Thin-section CT Scans Research Articles

Intrapulmonary lymph nodes: thin-section CT findings, pathological findings, and CT differential diagnosis from pulmonary metastatic nodules.

We compared the thin-section CT findings of 11 intrapulmonary lymph nodes with pathological findings and evaluated the possibility of CT scan differential diagnosis from pulmonary metastatic nodules. First, we retrospectively reviewed CT scan and pathological findings of intrapulmonary lymph nodes. The median size of these nodules was 6.2 mm. The nodules appeared round (n=3) or angular (n=8) in shape with a sharp border, and they were found below the level of the carina. The median distance from the nearest pleural surface was 4.6 mm, and 3 of the 11 nodules were attached to the pleura. On thin-section CT scan, linear densities extending from the intrapulmonary lymph nodes were frequently visualized, and were pathologically proven to be ectatic lymphoid channels. We then compared the thin-section CT findings of 8 metastatic nodules less than 1 cm in diameter with those of the 11 intrapulmonary lymph nodes. The median size of these nodules was 6.8 mm, and the median distance from the nearest pleural surface was 16 mm. All nodules appeared round in shape. None of the nodules had linear densities extending from the nodules. The linear densities on thin-section CT scan may be the most useful characteristic of intrapulmonary lymph nodes, when differential diagnosis from metastatic nodules is necessary.

Pulmonary tuberculosis in patients with idiopathic pulmonary fibrosis

Objectives: Patients with idiopathic pulmonary fibrosis (IPF) have an increased risk of pulmonary tuberculosis. However, detecting pulmonary tuberculosis may be difficult due to the underlying fibrosis. The aim of this report is to describe the radiological and clinical findings of pulmonary tuberculosis in patients with idiopathic pulmonary fibrosis. Materials and methods: We reviewed 143 consecutive patients in whom IPF was diagnosed by either the histological or radio-clinical criteria. Among them, nine patients were histologically ( n=2) or bacteriologically ( n=7) confirmed to have active pulmonary tuberculosis. The location and patterns of pulmonary tuberculosis were examined on a thin section CT scan. Results: The most common thin section CT findings were subpleural nodules ( n=6; mean diameter, 3.2 cm) and a lobar or segmental consolidation ( n=3). The lesions were located most commonly in the right lower lobe ( n=4). The incidence of tuberculosis in patients with idiopathic pulmonary fibrosis was more than five times higher than that of the general population. Conclusion: The atypical manifestation of pulmonary tuberculosis is common in patients with idiopathic pulmonary fibrosis, which may mimic lung cancer or bacterial pneumonia.

CT findings of surgically resected large cell neuroendocrine carcinoma of the lung in 38 patients.

We sought to assess the CT features of surgically resected large cell neuroendocrine carcinoma of the lung. The cases of all patients who underwent surgical resection for primary lung cancer in a single institution from 1993 to 2000 and who received an initial diagnosis of poorly differentiated non-small cell lung carcinoma, small cell carcinoma, carcinoid tumor, and large cell neuroendocrine carcinoma were histologically reviewed. The findings for 43 patients were histologically reclassified and confirmed as large cell neuroendocrine carcinoma. The CT scans available for 38 patients were evaluated by two observers. In the 38 patients, six central tumors and 32 peripheral tumors, with diameters ranging from 12 to 92 mm (mean +/- SD, 32 +/- 19 mm), were identified. None of the tumors had air bronchograms or calcification in the mass or nodule. Of the 19 patients with thin-section CT scans, 14 (74%) showed the tumor-lung interface as well defined and five (26%) showed the interface to be ill defined. Lobulation was identified on 15 scans (79%) and spiculation was evident on six scans (32%). On contrast-enhanced CT scans, inhomogeneously enhanced tumors appeared to be larger (51 +/- 18 mm) than homogeneously enhanced tumors (25 +/- 10 mm; p < 0.001). At histopathologic examination, gross necrosis was noted in 20 of 28 patients who had undergone contrast-enhanced CT, and the cause of inhomogeneous enhancement on CT scans was determined to be intratumoral necrosis. Multiple microscopic necroses were present in all 28 patients. Large cell neuroendocrine carcinoma usually appears as a well-defined and lobulated tumor with no air bronchograms or calcification. The inhomogeneous enhancement (caused by necrosis) seen in large cell neuroendocrine carcinomas with large diameters is not necessarily apparent in small-diameter (< 33 mm) large cell neuroendocrine carcinomas, even if the tumor contains necrosis.

