Areas Of Air Trapping Research Articles

Bronquiolitis obliterante posinfecciosa secundaria a adenovirus

Bronchiolitis obliterans is a rare chronic obstructive respiratory disease secondary to damage of the lower respiratory tract causing inflammation and partial or total obliteration of it. There are different causes, being infectious the most frequent in pediatrics, mainly due to adenovirus. We present the case of an 18-month-old male infant with a history of admission to the Pediatric Intensive Care Unit at 8 months of age due to bronchitis secondary to respiratory syncytial virus and adenovirus. After this episode, he presented persistent respiratory distress and pathological pulmonary auscultation. High resolution pulmonary computed tomography showed a mosaic pattern with areas of air trapping and decreased vascular caliber in the affected areas, findings suggestive of bronchiolitis obliterans.

Computed tomography findings in bronchial asthma: quantification of air trapping and correlation with pulmonary function tests.

High-resolution computed tomography (HRCT) scans can help identify subsets of asthma patients who show rapid decline in lung function. To evaluate high-resolution computed tomography (HRCT) findings in adult patients with asthma, obtain quantitative measurements of air trapping on expiratory scans, and correlate the findings with pulmonary function tests (PFTs). Thirty adults with asthma with persistent-mild, persistent-moderate, and persistent-severe categories as per standard clinical guidelines were evaluated with inspiratory and expiratory HRCT for various imaging features of bronchial asthma. Expiratory HRCT scan were used to quantify degree of air-trapping, and their values quantified as "pixel index," using a special "density' mask" software. Complete spirometry and body plethysmography were performed on each patient within 0-2 days of HRCT scans. HRCT findings were correlated with the clinical severity groups and the CT pixel indices (PI) were correlated with the PFT results using correlation coefficients and linear regression analysis. The inspiratory CT findings did not correlate with increase in disease severity. Expiratory scans accurately quantified areas of air trapping. CT-PI correlated well with PFT values indicative of airway obstruction and airflow limitation, which helped differentiate patients with asthma with increasing severity from those with milder forms of the disease. Expiratory thin-section CT is a useful objective method to quantify air-trapping in people with asthma. The air-trapping score measured in "pixel indices" correlates well with PFT results and can successfully identify patients with severe asthma. Further studies are needed to confirm if this parameter can serve as a potential marker for airway remodeling and declining lung function.

An unusual cause of "reverse batwing" sign.

An unusual cause of "reverse batwing" sign.

Journal Club - Bronchiectasis/COPD Overlap: Syndrome Versus Treatable Trait?

Journal Club - Bronchiectasis/COPD Overlap: Syndrome Versus Treatable Trait?

Niemann-Pick disease type B: HRCT assessment of pulmonary involvement.

ABSTRACTObjective:To analyze HRCT findings in patients with Niemann-Pick disease (NPD) type B, in order to determine the frequency of HRCT patterns and their distribution in the lung parenchyma, as well as the most common clinical characteristics. Methods:We studied 13 patients (3 males and 10 females) aged 5 to 56 years. HRCT images were independently evaluated by two observers, and disagreements were resolved by consensus. The inclusion criteria were presence of abnormal HRCT findings and diagnosis of NPD type B confirmed by histopathological examination of a bone marrow, lung, or liver biopsy specimen. Results:The most common clinical findings were hepatosplenomegaly and mild to moderate dyspnea. The most common HRCT patterns were smooth interlobular septal thickening and ground-glass opacities, which were both present in all patients. Intralobular lines were present in 12 patients (92.3%). A crazy-paving pattern was observed in 5 patients (38.4%), and areas of air trapping were identified in only 1 case (7.6%). Pulmonary involvement was bilateral in all cases, with the most affected area being the lower lung zone. Conclusions:Smooth interlobular septal thickening, with or without associated ground-glass opacities, in patients with hepatosplenomegaly is the most common finding in NPD type B.

Characterizing Lung Disease in Cystic Fibrosis with Magnetic Resonance Imaging and Airway Physiology.

