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The aim of the present study was to investigate the difference in doubling time between squamous cell carcinoma (SCC) and adenocarcinoma of solid pulmonary cancer using three-dimensional volumetric software. We included 40 patients with adenocarcinoma and 11 patients with SCC, who underwent CT examinations more than once before surgical treatment. Tumor volumes and doubling times were obtained using three-dimensional volumetric computer software. Statistical analysis was performed using Mann-Whitney's U-test except for negative doubling times (doubling times less than 0 day). Negative doubling time was found in 5 of the 40 adenocarcinomas (13%), but not in any of the patients with SCC. Doubling time was beyond 400 days in 11 of the 40 adenocarcinomas (28%), but was always less than 400 days in SCC. The mean doubling time of SCC was 126+/-58 days (range, 39-221 days; median, 131 days), while that of adenocarcinomas, except for the negative doubling times, was 976+/-3134 days (range, 69-18,678 days; median, 258 days). Doubling time differed significantly between adenocarcinomas and SCC (p<0.01). In conclusion, the median doubling time of SCC lung cancers is less than that of adenocarcinomas, as measured with automated volumetric measurement software.

Rationale and Objectives: Most studies of computer-aided detection (CAD) for pulmonary nodules have focused on solid nodule detection. The aim of this study was to evaluate the performance of a commercially available CAD system in the detection of pulmonary nodules with or without ground-glass opacity (GGO) using 64-detector-row computed tomography compared to visual interpretation., Materials and Methods: Computed tomographic examinations were performed on 48 patients with existing or suspicious pulmonary nodules on chest radiography. Three radiologists independently reported the location and pattern (GGO, solid, or part solid) of each nodule candidate on computed tomographic scans, assigned each a confidence score, and then analyzed all scans using the CAD system. A reference standard was established by a consensus panel of different radiologists, who found 229 noncalcified nodules with diameters > or = 4 mm. True-positive and false-positive results and confidence levels were used to generate jackknife alternative free-response receiver-operating characteristic plots., Results: The sensitivity of GGO for 3 radiologists (60%-80%) was significantly higher than that for the CAD system (21%) (McNemar's test, P < .0001). For overall and solid nodules, the figure-of-merit values without and with the CAD system were significantly different (P = .005-.04) on jackknife alternative free-response receiver-operating characteristic analysis. For GGO and part-solid nodules, the figure-of-merit values with the CAD system were greater than those without the CAD system, indicating no significant differences., Conclusion: Radiologists are significantly superior to this CAD system in the detection of GGO, but the CAD system can still play a complementary role in detecting nodules with or without GGO.

The purpose of our investigation was to compare the usefulness of the subjective visual assessment of ground-glass opacity (GGO) with a quantitative method that used a profile curve to determine prognosis. 96 adenocarcinomas were studied. Three diameters ([D1]-[D3]) were defined for estimating the diameter of tumours on the monitor: the distance between two points was measured using software that displays a CT density profile across the tumour. One experienced and one less experienced radiologist independently evaluated the following six parameters: the three diameters [D1]-[D3]; the solid portion of total tumour in the two different ratios ([D2]/[D1], [D3]/[D1]); and the area ratio of GGO for total opacity to subjective visual evaluation. Interobserver agreement between the two radiologists of the diameters (mean bias+/- 1.96 standard deviations) was as follows: [D1], -0.7 +/- 6 mm; [D2], 0.4 +/- 4.4 mm; and [D3], -0.1 +/- 4.2 mm (Bland and Altman's method). Interobserver agreement was fair in evaluating the area ratio of GGO (kappa test, kappa = 0.309). Univariate logistic regression analysis revealed that two ratios ([D2]/[D1], [D3]/[D1]) might be significantly useful in estimating lymph node metastasis (p < 0.026), lymph duct invasion (p < 0.001) and recurrence (p < 0.015). Observation of the area ratio of GGO by an experienced radiologist would be necessary for estimating lymph node metastasis (p = 0.04) and lymph duct invasion (p < 0.001). We concluded that the ratio of solid component to total tumour, which is obtainable in a more objective and simple way using profile curves obtained by software, is a more useful method of estimating prognosis than is visual assessment.

Purpose: To determine the pathological correlation with various high-resolution CT (HRCT) findings in cases with nonspecific interstitial pneumonia (NSIP), paying special attention to pathological subgroups., Material and Methods: The study involved 29 patients diagnosed with NSIP by surgical lung biopsy. A total of 54 specimens were obtained and grouped according to Katzenstein's classification (groups 1-3) for NSIP. Two observers then evaluated the HRCT findings for every biopsy site and classified the findings according to the main pattern evident into the following four radiologic pattern groups: A, ground-glass attenuation and fine reticulation; B, ground-glass and coarse reticulation; C, consolidation and D, ground-glass attenuation and consolidation., Results: The pathological pattern was NSIP group 1 in 6 patients, group 2 in 22 and group 3 in 25, while 1 specimen was normal. The main HRCT pattern was pattern A in 15 specimens, B in 8, C in 9 and D in 21. Although there were no significant correlation between HRCT patterns and histological subgroups (Chi-square test, p=0.07), pattern C was more frequently seen in group 2 (7 of 9) and pattern A was more common in group 3 (11 of 15). HRCT pattern A corresponded pathologically to areas of thickened alveolar septa with temporal uniformity. Pattern B correlated with areas with airspace enlargement/emphysema or dilation of small airways superimposed on thickened alveolar septa. Pattern C was pathologically associated with areas of severe thickened alveolar septa, mucin stasis in the small airways and intraluminal organization., Conclusion: The pathological backgrounds of the same CT findings in patients with NSIP varied among all pathological subgroups. Areas of ground-glass attenuation and air-space consolidation did not always correspond to reversible pathological findings.