Hepatopulmonary syndrome induced by common bile duct ligation in a rabbit model: correlation between pulmonary vascular dilatation on thin-section CT and angiography and serum nitrite concentration or endothelial nitric oxide synthase (eNOS)1 expression.

ObjectiveTo investigate the correlation between radiologic vascular dilatation and serum nitrite concentration and eNOS expression in the endothelial cell and pneumocyte in a rabbit model of hepatopulmonary syndrome induced by common bile duct ligation (CBDL).Materials and MethodsThin-section CT scans of the lung and pulmonary angiography were obtained 3 weeks after CBDL (n=6), or a sham operation (n=4), and intrapulmonary vasodilatation was assessed. The diameter and tortuosity of peripheral vessels in the right lower lobe by thin-section CT and angiography at the same level of the right lower lobe in all subjects were correlated to serum nitrite concentration and eNOS (endothelial nitric oxide synthase) expression as determined by immunostaining.ResultsThe diameters of pulmonary vessels on thin-section CT were well correlated with nitrite concentrations in serum (r = 0.92, p < 0.001). Dilated pulmonary vessels were significantly correlated with an increased eNOS expression (r = 0.94, p < 0.0001), and the severity of pulmonary vessel tortuosity was found to be well correlated with serum nitrite concentration (r = 0.90, p < 0.001).ConclusionThe peripheral pulmonary vasculature in hepatopulmonary syndrome induced by CBLD was dilated on thin-section CT and on angiographs. Our findings suggest that peripheral pulmonary vascular dilatations are correlated with serum nitrite concentrations and pulmonary eNOS expression.

Virtual colonoscopy

Computed tomographic colonography (CTC) is a safe and reliable imaging examination of the colon interpreted by radiologists. First described by Vining and colleagues 1 Vining DJ Gelfand DW Non-invasive colonoscopy using helical CT scanning, 3D reconstruction and virtual reality. Syllabus: 23rd annual meeting. Society of Gastrointestinal Radiologists, Maui, Hawaii1994 Google Scholar in 1994, the technique developed from the need for a noninvasive screening examination for colon cancer that would be more acceptable to patients than conventional colonoscopy. CTC is done after colonic cleansing. Air or CO2 is insufflated through a rectal catheter. Prone and supine helical thin-section CT scans of the abdomen and pelvis during a breath-hold are obtained, and three-dimensional reconstructions are made. Th Gluecker and colleagues 2 Gluecker Th Dorta G Keller W Jornod P Meuli R Schnyder P Performance of multidetector computed tomography colonography compared with conventional colonoscopy. Gut. 2002; 51: 207-211 Crossref PubMed Scopus (48) Google Scholar recently compared CTC with conventional colonoscopy in 50 patients with a history of polyps or colon cancer, unexplained abdominal pain, or iron-deficiency anaemia. Sensitivity for detecting lesions of 10 mm or larger was 82% with CTC compared with conventional colonoscopy. These and other 3 Macari M Bini EJ Xue X et al. Colorectal neoplasms: prospective comparison of thin section low dose multidetector row CT colonography and conventional colonoscopy for detection. Radiology. 2002; 224: 383-392 Crossref PubMed Scopus (203) Google Scholar data show that multidetector helical CT performs well in detection of polyps that are 10 mm or greater.

Thoracic manifestation of Wegener's granulomatosis: CT findings in 30 patients.

