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Background The aim of this study was to evaluate the difference in the ability of 1-mm and 5-mm section Computed Tomography(CT) to detect pulmonary metastases in patients with pulmonary metastases. Methods We retrospectively analyzed the CT findings of 106 patients with pulmonary metastases due to malignancies treated at Toho University Omori Medical Center between 2013 and 2020. Results Cases with only one nodule evaluated by 5-mm section CT had significantly lower discordance with 1-mm section CT than cases with two or more nodules detected by a 5 mm section (p = 0.0161). After reference to a 1 mm section, cases with only one nodule reevaluated by 5-mm section CT had significantly lower discordance than cases with two or more nodules reevaluated using 5-mm section CT. In cases with only one nodule, reevaluation using a 5 mm section was consistent with evaluation using a 1 mm section. However, this was not observed in cases with two or more nodules, with a significant difference between one nodule and two or more nodules. Conclusions If there are two or more nodules observed in 5-mm section CT it may be necessary to reevaluate using 1-mm section CT to determine the exact number of pulmonary metastases.

We examined characteristics of chest CT during different time periods for patients with coronavirus disease 2019 (COVID-19) pneumonia in Huizhou, China. This study included 56 COVID-19 patients having abnormal CT acquired between January 22 and March 3, 2020. Scans of 56 patients were classified into 4 groups (Group 1-Group 4) based on the date on which scan was obtained at the 1st, 2nd, 3rd week and longer than 3 weeks after illness onset. Forty-five patients with follow-up scans were categorized into 4 groups according to extents that lesions reduced. GGO was prevalent in Groups 1-4 (58.1-82.6%). Consolidation was the more common in Group 2 (26.2%) and then declined in Group 3 and 4 (20.0%; 9.7%). The highest frequency of fibrous stripes occurred in Group 3 (46.7%) and then decreased to 35.5% in Group 4. CT scores were higher for Group 2 than others. Among 45 follow-up patients, 11 (24.4%) of them recovered with lesions reducing ≥75% and had shorter hospital durations compared with others. There were temporal patterns of lung abnormalities in COVID-19 patients, with the highest extent of lesion involvement occurring in the 2nd week. Isolation and review are required for COVID-19 patients who have been discharged from hospital.

OBJECTIVE. The purpose of this article was to assess thin-section CT features of ciliated muconodular papillary tumors (CMPTs) of the lung and correlations between radiologic and pathologic findings. MATERIALS AND METHODS. Thin-section CT findings of 16 patients (10 men and six women; mean age, 70.7 years) with surgically resected CMPTs were retrospectively analyzed. Size, location, and internal characteristics of the tumors were evaluated. The amount of mucin in the tumors was assessed histopathologically and compared with CT findings. Tumor growth speed was calculated on the basis of size changes on thin-section CT. RESULTS. In all 16 patients, tumors were detected as a solitary pulmonary nodule. Thirteen tumors (81.3%) were located in the lower lobes, and 10 (62.5%) were adjacent to the pleura. Mean maximal diameter of the tumors was 9.1 mm (range, 6-14 mm). One tumor (6.3%) presented as a pure ground-glass nodule (GGN), seven (43.8%) as dense GGNs, and eight (50.0%) as solid nodules. Pathologically, the pure GGN and five of seven dense GGNs had a large amount of mucin, whereas seven of eight solid nodules had an intermediate or small amount of mucin. The mean annual tumor growth rate (in diameter) was 0.49 mm/y. CONCLUSION. CMPTs appear as solitary, small, and peripheral pulmonary nodules with very slow growth rates. CMPTs appearing as pure GGNs and dense GGNs tend to contain more mucin than CMPTs appearing as solid nodules.

Background The need for quantitative assessment of interstitial lung involvement on thin-section computed tomography (CT) has arisen in interstitial lung diseases including connective tissue disease (CTD). Purpose To evaluate the capability of machine learning (ML)-based CT texture analysis for disease severity and treatment response assessments in comparison with qualitatively assessed thin-section CT for patients with CTD. Material and Methods A total of 149 patients with CTD-related ILD (CTD-ILD) underwent initial and follow-up CT scans (total 364 paired serial CT examinations), pulmonary function tests, and serum KL-6 level tests. Based on all follow-up examination results, all paired serial CT examinations were assessed as “Stable” (n = 188), “Worse” (n = 98) and “Improved” (n = 78). Next, quantitative index changes were determined by software, and qualitative disease severity scores were assessed by consensus of two radiologists. To evaluate differences in each quantitative index as well as in disease severity score between paired serial CT examinations, Tukey's honestly significant difference (HSD) test was performed among the three statuses. Stepwise regression analyses were performed to determine changes in each pulmonary functional parameter and all quantitative indexes between paired serial CT scans. Results Δ% normal lung, Δ% consolidation, Δ% ground glass opacity, Δ% reticulation, and Δdisease severity score showed significant differences among the three statuses ( P 2 ≤0.42; P Conclusion ML-based CT texture analysis has better potential than qualitatively assessed thin-section CT for disease severity assessment and treatment response evaluation for CTD-ILD.

Bronchiectasis and bronchiolectasis are defined as irreversible airways dilation of the central and peripheral bronchi, respectively. Bronchiectasis is a common finding on thin-section (

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Rationale and Objectives To retrospectively analyze the chest imaging findings in patients with coronavirus disease 2019 (COVID-19) on thin-section CT. Materials and Methods Fifty-three patients with confirmed COVID-19 infection underwent thin-section CT examination. Two chest radiologists independently evaluated the imaging in terms of distribution, ground-glass opacity (GGO), consolidation, air bronchogram, stripe, enlarged mediastinal lymph node, and pleural effusion. Results Fourty-seven cases (88.7%) had findings of COVID-19 infection, and the other six (11.3%) were normal. Among the 47 cases, 78.7% involved both lungs, and 93.6% had peripheral infiltrates distributed along the subpleural area. All cases showed GGO, 59.6% of which were round and 40.4% patchy. Other imaging features included “crazy-paving pattern” (89.4%), consolidation (63.8%), and air bronchogram (76.6%). Air bronchograms were observed within GGO (61.7%) and consolidation (70.3%). Neither enlarged mediastinal lymph nodes nor pleural effusion were present. Thirty-three patients (62.3%) were followed an average interval of 6.2 ± 2.9 days. The lesions increased in 75.8% and resorbed in 24.2% of patients. Conclusion COVID-19 showed the pulmonary lesions in patients infected with COVID-19 were predominantly distributed peripherally in the subpleural area.