Purpose: Motion artifacts, which can mimic thickened bronchial wall and the cystic appearance of bronchiectasis, constitute a potential pitfall in the diagnosis of interstitial or bronchial disease. Therefore, purpose of our study was to evaluate whether 64-detector row CT (64-MDCT) enables a reduction in respiratory or cardiac motion artifacts in the lung area on thin-section CT without ECG gating, and to examine the correlation between cardiac motion artifact and heart rate., Materials and Methods: Thirty-two patients with suspected diffuse lung disease, who underwent both 8- and 64-MDCT (gantry rotation time, 0.5 and 0.4s, respectively), were included. The heart rates of an additional 155 patients were measured (range, 48-126 beats per minute; mean, 76 beats per minute) immediately prior to 64-MDCT, and compared to the degree of cardiac motion artifact. Two independent observers evaluated the following artifacts on a monitor without the knowledge of relevant clinical information: (1) artifacts on 8- and 64-MDCT images with 1.25-mm thickness and those on 64-MDCT images with 0.625-mm thickness in 32 patients; and (2) artifacts on 64-MDCT images with 0.625-mm thickness in 155 patients., Results: Interobserver agreement was good in evaluating artifacts on 8-MDCT images with 1.25-mm thickness (weighted Kappa test, kappa=0.61-0.71), and fair or poor in the other evaluations (kappa<0.31). Two observers stated that cardiac motion artifacts were more significant on 8-MDCT than on 64-MDCT in all 32 patients. Statistically significant differences were found at various checkpoints only in comparing artifacts between 8- and 64-MDCT for 1.25-mm thickness (Wilcoxon's signed-rank test, p<0.0017). Cardiac motion artifacts on 64-MDCT had no significant correlation with heart rate (Spearman's correlation coefficient by rank test)., Conclusion: The high temporal resolution of 64-MDCT appears to reduce cardiac motion artifact that can affect thin-section scans of the lung parenchyma.

Purpose: To determine thin-section computed tomography (CT) characteristics of acute eosinophilic pneumonia (AEP)., Materials and Methods: Thin-section CT scans of 29 patients (14 males, 15 females; mean age, 26+/-15 years; age range, 15-72 years) with AEP were included this retrospective study. The clinical diagnosis of AEP was established by Allen's criteria. Each thin-section CT was reviewed by two observers., Results: Bilateral areas with ground-glass attenuation were observed on thin-section CT in all patients. Areas of air-space consolidation were present in 16 (55%) of 29 patients. Poorly defined centrilobular nodules were present in 9 patients (31%). Interlobular septal thickening was present in 26 patients (90%). Thickening of bronchovascular bundles was present in 19 patients (66%). Pleural effusions were present in 23 patients (79%) (bilateral=22, right side=1, left side=0). The predominant overall anatomic distribution was central in only 2 (7%) of 29 patients, peripheral in 9 patients (31%), and random in 18 patients (62%). The overall zonal predominance was upper in 4 patients (14%), lower in 8 patients (28%), and random in 17 patients (58%)., Conclusion: CT findings in AEP patients consisted mainly of bilateral areas of ground-glass attenuation, interlobular septal thickening, thickening of bronchovascular bundles, and the presence of a pleural effusion without cardiomegaly. The most common overall anatomic distribution and zonal predominance of the abnormal CT findings were random.

Rationale: Patients with a clinicopathological diagnosis of idiopathic pulmonary fibrosis (IPF) may have typical findings of usual interstitial pneumonia (UIP) on computed tomography (CT) or nonspecific or atypical findings, including those often seen in nonspecific interstitial pneumonia., Objectives: The aims of this study were to revisit the high-resolution CT findings of IPF and to clarify the correlation between the CT findings and mortality., Methods: The study included 98 patients with a histologic diagnosis of UIP and a clinical diagnosis of IPF. Two observers evaluated the CT findings independently and classified each case into one of the following three categories: (1) definite UIP, (2) consistent with UIP, or (3) suggestive of alternative diagnosis. The correlation between the CT categories and mortality was evaluated using the Kaplan-Meier method and the log-rank test, as well as Cox proportional hazards regression models., Measurements and Main Results: Thirty-three of the 98 CT scans were classified as definite UIP, 36 as consistent with UIP, 29 as suggestive of an alternative diagnosis. The mean survival was 45.7, 57.9, and 76.9 months, respectively. There was no significant difference in survival among the three categories (all P > 0.05). Traction bronchiectasis and fibrosis scores were significant predictors of outcome (hazard ratios: 1.30 and 1.10, respectively; 95% confidence intervals: 1.18-14.2 and 1.03-1.19, respectively)., Conclusions: In patients with IPF and UIP pattern on the biopsy, the pattern of abnormality on thin-section CT, whether characteristic of UIP or suggestive of alternative diagnosis, does not influence prognosis. Prognosis is influenced by traction bronchiectasis and fibrosis scores.

Purpose: The purpose of this study was to evaluate software designed to calculate whole tumor volumes and the ratio of the solid component to whole volume (%solid) in pulmonary nodules with ground-glass opacity in three dimensions., Methods: The study included 49 patients with histologically diagnosed adenocarcinomas smaller than 2 cm in diameter. The %solid was calculated both automatically using new software, and by manual measurement of the following four parameters by two observers: the ratio of the largest diameter (a) and the area (b) at the mediastinal window to those at the lung window, and the ratio of the largest diameter (c) and the area (d) of the solid component to those of the ground-glass component at the lung window. Agreement of intra- and inter-observer data by both Spearman's rank correlation test and Bland-Altman's method, and a comparison by Spearman's rank correlation test of the %solid in both Noguchi sub-classifications and vessel invasion in histologic specimens, between the software and manual methods, were assessed., Results: Of the 49 nodules, 48 were successfully measured and assessed. The agreement of the observers with the software was better (Bland-Altman's method; mean difference, -0.3%; 95% limits of agreement, -3.1 to 2.5%) than with the manual measurements (a: 5.3%, -17.6 to 28.3%; b: 8.3%, -10.6 to 26.9%; c: 10.7%, -17.6 to 39%; d: 6.4%, -22 to 34.8%). The correlation between %solid and the histological group was worse with the software (Spearman's rank correlation test; r=0.487, p<0.001) than with the manual method (a, r=0.534; b, r=0.557; c, r=0.552; d, r=0.545)., Conclusion: Although the software requires improvement in the calculation of %solid with volumetric analysis, this is a reproducible and promising quantitative method for determining the grades of malignancy of small lung cancers.