Translational investigations in cystic fibrosis (CF) have a need for improved quantitative and longitudinal measures of disease status. To establish a non-invasive quantitative MRI technique to monitor lung health in patients with CF and correlate MR metrics with airway physiology as measured by multiple breath washout (MBW). Data were collected in 12 CF patients and 12 healthy controls. Regional (central and peripheral lung) measures of fractional lung water density (FLD: air to 100% fluid) were acquired both at FRC and TLC on a 1.5T MRI. The median FLD (mFLD) and the FRC-to-TLC mFLD ratio were calculated for each region at both lung volumes. Spirometry and MBW data were also acquired for each subject. Ventilation inhomogeneities were quantified by the lung clearance index (LCI) and by indices Scond* and Sacin* that assess inhomogeneities in the conducting (central) and acinar (peripheral) lung regions, respectively. MBW indices and mFLD at TLC (both regions) were significantly elevated in CF (p<0.01) compared to controls. The mFLD at TLC (central: R = 0.82) and the FRC-to-TLC mFLD ratio (peripheral: R = -0.77) were strongly correlated with Scond* and LCI. CF patients had high lung water content at TLC when compared to controls. This is likely due to the presence of retained airway secretions and airway wall edema (more water) and to limited expansions of air trapping areas (less air) in CF subjects. FRC-to-TLC ratios of mFLD strongly correlated with central ventilation inhomogeneities. These combined measures may provide a useful marker of both retained mucus and air trapping in CF lungs.

Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP) is a complex syndrome resulting from repeated exposure to a variety of organic particles. HP may present as acute, subacute, or chronic clinical forms but with frequent overlap of these various forms. An intriguing question is why only few of the exposed individuals develop the disease. According to a two-hit model, antigen exposure associated with genetic or environmental promoting factors provokes an immunopathological response. This response is mediated by immune complexes in the acute form and by Th1 and likely Th17 T cells in subacute/chronic cases. Pathologically, HP is characterized by a bronchiolocentric granulomatous lymphocytic alveolitis, which evolves to fibrosis in chronic advanced cases. On high-resolution computed tomography scan, ground-glass and poorly defined nodules, with patchy areas of air trapping, are seen in acute/subacute cases, whereas reticular opacities, volume loss, and traction bronchiectasis superimposed on subacute changes are observed in chronic cases. Importantly, subacute and chronic HP may mimic several interstitial lung diseases, including nonspecific interstitial pneumonia and usual interstitial pneumonia, making diagnosis extremely difficult. Thus, the diagnosis of HP requires a high index of suspicion and should be considered in any patient presenting with clinical evidence of interstitial lung disease. The definitive diagnosis requires exposure to known antigen, and the assemblage of clinical, radiologic, laboratory, and pathologic findings. Early diagnosis and avoidance of further exposure are keys in management of the disease. Corticosteroids are generally used, although their long-term efficacy has not been proved in prospective clinical trials. Lung transplantation should be recommended in cases of progressive end-stage illness.

Bronchiolitis Obliterans Following Unrelated-Donor Allogeneic Hematopoietic Stem Cell Transplantation.

AbstractAbstract 4504Bronchiolitis obliterans (BO), occurring beyond 3 months after allogeneic hematopoietic stem cell transplantation (allo-HSCT), has been recognized as a late-onset noninfectious pulmonary complication associated with substantial morbidity and mortality. Some reports have described this complication with different incidence, associated risk factors, prognoses and therapeutic strategies. However, up to date, there is no unified understanding with respect to BO worldwide. In this study, we retrospectively analyzed the incidence, risk factors, clinical characteristics, management approaches and prognosis of BO among unrelated donor allo-HSCT recipients in our transplant center, aiming to improve cognition, reduce misdiagnose and dicrease motality in the future. Between June 2005 and May 2009, 117 patients underwent unrelated donor allo-HSCT while 98 patients who survived and were free of disease for more than 3 months after engraftment were enrolled. Myeloablative conditioning therapies for HLA-mathced transplant included busulfan-Cyclophosphamide (Bu-Cy) based regimens. In HLA-mismatched transplant, anti-thymocyte globulin (ATG) were added in addition to Bu-Cy based regimen. Patients were offered nonmyeloablative conditioning regimens when they were ineligible for myeloablative preparative regimens with fludarabine-based regimens including fludarabine, ATG and Bu. The diagnosis of BO was based on pulmonary function abnormalities, chest high-resolution CT (HRCT) findings and exclusion from respiratory infections. Management approaches for BO included immunosuppressive agents, azithromycin and symptomatic support. Some patients were further treated with etanercept (anti-tumour necrosis factor). In total 14 of the 98 patients (14.3%) developed BO at a median interval of 307.5 days post engraftment (range, 188–1316 days). Pulmonary function tests showed a decline in FEV1/FVC to a median interval of 0.51 (0.33-0.69) and FEV1 to 32% (17-46.2%) of predicted at BO diagnosis. Chest HRCT of BO patients showed areas of air trapping on expiratory views (71.4%), hyperinflation or bronchial dilatation (64.3%). All the 14 patients (100%) with BO complicated with chronic GVHD versus 41 of the 84 patients(48.6%) without BO (P<0.05). In total 1 of the 14 patients (7.1%) with BO underwent ATG-containing conditioning regimen versus 30 of 84 patients (35.7%) without BO (P<0.05). Multivariate analysis showed that primary disease type, donor and recipient's sex or age, stem cell type, myeloablative or nonmyeloablative conditioning regimen, aGVHD complication and HLA-disparities were not associated with the incidence of BO statistically. The prognoses of most BO patients were poor. In total only 4 of the 14 patients got improved and 3 were stable due to treatment while 2 were progressive and 5 (35.7%) died. Pulmonary failure was the leading cause of death for BO patients. In non-BO group, 23 of the 84 patients (28.6%) died, with a non-relapse mortality of 15.5% and infection became the leading cause of death. The non-relapse mortality in BO patients was higher than that in non-BO patients although there was no statistical significance (P>0.05). In all, our results demonstrated that chronic GVHD and conditioning regimen containing ATG, but not others which had been reported to be related with BO, were two risk factors associated with BO and the prognosis was extremely poor. More clinical trials and basic researches should be carried out to allow prospective identification of patients at greatest risk and early new therapeutic intervention to finally improve the survival of patients in this group. Disclosures:No relevant conflicts of interest to declare.