Background: To investigate the value of dual energy computed tomography (DECT) parameters (including iodine concentration and monochromatic CT numbers) for predicting pure ground-glass nodules (pGGNs) of invasive adenocarcinoma (IA). Methods: A total of 55 resected pGGNs evaluated with both unenhanced thin-section CT (TSCT) and enhanced DECT scans were included. Correlations between histopathology [adenocarcinoma in situ (AIS), minimally IA (MIA), and IA] and CT scan characteristics were examined. CT scan and clinicodemographic data were investigated by univariate and multivariate analysis to identify features that helped distinguish IA from AIS or MIA. Results: Both normalized iodine concentration (NIC) of IA and slope of spectral curve [slope(k)] were not significantly different between IA and AIS or MIA. Size, performance of pleural retraction and enhanced monochromatic CT attenuation values of 120–140 keV were significantly higher for IA. In multivariate regression analysis, size and enhanced monochromatic CT number of 140 keV were independent predictors for IA. Using the two parameters together, the diagnostic capacity of IA could be improved from 0.697 or 0.635 to 0.713. Conclusions: DECT could help demonstrate blood supply and indicate invasion extent of pGGNs, and monochromatic CT number of higher energy (especially 140 keV) would be better for diagnosing IA than lower energies. Together with size of pGGNs, the diagnostic capacity of IA could be better.

To review thin-section CT findings of thoracolithiasis. Thirty-three thin-section CT scans of 9 patients with thoracolithiasis diagnosed between 2008 and 2016 were reviewed for the location, shape, longest diameter, and calcification of each freely mobile nodule (thoracolith) and for the presence of coexisting abnormalities. The mean age of 9 patients (5 women) was 65.8 years (SD 14.9; range 37–83 years). Eight were > 50 years of age. Three patients had two thoracoliths, and the remaining 6 patients had one. Thoracoliths were in the left (n = 9) or right (n = 3) pleural cavity, with most in the lower pleural cavity. Nine thoracoliths were found to be larger at follow-up. The median diameters of the 12 thoracoliths were 4.9 mm (range 2.1–10.6 mm) and 6.2 mm (range 3.6–11.0 mm) on the initial and latest follow-up CT scans, respectively. Concomitant old granulomatous disease (n = 6) and diffuse systemic sclerosis-related interstitial lung disease (n = 2) were noted. Thoracolithiasis can manifest as one or two small calcified nodules. It tends to occur in the left lower pleural cavity, occur in a patient aged > 50 years, be larger on follow-up, and coincide with other diseases.

Screening for lung cancer with low-dose computed tomography (CT) has led to increased recognition of small lung cancers and is expected to increase the rate of detection of early-stage lung cancer. Major concerns in the implementation of the CT screening of large populations include determining the appropriate management of pulmonary nodules found on a scan. The identification of patients with early-stage lung cancer who have a higher risk for relapse and who require more aggressive surveillance has been a target of the intense investigation. This study was performed to investigate whether the computer-aided CT image features could improve the discrimination ability of lung cancer prediction models for nodules in whom malignancy was suspected.

Purpose We aimed to perform an imaging analysis of interlobar fissures and their variations using thin-section computed tomography (CT). Methods Volumetric thin-section CT scanning was performed in 208 subjects. Interlobar fissures were observed on axial images, and reconstructed coronal and sagittal images were observed by multiplanar reformatting (MPR). The vessel distributions were verified by maximal intensity projection (MIP). On the axial images, the interlobar fissures were characterized by lines of hyperattenuation, bands of hyperattenuation, avascular zones, and mixed imaging. The interlobar fissures were divided into seven grades according to the percentage of defects over the entire fissure. Results On the axial images, of all interlobar fissures without avascular zones, 70.2% of the right oblique fissures (ROFs) and 94.2% of the left oblique fissures (LOFs) appeared as lines, and 83.2% of the horizontal fissures (HFs) appeared as bands. All of the interlobar fissures appeared as lines on the coronal and sagittal images. Of all cases, 17.8% showed fully complete interlobar fissures for all three fissures. Incomplete fissures included 41.3% of ROFs, 58.2% of HFs, and 45.2% of LOFs. In ROFs and LOFs, discontinuity was most frequently below 20%, while in HFs discontinuity was most frequently 41%-60%. The most common classification of incomplete interlobar fissures was a discontinuous avascular zone. Conclusion Incomplete interlobar fissures are common variations of interlobar fissures. Techniques including volumetric thin-section CT, MPR, and MIP can assist in the diagnosis of incomplete interlobar fissures.

To compare the use of dynamic oxygen-enhanced magnetic resonance (MR) imaging with the use of quantitatively assessed computed tomography (CT) for assessment of clinical stage and evaluation of pulmonary functional change due to treatment in patients with asthma.The institutional review board of Kobe University Hospital approved this study, and written informed consent was obtained from each subject. Thirty consecutive patients with asthma (17 men and 13 women; age range, 27-78 years) underwent dynamic oxygen-enhanced MR imaging, multidetector CT, and assessment of forced expiratory volume in 1 second. All patients were classified as having one of four stages of asthma according to the guidelines of the National Asthma Education and Prevention Program. Relative enhancement ratio ( RER relative enhancement ratio ) and wash-in time maps were generated by means of pixel-by-pixel analyses. Regions of interest were placed on images of the lung in all sections, and all measurements were averaged to determine mean RER relative enhancement ratio and mean wash-in time for each subject. Percentage of airway wall area and mean lung density were determined at quantitative CT. For comparison of the modalities for assessment of clinical stage, indexes of subjects at all clinical stages were compared by means of the Tukey honestly significant difference test. Evaluation of pulmonary functional improvement was assessed by correlating improvement of each index with that of forced expiratory volume.Mean wash-in time was significantly different among patients with asthma of different clinical stages (P.05), but significant differences between mean RER relative enhancement ratio and percentage of airway wall area were observed for a limited number of clinical stages (P.05). Improvement of mean RER relative enhancement ratio (r = 0.63, P = .0002) and mean wash-in time (r = -0.75, P.0001) was significantly correlated with forced expiratory volume.Dynamic oxygen-enhanced MR imaging has potential as a tool for assessment of clinical stage and evaluation of pulmonary functional change due to treatment in patients with asthma.

Background Measuring the size of invasiveness on computed tomography (CT) for the T descriptor size was deemed important in the 8th edition of the TNM lung cancer classification. We aimed to correlate the maximal dimensions of the solid portions using both lung and mediastinal window settings on CT imaging with the pathologic invasiveness (> 0.5 cm) in lung adenocarcinoma patients. Materials and Methods The study population consisted of 378 patients with a histologic diagnosis of adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), invasive adenocarcinoma (IVA)-lepidic, IVA-acinar and/or IVA-papillary, and IVA-micropapillary and/or solid adenocarcinoma. A panel of 15 radiologists was divided into 2 groups (group A, 9 radiologists; and group B, 6 radiologists). The 2 groups independently measured the maximal and perpendicular dimensions of the solid components and entire tumors on the lung and mediastinal window settings. The solid proportion of nodule was calculated by dividing the solid portion size (lung and mediastinal window settings) by the nodule size (lung window setting). The maximal dimensions of the invasive focus were measured on the corresponding pathologic specimens by 2 pathologists. Results The solid proportion was larger in the following descending order: IVA-micropapillary and/or solid, IVA-acinar and/or papillary, IVA-lepidic, MIA, and AIS. For both groups A and B, a solid portion > 0.8 cm in the lung window setting or > 0.6 cm in the mediastinal window setting on CT was a significant indicator of pathologic invasiveness > 0.5 cm (P Conclusion A solid portion > 0.8 cm on the lung window setting or solid portion > 0.6 cm on the mediastinal window setting on CT predicts for histopathologic invasiveness to differentiate IVA from MIA and AIS.

