Bronchovascular anatomy of the upper lobes: evaluation with thin-section CT

The anatomy of the bronchovascular trees of the upper lobes was evaluated with thin-section computed tomography (CT) in 50 patients. In all patients, the subsegmental bronchi could be seen, except the right B2b, left B1 + 2c, and left B3c. Regular anatomic relationships were seen between the right A3b and B3b (A3b was seen along the medial aspect of B3b in 45 patients [90%]), right A2a and B2a (A2a was seen along the posteromedial aspect of B2a in 45 patients [90%]), and left A1 + 2c and B1 + 2c (A1 + 2c was seen along the posterior aspect of B1 + 2c in 41 patients [82%]). Four patterns of bronchial branching were seen in the left upper lobe. The lateral branch of the posterior segmental vein of the upper lobes was an anatomic landmark dividing the anterior and posterior segments of the upper lobes. Three kinds of venous drainage patterns were identified in both the right and left upper lobes.     

Hydrostatic pulmonary edema: evaluation with thin-section CT in dogs

PURPOSE: To identify the hemodynamic determinants of ground-glass opacification on thin-section computed tomographic (CT) scans of hydrostatic pulmonary edema and to compare attenuation and subjective assessments of ground-glass opacification with extravascular lung water. MATERIALS AND METHODS: Left atrial pressure, pulmonary arterial pressure, effective pulmonary capillary pressure, and extravascular lung water were measured in six dogs before and during progressive increase of effective pulmonary capillary pressure. A thin-section CT scan was obtained at each step. Lung attenuation and subjective assessments of ground-glass opacification were compared with hemodynamic variables and extravascular lung water. RESULTS: Ground-glass opacification was identified when effective pulmonary capillary pressure equaled critical pulmonary capillary pressure. Extravascular lung water increased, and the distribution curve of lung attenuation coefficients shifted to higher attenuation from the second measurement at an effective pulmonary capillary pressure greater than the critical pulmonary capillary pressure. Attenuation was highly correlated (r = 0.98, P < .001) with extravascular lung water; ground-glass opacification was detected before a significant (P = .615, analysis of variance) increase in extravascular lung water. CONCLUSION: Thin-section CT depicts ground-glass opacification when effective pulmonary capillary pressure equals critical pulmonary capillary pressure and before a detectable increase in extravascular lung water. Attenuation reflects extravascular lung water.     

Severe acute respiratory syndrome: temporal lung changes at thin-section CT in 30 patients

PURPOSE: To evaluate lung abnormalities on serial thin-section computed tomographic (CT) scans in patients with severe acute respiratory syndrome (SARS) during acute and convalescent periods. MATERIALS AND METHODS: Serial thin-section CT scans in 30 patients (17 men, aged 42.5 years +/- 12.2 [SD]) with SARS were reviewed by two radiologists together for predominant patterns of lung abnormalities: ground-glass opacities, ground-glass opacities with superimposed linear opacities, consolidation, reticular pattern, and mixed pattern (consolidation, ground-glass opacities, and reticular pattern). Scans were classified according to duration in weeks after symptom onset. Longitudinal changes of specific abnormalities were documented in 17 patients with serial scans obtained during 3 weeks. Each lung was divided into three zones; each zone was evaluated for percentage of lung involvement. Summation of scores from all six lung zones provided overall CT score (maximal CT score, 24). RESULTS: Median CT scores increased from 1 in the 1st week to 12.5 in the 2nd week. Ground-glass opacities with or without smooth interlobular septal thickening and consolidation were predominant patterns found during the 1st week. Ground-glass opacities with superimposed irregular reticular opacities, mixed pattern, and reticular opacities were noted from the 2nd week and peaked at or after the 4th week. After the 4th week, 12 (55%) of 22 patients had irregular linear opacities with or without associated ground-glass opacities and CT scores greater than 5; five of these patients had bronchial dilatation. When specific opacities were analyzed in 17 patients, consolidation generally resolved completely (n = 4) or to minimal residual opacities; six (55%) of 11 patients with ground-glass opacities had substantial residual disease (CT scores > 5) on final scans. CONCLUSION: There is a temporal pattern of lung abnormalities at thin-section CT in SARS. Predominant findings at presentation are ground-glass opacities and consolidation. Reticulation is evident after the 2nd week and persists in half of all patients evaluated after 4 weeks. Long-term follow-up is required to determine whether the reticulation represents irreversible fibrosis.     

