慢性阻塞性肺疾病的肺高分辨率CT呼气相研究

目的　分析慢性阻塞性肺疾病 (COPD)患者吸气相和呼气相高分辨率CT(HRCT)表现 ,对呼气相HRCT上的空气潴留征进行定量分析。方法　 44例COPD患者进行吸气相、呼气相HRCT和肺功能试验检查 ,分析其HRCT表现 ,统计双肺吸 -呼气相密度差值 (VD)和面积缩小率 (AD)、空气潴留评分值并与肺功能试验指标进行相关性分析。结果　 40例患者呼气相HRCT上出现空气潴留征 ,超出了吸气相异常征象的范围 ;双肺VD和AD、空气潴留评分值与肺功能试验指标显著相关 (Ρ <0 .0 5 )。结论　呼气相HRCT可以作为吸气相HRCT的补充手段 ,空气潴留征能够定量分析并且反映患者的肺功能状况     

肺气肿的肺高分辨率CT:吸气相和呼气相研究

目的　探讨呼气相HRCT对肺气肿患者的辅助诊断价值。方法　 2 8例肺气肿患者和健康志愿者进行吸气相、呼气相HRCT检查 ,肺气肿患者还进行了肺功能试验检查 ,对肺气肿患者和健康志愿者的双肺吸气相密度平均值 (ID)、双肺吸 -呼气相密度差值 (VD)进行统计学比较 ,并对患者的双肺ID、双肺VD和空气潴留评分值与肺功能试验指标进行相关性分析。结果　肺气肿患者和健康志愿者的双肺ID、双肺VD均存在显著性差异 ;双肺VD、空气潴留评分值与肺功能试验指标显著相关 (Ρ <0 .0 5 )。结论　呼气相HRCT能够反映肺气肿患者的肺功能状况 ,作为吸气相HRCT的辅助手段。     

肺HRCT的吸气相和呼气相的定量研究及其与肺功能关系的初步研究

目的　研究正常人和患者高分辨率CT的呼气相表现及肺功能状况对定量指标的影响。方法　 2 6例健康成人和 2 9例患者进行了HRCT的吸气相和呼气相扫描。观察呼气相的空气潴留征以及累及的范围 ,计算测量阈值范围内的双肺吸 -呼气相的平均密度差值 (VD)和面积缩小率 (AD)。患者组按肺功能试验结果分为两组 ,和正常对照组一起 ,进行VD和AD的统计学比较。结果　 2 9例患者中 ,肺功能正常组 13例 ,肺功能异常组 16例。正常对照组与肺功能异常组、肺功能正常组进行双肺VD和双肺AD方差分析检验 ,正常对照组与肺功能异常组之间、肺功能正常组与异常组之间的四项指标均存在显著性差异 (Ρ <0 .0 5 )。结论　呼气相HRCT的空气潴留征可以辅助吸气相HRCT评价阻塞性肺疾患 ,初步判断患者的肺功能状况。     

正常成人肺HRCT呼气相密度改变的定量研究

目的研究正常成人肺HRCT呼气相表现和对其进行定量分析。方法分析97例20～70岁健康志愿者的肺呼气相HRCT表现,计算双肺吸呼气相密度差值（VD）、面积缩小率（AR）、呼气相上左前、左后、右前、右后肺局部区域的密度值（LD）,并对其进行统计学分析。结果左肺与右肺之间,上肺与下肺之间的VD和AR存在显著性差异;前肺与后肺的LD有显著性差异;双肺的VD和AR有显著性相关。结论健康成人的肺呼气相HRCT上各区域间存在着密度差异。     

儿童哮喘肺HRCT空气潴留与肺功能的相关性研究

目的: 观察儿童哮喘患者呼气末HRCT空气潴留的表现;明确空气潴留的面积与肺功能阻塞性指标如FEV1、FEF25%～75%等的相关性.方法:选择21名哮喘儿童行呼气末HRCT扫描,并于同一天或第2天做肺功能检查.在HRCT上分别于上、中、下肺野选取2个可清晰显示空气潴留的层面.用一张规格为2mm×2mm的透明方格纸对空气潴留的面积进行评估.根据空气潴留面积占全肺面积的比例,将其分为3级:Ⅰ级<5%,Ⅱ级5%~25%,Ⅲ级>25%.然后将空气潴留的级别与肺功能的指标做相关性分析.结果:①哮喘儿童肺呼气末HRCT空气潴留出现率为90.5% (19/21);②下叶是空气潴留最好发的部位,占100% (19/19);③空气潴留级别与肺功能阻塞性指标FEV1、FEF25%～75%、FEF50%显著相关,相关系数分别为(r=-0.565,P<0.01;r=-0.499,P<0.05;r=-0.521,P<0.05).④肺功能正常的哮喘儿童肺HRCT空气潴留出现率为 87.5% (14/16).肺功能正常的哮喘儿童在肺HRCT可观察到明显的空气潴留征,其空气潴留级别可达到Ⅱ、Ⅲ级.结论:肺呼气末HRCT空气潴留可直观显示气道病变的不均匀分布及病变的严重程度;空气潴留征比肺功能异常改变出现早,其敏感性明显高于肺功能检查,可用于评价肺功能正常的哮喘儿童的小气道病变.     