A 57-year-old woman was seen in an outpatient neurosurgery clinic after reporting daily headaches, a ‘whooshing and squelching’ sound in her head and reduced hearing in her left ear. Three months' prior she required admission following serious head trauma. Imaging at that time revealed multiple skull fractures with extra-axial haemorrhages. Follow-up thin section CT of the petrous …

PURPOSE: To retrospectively identify features that allow prediction of the disappearance of solid, indeterminate, intraparenchymal nodules detected at baseline computed tomographic (CT) screening of individuals at high risk for lung cancer.MATERIALS AND METHODS: The study was institutional review board approved. Participants gave informed consent. Participants with at least one noncalcified, solid, indeterminate, intraparenchymal nodule (volume range, 50-500 mm(3)) at baseline were included (964 nodules in 750 participants). According to protocol, indeterminate nodules were re-examined at a 3-month follow-up CT examination. Repeat screening was performed at years 2 and 4. A nodule was defined as resolving if it did not appear at a subsequent CT examination. Nodule resolution was regarded as spontaneous, not the effect of treatment. CT features of resolving and nonresolving (stable and malignant) nodules were compared by means of generalized estimating equations analysis.RESULTS: At subsequent screening, 10.1% (97 of 964) of the nodules had disappeared, 77.3% (n = 75) of these at the 3-month follow-up CT and 94.8% (n = 92) at the second round of screening. Nonperipheral nodules were more likely to resolve than were peripheral nodules (odds ratio: 3.16; 95% confidence interval: 1.76, 5.70). Compared with smooth nodules, nodules with spiculated margins showed the highest probability of disappearance (odds ratio: 4.36; 95% confidence interval: 2.24, 8.49).CONCLUSION: Approximately 10% of solid, intermediate-sized, intraparenchymal pulmonary nodules found at baseline screening for lung cancer resolved during follow-up, three-quarters of which had disappeared at the 3-month follow-up CT examination. Resolving pulmonary nodules share CT features with malignant nodules.

Introduction:We aimed to evaluate the correlation between the size of the solid component on thin-section computed tomography (CT) and invasive component on pathology in small lung adenocarcinomas manifesting as subsolid nodules.Methods:Fifty-nine subsolid nodules in 58 patients were evaluated. The maximum diameters of subsolid nodules and the solid component on CT were measured by two radiologists in three-dimensional (3D) and two-dimensional (2D) planes using in-house software. In addition, the maximum diameters of the tumor and invasive component were measured on pathology by two pathologists. CT measurements were compared with pathologic measurements.Results:There was a strong correlation between the size of the solid component on CT and invasive component on pathology, as well as the size of subsolid nodules and the tumor size (r = 0.82–0.87 for 3D measurement, 0.72–0.88 for 2D measurement; p < 0.0001). The size of subsolid nodules in 3D and 2D measurements was significantly larger than tumor size (p < 0.0001). In regard to measurement of the solid component, 3D measurements tended to be larger than the size of the invasive component whereas 2D measurement tended to be similar to the size of the invasive component. By applying a size criteria of solid component that was 3 mm or lesser in maximum diameter, preinvasive and minimally invasive adenocarcinoma was predicted with a specificity of 100% (28 of 28).Conclusion:We found a significant correlation between the size of the solid component on thin-section CT and the invasive component on pathology.

The evaluation of the medial clavicular epiphysis via CT plays an important role in the determination of age, particularly the 19th and 22nd ages. Several authors have recommended the use of the Schmeling and Kellinghaus methods in conjunction in the evaluation of the medial clavicular epiphysis. The aim of this retrospective study was to evaluate thin section CT scan images of the medial clavicular epiphysis according to the Schmeling and Kellinghaus method, and to discuss the obtained data in the light of the literature. The thoracic CT scan images (0.6 mm section thickness) of 601 patients (202 female and 399 male) aged between 10 and 35 years obtained by 16-detector CT were evaluated by two examiners. The stage 2 was seen between 13 and 23 years of age; stage 3 was seen between 16 and 27 years of age. However, 100% of the female cases with stage 3c were >= 18 years of age, and 100% of the male cases with stage 3c were >= 19 years of age. Stage 4 was first observed at 20 years of age in both sexes, and stage 5 was first observed at 25 years of age in both sexes. We believe that stage 3c may be used, particularly in the determination 18-year age limit for both sexes. The outcomes of our study are consistent with those of our previous study and other studies in the literature, which is important for the confirmation of the reliability of the method.

To assess the interobserver agreement for a semi-quantitative evaluation of the interlobar fissures integrity in volumetric thin-section CT images, looking for more detailed information regarding fissural defects; and describe prevalence and severity of fissural defects between the different functional groups of subjects.Volumetric scans of 247 individuals exposed to tobacco with different functional status (normal to severe COPD), were retrospectively and independently evaluated by 2 chest radiologists, with a consensual reading additionally with a third reader in disagreement cases. Right oblique (RO), right horizontal (RH) and left oblique fissures (LO) integrity was estimated using a 5% scale. GOLD classification was available for all subjects.Interobserver agreement (weighted Kappa-index) for fissural categorization was 0.76, 0.70 and 0.75, for RO, RH and LO, respectively. Final evaluation found 81%, 89% and 50% of RO, RH and LO to be incomplete, with respective mean integrity of 80%, 58% and 80%. Small fissure gaps (10%) were present in 30% of patients. Prevalence and severity of fissural defects were not different between the GOLD categories.A substantial agreement between readers was found in the analysis of interlobar fissures integrity. The semi-quantitative method allowed a detailed description of the fissural defects, information that can be important, for example, in endoscopic lung volume reduction therapies for emphysema. Small fissure gaps, overlooked in previous studies, were found in almost a third of the patients. A higher than previously described prevalence of fissural defects was described, but without significant differences among the distinct functional groups.