Our objective was to describe the CT findings of thoracic Wegener's granulomatosis. At presentation, both conventional and thin-section CT scans were available in 30 patients with Wegener's granulomatosis. Serial CT scans (range of intervals: 1-25 months, mean 4.5 months) were available in 20 patients. The initial and follow-up CT scans were analyzed retrospectively by two observers in terms of pattern and extent of parenchymal and airway lesions. Positive CT findings were seen in 29 of 30 (97%) patients at initial presentation. The most common pattern was nodules or masses seen in 27 of 30 (90%) patients. They were multiple in 23 of 27 (85%) patients, bilateral in 18 (67%), subpleural in 24 (89%), and peribronchovascular in 11 (41%) in distribution. Bronchial wall thickening in the segmental or subsegmental bronchi was seen in 22 (73%) patients. Large airways were also abnormal in 9 (30%) patients. Patchy areas of consolidation and ground-glass opacity were seen in 7 (23%) patients, respectively. In 17 of 20 (85%) patients in whom follow-up CT scans were available, the parenchymal or airway lesion showed complete or partial improvement with treatment. The CT findings of Wegener's granulomatosis, although multiple and variable, consist mainly of bilateral subpleural or peribronchovascular nodules or masses and bronchial wall thickening in the segmental or subsegmental bronchi. Parenchymal and airway lesions improve with treatment in most patients.

Inspiratory and Expiratory Helical CT of Normal Adults

To evaluate and compare thin section CT scans (TSS) and minimum intensity projection images (MinIPs) in healthy individuals, 10 nonsmokers with normal pulmonary function tests were studied using ten 1-mm collimated, helically acquired TSS images after full inspiration and expiration at two anatomic levels. Ten-millimeter-thick MinIPs were generated from the helical scans. Two thoracic radiologists compared TSS and MinIPs for artifacts and air trapping. Hounsfield unit (HU) measurements of TSS and MinIPs were obtained. The lung parenchyma on MinIPs demonstrates a smooth anterior-to-posterior attenuation gradient, accentuated by expiration. Motion and beam-hardening artifacts on TSS images resulted in regions of high and low attenuation on MinIPs, respectively. Expiratory TSS and MinIPs demonstrated air trapping (n = 31/40; range, 0-25%; mean, 7.2%). In comparison with TSS, MinIPs improved the conspicuity of air trapping (n = 20) and appeared to detect more air trapping (n = 7). No statistical differences were found when comparing the mean HU values of TSS and MinIPs. MinIPs demonstrated a smooth anterior-to-posterior attenuation gradient. Compared with TSS, MinIPs improve the conspicuity of air trapping in healthy individuals. Therefore, expiratory MinIPs may be useful in detecting air trapping as a result of disease.

Dependent lung opacity at thin-section CT: evaluation by spirometrically-gated CT of the influence of lung volume.

ObjectiveTo evaluate the influence of lung volume on dependent lung opacity seen at thin-section CT.Materials and MethodsIn thirteen healthy volunteers, thin-section CT scans were performed at three levels (upper, mid, and lower portion of the lung) and at different lung volumes (10, 30, 50, and 100% vital capacity), using spirometric gated CT. Using a three-point scale, two radiologists determined whether dependent opacity was present, and estimated its degree. Regional lung attenuation at a level 2 cm above the diaphragm was determined using semiautomatic segmentation, and the diameter of a branch of the right lower posterior basal segmental artery was measured at each different vital capacity.ResultsAt all three anatomic levels, dependent opacity occurred significantly more often at lower vital capacities (10, 30%) than at 100% vital capacity (p = 0.001). Visually estimated dependent opacity was significantly related to regional lung attenuation (p < 0.0001), which in dependent areas progressively increased as vital capacity decreased (p < 0.0001). The presence of dependent opacity and regional lung attenuation of a dependent area correlated significantly with increased diameter of a segmental arterial branch (r = 0.493 and p = 0.0002; r = 0.486 and p = 0.0003, respectively).ConclusionVisual estimation and CT measurements of dependent opacity obtained by semiautomatic segmentation are significantly influenced by lung volume and are related to vascular diameter.