Purpose: To retrospectively evaluate the effect of contrast medium on the three-dimensional volumetric measurement of pulmonary nodules., Materials and Methods: The study was approved by the local institutional review committee, with waiver of informed consent. Sixty pulmonary nodules in 60 patients (17 women, 43 men; age range, 29-82 years) were imaged before and after administration of contrast medium with a 64-channel multidetector computed tomographic (CT) scanner; reconstructed images with a section thickness of 0.625 mm were obtained by using a bone algorithm and a standard algorithm. Volumetric measurements of pulmonary nodules were performed by using commercially available software, and the postcontrast volume ratio was calculated by dividing the postcontrast volume by the precontrast volume. Precontrast and postcontrast volumes were then analyzed by using a Wilcoxon signed rank test., Results: The median measured volumes of pulmonary nodules were 817 mm(3) (precontrast imaging, bone algorithm), 887 mm(3) (postcontrast imaging, bone algorithm), 812 mm(3) (precontrast imaging, standard algorithm), and 855 mm(3) (postcontrast imaging, standard algorithm). The measured volumes obtained with the bone algorithm were significantly larger than those obtained with the standard algorithm, both before and after administration of contrast medium (P < .01); with both the standard algorithm and the bone algorithm, the measured postcontrast volumes were significantly larger than the precontrast volumes (P < .01). The postcontrast volume ratio was more than 1.0 in 45 cases (75%) when the bone algorithm was used and in 53 cases (88%) when the standard algorithm was used. The mean postcontrast volume ratio was 1.054 with the bone algorithm and 1.065 with the standard algorithm., Conclusion: The measured volume of pulmonary nodules obtained by using three-dimensional volumetric software increased after administration of contrast medium. Moreover, the measured volume of pulmonary nodules that was obtained with the bone algorithm was larger than that obtained with the standard algorithm, regardless of whether contrast medium was used., ((c) RSNA, 2007.)

Objective: The aim of this study was to evaluate volume histogram analysis between usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP)., Methods: Sixty cases (UIP, n = 22; NSIP, n = 38) were evaluated retrospectively. Three parameters (contrast, variance, and entropy) were calculated in 3 types of regions of interest (ROIs): (a) whole lung, (b) right lower lobe, and (c) cubic ROIs. To evaluate the influence of extent of abnormal findings, the numbers of voxels with low or high density in whole lung were compared with the 3 parameters., Result: No significant differences were observed between the ROIs of whole lung and the right lower lobe. In all cubic ROIs, entropy in UIP was larger than that in NSIP (P < 0.001). The numbers of voxels with low-density areas significantly correlated with the values of contrast and entropy, whereas those with high-density areas significantly correlated with all 3 parameters., Conclusion: Volume histogram analysis for cubic ROIs may be feasible for differentiating between UIP and NSIP.

Objective: To establish computed tomographic findings that enable accurate differentiation between malignant and benign cavitary lung nodules., Methods: Computed tomographic scans from 39 patients with malignant cavitary nodules and from 39 patients with benign cavitary nodules were independently assessed by 2 observers. They recorded the computed tomographic findings of both types of cavitary nodules and surrounding pulmonary parenchyma. The computed tomographic findings were then compared using chi test., Results: The notch was found in 29% of benign cavitary nodule cases and in 54% of malignant cavitary nodule cases (P < 0.01). An irregular internal wall was found in 26% of benign nodules and in 49% of malignant nodule cases (P < 0.01). A linear margin (P < 0.01), satellite nodule presence (P < 0.01), bronchial wall thickening (P < 0.05), consolidation (P < 0.05), and ground-glass attenuation (P < 0.01) were significantly more frequent in benign cavitary nodules than in malignant ones., Conclusions: Although the computed tomographic findings of benign and malignant cavitary nodules overlap, some computed tomographic findings are useful for differentiating cavitary nodules.

Purpose: Preoperative localization of the thymic veins is considered important to prevent intraoperative severe bleeding prior to video-assisted thoracoscopic thymectomy. The purpose of this study was to determine the optimal dose of contrast material for preoperative CT imaging for the detection of thymic veins on the basis of patient weight., Materials and Methods: The records of 31 patients who underwent thymectomy were examined retrospectively. All patients were scanned using an eight-channel multidetector-row computed tomography (CT) scanner at 1.25 mm collimation and a 0.625-mm reconstruction interval. CT scans were obtained after injection of 300 mg I/ml nonionic contrast material at a rate of 2 ml/s. A 90-ml contrast bolus was used for the first 16 consecutive patients (group I), and a 150-ml bolus was used for the following 15 patients (group II). The scan delay was 60 s and 90 s in groups I and II respectively. Two independent radiologists who were blinded to the surgical results evaluated the number of thymic veins observed on preoperative CT, which was later correlated with the actual number of thymic veins clipped during surgery. The responses were analyzed with respect to contrast amount by single bolus and per kilogram of body weight., Results: Thymic veins were correctly detected in 9 of 16 (56%) patients in group I and 14 of 15 (93%) patients in group II. Thymic vein detection was significantly better in patients who received the >or=2.0 ml/kg contrast medium compared to those who received the 1.00-1.99 ml/kg medium (P < 0.05)., Conclusion: An intravenous contrast material volume of 2 ml/kg (300 mg I/ml) is appropriate for the identification of thymic veins on prethymectomy CT.

Purpose: To investigate differences in volumetric measurement of pulmonary nodules caused by changing the reconstruction parameters for multi-detector row CT., Materials and Methods: Thirty-nine pulmonary nodules less than 2 cm in diameter were examined by multi-slice CT. All nodules were solid, and located in the peripheral part of the lungs. The resultant 48 parameters images were reconstructed by changing slice thickness (1.25, 2.5, 3.75, or 5 mm), field of view (FOV: 10, 20, or 30 cm), algorithm (high-spatial frequency algorithm or low-spatial frequency algorithm) and reconstruction interval (reconstruction with 50% overlapping of the reconstructed slices or non-overlapping reconstruction). Volumetric measurements were calculated using commercially available software. The differences between nodule volumes were analyzed by the Kruskal-Wallis test and the Wilcoxon Signed-Ranks test., Results: The diameter of the nodules was 8.7+/-2.7 mm on average, ranging from 4.3 to 16.4mm. Pulmonary nodule volume did not change significantly with changes in slice thickness or FOV (p>0.05), but was significantly larger with the high-spatial frequency algorithm than the low-spatial frequency algorithm (p<0.05), except for one reconstruction parameter. The volumes determined by non-overlapping reconstruction were significantly larger than those of overlapping reconstruction (p<0.05), except for a 1.25 mm thickness with 10 cm FOV with the high-spatial frequency algorithm, and 5mm thickness. The maximum difference in measured volume was 16% on average between the 1.25 mm slice thickness/10 cm FOV/high-spatial frequency algorithm parameters and overlapping reconstruction., Conclusion: Volumetric measurements of pulmonary nodules differ with changes in the reconstruction parameters, with a tendency toward larger volumes in high-spatial frequency algorithm and non-overlapping reconstruction compared to the low-spatial frequency algorithm and overlapping reconstruction.