呼气相肺部高分辨力CT扫描的临床应用研究

目的:探讨在不增加放射剂量的情况下HRCT呼气相肺容积测定,对存在小气道异常的弥散性肺疾病的临床应用价值。方法:45例研究对象行吸气末和呼气末屏气HRCT全肺扫描(层厚1.25mm,间隔20mm,骨算法)并进行冠状面图像重组,测定肺容积。结果:45例患者呼气相HRCT表现为支气管扩张、气管及支气管软化、全小叶型肺气肿、空气潴留等。呼气相HRCT对与空气潴留区相通的气道显示率达100%,冠状面重组图像对空气潴留的范围和分布所提供的诊断信息达到90%,与吸气相HRCT相比,差异均有极显著性意义(P<0.0001)。结论:在不增加患者有效的照射剂量或不降低图像质量的情况下,HRCT呼气相肺容积测定技术可以获得容积数据对显示气道病变及空气潴留区域的范围和分布有重要价值。     

无症状非吸烟者肺空气潴留的HRCT评估及其与肺功能的相关性研究

目的分析不同年龄组无症状非吸烟者呼气相高分辨率CT（HRCT）空气潴留情况,探讨年龄对呼气相CT空气潴留的影响以及空气潴留与肺功能的相关性。资料与方法对经严格选择的63名无症状非吸烟者进行肺吸气末与呼气末HRCT扫描,其中32名进行肺功能测试。将所有受试者按年龄分为5组,对呼气相HRCT上空气潴留进行定量分析并与肺功能指标进行相关性分析。结果所有受试者吸气相HRCT均未见异常,呼气相HRCT空气潴留总的出现率为39．7％（25／63）,其中Ⅰ型22．2％（14／63）,Ⅱ型17．5％（11／63）,各组均未出现Ⅲ型空气潴留。以小叶型空气潴留为主者16例,以肺段型为主者9例,未出现肺叶型。空气潴留组与无空气潴留组之间的用力肺活量（FVC）和1s用力呼气容积（FEV1）／FVC平均值之间存在显著差异（P〈0．05）;FEV1／FVC更是与空气潴留的分级有明显的相关性（r=-0．529,P〈0．05）。结论无症状非吸烟者呼气相HRCT出现的空气潴留约40％．年龄为其形成原因之一。空气潴留的面积分级与FEV1／FVC呈明显的相关性。     

小气道疾病的呼气相CT研究

目的　通过对小气道疾病患者进行呼气相CT扫描 ,结合吸气相CT扫描 ,评价呼气相CT在诊断小气道疾病方面的应用价值。方法　对 3 1例小气道疾病患者及对照组 12例 ,使用螺旋CT进行呼气末的胸部CT扫描 ,结合吸气末CT扫描 ,测量和计算肺横断面积衰减分数 (CLARS) ,肺密度衰减值 (LDAV)。同时 ,对 2组分别进行了吸气末和呼气末的高分辨率扫描 (HRCT) ,重点观察呼气末的空气潴留征象。结果　病例组和对照组的横断面积衰减分数分别为 2 5和 48,肺密度衰减值分别为 79HU和 186HU ,2组结果有显著统计学差异。在呼气相HRCT扫描时观察空气潴留征象 (airtrapping) ,正常对照组中没有见到此征象 ( 0 % ) ,而 3 1例病例组中有 13例 ( 4 2 % )可见到空气潴留。结论　呼气相CT能够观察空气潴留征象 ,结合吸气相CT扫描 ,测量和计算CLARS、LDAV等指标 ,对小气道疾病的早期诊断和定量有较大的帮助 ,是一种有发展前途的检查方法     

肺气肿患者HRCT和肺功能的相关分析

目的：通过与肺功能检测的对照研究，评价高分辨率CT(HRCT)诊断肺气肿的价值。方法：对40例确诊为肺气肿的患者行吸气末和呼气末的HRCT扫描。对全部患者行肺功能检查，以HRCT图像为依据测定肺密度，并将测定的结果与肺功能资料相对照。结果：HRCT与肺功能检测均能对肺气肿做出正确的诊断。呼气末肺密度值较吸气末肺密度值与肺功能检测有更密切的相关性。结论：HRCT，尤其是呼气末的HRCT扫描可正确地诊断肺气肿。     

