroundShort-acting beta2-agonists like salbutamol and terbutaline are used as rescue medications for acute bronchoconstriction and relief of symptoms due to their rapid onset of action. The aim of this study was to assess whether inhaled beclomethasone dipropionate (BDP)/formoterol fumarate (FF) combination in extrafine formulation is non-inferior to salbutamol in the speed of reverting methacholine-induced bronchoconstriction and symptoms.MethodsFifty-six asthmatic patients were examined in a multicentre, randomised, double blind, double dummy, active treatment and placebo controlled three period cross-over study. On three different days, a single dose of BDP/FF 100/6 μg in pressurised metered-dose inhaler (pMDI) extrafine formulation or salbutamol 200 μg pMDI or placebo was inhaled after FEV₁ had dropped by 30–45% with methacholine challenge.ResultsThe median time to recovery of FEV₁ to 85% of baseline was similar for BDP/FF and salbutamol (3.66 and 2.15 min, respectively), but significantly longer for placebo (21.1 min). The planned analysis on adjusted mean time to recovery showed that the difference from methacholine-induced bronchoconstriction between BDP/FF and salbutamol was 3.82 min (95% confidence interval: ?0.85 to 8.5), therefore greater than 3 min supposed in the study design. The difference between BDP/FF and salbutamol was not clinically significant. The two active treatments were also comparable in terms of the relief of symptoms (as assessed by the Borg dyspnoea scale).ConclusionsBDP/FF combination has a fast onset of action, similar to that of salbutamol, and may represent a good alternative as rescue medication in asthmatic patients.     

Does acute-phase beta-blockade reduce mortality in acute myocardial infarction by limiting infarct size?

The mechanism by which early intervention with beta-blockers reduces mortality in acute myocardial infarction is unclear. Therefore the effects of intravenous, followed by oral, metoprolol on indices of infarct size were studied in a double-blind fashion with a median delay of 6.75 hours from onset of symptoms. In 129 patients peak enzyme release and QRS score on the electrocardiogram were assessed, while myocardial perfusion score on thallium-201 scintigraphy was studied in 45 patients. There was a close correlation between all the indices of infarct size. While the correlation coefficients did not appear to be influenced by metoprolol treatment, the slope of the regression was affected. Peak aspartate aminotransferase and lactic dehydrogenase were lower by 11 and 7%, respectively, in the metoprolol-treated group, but no reduction was noted in QRS score or in thallium-201 perfusion defect size in the actively treated group. Thus, it seems likely that early intervention with metoprolol in acute myocardial infarction reduces mortality, not by limiting infarct size, but by some other mechanism.     

A left ventricular epicardial to right ventricular endocardial dominant frequency gradient exists in human ventricular fibrillation

Purpose  

We hypothesized that in patients with left ventricular dysfunction undergoing implant of a biventricular ICD, the local dominant frequency during early induced ventricular fibrillation would be higher at an epicardial left ventricular position compared to an endocardial right ventricular position.