Purpose: To retrospectively analyze computed tomographic (CT) findings of chronic idiopathic interstitial pneumonia (IIP) and to determine which findings are most helpful for distinguishing IIP from usual interstitial pneumonia (UIP) with univariate and multivariate analyses., Materials and Methods: Institutional review board approval and informed consent were not required for this retrospective review of patient records and images. Two observers working independently and without knowledge of the diagnosis evaluated the extent and distribution of various thin-section CT findings (ground-glass opacity, consolidation, reticulation, and honeycombing) in 92 patients (51 men, 41 women; mean age, 56 years; age range, 29-81 years) with a histologic diagnosis of UIP (n = 20), cellular nonspecific interstitial pneumonia (NSIP) (n = 16), fibrotic NSIP (n = 16), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) (n = 11), desquamative interstitial pneumonia (DIP) (n = 15), or lymphoid interstitial pneumonia (LIP) (n = 14). Observers used univariate and multivariate statistical analyses to compare their findings with the extent and distribution of UIP., Results: Observers made the correct diagnosis in 145 (79%) of 184 readings. Multivariate logistic regression analysis showed that the independent findings that distinguished UIP from cellular NSIP were the extent of honeycombing and the most proximal bronchus with traction bronchiectasis (odds ratio, 5.16 and 0.37, respectively); the finding that distinguished UIP from fibrotic NSIP was the extent of honeycombing (odds ratio, 2.10). CT features that distinguished UIP from RB-ILD and DIP included extent of ground-glass opacity (odds ratio, 0.76), thickening of bronchovascular bundles (odds ratio, 1.58), the most proximal bronchus with traction bronchiectasis (odds ratio, 0.22), and the number of segments with traction bronchiectasis (odds ratio, 3.64)., Conclusion: UIP has a characteristic appearance that usually facilitates distinction from other types of chronic IIPs at thin-section CT. The most useful finding when differentiating UIP from NSIP was the extent of honeycombing., ((c) RSNA, 2006.)

Objectives: : The aim of this study was to achieve the quantitative analysis of the characteristic computed tomography (CT) findings and course of interstitial pneumonia using the volume histogram method., Methods: : Contrast (CNT), variance (VAR), and entropy (EPY) values from whole-lung volume data were compared between normal lungs and 5 diseases that have characteristic CT findings. Thirteen cases with nonspecific interstitial pneumonia (NSIP) were evaluated before and after treatment., Results: : In cases with thickening of the bronchovascular bundles and interlobular thickening, ground-glass attenuation, airspace consolidation, and honeycombing, the values of VAR and EPY were greater than those in the normal cases (P < 0.05). In the cases with NSIP, the CNT value after treatment was significantly greater and the values of VAR and EPY after treatment were significantly lower than those before treatment (P < 0.05)., Conclusions: : Volume histogram analysis is a promising method for the evaluation of diffuse lung diseases and the effectiveness of treatment.

Objective: The purpose of this study was to compare the quality of coronal multiplanar reconstructions with the quality of direct coronal thin-section multidetector CT (MDCT) scans., Materials and Methods: Axial multidetector CT (MDCT) scans were obtained through the entire lung in 10 normal autopsy lung specimens using an MDCT scanner. Four protocols were used: 0.5-mm collimation with a 0.5-mm reconstruction interval; 0.5-mm collimation with a 0.3-mm reconstruction interval; 1-mm collimation with a 0.5-mm reconstruction interval; and 2-mm collimation with a 1-mm reconstruction interval. Multiplanar reconstruction images with 0.5-mm slice thickness were obtained from the four types of data sets. Direct coronal thin-section CT of the same 10 autopsy lung specimens was performed using 0.5-mm scan collimation, a 0.3-mm reconstruction interval, a 25.6-cm field of view, and a 512 x 512 matrix. Two independent observers compared the image quality of each of the four coronal multiplanar reconstruction sets with that of direct coronal thin-section CT scans. The observers analyzed visualization of anatomic features and artifacts., Results: The total image quality of the multiplanar reconstructions obtained from 0.5-mm collimation data with or without 0.3-mm overlapping reconstruction was equal to that of direct coronal thin-section CT scans in all 20 interpretations. The image quality of multiplanar reconstruction images from 0.5-mm collimation data either with or without overlapping reconstruction was superior to multiplanar reconstruction images obtained from 1- or 2-mm collimation scans (p < 0.01, Fisher's exact test). Stairstep artifacts in multiplanar reconstructions using 0.5-mm collimation without overlapping reconstruction were equal to those with overlapping reconstruction and were fewer than those on 1- or 2-mm collimation (p < 0.01, Mann-Whitney U test)., Conclusion: The image quality of coronal multiplanar reconstructions from isotropic voxel data obtained using 0.5-mm collimation, with or without overlapping reconstruction, is similar to that of direct coronal thin-section CT scans.

Objective: Our purpose was to assess the CT features of various subtypes of thymic epithelial neoplasms on the basis of the 1999 World Health Organization classification., Materials and Methods: Thymic epithelial neoplasms in 53 patients who underwent thymectomy were retrospectively assessed histologically according to the 1999 World Health Organization classification. Type A and B neoplasms correspond to thymomas and type C, to thymic carcinoma. The study included four patients with type A, 14 with type AB, nine with type B1, 14 with type B2, four with type B3, and eight with type C epithelial tumors. Two observers independently assessed the CT scans without knowledge of the histologic findings., Results: Type A tumors were more likely to have smooth contours on CT (4/4, 100%) and round shapes (3.5/4, 88%) than any other type of thymic epithelial tumor (all, p < 0.05). Type C tumors had a higher prevalence of irregular contours (6/8, 75%) than any other type of thymic epithelial tumor (all, p < 0.05). Calcification was more frequently seen in type B1 (4/9, 44%), type B2 (8.5/14, 61%), and type B3 (3/4, 75%) tumors than in type AB (2/14, 14%) and type C (0.5/8, 6%) tumors (all, p < 0.05)., Conclusion: Smooth contours and a round shape are most suggestive of type A thymic epithelial tumor, whereas irregular contours are most suggestive of type C tumor. Calcification is suggestive of type B tumors. CT is of limited value, however, in differentiating type AB, B1, B2, and B3 tumors.