Purpose To elucidate the underlying lung changes responsible for the computed tomographic (CT) features of idiopathic pulmonary fibrosis (IPF) and to gain insight into the way IPF proceeds through the lungs and progresses over time. Materials and Methods Micro-CT studies of tissue cores obtained from explant lungs were examined and were correlated 1:1 with a CT study obtained immediately before transplantation. Samples for histologic analysis were obtained from selected cores. Results In areas with no or minimal abnormalities on CT images, small areas of increased attenuation located in or near the interlobular septa can be seen on micro-CT studies. In more involved lung areas, the number of opacities increases and opacities enlarge and approach each other along the interlobular septa, causing a fine reticular pattern on CT images. Simultaneously, air-containing structures in and around these opacities arise, corresponding with small cysts on CT images. Honeycombing is caused by a progressive increase in the number and size of these cystic structures and tissue opacities that gradually extend toward the centrilobular region and finally replace the entire lobule. At histologic analysis, the small islands of increased attenuation very likely correspond with fibroblastic foci. Near these fibroblastic foci, an abnormal adjacency of alveolar walls was seen, suggesting alveolar collapse. In later stages, normal lung tissue is replaced by a large amount of young collagen, as seen in patients with advanced fibrosis. Conclusion Fibrosis and cyst formation in patients with IPF seem to start at the periphery of the pulmonary lobule and progressively extend toward the core of this anatomic lung unit. Evidence was found that alveolar collapse might already be present in an early stage when there is only little pulmonary fibrosis. (©) RSNA, 2016. ispartof: Radiology vol:283 issue:1 pages:252-263 ispartof: location:United States status: published

To correlate the tumor size and solid component size on thin-section CT (TS-CT) with pathological findings including lymph node (LN) metastasis and local invasion in T1 lung adenocarcinoma. 188 patients with surgically resected T1 lung adenocarcinoma were retrospectively analyzed. Two chest radiologists measured the long-axis and short-axis dimensions of nodules and solid components with a lung and/or a mediastinal window setting (WS) on TS-CT. After analyzing interobserver agreement, average long-axis dimensions of the measured tumors and solid components were correlated with pathological findings. Seven of 188 patients (3.7%) had pathologic LN-positive metastasis. In patients in whom the long axis of the solid component was

Background Early detection and treatment of pulmonary fungal infection in immunocompromised patients has a profound impact on mortality. However, information available about the thin-section computed tomography (CT) findings of Candida pneumonia has largely been limited to isolated cases seen in reviews of various infections and to other acute lung diseases seen in immunocompromised patients. Purpose To dynamically observe and evaluate CT findings in immunosuppressed animals with histopathologically confirmed pulmonary candidiasis at the acute stage. Material and Methods Twenty-four New Zealand rabbits were randomly divided into an experimental group ( n = 21) and a control group ( n = 3). Pulmonary candidiasis was established by C. albicans inoculation via a transtracheal route in immunosuppressed rabbits in the experimental group, and an equivalent amount of normal saline was injected via the same way in the control group. Chest CT scan was performed before and on alternative days after inoculation/injection. Microbiological and pathological results were obtained by autopsy. Results In the experiment group, pulmonary candidiasis was successfully established in 13 rabbits as confirmed by microbiology and pathology. Areas of air-space consolidation were present in 10 (10/13) rabbits, with lobular distribution in six and lobar or segmental distribution in four, pathologically presenting as bronchopneumonia or hemorrhagic lung infarcts. Areas of ground-glass opacity (GGO) were identified in five (5/13) rabbits, three of which were associated with other abnormalities, presenting as bronchopneumonia or interstitial pneumonitis. Multiple nodules were seen in three (3/13) rabbits. They were clustered around bronchovascular bundles in two rabbits, and subpleural in the remaining one, pathologically presenting as hemorrhagic granulomas. Other less common CT findings included thickening of bronchovascular bundles ( n = 3), linear opacity ( n = 1), and pneumothorax ( n = 1). No abnormality was detected by CT scan and pathological examination in the three rabbits of the control group. Conclusion Peripheral multiple areas of lobular consolidation and/or GGO representing bronchopneumonia were the most common thin-section CT findings of pulmonary candidiasis at the early stage.

Study objectives Previously, we reported that small pulmonary adenocarcinomas (tumor diameter 20 mm or less) could be classified according to attenuation on thin-section CT (TS-CT) images as either ‘air-containing type’ or ‘solid-density type’ (Lung Cancer 2002;36:49–57). Air-containing type was defined as having areas where TOM (tumor opacity on mediastinal window images) was half or less than half the size of those noted on lung window images. Solid-density type was defined as having areas where TOM was greater than half the size of those noted on lung window images. Our findings indicated that there was no microscopic evidence of metastasis with air-type nor any relapses nor deaths, after resection. By contrast, patients with solid-density types demonstrated a poor prognosis. At this time, the histopathological characteristics of areas of TOM have not been fully investigated. The purpose of this study is to define the correlations between TOM and histopathological findings of small lung adenocarcinomas. Method We retrospectively reviewed the records and CT scans of 134 patients, who had undergone surgical resection of peripheral adenocarcninomas. All tumor diameters were 20 mm or less in size. All 134 patients had undergone TS-CT prior to surgery. TS-CT Images were acquired by a model X-Vigor/Real or an Aquillion CT scanner (Toshiba Medical Systems). Thin-section images of tumors were obtained at 135 kVp at 250 mAs with 1–2 mm section thicknesses. All images were photographed using mediastinal (level, 40 HU; width, 400 HU) and lung (level, −600 HU; width, 1600 HU) window settings. We researched the histopathological components corresponding to the areas of TOM. Results Areas of TOM demonstrated five possible histopathological findings; (1) collapse (C), (2) collapse with bronchioloalveolarcell carcinoma (CwB), (3) adenocarcinoma cells (Cells), (4) fibroblasts (F), and (5) mucus (M). Areas of TOM in air-containing type adenocarcinomas (52 cases) demonstrated predominantly C and/or CwB (C/CwB type, 44 cases). Areas of TOM in solid-density type adenocarcinomas (82 cases), in comparison, demonstrated predominantly Cells and/or Cells/F (Cell/F type, 67 cases). We noted a statistically significant difference between the histopathological findings of the areas of TOM of air-containing type and solid-density type tumors. The 39 cases of Cell/F type adenocarcinomas revealed microscopic evidence of metastasis (pleural involvement, vascular invasion, lymphatic permeation, or lymphnode metastasis). Whereas, no C/CwB type adenocarcinomas cases revealed any microscopic metastasis. The prognosis of C/CwB type after resection is better than for Cell/F type. Conclusion We found that air-containing type adenocarcinomas demonstrated C/CwB type, and that solid-density type adenocarcinomas demonstrated Cell/F type. The histopathological findings of small pulmonary adenocarcinomas could be classified into three groups: C/CwB type, Cell/F type and M type. The prognosis of C/CwB type is better than for Cell/F type. Our results indicate that there are clear correlations between the areas of TOM and the histopathological components of small pulmonary adenocarcinomas. Therefore TS-CT findings are a useful aid in determining the best surgical methods.