动态CT扫描在慢性阻塞性肺病中的应用研究

目的 :探讨和定量分析慢性阻塞性肺疾病 (COPD)患者动态CT扫描的表现及其应用价值。材料和方法 :34例COPD患者分别进行呼、吸气末动态CT扫描及肺功能检查。以呼、吸气末肺野密度变化、像素指数 (PI)值作为CT评价指标。观察上述指标在左、右侧肺 ,上、中、下肺区及前、后肺区的变化规律 ,并比较全肺和局部感兴趣区 (ROI)法对肺野密度测量结果的相关性及以上CT分析参数值与肺功能参数值的相关性。结果 :COPD患者呼、吸气末CT值和CT值差值呈节段性差异。上肺区低于下肺区 ,前肺区低于后肺区 ,此差异在呼气末更显著 (P<0.05) ;左右肺之间各参数值无差异 (P>0.1)。呼气末PI值低于吸气末。全肺法测量结果与局部ROI法显著相关 (P<0.05)。呼、吸气末CT值差值及PI值与反映气流阻塞 (FEV1、FEV1/FVC)及气体潴留 (RV、RV/TLC)的肺功能参数均相关 ,且呼气末相关性大于吸气末 (P<0.05)。结论 :COPD患者存在气体潴留 ,呼气末CT参数值与反映气流阻塞及气体潴留的相应肺功能参数有良好相关性 ,可应用于COPD等其他慢性阻塞性肺疾病的诊断和肺功能的评价     

Air trapping in sarcoidosis on computed tomography: correlation with lung function

AIMS: To document the presence and extent of air trapping on high resolution computed tomography (HRCT) in patients with pulmonary sarcoidosis and correlate HRCT features with pulmonary function tests. METHODS: Twenty-one patients with pulmonary sarcoidosis underwent HRCT and pulmonary function assessment at presentation. Inspiratory and expiratory HRCT were assessed for the presence and extent of air trapping, ground-glass opacification, nodularity, septal thickening, bronchiectasis and parenchymal distortion. HRCT features were correlated with pulmonary function tests. RESULTS: Air trapping on expiratory HRCT was present in 20/21 (95%) patients. The extent of air trapping correlated with percentage predicted residual volume (RV)/total lung capacity (TLC) (r = 0.499;P < 0.05) and percentage predicted maximal mid-expiratory flow rate between 25 and 75% of the vital capacity (r = -0.54;P < 0.05). Ground-glass opacification was present in four of 21 (19%), nodularity in 18/21 (86%), septal thickening in 18/21 (86%), traction bronchiectasis in 14/21 (67%) and distortion in 12/21 (57%) of patients; there were no significant relationships between these CT features and pulmonary function results. CONCLUSION: Air trapping is a common feature in sarcoidosis and correlates with evidence of small airways disease on pulmonary function testing.     

Early bronchiolitis obliterans following lung transplantation: accuracy of expiratory thin-section CT for diagnosis

PURPOSE: To evaluate the accuracy of thin-section computed tomography (CT) with expiratory scans in diagnosing early bronchiolitis obliterans after lung transplantation. MATERIALS AND METHODS: Thin-section CT scans were reviewed by two observers blinded to the diagnoses in seven consecutive lung transplant recipients with histopathologically proved bronchiolitis obliterans (group A) and 21 with normal biopsy findings (group B). All patients had normal biopsy and stable pulmonary function test (PFT) results 2-36 weeks prior to CT. Patients with normal biopsy results were placed into subgroups based on abnormal (group B1) or stable (group B2) PFT results. Air-trapping extent on expiratory scans was scored on a 24-point scale. RESULTS: The mean air-trapping score in group A (6.6) was not significantly different from that in group B (4.5, P =. 17). The air-trapping score was significantly higher in groups A and B1 than in group B2 (6.2 and 2.6, respectively; P =.03). The frequency of an air-trapping score of 3 or more in groups A and B1 was significantly higher than that in group B2 (P =.03). By using a score of 3 or more to indicate air trapping, the sensitivity of expiratory CT was 74%, specificity was 67%, and accuracy was 71%. CONCLUSION: Thin-section CT, including expiratory scans, is of limited accuracy in diagnosing early bronchiolitis obliterans after lung transplantation.     