This study compared high-resolution computed tomography (CT) findings between 10 survivors and 21 nonsurvivors of acute interstitial pneumonia and evaluated whether the CT findings were predictive of patients' response to treatment. The survivor and nonsurvivor groups with pathologically or clinically diagnosed acute interstitial pneumonia were similar in age, sex, disease duration, and lung injury score. Retrospective, subjective evaluations of the CT scans were conducted by two independent observers without knowledge of patient outcomes. CT findings were graded on a one to six scale corresponding to consecutive pathologic phases as follows: areas of (1) normal attenuation, (2) ground-glass attenuation, (3) consolidation, (4) ground-glass attenuation associated with traction bronchiolectasis or bronchiectasis, (5) consolidation associated with traction bronchiolectasis or bronchiectasis, and (6) honeycombing. An overall score was obtained by quantifying the extent of each abnormality in three lung zones in each lung. The extent of ground-glass attenuation or consolidation associated with traction bronchiolectasis or bronchiectasis was less in survivors than nonsurvivors (p = 0.004 and p = 0.009, respectively). Architectural distortion was less frequent, and ground-glass attenuation or consolidation without traction bronchiolectasis or bronchiectasis was more extensive in survivors than in nonsurvivors (p = 0.007, p = 0.002, and p = 0.029, respectively). Overall CT scores of survivors were significantly lower than those of nonsurvivors (p = 0.0003). A CT score of less than 245 had an 80% positive and a 90% negative predictive value for survival. There was good interobserver agreement in the assessment of the CT findings (Kappa 0.75). The results indicate that CT assessment is potentially helpful in predicting patient prognosis in acute interstitial pneumonia regardless of the degree of physiologic abnormality.

The goals of this study were (1) to evaluate the quality of compressed lung CT images obtained using high resolution CT (HRCT: 2 mm slice thickness) for degree of compression and conventional CT (10 mm slice thickness) images by using physical and subjective evaluations, and (2) to analyze the distortion of density distribution on lung CT images using histogram analysis for each compression ratio. The coding method was performed according to the Joint Photographic Experts Group (JPEG). We physically evaluated the quality of compressed lung CT images using the peak signal-to-noise ratio (PSNR) as given by the square root of the ratio of the peak value of the gray level squared to the mean square error (dB) and subjectively evaluated the CT images using the mean opinion score (MOS). The acceptable compression ratio for diagnosis was about 1:6 to 1:7 for conventional CT images and about 1:4 to 1:5 for HRCT images as determined by MOS. The PSNR corresponding to acceptable compression ratios was about 50 dB. The difference in density distribution between HRCT and conventional CT was statistically significant (Friedman test: p<0.02) in histogram analysis. Results suggested that, in comparison with conventional CT, a high compression ratio was not suitable for HRCT.

Purpose: The aim of this study was to evaluate whether low-dose high-pitch (6:1) multidetector-row helical high-resolution CT is appropriate for the evaluation of various pulmonary abnormalities, including faint opacities., Methods: Eleven autopsy lungs were scanned with a multidetector-row CT scanner using 2.5 mm x 4 beam collimation, effective slice thickness 3 mm, 6:1 pitch, 0.8 second gantry rotation speed, 20 cm Display FOV, high spatial frequency (bone) algorithm, and various radiation doses (120 kVp; 160, 80, 40, 24, and 8 mAs). The image quality of each CT set was assessed as adequate or inadequate for diagnosis by two independent observers. In addition, a wire phantom was scanned with the same parameters in order to describe the MTF curves., Results: There was excellent agreement between the observers for the evaluation of image quality (kappa statistic, 0.84). The ratio of images evaluated as inadequate for 8 mAs and 24 mAs was significantly higher than that for 160, 80, and 40 mAs (p<0.01: chi-square test). MTF curves of both 8 and 24 mAs were significantly inferior to those of 40, 80, and 160 mAs (p<0.0 1, Friedman test), while the MTF curve of 40 mAs was relatively inferior to that of 160 mAs (p<0.05, Friedman test)., Conclusion: More than 40 mAs in combination with 120 kVp is preferable for the evaluation of details of lung parenchyma by high-pitch. multidetector-row helical high-resolution CT.

Objective: The aim of this study was to evaluate the image quality and diagnostic efficacy of multidetector high-resolution CT (HRCT) by comparing it with single-detector HRCT and by comparing the noise and artifact of multidetector HRCT images with a phantom., Subjects and Methods: Multidetector HRCT with six parameters and single-detector HRCT were performed on cadaveric lungs. The image quality and diagnostic efficacy of multidetector HRCT were evaluated in comparison with those of single-detector HRCT. A phantom was scanned, and image artifact and noise were investigated., Results: . The image quality of multidetector HRCT with axial 1.25 mm x 4i (four images per gantry rotation) mode was equal to that of single-detector HRCT. The image quality of multidetector HRCT with other modes was worse than that on single-detector HRCT. The diagnostic efficacy of multidetector HRCT with high-quality mode (pitch, 3:1) and axial mode was equal to that of single-detector HRCT. The diagnostic efficacy on multidetector HRCT with high-speed mode (pitch, 6:1) was worse than that on single-detector HRCT. In the phantom study, images made in high-speed mode had strong artifacts. Noise in the axial mode was milder than that in high-speed mode but more severe than that in high-quality mode., Conclusion: The image quality of axial HRCT with multidetector CT is equal to that on single-detector HRCT. Axial HRCT with multidetector CT is appropriate for evaluating subtle lung abnormalities, but high-speed mode is unsuitable. Using the high-quality mode degrades image quality but is still worthwhile.