A Case of Bronchus-Associated Lymphoid Tissue(BALT) Lymphoma in the Lung of the Patient with Primary Sjogren's Syndrome

A bronchus-associated lymphoid tissue(BALT) lymphoma of the lung is a rare disorder of patients with Sjogren's syndrome.A 49-year-old woman was admitted for an evaluation of exertional dyspnea and general weakness which had persisted for two years. The patient had suffered from dry mouth and dry eyes for five years. The physical examinations showed a coarse breath sound with inspiratory crackles on the whole lung field, particularly on the both basal lungs. The laboratory data disclosed high titers of anti-nuclear antibodies, and anti-SSA (Ro), and anti-SSB(La) antibodies. Chest radiographs demonstrated the presence of bilateral, diffuse, reticulonodular densities in both lungs. Thin-section CT scans showed diffusely distributed mosaic pattern of an inhomogeneous attenuation extending over the entire lung zone. The histological findings from an open-lung biopsy specimen revealed an accumulation of lymphoid cells around the bronchioles and an extension of malignant lymphoma cells from the bronchiolar epithelium toward the alveolar space. Immunohistochemically, the neoplastic cells reacted positively to the CD 20 antigen and were focally positive for the UCHL 1 antigen. The histological diagnosis was consistent with a low grade marginal zone B-cell lymphoma originating in the BALT. Here, we present a case of a histologically proven BALT lymphoma of the lung in a patient with primary Sjogren's Syndrome.

Journal Club of Boston Medical Center for Radiology Nonspecific Interstitial Pneumonia and Usual Interstitial Pneumonia: Comparative Appearances at and the Diagnostic Accuracy of Thin-Section CT; Radiology December 2001

WHAT IS THE QUESTION BEING ASKED? In patients clinically diagnosed with “interstitial pulmonary fibrosis” can thin-section CT distinguish between Nonspecific Interstitial Pneumonia (NSIP) and Usual Interstitial Pneumonia (UIP) histologic subtypes? WHY IS THIS IMPORTANT? The different histologic subtypes of idiopathic pulmonary fibrosis have different prognoses. Being able to distinguish between the various types based on thin-section CT would theoretically predict patient prognosis better than simply giving a more generic diagnosis of IPF. 4 HISTOLOGICAL SUBTYPES OF CLINICALLY DIAGNOSED IDIOPATHIC PULMONARY FIBROSIS Usual Interstitial Pneumonia (UIP) – most common. Bad prognosis. Nonspecific interstitial pneumonia (NSIP) – Best prognosis Desquamative interstitial pneumonia (DIP) Acute interstitial pneumonia (AIP) WHAT IS THE BACKGROUND WORK? The technology of thin-section CT. Not a new invention, but not ancient either The establishment of various histological subtypes and diagnostic criteria of IPF. The discovery that different histopathologic subtypes carry different prognoses. WHAT IS THE NULL HYPOTHESIS? The null hypothesis states that thin-section CT is not capable of distinguishing the various subtypes of IPF. WHO IS THE TEST POPULATION? Patients who were given the diagnosis of Idiopathic pulmonary fibrosis by clinical grounds: (bibasilar crackles, restrictive defect by PFTs, absence of known cause of IPF.) Of these, some received the diagnosis of either NSIP or UIP by lung biopsy. This group was further refined into a group that underwent thin-section CT scan within 12 months of biopsy. 53 patients were included –all 53 had thin-section CT and lung biopsy with a histologic diagnosis of either UIP or NSIP, and all were diagnosed with IPF based on clinical grounds. WHAT ARE THE METHODS USED? PATHOLOGY: 2 pathologists, basing final diagnosis on predominant histologic findings. Certain histopath criteria was given for the diagnosis of either UIP or NSIP. NSIP patients were further subdivided into cellular or fibrotic subtypes. Indeterminate cases settled by concensus. CT SCANNING: 1.5mm slices, 100 msec acquisition, same w/l SCORING OF CT SCANS: 2 staff chest radiologists and 2 chest fellows scoring the Journal Club of Boston Medical Center for Radiology Nonspecific Interstitial Pneumonia and Usual Interstitial Pneumonia: Comparative Appearances at and the Diagnostic Accuracy of Thin-Section CT; Radiology December 2001 2 of 4 scans independently, without clinical information. They were asked to categorize these as either UIP or NSIP based on thin-section criteria in the literature. NSIP further subclassified into cellular or fibrotic types. Readers asked to assess the lung parenchymal abnormalities : ground glass, reticular or mixed. If reticular, they were asked to score the fineness or coarseness of the reticular pattern. Observers were asked to score the location of abnormality. Degree of confidence was rated as “possible” or “confident.” STATISTICAL ANALYSIS: Sample size of 53 as described above Sensitivity/specificity/accuracy calculations