Asthma and COPD have a high personal, societal, and economic impact. Both diseases are characterized by airway obstruction and an inflammatory process. The inflammatory process affects the whole respiratory tract, from central to peripheral airways that are

The purpose of this study was to prospectively compare the efficacy of oxygen-enhanced MR imaging (O(2)-enhanced MRI) and CT for pulmonary functional loss assessment and clinical stage classification of asthmatics.O(2)-enhanced MRI, CT and %FEV(1) measurement were used 34 consecutive asthmatics classified into four stages ('Mild Intermittent [n=7]', 'Mild Persistent [n=8], 'Moderate Persistent [n=14]' and 'Severe Persistent [n=5]'). Relative enhancement ratio maps for every subject were generated, and determine mean relative enhancement ratios (MRERs). Mean lung density (MLD) and the airway wall area (WA) corrected by body surface area (WA/BSA) were also measured on CT. To compare the efficacy of the two methods for pulmonary functional loss assessment, all indexes were correlated with %FEV(1). To determine the efficacy of the two methods for clinical stage classification, all parameters for the four clinical stages were statistically compared.%FEV(1) showed fair or moderate correlation with all parameters (0.15≤r(2)≤0.30, p0.05). WA, WA/BSA and MRER of the 'Severe Persistent' group were significantly larger than those of 'Mild Intermittent' and 'Mild Persistent' groups (p0.05), and MRER of the 'Moderate Persistent' group significantly lower than that of the 'Mild Intermittent' group (p0.05).O(2)-enhanced MRI is as effective as CT for pulmonary functional loss assessment and clinical stage classification of asthmatics.

目的．小型肺腺癌における浸潤癌・非浸潤癌鑑別の評価方法としてthin-section CT（TS-CT）の肺野条件画像と縦隔条件画像の腫瘍長径の比率を用いる方法（消失率法）と，TS-CT縦隔条件画像の腫瘍長径のみを用いる方法（縦隔画像長径値法）との比較検討を行った．対象・方法．対象は1997年7月から2008年5月までに切除された病理腫瘍径20 mm以下の末梢小型肺腺癌430症例（441病変）で，リンパ節転移・胸膜浸潤・血管浸潤・リンパ管浸潤・術後再発のいずれも認めないものを非浸潤癌とし，いずれか1つでも認めるものを浸潤癌とした．方法は術前TS-CT画像を用いて，（1）消失率法：消失率=（1-縦隔画像長径/肺野画像長径）×100（％），および（2）縦隔画像長径値法：縦隔条件画像における縦隔画像長径（mm）を求め，非浸潤癌鑑別に関する消失率法と縦隔画像長径値法の有用性をROC解析とロジスティック回帰分析による多変量解析を用いて行った．結果．対象の性別は男性189例，女性241例であり，病理学的には非浸潤癌328病変，浸潤癌113病変であった．ROC解析では縦隔画像長径値法よりも消失率法がより良好な結果であり，ロジスティック回帰分析を用いた多変量解析では，女性であることと消失率が高値であることが非浸潤癌に関連する独立因子であった．結論．末梢小型肺腺癌における浸潤癌・非浸潤癌鑑別の評価方法としてTS-CT画像の縦隔条件画像を用いた評価方法よりも，その肺野条件画像の長径との比率を用いた方法がより有用な鑑別方法である．

To prospectively investigate the effect of submaximal inspiration on computed tomographic (CT) indexes used to quantify emphysema and to discriminate between effects of lung tissue loss and increase in total lung capacity (TLC) on these indexes.In this ethical committee-approved study, 20 control subjects and 16 patients with chronic obstructive pulmonary disease (COPD) who provided written informed consent were included. Three 1-mm-thick sections were obtained from each participant at 100%, 90%, 80%, 70%, and 50% of vital capacity (VC). At each volume, eight percentiles of attenuation distribution, as well as relative area (RA) of lung occupied by attenuation coefficients lower than nine thresholds, were calculated. A linear regression line between TLC and each CT index was plotted for control subjects. Mean distance from data points measured in patients with COPD to the normal regression line was used to reflect the effect of lung tissue loss, regardless of TLC.The RA of lung occupied by attenuation coefficients lower than -950 HU (RA(950)) at any percentage of VC lower than 100% decreased significantly from that at 100% VC (P ≤ .002) in control subjects and patients with COPD; however, between 100% VC and 90% VC, the average difference in RA(950) was only 3% and 2% in control subjects and patients with COPD, respectively. The 1st percentile at any percentage of VC lower than 100% increased from that at 100% VC (P.001) in control subjects. This percentile did not significantly differ from 100% VC at 90% VC or 80% VC (P = .176 and P = 0.077, respectively), but it did significantly differ from 100% VC at 70% VC and 50% VC (P ≤ .002 for both) in patients with COPD. Slope and mean distance were different from zero for all RAs and percentiles except for mean distance for RAs between RA(900) and RA(920).Submaximal inspiration induces underestimation of pulmonary emphysema. Both lung tissue loss and TLC influence CT indexes, suggesting the need to establish normal CT values.

To retrospectively investigate clinical and computed tomographic (CT) features of transient part-solid nodules (PSNs) initially detected at screening thin-section CT for lung cancer and to determine predictive factors that may differentiate transient PSNs from persistent PSNs.This study was approved by the institutional review board. From January 2006 to August 2008, 93 individuals with 126 PSNs were identified from among 16777 individuals who underwent chest CT. Clinical features and CT characteristics of PSNs were reviewed, and clinical and thin-section CT features were compared between transient and persistent PSNs. To identify predictive factors of transient PSNs and evaluate predictive performance, logistic regression analysis and C statistic analysis were performed.Eighty-eight (69.8%) of 126 PSNs were transient. Between transient and persistent PSNs, there were significant differences (P.05) in patient age, patient sex, risk of lung cancer, presence of eosinophilia, mode of detection, lesion size, lesion multiplicity, size of solid portion, and lesion border. Multivariate analysis revealed that young patient age, detection of the lesion at follow-up, blood eosinophilia, lesion multiplicity, large solid portion, and ill-defined border were significant (P.05) independent predictors of transient PSNs. The performance in the discrimination of transient PSNs from persistent PSNs of the logistic regression model that incorporated both clinical and thin-section CT features was significantly higher than the performance of the models that incorporated clinical features or thin-section CT features alone.A substantial proportion of PSNs detected at screening CT were transient. Transient PSNs could be predicted with high accuracy by using the features of young patient age, detection of the PSN at follow-up, blood eosinophilia, lesion multiplicity, large solid portion, and ill-defined lesion border.

Objectives The objective of this study is to examine the correlation between enlarged vestibular aqueduct (EVA) anomaly and other inner ear anomalies such as cochlear dysplasia, vestibulocochlear dysplasia and modiolar hypoplasia. Methods Retrospective chart review, with institutional review board approval, of patients with EVA who received treatment at Primary Children's Medical Center or University Hospital at the University of Utah, between 1997 and 2006. Review of radiographs was done to evaluate for the presence of EVA and other inner ear anomalies. Results Twenty patients (40 ears) were included in the study, 17 patients had bilateral EVA and three patients had unilateral EVA. There were 10 females and 10 males. The average age of all patients at the time of initial diagnosis was 1.7 years (0–6 years). Thirty-seven ears were shown to have EVA (92.5%). Of those ears with EVA, 29 (78.4%) had one or more inner ear anomalies. Twenty-three (62.2%) ears had cochlear dysplasia, six (16.2%) had vestibulocochlear dysplasia, and 18 (48.7%) had modiolar hypoplasia. Conclusions Using small field of view, thin section CT and/or MR imaging, cochleovestibular abnormalities are commonly identified in association with EVA.