This article describes pitfalls in the interpretation of multidetector-row helical CT (MDCT) images at the window width and level settings for lung parenchyma. On MDCT, linear artifacts, which look like black and white linear densities and are called "hurricane artifacts," radiate out from objects that have very different densities from their neighbors. For the evaluation of fine parenchymal details, a low table speed/slice collimation should be used. In fact, axial (step and shoot) scanning may be more effective for the evaluation of fine details. Since artifacts from vessels highly enhanced by contrast medium cause data blackout in the surrounding areas at high table speed/slice collimation, pulmonary parenchyma in such situations should be evaluated with unenhanced CT. Although multidetector-row helical CT is a promising tool for the evaluation of lung parenchyma, it is important to identify its shortcomings due to artifacts when interpreting images at the window width and level settings for lung parenchyma and to apply the appropriate methods for eliminating such artifacts.

Purpose: The purpose of this work was to evaluate the CT features of thymoma and to determine the most helpful findings in differentiating invasive from noninvasive thymoma., Method: The CT scans from 27 patients with invasive thymoma and 23 with noninvasive thymoma were independently assessed by two observers without knowledge of their invasiveness. The presence and distribution of various CT findings were independently analyzed., Results: Invasive thymomas were more likely to have lobulated (16/27, 59%) or irregular (6/27, 22%) contours than noninvasive thymomas (8/23, 35% and 1.5/23, 6%, respectively) (p < 0.05). Invasive thymomas had a higher prevalence of low attenuation areas within the tumor (16/27, 60%) than noninvasive thymomas (5/23, 22%) (p < 0.001) as well as foci of calcification (14.5/27, 54% vs. 6/23, 26%; p < 0.01)., Conclusion: The presence of lobulated or irregular contour, areas of low attenuation, and multifocal calcification is suggestive of invasive thymoma.

The objective of this study was to describe the pulmonary abnormalities on high-resolution computed tomography (CT) in patients with mixed connective tissue disease (MCTD). The study included 41 patients who met the diagnostic criteria for MCTD and showed abnormal findings on high-resolution CT. The presence, extent, and distribution of various high-resolution CT findings were evaluated. The predominant abnormalities included areas of ground-glass attenuation (n = 41), subpleural micronodules (n = 40), and nonseptal linear opacities (n = 32). Other common findings included peripheral predominance (n = 40), lower lobe predominance (n = 39), intralobular reticular opacities (n = 25), architectural distortion (n = 20), and traction bronchiectasis (n = 18). Less common findings included honeycombing, ill-defined centrilobular nodules, airspace consolidation, interlobular septal thickening, thickening of bronchovascular bundles, bronchial wall thickening, bronchiectasis, and emphysema. Pulmonary involvement of MCTD is characterized by the presence of ground-glass attenuation, nonseptal linear opacities, and peripheral and lower lobe predominance. Ill-defined centrilobular opacities were uncommonly seen.

Purpose: The purpose of this work was to compare the thin-section CT findings of acute respiratory distress syndrome (ARDS) with those of acute interstitial pneumonia (AIP)., Method: The thin-section CT scans from 25 patients with ARDS and 25 with AIP were independently assessed by two observers without knowledge of clinical and pathologic data. The presence, extent, and distribution of various CT findings were independently analyzed., Results: Honeycombing was seen more frequently in lobes of patients with AIP (26%) than in lobes with ARDS (8%) (p < 0.001). Compared with patients with ARDS, a greater number of patients with AIP had a predominantly lower lung zone distribution (p < 0.05) and a symmetric distribution (p < 0.05) of the parenchymal abnormalities., Conclusion: Patients with AIP have a greater prevalence of honeycombing and are more likely to have a symmetric bilateral distribution and a lower lung zone predominance than patients with ARDS. However, significant overlap exists among the CT findings.

A respiratory gating technique was developed to allow computed tomography-guided needle biopsy of small pulmonary nodules. Twenty-three pulmonary nodules less than 15 mm in diameter underwent biopsy with the use of this technique. There were 14 true-positive, eight true-negative, and one false-negative result (diagnostic accuracy, 96%). The diagnostic accuracy for small nodules without this technique in a historical control was 69% (P: <.05).

Rationale and Objectives: To investigate whether expiratory high-resolution computed tomography (HRCT) is more useful than inspiratory HRCT for the detection of early-phase diffuse alveolar damage., Methods: Eleven anesthetized rabbits were scanned with both inspiratory and expiratory HRCT every 30 minutes during mechanical ventilation. Ten rabbits were killed after the detection of pulmonary abnormalities on both inspiratory and expiratory HRCT. The remaining rabbit was killed when the pulmonary abnormalities appeared only on expiratory HRCT., Results: In four cases (36%), the abnormal findings were detected earlier on expiratory HRCT than on inspiratory HRCT. In seven cases (64%), the abnormalities appeared simultaneously on inspiratory and expiratory HRCT. In all 11 cases, the histopathological changes of areas with abnormal CT findings corresponded to the exudative or proliferative phase of diffuse alveolar damage., Conclusions: Expiratory HRCT has the potential to detect the abnormalities of diffuse alveolar damage earlier than inspiratory HRCT.

Purpose: To determine whether various eosinophilic lung diseases can be differentiated by means of thin-section computed tomography (CT)., Materials and Methods: Thin-section CT scans in 111 patients with eosinophilic lung diseases-40 with chronic eosinophilic pneumonia, 16 with Churg-Strauss syndrome, 16 with allergic bronchopulmonary aspergillosis (ABPA), 13 with acute eosinophilic pneumonia, 12 with simple pulmonary eosinophilia, 11 with drug-induced eosinophilic pneumonia, and three with hypereosinophilic syndrome-were assessed independently by two observers. The observers recorded the abnormalities, diagnosis, and degree of confidence in the diagnosis., Results: The two observers made a correct first-choice diagnosis on average in 61% of readings. The correct diagnosis was made in 78% of cases of chronic eosinophilic pneumonia; 81%, acute eosinophilic pneumonia; 44%, Churg-Strauss syndrome; 84%, ABPA; 17%, simple pulmonary eosinophilia; 27%, drug-induced eosinophilic pneumonia; and 33%, hypereosinophilic syndrome. The two observers made a correct diagnosis with a high degree of confidence in 36% of readings. There was moderate agreement between the observers for the correct diagnosis (kappa, 0.47) and for the correct diagnosis with a high degree of confidence (kappa, 0.59)., Conclusion: Although eosinophilic lung diseases often can be differentiated by means of thin-section CT, correlation between CT findings and careful clinical evaluation are required for a definitive diagnosis.