Expiratory High-Resolution CT in Diffuse Lung Diseases

High-resolution computed tomography (CT) of the lung is a powerful diagnostic tool in revealing morphological abnormalities that closely correspond to those of the pathological tissue specimen. High-resolution CT is usually obtained at the end of deep inspiration; however, additional CT obtained at the end of deep exhalation (expiratory CT) provides a different set of information. The lung usually shows a homogeneous increase in lung density after forced exhalation, and the cross-sectional area decreases accordingly in healthy subjects; however, those areas peripheral to diseased airways often show no increase in lung density or decrease in cross-sectional area after exhalation. These areas (airtrapping areas) are seen in various diffuse lung diseases, including small airway diseases, some interstitial lung diseases, and even in normal subjects. Irrespective of the disease or condition, the extent of air-trapping approximately correlates with obstructive functional impairment. In patients with suspected lung parenchymal disease, air-trapping can be the only imaging abnormality; thus, expiratory CT can visualize early or mild parenchymal lung disease before the development of overt abnormalities. In this manuscript, the various techniques of paired inspiratory and expiratory high-resolution CT are reviewed and the normal appearances of expiratory images are described. Correlation of imaging findings with pulmonary function tests is discussed and the clinical impact of the technique is reviewed for some of the diffuse parenchymal lung diseases. Keywords: Tomography, X-ray computed, respiratory function test, lung diseases, obstructive

Study of Pulmonary Function Tests in Thalassemic Children

The present study aimed to investigate pulmonary function tests (PFTs) in children with thalassemia and to assess the relation between the degree respiratory impairment with the body iron status. High resolution computed tomography of chest (CHRCT) and bronchoalveolar lavage (BAL) was performed to study the cause of pulmonary dysfunction. Thirty-one children with thalassemia over 8 years were included. PFTs were studied including lung volumes and carbon monoxide diffusion capacity (DLco). Patients with abnormal PFTs and/or impaired DLco were further subjected to CHRCT and BAL. Total cell count was measured; differential count was performed on Giemsa and PAP smears. Iron laden macrophages were identified on Perl's stain. PFTs were normal in 51.61%, diffusion capacity impaired in 41.16%, restriction in 16.12%, while obstruction in 3.22% of cases, respectively. There was significant inverse correlation between DLco and serum ferritin. Through multivariate regression analysis, ferritin was found to be a strong predictor for forced vital capacity and total lung capacity. Bronchial dilatation and areas of air trapping were the predominant CHRCT findings. Iron laden macrophages were demonstrated in 14 of 15 patients in BAL. A significant correlation between serum ferritin and DLco, forced vital capacity, total lung capacity, and the presence of iron laden macrophages in BAL indicates that iron plays a major role in the etiopathogenesis of these abnormalities.

Assessment of pulmonary air trapping and obstruction in expiration: an experimental MRI study