Rationale and Objectives The aim of this study was to investigate the subjective similarity for pairs of images with various abnormal patterns of diffuse interstitial lung disease on thin-section computed tomography by experienced radiologists to explore a basis for selecting similar images to assist radiologists' interpretation. Materials and Methods Four major patterns (ground-glass opacity, nodular opacity, reticular opacity, and honeycombing) on thin-section computed tomographic images were identified by at least two of three radiologists. One radiologist manually selected 104 image pairs, in which the images in each pair had the same pattern and were similar in appearance. An additional 208 image pairs were randomly selected and evenly divided among the four patterns. These pairs were then rated for subjective similarity (on a continuous scale ranging from 0 = not similar at all to 1.0 = almost identical) by 12 radiologists. Results For radiologist-selected pairs, the mean similarity rated by the 12 radiologists was 0.72. For randomly selected pairs, the mean similarity was higher for the same pattern (0.47) than for the varying patterns (0.27) (P Conclusion Subjective similarity ratings for pairs of abnormal images can be measured reliably and reproducibly by radiologists and will provide a basis for the selection of similar images to assist radiologists' interpretation.

Aim: This study aimed to evaluate the validity of 0.5-mm thin-section computed tomography (CT) for the assessment of pulmonary nodular lesion in comparison with 1-mm CT. Materials and Methods: A total of 38 focal lesions from 30 patients, which were scanned with 0.5- and 1.0-mm collimation, were evaluated regarding the extent of ground-glass opacity (GGO) and well-defined margin, and the presence of pleural indentation, spicula, and internal air density. The frequency of each finding was statistically compared between 0.5- and 1-mm CT using the McNemar test. Results: No statistically significant difference was observed between 0.5- and 1-mm CT for each finding. Conclusion: The use of 0.5-mm CT is not justified if the original collimation of multi-detector row CT is near 1 mm.

高分解能の薄切CT（Thin-section CT：TS-CT）画像により，肺野腫瘤陰影の精細な画像が得られるようになり，CT画像による小型肺腫瘤の質的診断が可能になってきた．肺野小型腫瘤陰影は，TS-CT画像の縦隔条件と肺野条件を比較することで，含気型陰影と充実型陰影に分類される．また，肺野条件画像所見からは，（1）Non-solid nodule（GGO：ground-glass opacity），（2）Part-solid nodule，（3）Solid noduleに分類される．GGOを呈する腫瘍性病変の代表的なものは，野口type A腺癌やAAHである．Part-solid noduleは野口type Bやtype C腺癌の病理組織を反映している．Part-solid noduleのsolid部分は，含気型腺癌では虚脱の病理組織所見に相当するのに対し，充実型腺癌では肺胞構築を破壊して増殖する腫瘍細胞の病理組織を反映しており，充実型腺癌は含気型に比べ術後の予後が不良である．Solid noduleは野口type D腺癌，扁平上皮癌・小細胞癌などが呈する画像である．TS-CTの水平断面画像所見からだけでなく，MPR画像，造影TS-CT画像，経時的変化などの多角的な画像診断を行なうことで，質的診断の精度が向上する．

We hypothesized that that the summation or axial slab average intensity projection (AIP) techniques can substitute for the primary reconstruction (PR) from a raw projection data for abdominal applications. To compare with PR datasets (5-mm thick, 20% overlap) in 150 abdominal studies, corresponding summation and AIP datasets were calculated from 2-mm thick images (50% overlap). The root-mean-square error between PR and summation images was significantly greater than that between PR and AIP images (9.55 [median] vs. 7.12, p

To retrospectively evaluate short linear shadows connecting pulmonary segmental arteries to oblique fissures in thin-section CT images and determine their anatomical basis. CT scanning was performed on 108 patients and 11 lung specimens with no lung diseases around the oblique fissures or hila. Two radiologists evaluated the imaging. The parameters included length, thickness of short linear shadows, pulmonary segmental artery variations, and traction interlobar fissures, etc. The short linear shadows were not related to sex, age, or smoking history. The lengths of the short linear shadows were generally within 10 mm. The thicknesses of the short linear shadows ranged from 1 to 2 mm. Of the patients, 26.9 % showed pulmonary segmental artery variations; 66.7 % of short linear shadows pulled oblique fissures. In three-dimensional images, the short linear shadows appeared as arc planes, with one side edge connected to the oblique fissure, one side edge connected to a pulmonary segmental artery. On the tissue slices, the short linear shadow exhibited a band structure composed of connective tissues, small blood vessels, and small lymphatic vessels. Short linear shadows are a type of normal intrapulmonary membranes and can maintain the integrity of the oblique fissures and hilar structure. • Volumetric thin-section CT scanning is commonly used to study lung anatomy. • Short linear shadows are a common intrapulmonary structure in thin-section CT. • Short linear shadows correlate with band structures on the correlative tissue slices.

Background: The analysis of the number and size of low-attenuation clusters has been adopted as quantitative computed tomography (CT) analysis of emphysema; however, a detailed examination has not been made on the relation between the number of various cluster sizes and the extent of emphysema. Objective: The aim of this study was to evaluate the relationship between the size and number of clusters on CT scans in patients with emphysema. Methods: This retrospective study included 31 emphysema patients. The number (LAN) and mean size (LAS) of clusters below –950 HU, and relative low-attenuation area below –950 HU (RA950) were calculated using an image-processing program. The size of clusters was divided into 3 categories, and the number in each size category was obtained as follows: small (sLAN 0.4–8 mm2), medium (mLAN 8.4–40 mm2), and large (lLAN >40 mm2). The relationships between the RA950 and sLAN, mLAN, or lLAN were evaluated. Patients were divided according to the extent of RA950 (>25% = severe emphysema, Results: The sLAN decreased as RA950 increased (r = –0.477), whereas mLAN and lLAN increased (r = 0.421, and r = 0.819). In severe emphysema, sLAN and mLAN decreased as RA950 increased (r = –0.722, and r = –0.698). In mild emphysema, mLAN and lLAN increased as RA950 increased (r = 0.732, and r = 0.972). Conclusions: The degree of the coalescence of the clusters depends on the size of clusters and the extent of emphysema. Quantitative CT analyses of clusters are helpful to elucidate the pathophysiology and progressive nature of emphysema.