Basilar segmental bronchi: thin-section CT evaluation

Thin (1.5- and 5.0-mm) section contiguous computed tomographic (CT) scans obtained through the basilar segmental bronchi in 31 patients were reviewed in order to delineate normal anatomy and common variations of lower lobe airways. In each case, the frequency with which individual segmental and subsegmental bronchi were seen was established, as were variations in branching patterns. All basilar segmental bronchi were identified except in one case in which images of the left lung were obscured due to respiratory and cardiac motion. In the right lung, a division into subsegmental bronchi was identified in 84 of 150 (56%) visualized segmental bronchi. Six separate patterns of basilar segmental subdivision were found. In the left lung, subsegmental bronchi were identified arising from 51 of 145 (35%) visualized segmental bronchi. Five separate patterns of bronchial subdivision were found in the left lung. It is concluded that thin-section CT allows precise identification of all basilar segmental bronchi and, consequently, can play a significant role in the cross-sectional evaluation of lower lobe bronchial and parenchymal abnormalities.     

Anatomy of the major fissure: evaluation with standard and thin-section CT

The major fissures of the right and left lungs were studied with standard computed tomography (CT) (10-mm-thick sections) and thin-section CT (2-mm-thick sections) in 50 patients. On standard CT scans, the major fissures were seen in 90%-100% of cases at each of three selected levels. They usually appeared as hypoattenuating bands and less often as lines or hyperattenuating bands. Although in most cases the major fissure was seen as a line on thin-section CT scans, this appearance was more common in the upper portion of the left major fissure than in the upper portion of the right major fissure. A "double-fissure sign" was most frequently seen at the base of the left lung; however, the sign was also seen at higher levels, with approximately equal frequency in the right and left lungs. An incomplete major fissure was noted in the right lung in 32 cases (64%) and in the left lung in 26 cases (52%). The upper and middle portions of the left major fissure were less frequently incomplete than were the comparable portions of the right major fissure. Thin-section CT provided better delineation of the major interlobar fissures than did standard CT.     

Pulmonary sequelae in convalescent patients after severe acute respiratory syndrome: evaluation with thin-section CT

PURPOSE: To prospectively evaluate lung parenchyma on paired inspiration-expiration thin-section computed tomographic (CT) scans in patients recovering from severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.     

Mandibulofacial dysostosis: CT findings of the temporal bones

Six patients of two families with clinically suspected and genetically proven Treacher Collins syndrome and hearing loss were studied by CT of the temporal bone. The objective of this study was to detect the abnormalities and to show the variation of expression of abnormalities. We found a high incidence of asymmetry in the different ear malformations and a slightly lower incidence of some other classical features, probably due to our patient selection.     

Volumetric thin-section CT: evaluation of pulmonary interlobar fissures

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 multi-planar 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.The pulmonary interlobar fissures are important landmarks for pulmonary anatomy. They adopt a double membrane structure formed by invagination of the visceral pleura. The interlobar fissures are 1–3 mm thick and consist of the right oblique fissure (ROF), horizontal fissure (HF), and left oblique fissure (LOF) (1, 2). The recognition of pulmonary interlobar fissures and their variations is beneficial for identifying pulmonary lesion locations, evaluating disease progression, selecting surgical operations, and applying endoscopic therapy (3–5). With the constant development of imaging techniques, thin-section computed tomography (CT) can provide more detailed information regarding lung structure with respect to the anatomy (5–7). Multiplanar reformatting (MPR) (8) and maximal intensity projection (MIP) are reconstruction techniques based on a noninvasive methodology that detect pulmonary interlobar fissure variations. The results generated by these techniques highly resemble the results of an autopsy (8). In this study, the pulmonary interlobar fissures and their variations were investigated and analyzed by volumetric thin-section MPR and MIP images.     