Anatomy of the minor fissure: assessment with high-resolution CT and classification.

The aims of this study were to investigate the anatomy of the minor fissure and its variations on high-resolution CT (HRCT) sections and to propose a detailed classification. The prospective study included 67 patients who were referred to CT for various indications. High-resolution CT examinations (1.5-mm collimation) were obtained through the region of the minor fissure. The CT scans were assessed for the presence, completeness, and configuration of the minor fissure. Various configurations of the minor fissure were classified into four major types, based on whether the highest portion of the middle lobe upper surface was medial (type I), lateral (type II), posterior (type III), or central (type IV). Minor fissure was identified in 65 (97%) of 67 patients, and absent in 2 (3%) cases. The fissure was incomplete in 35 (54%) of 65 patients. Type-I minor fissure is seen in 28 (43%) patients, type II in 22 (34%), type III in 5 (8%), and type IV in 2 (3%) patients. Because the majority of the fissure was absent in 8 (12%) of 35 patients with incomplete fissure, they were considered indeterminate. Comprehensive knowledge of the various configurations of the minor fissure is helpful in correct localization of a lesion and its extension. In equivocal cases, limited thin-section CT scans through the fissure delineate the anatomy more clearly and provide greater degree of precision in localizing pulmonary lesions.

Acute diverticulitis of the cecum and ascending colon: the value of thin-section helical CT findings in excluding colonic carcinoma.

The purpose of this study was to assess the value of characteristic thin-section helical CT findings of acute diverticulitis involving the cecum and ascending colon in excluding colonic carcinoma. Thin-section helical CT scans (5-mm collimation) of 19 consecutive patients with proven diverticulitis and 21 consecutive patients with surgically proven carcinoma involving the cecum and ascending colon were reviewed retrospectively. Two radiologists independently analyzed these parameters: degree of pericolic infiltration, mesenteric fluid, vascular engorgement, arrowhead-shaped wall thickening, air-filled diverticula, inflamed diverticula, and preserved enhancement pattern of involved colonic wall. Inter-observer agreement was assessed with a kappa statistical analysis, and the features that most distinguished diverticulitis from colonic carcinoma were selected with a stepwise logistic-regression analysis. The two CT findings of right-sided colonic diverticulitis that most distinguished it from colonic carcinoma were inflamed diverticula and the preservation of an enhancement pattern of the involved colonic wall. Excellent interobserver agreement (kappa > 0.60) was obtained for both findings. Inflamed diverticula (kappa = 0.80) had a mean sensitivity, specificity, and accuracy for diverticulitis of 86.8%, 92.9%, and 90.0%, respectively, in differentiating right-sided colonic diverticulitis from colonic carcinoma. Preserved wall enhancement pattern (kappa = 0.70) had a mean sensitivity, specificity, and accuracy of 89.5%, 95.3%, and 92.5%, respectively. On thin-section helical CT, an inflamed diverticula and a preserved enhancement pattern of the thickened colonic wall were the two most statistically significant CT findings of acute diverticulitis involving the cecum and ascending colon that distinguished diverticulitis from colonic carcinoma.