To use eye-tracking analysis to identify the differences in approach to and efficiency of reading thin-section CT of the lungs presented tiled and stacked soft-copy displays.Four chest radiologists read 16 thin-section CT examinations displayed in either a tiled (four images at once) or stacked (full screen cine) format. Eye-movements were recorded and analysed in terms of movement type; saccade distance (classified by the calculated range of useful peripheral vision), number of fixations, duration and direction of gaze-comparison of the areas of the images viewed.Cases presented in stacked format were read quicker than when presented in tiled format with a greater fixation frequency (5 fixations versus 4.5 fixations points per 100 data points; p0.001) and a greater proportion of short saccades (97% versus 94%; p0.005). The consistency with which the observers viewed equivalent areas of the scan images in different cases was greater when viewing in stacked format (mean kappa 0.45 versus 0.36; p0.05) suggesting a more systematic approach to reading.Eye-tracking data demonstrates why thin-section CT examinations of the lungs are read more efficiently when displayed in a stack as opposed to a tiled format.

The objective of our study was to report the thin-section CT findings 12 months after the diagnosis of severe acute respiratory syndrome (SARS) in pediatric patients who had recovered clinically but had persistent abnormal CT findings 6 months after the diagnosis. The clinical data for these patients were correlated to identify risk factors that might increase the likelihood of the development of CT abnormalities.The study involved an extended 12-month thin-section CT follow-up of 16 of 47 pediatrics patients with SARS coronavirus-associated pneumonia proven serologically (21 girls and 26 boys; age range, 1.5-17 years; median age, 13.6 years). Patients' clinical information, the extent of radiographic opacification during the acute phase of illness, and conventional pulmonary function test results on follow-up were obtained for correlation. The clinical parameters were compared with other pediatric SARS patients who had normal CT findings at the 6-month follow-up.Fifteen patients still had abnormal CT findings 12 months after diagnosis, all of whom were older than 10 years (age range, 10-17 years). In seven patients with previous residual ground-glass opacification at the 6-month follow-up, two showed persistent changes and three had a reticular pattern in the area of the previously detected abnormality, whereas two showed complete resolution. The extent of air trapping remained similar to that at the 6-month follow-up in nine of 11 patients while two showed a slight increase in the same segments. Parenchymal scars remained unchanged from the 6- to 12-month follow-up in all six patients with that finding. None of our patients showed any evidence of bronchiectasis or bronchial wall thickening. Lymphopenia (p = 0.03), extent of radiographic opacification at acute illness (p = 0.047), and duration of use of ribavirin (p = 0.03) were significant risk factors in predicting whether abnormal CT features persisted 12 months after diagnosis.We found that 32% of the children (15/47) affected with SARS showed thin-section CT abnormalities up to 12 months after diagnosis despite clinical remission and unremarkable pulmonary function assessment. Persistent CT abnormalities are more likely to develop in patients who are older and who present with more severe disease. The CT changes in children with SARS are, however, minor.

The secondary pulmonary lobule is a fundamental unit of lung structure, and it reproduces the lung in miniature. Airways, pulmonary arteries, veins, lymphatics, and the lung interstitium are all represented at the level of the secondary lobule. Several of these components of the secondary lobule are normally visible on thin-section computed tomographic (CT) scans of the lung. The recognition of lung abnormalities relative to the structures of the secondary lobule is fundamental to the interpretation of thin-section CT scans. Pathologic alterations in secondary lobular anatomy visible on thin-section CT scans include interlobular septal thickening and diseases with peripheral lobular distribution, centrilobular abnormalities, and panlobular abnormalities. The differential diagnosis of lobular abnormalities is based on comparisons between lobular anatomy and lung pathology. © RSNA, 2006

Objective We wanted to demonstrate and compare the serial high-resolution CTs (HRCT) and the pulmonary function test (PFT) findings of the usual interstitial pneumonia (UIP) and the non-specific interstitial pneumonia (NSIP). Materials and Methods The serial HRCT scans and the PFT results were retrospectively analysed and compared for 35 patients having UIP without significant honeycombing (UIP-w/o hc, < 5% of honeycombing at CT), 35 patients having UIP with honeycombing (UIP-w/i hc, ≥ 5% of honeycombing), and 25 patients with NSIP. The mortality rates were also compared. Follow-up CT scans were available in 75 patients (29 UIP-w/o hc patients, 22 UIP-w/i hc patients and 24 NSIP patients) and the follow-up periods ranged from 150 to 2,370 days. The initial and follow-up PFT data were available for 71 patients. Results On the initial CT, significant differences were present between the UIP-w/i hc patients and both the UIP-w/o hc patients and the NSIP patients in the overall extent, ground-glass opacity (GGO) away from the reticulation, reticulation and honeycombing (all p < 0.05). Improvement was noticed in five (17%) of 29 UIP-w/o hc patients, none of 22 UIP-w/i hc patients, and 9 (37%) of 24 NSIP patients; deterioration was noted in six (21%) UIP-w/o hc patients, two (9%) UIP-w/i hc patients and three (13%) NSIP patients (p = 0.044 between UIP-w/o and UIP-w/i hc; p = 0.637 between UIP-w/o hc and NSIP; p = 0.007 between UIP-w/i hc and NSIP). The serial changes of the pulmonary function in the NSIP patients were different from those noted for the UIP-w/i hc and UIP-w/o hc patients (p = 0.440 between UIP-w/o and UIP-w/i hc; p = 0.022 between UIP-w/o hc and NSIP; p = 0.003 between UIP-w/i hc and NSIP). Five (14%) of the 35 patients with UIP-w/o hc, 16 (46%) of the 35 patients with UIP-w/i hc and three (12%) of the 25 patients with NSIP died (p = 0.002, comparison for the three groups). Conclusion On CT, NSIP and UIP-w/o hc patients have similar patterns of parenchymal abnormalities and a similar likelihood of change in the extent of disease on follow-up. Patients with UIP-w/i hc have distinctive features and a worst prognosis.

To prospectively evaluate lung parenchyma on paired inspiration-expiration thin-section computed tomographic (CT) scans in patients recovering from severe acute respiratory syndrome (SARS).After the institutional review board approved the study and written consent was obtained from patients, 40 patients (25 female, 15 male; mean age, 42.8 years +/- 12.3 [standard deviation]) underwent thin-section CT at 51.8 days +/- 20.2 after onset of SARS symptoms. Twenty of the 40 patients underwent follow-up thin-section CT at 140.7 days +/- 26.7 after symptom onset. Lung findings were scored according to extent and then grouped in three categories (ground-glass opacity, interstitial opacity, and air trapping) for analysis. Mean CT scores for each finding in the various patient subgroups were compared by using the Mann-Whitney test. Clinical parameters and scores were evaluated for correlation by using Spearman rank correlation analysis. Mean scores for each finding were compared between the two serial examinations by using the Wilcoxon matched-pairs signed rank test.Air trapping, ground-glass opacity, and reticulation were found in 37 (92%), 36 (90%), and 28 (70%) of 40 patients, respectively, at initial thin-section CT examination and in 16 (80%), 14 (70%), and 10 (50%) of 20 patients, respectively, at follow-up examination. Scans from patients with adult respiratory distress syndrome (ARDS) had a significantly higher score for ground-glass opacity than did those from patients without ARDS (P = .009). A comparison of scores for the serial thin-section CT examinations indicated a significant reduction in the extent of ground-glass opacity (P.001) and interstitial opacity (P.001) but not in that of air trapping (P = .38) at follow-up examination. At initial thin-section CT, scores for ground-glass opacity, interstitial opacity, and air trapping correlated with age; those for ground-glass opacity and air trapping, with peak C-reactive protein level. At the second examination, scores for ground-glass opacity and interstitial opacity correlated with peak lactate dehydrogenase level; that for air trapping, with age and peak C-reactive protein level.Thin-section CT scores correlated with clinical and laboratory parameters in patients after SARS. Although ground-glass opacity and interstitial opacity resolve over time, air trapping persists.