Oleic acid-induced lung injury: thin-section CT evaluation in dogs

PURPOSE: To validate lung attenuation measurements for quantifying extravascular lung water in oleic acid-induced pulmonary edema, compare subjective assessment with attenuation measurements, and compare this permeability-type pulmonary edema with hydrostatic-type pulmonary edema. MATERIALS AND METHODS: Thin-section computed tomography (CT) and pulmonary hemodynamic examinations were performed sequentially in six dogs before and after intravenous administration of 0.08 mg of oleic acid per kilogram of body weight. Extravascular lung water and pulmonary capillary pressure were measured. Results were compared with those reported in a canine model of hydrostatic edema. RESULTS: Oleic acid induced a progressive increase in extravascular lung water without a change in capillary pressure, which indicated pure permeability-type edema. Ground-glass opacification was detected as soon as extravascular lung water increased. Lung attenuation was highly correlated to extravascular lung water (r = 0.76, P<.001), as in hydrostatic edema, but was characterized by an almost absent gravitational gradient. CONCLUSION: Thin-section CT is sensitive for early detection and quantification of oleic acid-induced pulmonary edema in a canine model. Different from early canine hydrostatic edema, which is characterized by a gravitational gradient, early oleic acid-induced pulmonary edema in a supine dog is characterized by nearly homogeneous distribution, except for ventral sparing.     

Patients with dysplasia of the auricle and external ear abnormalities: Evaluation of the temporal bones malformation with thin-section computed tomography

Purpose

To correlate the relationship of the degree of external, middle, and inner ears abnormalities and the degree of dysplasia of the auricle (microtia).

Methods

We used high-resolution CT, with axial and coronal 1-mm contiguous sections to examine the temporal bones of patients with microtia.

Results

In cases of type II and III microtia, bony atresia of the external auditory canal was predominant. The degrees of middle ear malformations and ossicular dysplasia were correlated with the severity of the auricular anomalies. Inner ear changes were uncommon.

Conclusion

Microtia is commonly associated with a variety of external, middle, and, less frequently inner ear abnormalities. High-resolution multiplanar CT scanning is the primary imaging modality of choice in the preoperative evaluation of patients with microtia and external auditory canal dysplasia.     

Subpleural micronodules in diffuse infiltrative lung diseases: evaluation with thin-section CT scans

Thin-section computed tomography (CT) was performed in 244 patients with infiltrative lung diseases and 29 healthy control subjects to evaluate the frequency, profusion, and diagnostic value of subpleural parenchymal micronodules. These areas of increased attenuation (less than 7 mm in diameter) were analyzed in four groups: coal miners with chest radiographic findings of coal worker's pneumoconiosis (n = 61), coal miners with no radiographic evidence of pneumoconiosis (n = 73), patients with nonoccupational chronic infiltrative lung disease (n = 110), and healthy adults (n = 29). Subpleural parenchymal micronodules were observed with high frequency in pulmonary lymphangitic carcinomatosis, coal worker's pneumoconiosis, and sarcoidosis but were also seen in 14% of control subjects. Predominant sites of lesions were the posterior subpleural areas in the upper lobes. Subpleural parenchymal micronodules have no diagnostic value when observed as an isolated CT finding but may suggest that diagnosis of pneumoconiosis, sarcoidosis, or pulmonary lymphangitic carcinomatosis when observed in association with mild parenchymal lesions.     

Near drowning: thin-section CT findings in six patients

PURPOSE: The purpose of this study was to assess the thin-section CT findings of near drowning in six patients. METHOD: Thin-section (1 mm collimation) CT scans of six patients who experienced near drowning were retrospectively analyzed. The CT scans were performed 0-5 days (median 1 day) after near drowning. RESULTS: Thin-section CT findings included bilateral patchy or diffuse areas of ground-glass attenuation (n = 6) with geographic pattern (n = 3) and fine intralobular reticular opacities ("crazy-paving" appearance) (n = 3), ill-defined centrilobular nodules (n = 4), and air-space consolidation (n = 1). Distribution of ground-glass attenuation was predominantly central (n = 4) or diffuse (n = 2). Interstitial pulmonary emphysema and pneumomediastinum were present in two patients. CONCLUSION: The thin-section CT findings of near drowning consist of ground-glass opacities with or without associated reticular opacities and centrilobular nodules.     

