The authors performed this study to evaluate two physical measures used for quantifying interstitial lung abnormalities on chest radiographs: the normalized radiographic index (RI) and the fractal ...dimension (FD).
The RI and FD were obtained from 50 regions of interest (ROIs) in lungs with mild interstitial abnormalities, 50 ROIs in lungs with severe interstitial abnormalities, and 50 ROIs in normal lungs. The RI was defined as the normalized percentage area of extracted opacities in selected ROIs. FD was calculated with a box-counting algorithm. To extract linear opacities selectively, the authors processed ROIs with four-directional Laplacian-Gaussian filtering and binarization, linear opacity judgment (LOJ), and linear opacity subtraction (LOS). The usefulness of the physical measures for quantifying interstitial lung abnormalities was evaluated with receiver operating characteristic analysis.
In normal and mild abnormality groups, observer performance with the RI was worse with LOJ images (area under the receiver operating characteristic curve Az = .812 +/- .042) than with LOS images (Az = .912 +/- .028, P < .05), and performance with FD was better with LOJ images (Az = .867 +/- .037) than with LOS images (Az = .750 +/- .048, P < .05). In the normal and severe abnormality groups, performance with RI and FD was better with LOJ images (RI: Az = .992 +/- .007; FD: Az = .968 +/- .016) than with LOS images (RI: Az = .883 +/- .034, P < .001; FD: Az = .767 +/- .047, P < .0001).
The RI is considered to reflect the sensitivity in the detection of interstitial lung abnormalities on chest radiographs. Conversely, the FD is considered to reflect specifically the linear opacities processed with LOJ.
We examined whether angiotensin converting enzyme (ACE) inhibitors and angiotensin II type 1 receptor blockers (ARB) prevent isoproterenol (ISO)-induced left ventricular (LV) dysfunction in dogs. The ...effects of a large dose of ISO, 1 microg/kg/min, 3 h infusion, were investigated in three groups with simultaneous infusion of an ACE inhibitor (quinaprilat), ARB (candesartan) or saline. ISO infusion significantly decreased LV dP/dt, LV ejection fraction and LV fractional shortening, and significantly increased tau, the time constant of isovolume relaxation of LV, and LV end diastolic pressure. All of these changes were significantly attenuated in both the ACE inhibitor and ARB groups, especially in the ARB group. Serum levels of creatinin kinase isoform MB, lactate dehydrogenase and lipid peroxide were significantly increased by ISO. However, the increases in these markers of myocardial damage were significantly diminished by simultaneous infusion of an ACE inhibitor or ARB, especially by ARB. In conclusion, an ACE inhibitor and ARB prevent LV systolic and diastolic dysfunction as well as myocardial damage induced by excess beta-adrenergic stimulation.
The purpose of this study was to analyze the CT findings in lymphangitic carcinomatosis and to determine how the abnormalities seen on CT correlated with histologic findings and the results of ...pulmonary function tests. Accordingly, we reviewed CT findings in 20 proved cases and correlated them with histologic findings and with results of pulmonary function tests (available in 11). Special attention was given to the extent and degree of thickening of the peripheral and/or axial interstitium as seen on CT. In 15 of 20 patients, CT scans showed marked thickening of axial interstitium and subtle or no thickening of peripheral interstitium (four diffuse and 11 localized). In three cases, CT showed marked thickening of both axial and peripheral interstitium (two diffuse and one localized). In two cases, CT showed marked thickening of peripheral interstitium and subtle or no thickening of axial interstitium (one diffuse and one localized). These CT findings correlated with the pathologic findings. Marked impairment of vital capacity and alveolar-arterial oxygen gradient was observed in three patients (one with diffuse and peripheral interstitial thickening and two with diffuse and both peripheral and axial interstitial thickening). We conclude that CT findings in patients with lymphangitic carcinomatosis are variable and that marked impairment of pulmonary function occurs in patients with diffuse and peripheral interstitial thickening. Marked impairment of pulmonary function can be predicted from CT findings.
This paper reports the clinical significance of a computer-analyzing system to detect and characterize interstitial lung diseases in chest radiographs. One hundred and sixty-four ROIs were selected ...in the right lungs of 41 patients with normal and those of 41 with diffuse interstitial involvement proved by X-ray CT. Selected ROIs were processed by 4-directional Laplacian-Gaussian filtering, binarization, and determination of linear shadows. For quantitative analysis of interstitial shadows, radiographic index, normalized percent-area of shadows in a ROI, was determined and evaluated in the images. Then, the radiographic indices were compared with CT-documented characteristics of interstitial lung shadows. The results were as follows: 1) Abnormal and normal lungs were well differentiated each other by all kinds of the radiographic indices obtained from the images filtered by 4-directional Laplacian-Gaussian filters and from those processed by determination of linear shadows. 2) ROIs with honeycombing shadows and with other interstitial shadows (interstitial changes other than honeycombing and nodulation) shown in CT were differentiated each other by the radiographic indices obtained from the summation image and the vertical directional image processed by determination of linear shadows (p less than .01). However, ROIs with multiple nodular shadows and with other interstitial shadows were not classified by these radiographic indices. These results indicate that this system may be useful for detection and characterization of interstitial diseases in chest radiographs.
Left atrial tumor, diagnosed as myxoma at first investigation, was later demonstrated to be a malignant fibrosarcoma with myxoid change. Myxoma should be diagnosed and managed carefully because of ...its wide range of histopathologic features.
The aim of this study was to evaluate the usefulness of a computer-aided diagnosis (CAD) system on radiologists' performance for distinction between benign and malignant pulmonary nodules on digital ...chest radiographs using temporal subtraction images. Fifty-one chest radiographs including 26 malignant nodules and 25 benign nodules were used. The nodule on subtraction image was segmented by thresholding with various pixel values which were determined from the area of the histogram of pixel values on the temporal subtraction image. A rule-based approach and a linear discriminant analysis (LDA) with six features were applied to determine the likelihood of malignancy of pulmonary nodules. Eight radiologists participated in an observer performance study in which cases were interpreted first without and then with use of the CAD scheme. The observers' performance was evaluated by use of receiver operating characteristic (ROC) analysis. The average area under the ROC curve increased significantly from 0.695 without computer output to 0.818 with computer output. This CAD system for digital chest radiographs using temporal subtraction images has a potential to assist radiologists for distinction between benign and malignant pulmonary nodules.
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