The aim of this experimental study was to evaluate the potential of a simple expiration technique by means of magnetic resonance imaging (MRI) in an animal model to detect pulmonary air-trapping areas after artificial bronchial obstruction. Sixteen pigs were evaluated by means of a modified T1-weighted FLASH with fat saturation in respiratory arrest (TR=4.6 ms, TE=1.8 ms, alpha=10 degrees, S.D.=3-5 mm). A measurement of the signal intensity (SI) in the peripheral lung tissue was made in both inspiration and expiration before and after inhalation of 2 ml of 0.5% acetylcholine to simulate a bronchial obstruction. A final measurement of the lung SI was also made after bronchospasmolytic induction through salbutamol (beta2-mimetic bronchodilator). In expiration, a mean SI increase in peripheral lung tissue of about 183% was seen in comparison to inspiration (mean SI increase of 11-32). After inhalation of 0.5% acetylcholine, the expirational signal increase in peripheral lung tissue was only 114% of the original SI. The expirational signal homogeneity decreased after inhalation of acetylcholine. After inhalation of salbutamol, the lung tissue signal elevation in expiration was 193%. We interpret the low expiratory signal elevation after acetylcholine inhalation as a result of an air-trapped bronchial constriction in certain areas. The simple expiratory technique in an animal model showed that it is suitable to demonstrate obstructive air trapping using MRI.

Imaging of unusual diffuse lung diseases.

Computed tomography scans are commonly used in imaging lung diseases. As more information accumulates, patterns of rare or new diseases on CT scans are being increasingly reported. Several pulmonary diseases have distinguishing features, which are better delineated on high resolution CT scans than plain chest radiographs. The radiographic features of unusual diffuse lung diseases published in the past two years are described. Severe acute respiratory syndrome generally manifests as focal or diffuse bilateral areas of consolidation on chest radiography and reticulation with ground-glass attenuation commonly seen on CT scans. A normal HRCT rules out the diagnosis of Pneumocystis carinii pneumonia while a normal chest radiograph does not. Immunocompromised patients without AIDS, who have CMV pneumonia, generally demonstrate a combination of ground-glass attenuation, air-space consolidation, and small nodules on HRCT. Nodules less than 10 mm in size in immunocompromised patients are highly suggestive of viral infections. Bronchial wall thickening on HRCT associated with cavitating nodules is suggestive of Wegner granulomatosis in the appropriate clinical setting. Small cysts may be seen in a minority of patients with subacute hypersensitivity pneumonitis and centrilobular emphysema in chronic farmer's lung. Reversed halo sign has a high specificity for cryptogenic organizing pneumonia. The triad of ground-glass opacities, ill-defined centrilobular nodules and cysts and focal areas of air trapping is highly suggestive of subacute hypersensitivity pneumonitis. Familiarizing with radiographic and CT scan patterns may help the clinician to exclude certain diagnoses and narrow the differential diagnosis for others.

Value of volumetric data acquisition in expiratory high-resolution computed tomography of the lung.

The purpose of this study is to determine the potential advantages of volumetric expiratory high-resolution computed tomography (HRCT) over noncontiguous expiratory HRCT in visualizing the airway conducting to the areas of air trapping and in providing additional significant information in patients with diffuse lung disease with small airway abnormalities. Forty-one consecutive patients with suspected diffuse lung diseases with airway abnormalities who underwent volumetric expiratory HRCT scans from April to June 2003 were studied. Respiratory motion artifacts were evaluated at 3 anatomic levels (aortic arch, carina, and lung bases). The detectability of air trapping and its conducting airway were compared on contiguous versus noncontiguous (6 evenly spaced images per patient) end-expiratory HRCT images. Additional findings on contiguous HRCT images were also assessed regarding their diagnostic significance. The volumetric expiratory HRCT was diagnostically acceptable in 93% (38/41) of patients at arch level, 95% (39/41) at carina level, and 83% (34/41) at the lung bases, even with respiratory motion artifacts. In 35 patients with air trapping, the contiguous HRCT images enabled better identification of the conducting airway to the areas of air trapping and added diagnostically significant findings compared with noncontiguous images (P < 0.0001). Volumetric expiratory HRCT allows for better identification of the airway conducting to the areas of air trapping compared with noncontiguous images as well as additional findings of diagnostic significance.

Volumetric expiratory high-resolution CT of the lung

We developed a volumetric expiratory high-resolution CT (HRCT) protocol that provides combined inspiratory and expiratory volumetric imaging of the lung without increasing radiation exposure, and conducted a preliminary feasibility assessment of this protocol to evaluate diffuse lung disease with small airway abnormalities. The volumetric expiratory high-resolution CT increased the detectability of the conducting airway to the areas of air trapping ( P<0.0001), and added significant information about extent and distribution of air trapping ( P<0.0001).