The purpose of this study was to scrutinize morphological characteristics of thin-section CT of the histopathological subtypes of adenocarcinoma of the lung. The subjects consisted of 83 patients with 87 adenocarcinomas measuring 3 cm or less in the largest. The tumors were divided into three groups (group I: Noguchi's histological subtypes type A and B tumors, group II: type C tumors, and group III: type D, E, and F tumors). In each group, tumor size, shape (round versus polygonal), presence of air bronchogram, bubble-like areas, coarse spiculation, pleural tag, and ratio of ground glass attenuation (GGA) were evaluated. Most of the group II lesions showed polygonal shape, whereas tumors in other groups were round in shape (P

We describe an algorithm for the extraction of interlobar fissures which is useful in discriminative diagnosis from thin-section CT images. In clinical diagnosis, interlobar fissures are important in identification of the lung structure and in discriminative diagnosis of lesions. Interlobar fissures are shadows whose density values are very low and whose shape differs greatly from that of the pulmonary blood vessels. The proposed technique performs reduction processing of linear artifacts on images and emphasis processing of interlobar fissures. Improved VanderBrug linear detection is used in this processing. Interlobar fissures are detected from the difference in structure by the morphology operations of erosion and dilation. The proposed technique is little affected by image artifacts. Its effectiveness is demonstrated by applying it to clinical images and evaluating the accuracy of the results. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 88(10): 59–68, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20225

To describe the appearance and frequency of a perilobular pattern at thin-section computed tomography (CT) in patients with organizing pneumonia.Thin-section CT scans of 21 consecutive patients with cryptogenic organizing pneumonia were retrospectively reviewed. Two thoracic radiologists in consensus recorded the presence and distribution of the CT abnormalities (consolidation, ground-glass opacification, nodules, bandlike opacities, interlobular septal thickening, and findings of fibrosis), with a particular focus on the presence and predominant location of the perilobular pattern, that is, a poorly defined arcadelike or polygonal appearance.The perilobular pattern was present in 12 (57%) of 21 patients, 10 of whom had five or more perilobular opacities. Other CT features were consolidation (20 patients, 95%), which was predominantly a subpleural and/or peribronchial distribution in 17 patients, and ground-glass opacification (18 patients, 86%). Bandlike opacities and interlobular septal thickening were observed in four patients and one patient, respectively. The perilobular pattern abutted the pleural surface in 10 of 12 patients and was surrounded by aerated lung parenchyma in 11 of 12 patients. There was no obvious relationship between perilobular opacities and CT findings indicative of established fibrosis.A perilobular pattern was present in more than half of the patients, along with the expected thin-section CT features of organizing pneumonia.

To determine the impact of prospective electrocardiographic (ECG) triggering on image quality and diagnostic outcome of thin-section computed tomography (CT) of the lung.Forty-five consecutive patients referred for thin-section CT of the lung were examined with prospectively ECG-triggered and nontriggered thin-section CT of the lung with a multi-detector row helical CT scanner. Subjective image quality criteria (image noise, motion artifacts, and diagnostic accessibility) were rated by three radiologists in consensus for the upper lobe, middle lobe and/or lingula, and lower lobe. Pathologic changes were assessed for the various lobes, and a diagnosis was assigned. The diagnoses were compared by two radiologists in consensus to determine the effects of CT technique on diagnostic outcome. Quantitative measurements were performed, including determination of image noise and signal-to-noise ratios in different anatomic regions. The Wilcoxon signed rank test and paired sign test (both with Bonferroni correction) were used for statistical analysis.Subjective assessment showed significant differences in motion artifact reduction in the middle lobe, lingula, and left lower lobe. The diagnostic assessibility of triggered CT was rated significantly higher only for the left lower lobe compared with nontriggered data acquisition. No differences in diagnostic outcome were determined between triggered and nontriggered techniques. Mean image noise in tracheal air was 68.2 +/- 17 (SD) for triggered CT versus 37.4 +/- 9 for nontriggered CT (P.05). Mean signal-to-noise ratio in the upper versus lower lobes was 22.5 +/- 8 versus 25.4 +/- 10 for triggered and 35.6 +/- 9 versus 39.2 +/- 10 for nontriggered techniques (P.05).Given the lack of improvement in diagnostic accuracy and the need for additional resources, ECG-triggered thin-section CT of the lung is not recommended for routine clinical practice.

A software system and database for computer-aided diagnosis with thin-section computed tomographic (CT) images of the chest was designed and implemented. When presented with an unknown query image, the system uses pattern recognition to retrieve visually similar images with known diagnoses from the database. A preliminary validation trial was conducted with 11 volunteers who were asked to select the best diagnosis for a series of test images, with and without software assistance. The percentage of correct answers increased from 29% to 62% with computer assistance. This finding suggests that this system may be useful for computer-assisted diagnosis.

To characterize the thin-section computed tomographic (CT) features of flock worker's lung (FWL) and to determine whether these features may be used to distinguish workers with FWL from flock workers who do not fulfill diagnostic criteria for FWL.Thin-section CT images obtained in 43 flock workers (including 11 with FWL) were reviewed independently by radiologists blinded to occupational and clinical details. CT features recorded included ground-glass opacities, consolidation, micronodules, reticular abnormality, and septal thickening. Thirty-five of the CT scans (including nine obtained in patients with FWL) were also studied by using quantitative image analysis. The Student t test was used to compare mean lung attenuation between the workers with FWL and those without it.Every patient with FWL and 19 (59%) of the 32 exposed flock workers who did not meet criteria for the disease had an abnormal thin-section CT scan. The most common findings in FWL were ground-glass opacities and micronodules. Quantitative analysis showed a mean lung attenuation of -736.4 HU in patients with FWL, compared with -775.0 HU in workers without the disease (P.05).While ground-glass opacities, micronodules, or both were found in all cases of FWL, these abnormalities were also present in a substantial proportion of symptomatic flock workers who did not satisfy current criteria for FWL. Although nonspecific, these findings should suggest the diagnosis of FWL in exposed individuals.