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A computer-aided differential diagnosis (CADD) system that distinguishes between usual interstitial pneumonia (UIP) and non-specific interstitial pneumonia (NSIP) using high-resolution computed tomography (HRCT) images was developed, and its results compared against the decision of a radiologist. Six local interstitial lung disease patterns in the images were determined, and 900 typical regions of interest were marked by an experienced radiologist. A support vector machine classifier was used to train and label the regions of interest of the lung parenchyma based on the texture and shape characteristics. Based on the regional classifications of the entire lung using HRCT, the distributions and extents of the six regional patterns were characterized through their CADD features. The disease division index of every area fraction combination and the asymmetric index between the left and right lungs were also evaluated. A second SVM classifier was employed to classify the UIP and NSIP, and features were selected through sequential-forward floating feature selection. For the evaluation, 54 HRCT images of UIP (n = 26) and NSIP (n = 28) patients clinically diagnosed by a pulmonologist were included and evaluated. The classification accuracy was measured based on a fivefold crossvalidation with 20 repetitions using random shuffling. For comparison, thoracic radiologists assessed each case using HRCT images without clinical information or diagnosis. The accuracies of the radiologists' decisions were 75 and 87%. The accuracies of the CADD system using different features ranged from 70 to 81%. Finally, the accuracy of the proposed CADD system after sequential-forward feature selection was 91%. [ABSTRACT FROM AUTHOR]

Interpolation artifact is known to occur when the heart rate is decreased lower than the critical value for the specific pitch. The purpose of our study is to determine the minimum heart rate (minHR) for the specific pitch that provides images without interpolation artifact when using dual-source computed tomography (DSCT). We scanned the ‘thin slice thickness block’ of the CT performance phantom provided by the American Association of Physicists in Medicine using DSCT for variable pitches. Change in heart rate was simulated through ECG editing by changing R–R interval. Axial, sagittal, and coronal image sets were reconstructed and assessed for the presence and extent of interpolation artifact. MinHR at which no interpolation artifact was detected for each pitch value was determined. Length of interpolation artifact (LOA) on sagittal view was also measured when the heart rate was simulated at 10 bpm lower than the minHR on each pitch setting. MinHRs for each pitch value were 9–10 bpm from the estimated heart rate. However, minHR for the lowest pitch value 0.2, estimated heart value 40 bpm was 37 bpm. LOA was larger in the low heart rate condition. Measured values of minHR were correlated exactly with the calculated values. MinHRs that provide images without interpolation artifact for each pitch value when using DSCT were determined. The concept of minHR is important for obtaining high quality images of cardiac CT angiography when using DSCT. [ABSTRACT FROM AUTHOR]

Xenon ventilation CT using a dual-source dual-energy technique is a promising functional imaging method for the lung. We report the typical ventilation abnormalities, collateral ventilation and air trapping in the affected lung segment demonstrated on xenon ventilation CT in a child with bronchial atresia. [ABSTRACT FROM AUTHOR]

The severity of chronic obstructive pulmonary disease (COPD) is evaluated not only by airflow limitation but also by factors such as exercise capacity and body mass index. Recent advances in CT technology suggest that it might be a useful tool for evaluating the severity of the disease components of COPD. The aim of this study is to evaluate the correlation between the parameters measured on volumetric CT, including the extent of emphysema, air trapping, and airway thickening, and clinical parameters. CT scans were performed in 34 patients with COPD at full inspiration and expiration. We used in-house software to measure CT parameters, including volume fraction of emphysema (V950), mean lung density (MLD), CT air trapping index (CT ATI), segmental bronchial wall area (WA), lumen area (LA), and wall area percent (WA%). We found that the CT parameters were correlated with the pulmonary function test (PFT) results, body mass index (BMI), the modified Medical Research Council Dyspnea scale (MMRC scale), the six-minute-walk distance (6MWD), and the BODE index. V950 insp correlated to the BMI, FEV1, 6MWD, and the BODE index. The CT ATI correlated with the physiologic ATI (VC – FVC) ( R = 0.345, p = 0.045) and the MMRC scale ( R = 0.532, p = 0.001). There was a positive correlation between the WA% and the BMI ( R = 0.563, p < 0.001). MLDexp showed the strongest correlation with the BODE index ( R = −0.756, p < 0.001). We conclude that the severity of emphysema and air trapping measured on CT correlated with the PFT parameters 6MWD and BMI. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the variation of the size of pulmonary vein ostia during cardiac cycle using ECG-gated multi-detector row CT (MDCT). Nineteen patients were included in this study. Transaxial images at the level of right inferior pulmonary vein (RIPV) were reconstructed in increments of 5%. The ostial diameter of RIPV was measured, the reconstruction windows showing maximal and minimal diameters were selected. The ostial areas of four pulmonary veins were measured at axial image sets of two selected reconstruction windows. The measurement of RIPV revealed that the maximal diameter (1.50±0.32 cm) was generally 35% and the minimal diameter (1.28±0.28 cm) was usually at 85%. The measurement of ostial areas showed that the ostia enlarged at the end of ventricular systole when compared with those at the end of ventricular diastole, by the factors of 1.44±0.55 for the right superior, 1.25±0.23 for the right inferior, 1.45±0.81 for the left superior, and 1.31±0.26 for the left inferior pulmonary vein ( P<0.05). The size of the pulmonary vein ostia is variable during the cardiac cycle and the measurement of the pulmonary veins should always be in the same phase of the cardiac cycle during the follow-up of patients. [ABSTRACT FROM AUTHOR]

Our objective was to ascertain whether displacement of the aortic knob on chest radiographs could be used as a sign to detect a left paratracheal esophageal mass. Sixty-one consecutive pathologically proven esophageal cancer patients were included in this study according to the following criteria: tumor at the aortic arch level; chest radiographs in the neutral position; no unilateral volume loss in the lung. Sixty-one sex- and age-matched subjects served as the control group. To measure the extent of displacement of the aortic arch, we drew a circle over the aortic knob, fitting more than one-quarter of the circumference on the chest radiograph. The distance between the medial end of the circle and the left margin of the trachea (aortic displacement value, ADV) was measured. The difference of the ADV between the study group and the control group was analyzed using a pairedttest. The aortic displacement value was significantly larger in the study group (11.7±4.5 mm) than in the control group (5.6±2.9 mm). When we applied 10 mm as a threshold level, sensitivity and specificity on detection of esophageal cancer were 78.7 and 78.7%, respectively. Displacement of the aortic knob may be a useful sign to indicate a left paratracheal esophageal mass. [ABSTRACT FROM AUTHOR]