Purpose: In the early stages, clinical and chest radiographic findings of acute interstitial pneumonia (AIP) are often similar to those of bronchiolitis obliterans organizing pneumonia (BOOP). However, patients with AIP have a poor prognosis, while those with BOOP can achieve a complete recovery after corticosteroid therapy. The objective of this study was to identify differences in high-resolution CT (HRCT) findings between the two diseases., Methods: The study included 27 patients with AIP and 14 with BOOP who were histologically diagnosed [open-lung biopsy (n=7), autopsy (n=17), transbronchial lung biopsy (n=17)]. The frequency and distribution of various HRCT findings for each disease were retrospectively evaluated., Results: Traction bronchiectasis, interlobular septal thickening, and intralobular reticular opacities were significantly more prevalent in AIP (92.6%, 85.2%, and 59.3%, respectively) than in BOOP (42.9%, 35.7%, and 14.3%, respectively) (p<0.01). Parenchymal nodules and peripheral distribution were more prevalent in BOOP (28.6% and 57.1%, respectively) than in AIP (7.4% and 14.8%, respectively) (p<0.01). Areas with ground-glass attenuation, air-space consolidation, and architectural distortion were common in both AIP and BOOP., Conclusion: For a differential diagnosis of AIP and BOOP, special attention should be given to the following HRCT findings: traction bronchiectasis, interlobular septal thickening, intralobular reticular opacities, parenchymal nodules, pleural effusion, and peripheral zone predominance.

The aim of the present study was to assess the evolution of various computed tomographic (CT) findings of lymphocytic interstitial pneumonia (LIP) with determination of potentially reversible or irreversible features. The study included 14 patients with biopsy-proved LIP who had serial thin-section CT examination 4 to 82 months (median 13 months) apart. Initial and follow-up CT scans were evaluated independently and then directly compared with each other by two observers. The main parenchymal abnormalities on the initial CT scan consisted of ground-glass attenuation (n = 14), thickening of interlobular septa (n = 13), centrilobular nodules (n = 12), cystic airspaces (n = 10), and airspace consolidation (n = 4). On follow-up CT, nine patients improved, one showed no change, and four showed increased extent of disease. With the exception of cysts, the parenchymal opacities were reversible. On follow-up CT, new cysts were seen in three patients; these developed mainly in areas with centrilobular nodules on initial CT. Honeycombing was seen on follow-up CT in four patients; in three patients it developed in areas of airspace consolidation and in one patient it developed in an area with ground-glass attenuation on initial CT. The majority of patients with LIP improved on follow-up. However, airspace consolidation may progress to honeycombing and centrilobular nodules may precede cystic formation.

Purpose: The purpose of this study was to survey the usefulness of high-resolution CT (HRCT) for the evaluation of activity in acute and subacute non-infectious diffuse infiltrative lung diseases before and after corticosteroid treatment., Patients and Methods: Sequential HRCT images and chest radiographs obtained before and after treatment were retrospectively evaluated in 33 patients with acute or subacute noninfectious diffuse infiltrative lung diseases. All these patients were histologically confirmed to have pulmonary Inflammation and to have responded to treatment with corticosteroid. Radiographic and CT scores were correlated with the degree of dyspnea and the results of arterial blood gas analysis using Spearman's rank-correlation coefficient., Results: On follow-up HRCT, the profusion score of areas with increased attenuation was significantly correlated with arterial oxygen tension (PaO2) (p=.003, r=-.53) and the alveolar-arterial oxygen tension difference (AaDO2) (p=.001, r=.57). No other correlation was found after treatment. Nodular and linear opacities were more commonly seen on follow-up chest radiographs and HRCT images than on initial ones., Conclusion: HRCT is useful for the evaluation of disease activity in acute and subacute noninfectious infiltrative lung diseases before and after treatment if paying special attention to the profusion of ground-glass attenuation. Even if pretreatment HRCT has not been performed, posttreatment HRCT should be examined.

Objective: The purpose of this study was to determine whether acute parenchymal lung diseases can be differentiated on the basis of the pattern and distribution of abnormalities revealed on high-resolution CT., Materials and Methods: High-resolution CT scans of 90 patients with acute parenchymal lung diseases (19 with bacterial pneumonia, 13 with mycoplasmal pneumonia, 21 with acute interstitial pneumonia, 18 with hypersensitivity pneumonitis, 10 with acute eosinophilic pneumonia, and nine with pulmonary hemorrhage) were independently assessed by two observers who had no knowledge of clinical or pathologic data. The observers recorded abnormalities, their first-choice diagnosis, and their degree of confidence in their first-choice diagnosis., Results: The two observers made a correct first-choice diagnosis in an average of 55 (61%) of 90 cases. Correct first-choice diagnosis was made in 50% of cases of bacterial pneumonia, 62% of mycoplasmal pneumonia, 90% of acute interstitial pneumonia, 72% of hypersensitivity pneumonitis, 30% of acute eosinophilic pneumonia, and 28% of pulmonary hemorrhage. CT findings allowed distinction between infectious and noninfectious causes in 81 (90%) of 90 cases., Conclusion: High-resolution CT is helpful in the differential diagnosis of infectious from noninfectious acute parenchymal lung disease. However, high-resolution CT is of limited value in making a specific diagnosis.

Objective: Lymphoproliferative disorders span a spectrum from inflammatory lesions to malignant neoplasms. The purpose of this study was to compare high-resolution CT findings of lymphocytic interstitial pneumonia with those of malignant lymphoma of the chest., Materials and Methods: The study included 17 patients with lymphocytic interstitial pneumonia and 44 patients with malignant lymphoma (35 with non-Hodgkin's lymphoma and nine with Hodgkin's disease). Without knowledge of the pathologic diagnosis, two chest radiologists evaluated the frequency and distribution of high-resolution CT findings in both groups of patients., Results: Cysts were more common in patients with lymphocytic interstitial pneumonia (14/17, 82%) than in patients with malignant lymphoma (1/44, 2%) (p < .0001). Air-space consolidation was more commonly seen in patients with malignant lymphoma (29/44, 66%) than in patients with lymphocytic interstitial pneumonia (3/17, 18%) (p < .001). Large nodules (11-30 mm in diameter) were more common in patients with malignant lymphoma (41%) than in patients with lymphocytic interstitial pneumonia (6%). Pleural effusions (25%) were seen only in patients with malignant lymphoma. We found no statistically significant difference in the distribution of lung lesions between patients with lymphocytic interstitial pneumonia and patients with malignant lymphoma., Conclusion: On high-resolution CT, cysts are characteristic in patients with lymphocytic interstitial pneumonia, whereas consolidation, large nodules, and pleural effusions are characteristic in patients with malignant lymphoma. These findings on high-resolution CT help differentiate lymphocytic interstitial pneumonia from malignant lymphoma.