Lung findings on high resolution CT in early ankylosing spondylitis

Objective: Ankylosing spondylitis (AS) is a chronic inflammatory disease mainly affecting the axial skeleton and pulmonary involvement is a well known feature of the disease. The aim of this study was to investigate the pulmonary high resolution computed tomography (HRCT) findings of patients with early AS. The relationship between pulmonary function tests (PFT) and HRCT findings was also determined. Subjects and methods: Twenty-eight patients with AS (mean age 30.8±7.4 and disease duration 7.0±2.6) were included in the study. Patients with a disease duration of >10 years or had other pulmonary diseases were excluded. All patients underwent plain chest radiography (posteroanterior and lateral views), thoracic HRCT and PFT. Results: All chest radiographs were normal and HRCT revealed abnormalities in 18 patients. The most common abnormalities seen on HRCT were mosaic pattern (ten of 28), subpleural nodule (seven of 28) and parenchymal bands (five of 28). Seven of ten patients with mosaic pattern revealed air trapping areas on end expiratory scans. Twelve patients had abnormal PFT and all had restrictive type of involvement. Ten of these 12 patients had abnormal HRCT and the remaining two patients had normal HRCT. On the other hand, eight patients with normal PFT had abnormalities on HRCT. Conclusion: Patients with early AS frequently have abnormalities on HRCT, even though they have normal PFT and chest X-ray. Small airway involvement was found as frequent as interstitial lung disease in early AS.

Functional significance of air trapping detected in moderate asthma.

The aim of this study was to evaluate bronchial and lung abnormalities in patients suffering from moderate asthma as defined by international guidelines, with special attention to air trapping on CT in comparison with that detected in smoking and non-smoking normal subjects. Twenty-two patients classified as moderate asthma and control subjects including healthy volunteers, smokers (n = 10) or non-smokers (n = 12) were prospectively explored by high-resolution CT (HRCT) performed at suspended full inspiration and expiration. The same expiratory protocol was performed 15 min after inhalation of 200 microg of salbutamol. Patients underwent pulmonary function tests within the same week and bronchodilator response was assessed following inhalation of salbutamol. Abnormalities of bronchi and lung parenchyma on inspiratory CT and air trapping on expiratory CT, in dependent and non-dependent areas, were assessed and scored semi-quantitatively by two independent observers. Comparison of score mean values between the different groups was performed using Mann-Whitney test and Spearman correlation between CT findings and pulmonary function tests were calculated. Mosaic perfusion was observed in 23% of asthmatics. Air-trapping scores were significantly higher in asthmatic patients than in non-smoking control subjects (p = 0.003), but not than in smokers. This difference was ascribed to non-dependent zones of the lung for which air-trapping scores were also higher in asthmatic patients (p = 0.003) and in smoking subjects (p = 0.004) than in normal controls. In the asthmatic group, a significant positive correlation was found between airways resistance and bronchial dilatation score (p = 0.01), and between small airways obstruction index and mosaic perfusion score (p = 0.05). In addition, both FEV1 and reversibility of small airways obstruction values correlated with air-trapping score (p = 0.03 and p = 0.007, respectively). No change could be detected in air-trapping score following salbutamol inhalation. Patients suffering from moderate asthma present mosaic perfusion and larger areas of air trapping than normal subjects, particularly in non-dependent areas of the lung. These lung abnormalities are related to small airways obstruction.

Bronchiolitis in adults: pathology and imaging.

The most common high resolution CT (HRCT) findings of bronchiolitis are centrilobular nodules and branching linear structures in the secondary pulmonary lobules or areas of air trapping. These findings can be helpful in suggesting the presence of bronchiolitis. However, they are nonspecific because there are overlapping features among various kinds of bronchiolitis. Bronchiolar or peribronchiolar inflammation appears as centrilobular nodule, while bronchiolectasis filled with secretions manifests with branching linear structure on HRCT. Air trapping is secondary to bronchiolitis. Proliferative bronchiolitis with the findings of patchy areas of consolidation or ground-glass opacity can be distinguished from other bronchiolitis. Mineral dust-induced bronchiolitis and peribronchiolar lesions in sarcoidosis present with perilymphatic (centrilobular plus perilobular) micronodules in the secondary pulmonary lobule. Bronchiolitis in hypersensitivity pneumonia appears with poorly defined centrilobular nodules, associated with ground-glass opacity and air trapping.

HIGH-RESOLUTION COMPUTED TOMOGRAPHY OF OBSTRUCTIVE LUNG DISEASE

High-resolution CT (HRCT) scanning and dynamic CT techniques have significantly improved our ability to image morphologic abnormalities associated with chronic airflow obstruction. Abnormalities visible on HRCT include emphysema, lung cysts, and large airways abnormalities, such as bronchiectasis, which are accurately assessed using this technique. Also visible are small airways abnormalities, such as bronchiolar dilation and filling of bronchioles with mucus or fluid. Perfusion abnormalities resulting from abnormal lung ventilation result in regional differences in lung attenuation, so-called mosaic perfusion. Expiratory HRCT scans or dynamic scans during expiration can show areas of air trapping.