Evaluation of air trapping at CT: comparison of continuous-versus suspended-expiration CT techniques

PURPOSE: To compare thin-section computed tomographic (CT) scans obtained during suspended end expiration with helical CT scans obtained during continuous expiration for the assessment of air trapping. MATERIALS AND METHODS: Forty-nine patients with an airway disease were examined with suspended-end-expiration CT after a 6-8-second expiratory maneuver, which was followed with continuous-expiration CT during a 10-second expiratory maneuver. The extent of expiratory air-trapping areas was calculated by two observers by using a semiquantitative grid score. The relative decrease in attenuation in the areas of air trapping was evaluated with a visual continuous-scale score. RESULTS: Air trapping was noted in 36 and 35 patients with continuous-expiration CT and with suspended-end-inspiration CT, respectively. The extents of and relative attenuation decreases in air-trapping areas in patients with air-trapping areas on at least one expiratory CT scan increased significantly in scans obtained with continuous-expiration CT compared with those obtained with suspended-end-expiration CT, respectively, with mean extent scores of 0.24 +/- 0.20 (SD) and 0.18 +/- 0.20 (paired t test, P: =.001) respectively, and with mean relative contrast decrease scores of 0.35 +/- 0.23 and 0.27 +/- 0.23 (paired t test, P: =.007), respectively. CONCLUSION: When suspended-end-expiration CT images are ambiguous, complementary continuous-expiration CT can be used to improve the conspicuity and apparent extent of air trapping.     

Chronic pulmonary thromboembolism. Air trapping on computed tomography and correlation with pulmonary function tests

OBJECTIVE: We evaluated lung attenuation on inspiratory/expiratory computed tomography (CT) and spiral CT angiography (CTA) from patients with chronic pulmonary embolism and correlated the CT findings with pulmonary function test (PFT) results. METHODS: We retrospectively reviewed 9 patients with chronic embolism (mean age, 62.3 years; 5 women and 4 men). Paired inspiratory, expiratory CT and matching CTA images were reviewed, and lung attenuation was evaluated in each segment. Lower attenuation on inspiratory images and air trapping on expiratory images were subjectively assessed and correlated with PFT results. The relationship between the presence of clot and lung attenuation was evaluated. Nine age-matched normal subjects served as controls. RESULTS: Lower attenuation with mosaic perfusion and air trapping were identified in 6 and 9 patients, respectively (mean scores, 8.1 and 11.3, respectively). Air trapping was identified in 19 (42.2%) of 45 segments with lower attenuation on inspiratory images, but was also noted in 31 segments with normal inspiratory attenuation. Air trapping was associated with the presence of proximal arterial stenosis (P<0.01), and the area showed less contrast enhancement than the adjacent lung (P<0.05). Extent of air trapping correlated inversely with PFT parameters of peripheral airway obstruction such as maximum mid-expiratory flow rate (r=-0.86, P=0.003). On the other hand, extent of mosaic perfusion did not correlate with PFT. CONCLUSIONS: Air trapping is commonly seen in chronic embolism and is found in areas of relative hypoperfusion. The extent of air trapping correlates with parameters of peripheral airway obstruction.     

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 μg 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. Received: 28 December 1999; Revised: 27 April 2000; Accepted: 2 May 2000     

Pulmonary sarcoidosis. Correlation of expiratory high-resolution CT findings with inspiratory patterns and pulmonary function tests

Purpose: To assess the presence and extent of air trapping (AT) on chest high-resolution CT (HRCT) in sarcoidosis and to correlate such findings with patterns, lesion extent on inspiratory CT and pulmonary function tests (PFT).Material and Methods: Thirty patients with sarcoidosis underwent inspiratory and expiratory HRCT and PFT. HRCT images were evaluated for presence, distribution and AT extent as well as the predominant HRCT pattern and the extent of lesions at inspiration. Attenuation difference in the AT regions at expiration and at inspiration were calculated. The presence and extent of AT were correlated with PFT, extent of involvement and predominant inspiratory patterns.Results: AT was present in 25/30 patients with no lung zone predilection. AT was the only CT indication of pulmonary sarcoidosis in 3/30 patients who also had normal PFT. Attenuation difference between inspiration and expiration ranged from -40 HU to 106 HU. In 2 patients, a paradoxical decrease of lung attenuation was observed at expiration. A significant correlation was found between AT extent at expiration, with residual volume-total lung capacity ratio and residual volume.Conclusion: AT is an additional HRCT finding in sarcoidosis. AT may involve any lung zone, including costophrenic angles and may be the only CT feature of pulmonary sarcoidosis. Strong correlation is only found with PFT values that are specific for incomplete lung emptying at expiration.     

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.