Objective: The purpose of this study was to correlate thin-section CT findings with histologic findings for the three histopathologic subtypes of localized bronchioloalveolar carcinoma., Conclusion: Thin-section CT can be used to predict the histologic subtype of bronchioloalveolar carcinoma.

Three-dimensional data on the left ventricle at quasi-end-diastole and quasi-end-systole were acquired by helical scanning CT in 12 patients. Short axial images of the left ventricle and long axial images of the papillary muscle were created using multiplanar reconstruction. Left ventricular dimensions and the length of the papillary muscle were measured, and fractional shortening of the papillary muscle was calculated. There was a good correlation between left ventricular dimensions measured by echocardiogram and helical scanning CT (end-diastole: r = 0.94: end-systole: r = 0.86; fractional shortening of left ventricular dimension: r = 0.84). Papillary muscle fractional shortening was 6.3% in the ischemic group and 21.5% in the non-ischemic group (p < 0.005). Helical scanning CT is clinically useful for the assessment of left ventricular papillary muscle function.

Purpose: The purpose of this study was twofold: to evaluate the change in size of honeycomb cysts with respiration using inspiratory-expiratory spiral volumetric CT (I-E SVCT) and to establish the pathologic basis of this change., Method: Ninety-seven patients, who had honeycombing associated with end-stage pulmonary fibrosis on end-inspiratory 1 to 2 mm collimation high-resolution CT (HRCT), underwent I-E SVCT (3 mm collimation, pitch 1, breath-hold time 20 s, reconstruction interval 1 mm, FOV 16-20 cm, high frequency algorithm). I-E SVCT scans were assessed on images obtained in the transverse plane and volumetric sagittal, coronal, and oblique reformations. The histologic findings were assessed in four inflated and fixed lungs that showed honeycombing at postmortem HRCT., Results: In 63 patients (65%), a small percentage of the cysts did not change in size at end-expiration, while in the remaining patients, all the cysts decreased in size. Assessment of volumetric multiplanar reformations showed that cysts that decreased in size during exhalation communicated with airways and represented bronchiolectasis rather than true cysts, while the other cysts did not communicate with the airways. Similar findings were found in pathologic specimens., Conclusion: The majority of, but not all, honeycomb cysts seen on HRCT represent dilated bronchioles that communicate with the proximal airways and change in size with respiration.

We report a case of histologically proved acute interstitial pneumonia (AIP) with subacute onset whose high-resolution CT (HRCT) findings were indistinguishable from those of bronchiolitis obliterans organizing pneumonia (BOOP)/cryptogenic organizing pneumonia (COP). The HRCT findings were air-space consolidation with air-bronchiologram associated with little ground-glass attenuation, and nodules. Some cases of AIP present HRCT findings indistinguishable from those of BOOP/COP.

We report a case of summer-type hypersensitivity pneumonitis that demonstrated air-trapping. In this case we used images at inspiratory and expiratory volumetric HRCT, which enabled us to obtain images of the same level at inspiratory and expiratory CT.

Purpose: To compare the diagnostic efficacy of pancreatic pharmacoangiographic CT using angiotensin II with conventional angiographic CT., Material and Methods: Eighteen patients with space-occupying pancreatic disease were examined in this study. Pharmacoangiographic CT was performed with a 1-3 micrograms/6-ml solution of angiotensin II injected through a catheter into the celiac artery during spiral CT., Results: In 17 of the 18 (94%) patients, the area of pancreatic parenchymal enhancement was the same or larger at pharmacoangiographic CT than at conventional angiographic CT. The attenuation value of the pancreatic parenchyma was significantly increased at pharmacoangiographic CT (p = 0.0010). Although the attenuation value of tumors was also increased on images obtained after the injection of angiotensin II, the tumor-to-pancreas contrast was significantly greater at pharmacoangiographic CT (p = 0.0479). The mean differences in attenuation between tumor and pancreas at angiographic CT with and without angiotensin II were respectively 182 HU and 115 HU., Conclusion: Pharmacoangiographic CT with angiotensin II proved superior to conventional angiographic CT in the diagnosis of pancreatic disease. We therefore recommend it as a supplementary technique at the angiographic examination of patients with suspected pancreatic tumor.

Purpose: To assess the usefulness of fractal geometry in quantitatively evaluating the convergence of peripheral vessels on peripheral lung tumors in maximum intensity projection (MIP) images., Materials and Methods: We studied the MIP images of 34 pathologically proved small peripheral lung tumors (lung cancer in 21, hamartoma in 13) in 34 patients. To obtain MIP images, spiral CT (SOMATOM PLUS; Siemens) was performed during a single breath hold (24-second scan time, 2-mm section thickness, and 2 mm/sec table feed time, reconstructed at 1-mm increments). To evaluate the convergence of the peripheral vessels and bronchi towards the tumor, we fixed a region of interest (ROI) on the hilar side of the lung tumor, parallel to the chest wall, which consisted of 64 x 64 square pixels, in the images that divided at the center of the window width. We counted the overlapping pixels by the two-dimensional box-counting method and obtained fractal dimensional data on lung cancers and hamartomas., Results: There was a statistically significant difference in the fractal dimension (D) between lung cancers (D = 1.81 +/- 0.13) and hamartomas (D = 1.67 +/- 0.10) (P = 0.0067)., Conclusion: Fractal geometry could be useful in the diagnosis of small peripheral lung tumors.

The high sensitivity of CT during arterial portography (CTAP) for hepatic lesions is accompanied with a lack of specificity for diagnosis. Combined CTAP and CT hepatic angiograpy (CTHA) had been proved to improves lesion detection and heightens confidence in interpreting perfusion abnormalities. We describe a new double lumen - coaxial catheter system for performing combined CTAP and CTHA without the need for repeated transfer of the patient or bilateral arterial punctures. This technique was employed in eight patients with liver neoplasms. In all eight patients, CTAP and CTA images were obtained successfully. We concluded that this method was useful for the evaluation of liver tumors.