Thoracic Manifestation of Churg-Strauss Syndrome: Radiologic and Clinical Findings

To describe the radiologic and clinical findings of Churg-Strauss syndrome (CSS) and its thoracic manifestations. We used retrospective analysis to review and characterize the radiographic, thin-section CT, and clinical findings of CSS. The study involved nine patients with CSS. The patients included four men and five women, whose ages ranged from 18 to 60 years (median, 35 years). Thin-section CT scans and chest radiographs were retrospectively analyzed by three radiologists in consensus. Clinical data were obtained by chart review. Histologic samples were available in eight patients. All patients had a history of asthma averaging 28 months (range, 4 to 72 months) prior to the initial symptom of vasculitis and marked peripheral blood eosinophilia (mean peak count, 8,726/microL; range, 3,000 to 32,000/microL; mean differential count, 41%; range, 19 to 67%). All patients had systemic vasculitis involving the lung and two to four extrapulmonary organs, most commonly the nervous system (n = 8) and skin (n = 7). Chest radiographs showed bilateral nonsegmental consolidation (n = 5), reticulonodular opacities (n = 3), bronchial wall thickening (n = 3), and multiple nodules (n = 1). The most common thin-section CT findings included bilateral ground-glass opacity (n = 9); airspace consolidation (n = 5), predominantly subpleural and surrounded by the ground-glass opacity; centrilobular nodules mostly within the ground-glass opacity (n = 8); bronchial wall thickening (n = 7); and increased vessel caliber (n = 5). Other findings were hyperinflation (n = 4), larger nodules (n = 4), interlobular septal thickening (n = 2), hilar or mediastinal lymph node enlargement (n = 4), pleural effusion (n = 2), and pericardial effusion (n = 2). In CSS, thoracic organs are invariably involved with additional diverse manifestations. The possibility of CSS should be raised in patients with a history of asthma and hypereosinophilia who present with thin-section CT findings of bilateral subpleural consolidation with lobular distribution, centrilobular nodules (especially within the ground-glass opacity) or multiple nodules, especially in association with bronchial wall thickening.

Airway reactivity to bronchoconstrictor and bronchodilator: assessment using thin-section and volumetric three-dimensional CT.

ObjectiveTo determine the extent to which thin-section and volumetric three-dimensional CT can depict airway reactivity to bronchostimulator, and to assess the effect of different airway sizes on the degree of reactivity.Materials and MethodsIn eight dogs, thin-section CT scans were obtained before and after the administration of methacholine and ventolin. Cross-sectional areas of bronchi at multiple levels, as shown by axial CT, proximal airway volume as revealed by three-dimensional imaging, and peak airway pressure were measured. The significance of airway change induced by methacholine and ventolin, expressed by percentage changes in cross-sectional area, proximal airway volume, and peak airway pressure was statistically evaluated, as was correlation between the degree of airway reactivity and the area of airways.ResultsCross-sectional areas of the bronchi decreased significantly after the administration of methacholine, and scans obtained after a delay of 5 minutes showed that normalization was insufficient. Ventolin induced a significant increase in cross-sectional areas and an increase in proximal airway volume, while the effect of methacholine on the latter was the opposite. Peak airway pressure increased after the administration of methacholine, and after a 5-minute delay its level was near that of the control state. Ventolin, however, induced no significant decrease. The degree of airway reactivity did not correlate with airway size.ConclusionThin-section and volumetric spiral CT with three-dimensional reconstruction can demonstrate airway reactivity to bronchostimulator. The degree of reactivity did not correlate with airway size.

Focal air trapping in patients with HIV infection: CT evaluation and correlation with pulmonary function test results.