Drug-induced pneumonitis: thin-section CT findings in 60 patients

PURPOSE: To describe thin-section computed tomographic (CT) findings in patients with drug-induced pneumonitis, to compare these CT findings, and to correlate them with arterial oxygen tension level. MATERIALS AND METHODS: Thin-section CT scans obtained in 60 patients with drug-induced pneumonitis were evaluated retrospectively. The patients had 31 cases of antineoplastic agent-induced pneumonitis and 29 cases of nonneoplastic agent-induced pneumonitis (antibiotic agent, 20 cases; herbal medicine [sho-saiko-to], four cases; antirheumatic agent, three cases; phenytoin, one case; disodium cromoglycate, one case). CT scans were reviewed by two chest radiologists in consensus. Correlation between arterial oxygen tension level and the extent of disease at CT was available in 21 patients. These two factors were compared by using the Spearman rank correlation coefficient. RESULTS: The predominant findings in antineoplastic agent-induced pneumonitis were diffuse or multifocal ground-glass opacities with intralobular interstitial thickening. The predominant CT findings in antibiotic agent-induced pneumonitis were patchy ground-glass opacities with centrilobular opacities and interlobular septal lines. The predominant CT findings in herbal medicine-induced pneumonitis were diffuse ground-glass opacities with patchy consolidation. Interlobular septal lines and centrilobular opacities were observed more frequently in antibiotic agent-induced pneumonitis, and intralobular interstitial thickening was observed more frequently in antineoplastic agent-induced pneumonitis. A significant correlation was established between arterial oxygen tension level and extent of disease at CT (r = -0.84, P <.05). CONCLUSION: In addition to ground-glass opacities and interlobular septal lines, the most common thin-section CT findings were intralobular interstitial thickening, observed in antineoplastic agent-induced pneumonitis, and centrilobular opacities, observed in antibiotic-induced pneumonitis.     

Bronchial measurement with three-dimensional quantitative thin-section CT in patients with cystic fibrosis

PURPOSE: To prospectively compare bronchial measurements obtained with three-dimensional quantitative thin-section computed tomography (CT) with those obtained with thin-section CT scores in the assessment of the severity of pulmonary cystic fibrosis (CF). MATERIALS AND METHODS: Ethics committee approval was obtained. Sixteen patients with CF (mean age, 26.6 years; range, 18-42 years) and five healthy volunteers (mean age, 27.4 years; range, 21-44 years) gave written informed consent, underwent multi-detector row CT and a pulmonary function test (PFT), and were divided into three groups: group A, healthy volunteers; group B, patients with mild CF (forced expiratory volume in 1 second [FEV(1)] > 80%); and group C, patients with severe CF (FEV(1) < 80%). Two observers obtained thin-section CT scores with eight scoring systems. Bronchial cross-sectional wall area (WA), lumen area (LA), airway area, and wall thickness (WT) were measured with customized software and were normalized on the basis of subject body surface. Morphologic characteristics, PFT results, thin-section CT scores, and quantitative measurements were compared among the three groups with analysis of variance. Correlations among bronchial measurements, PFT results, and CT scores were calculated with the Spearman correlation coefficient. RESULTS: Thin-section CT scores were different between group C and either group A or group B (P < .05). WA and WT were significantly different among all groups (P < .05). Interscore correlations and correlations between bronchial parameters and scores were high (r > 0.89, P < .0001). Scores, WA, and WT were significantly correlated with PFT obstructive indexes (P < .047). CONCLUSION: WA and WT assessed with dedicated software on multi-detector row CT images allow evaluation of the severity of pulmonary CF.