HIV-positive individuals commonly have symptoms of airway disease. We evaluated thin-section CT scans of HIV-infected individuals during inspiration and expiration for evidence of focal air trapping. We also correlated imaging findings with pulmonary function test results. Fifty-nine subjects, 48 of whom were HIV-positive and 11 of whom were HIV-negative, underwent thin-section CT of the thorax during inspiration and expiration. All subjects also underwent pulmonary function tests. Two radiologists, who were unaware of the subjects' HIV status and smoking history and of the results of pulmonary function tests, evaluated the CT scans for the presence and severity of focal air trapping. Expiratory CT revealed focal air trapping in 33 subjects: 30 were HIV-positive and three were HIV-negative (p = .0338). The mean values of forced expiratory volume in 1 sec (FEV1), forced mid expiratory flow, and diffusion capacity (DL(CO)) were significantly lower for subjects with focal air trapping (mean = 88.85, 84.52, and 80.80, respectively) than for those with normal findings on CT (mean = 100.84, 99.24, and 95.82, respectively; p = .001, p = .021, and p = .003, respectively). We found no significant differences in smoking history between HIV-positive and HIV-negative subjects. Severe air trapping on expiratory CT scans was seen in three subjects: All three had HIV infection, low CD4 counts, and abnormally decreased FEV1 and DL(CO) values. Focal air trapping was a common finding on thoracic CT scans obtained during expiration in HIV-positive subjects. In addition, focal air trapping was associated with significantly lower FEV1, forced mid expiratory flow, and DL(CO) values than those found for subjects in whom CT revealed no focal air trapping. These results suggest that small airways disease may accompany a decline in pulmonary function in HIV-positive individuals.

Value of spirometry-gated high resolution computerized tomography of the lung during inspiration and expiration

To compare mean lung density (MLD) of paired inspiratory and expiratory thin-section CT scans acquired after patient instruction or using spirometric gating. 21 patients (13 m, 8 f. median age 59 years, two with normal lung function, 15 with obstructive, 4 with restrictive impairment) underwent thin-section CT. Paired inspiratory and expiratory scans were performed in the upper, middle and lower lung fields. They were acquired after automatic patient instruction with constant intervals between instruction and scan. Spirometrically gated scans were acquired within 4 days at 80% and 20% of vital capacity (VC) which has been determined on the CT scanner in supine position directly prior to the examination using the built-in spirometric option. Semiautomatic segmentation of the lung was performed and MLD was calculated. VC of pulmonary function testing was available for correlation. Inspiratory MLD was -828 +/- 71 HU with spirometric gating and -818 +/- 87 HU without. Expiratory MLD was -750 +/- 119 HU (increase 78 +/- 58 HU) with spirometric gating and -748 +/- 119 HU (increase 70 +/- 46 HU) without. All differences were non-significant. Intraindividual differences were 10 +/- 21 HU for inspiration and 2 +/- 36 HU for expiration. VC under CT-conditions was significantly smaller than that known from pulmonary function tests (1.9 +/- 0.71 vs. 2.7 +/- 0.81, p < 0.005). Spirometric gating does not lead to different results for MLD as compared with acquisition of paired inspiratory and expiratory thin-section CT after automatic patient instruction.

Bronchiolitis obliterans organizing pneumonia manifesting as multiple large nodules or masses.

The purpose of this study was to describe the CT features and clinical features in bronchiolitis obliterans organizing pneumonia (BOOP) that manifest as multiple large nodules or masses. We reviewed thin-section CT scans and clinical records of 12 patients with histologically proven BOOP manifesting as multiple large nodules or masses. For all patients follow-up CT scans were available, which we also reviewed. Of 60 lesions found in the 12 patients, 53 (88%) had an irregular margin, 27 (45%) had an air bronchogram, 23 (38%) had a pleural tag, and 21 (35%) had spicules. Ancillary findings included focal thickening of the interlobular septa in five (42%) of the 12 patients, pleural thickening in four (33%) patients, and parenchymal bands in three (25%) patients. Follow-up CT scans showed that the lesions with surrounding ground-glass attenuation evolved into lesions with pleural tags or parenchymal bands or both. BOOP should be considered when multiple large nodular lesions are seen on chest CT. In particular, BOOP should be considered when the lesions contain air bronchograms; have irregular margins, relatively broad pleural tags in contact with the pleura, parenchymal bands, or subpleural lines; or are associated with focal thickening of interlobular septa.

Decreased nitric oxide in the exhaled air of patients with systemic sclerosis with pulmonary hypertension.

BACKGROUND: Systemic sclerosis (SSc) may be complicated by pulmonary hypertension (PHT), which can occur both in the setting of fibrosing alveolitis or as lone pulmonary vascular disease. Nitric oxide (NO)...

Early detection of pneumonia in febrile neutropenic patients: use of thin-section CT.

The purpose of this study was to evaluate the usefulness of thin-section CT for early detection of pneumonia in neutropenic patients with an unknown site of infection and normal or nonspecific findings on chest radiographs. Eighty-seven patients with febrile neutropenia that persisted for more than 2 days despite empiric antibiotic treatment underwent 146 prospective examinations. If findings on chest radiographs were normal (n = 126) or nonspecific (n = 20), thin-section CT (1-mm collimation, 10-mm increment) was done. If thin-section CT scans showed opacities, bronchoalveolar lavage was recommended. Findings on chest radiographs were nonspecific for pneumonia in 20 (14%) of 146 cases, and CT findings in those cases were suggestive of pneumonia. Microorganisms were detected in 11 of those 20 cases. Seven of the 11 cases were not optimally treated before CT diagnosis, the other four were sufficiently treated. Findings on chest radiographs and thin-section CT scans were normal in 56 (38%) of 146 cases. In 70 (48%) of 146 cases, findings on chest radiographs were normal, whereas findings on thin-section CT scans were suggestive of pneumonia. Microorganisms were detected in 30 of the 70 cases. Nineteen of 30 cases were not optimally treated before CT, whereas the other 11 cases were sufficiently treated before CT. In 22 (31%) of these 70 cases, an opacity was observed on the chest radiograph during the 7 days after the CT study. Only three (5%) of 56 pneumonias occurred during the first 7 days after thin-section CT studies with normal findings (p < .005). Additional risk factors for pneumonia occurring later that were detectable on chest radiographs were poorly defined nodules (p < .05), consolidation (p < .05), and younger age (p < .05). Thin-section CT scans show findings suggestive of pneumonia about 5 days earlier than chest radiographs show suggestive findings. When thin-section CT scans show findings suggestive of pneumonia, the probability of pneumonia being detected on chest radiographs during the 7-day follow-up is 31%, whereas the probability is only 5% when the findings on the prior thin-section CT scan were normal (p < .005). All neutropenic patients with fever of unknown origin and normal findings on chest radiographs should be examined with thin-section CT.

Strategies for the Treatment of Enophthalmos

The surgical correction of post-traumatic enophthalmos is among the most challenging problems for the surgeon. A thorough understanding of orbital anatomy and the purposed mechanisms of enophthalmos is crucial to the ultimate success or failure of the procedures. The successful orbital reconstruction begins with a careful physical examination of the patient that is attentive to ocular function, soft-tissue position, and visible or palpable defects of the facial skeleton. The physical examination combined with thin section CT scanning in the axial and coronal planes provides the basis of the operative plan. The anatomy of the deformity should dictate the anatomy and shape in the surgical correction. In many cases, multiple surgical incisions will be required; therefore, care must be taken to maximize exposure and minimize the cosmetic problems associated with large incisions. We advocate a step-wise approach consisting of mobilization of the soft tissues in the area of the fracture, repositioning of the anterior and middle sections of the bony orbit, and reattachment of the soft tissue to the bone at the proper location. The approach to reconstruction of the bony orbit that we advocate is to first sequentially reposition each segment of the rim, carefully examining each articulation. Once rim reconstruction is complete, reconstruction of the internal wall is performed. Recall that the largest source of error is in inadequate reduction of the orbital rim, owing to the fact that this error is "squared" (according to the model) in the computation of the orbital volume. Through the application of these principles, the cosmetic and functional sequelae of post-traumatic enophthalmos can be improved greatly with minimal complications.