CT双相扫描三维定量分析慢性阻塞性肺疾病CT肺功能与常规肺功能的关系

目的 应用64层螺旋CT双相扫描三维定量分析慢性阻塞性肺疾病(COPD)患者CT定量肺功能与常规肺功能(PFT)之间的关系,并评估CT定量分析肺功能在COPD患者中的应用价值.方法 收集84例COPD患者,采用64层螺旋CT扫描机,于深吸气末和深呼气末分别对患者行全肺扫描.采用全自动后处理软件,三维定量分析CT肺气肿参数和空气潴留评估参数.应用Spearman相关系数和多元线性回归分析CT肺功能参数与PFT之间的关系.结果 CT肺气肿评估参数最低1％衰减值[Perc1,(-984.28±17.93)HU]、最低15％衰减值[Perc15,(-948.35±22.26) HU]与片力呼气容积实测值与预计值百分比(FEV1％,48.69±23,47),第1秒用力呼气容积与用力肺活量比[FEV1/FVC,(45.89±15.36)％呈正相关(r=0.45 ～0.67,P＜O.01),与残气比[RV/TLC,(61.32±14.48)％]呈负相关(r=-0.33～-0.42,P＜0.01).CT评估肺气肿指数(EI)和空气潴留评估参数:-860～-950 HU范围内呼气相、吸气相衰减区占全肺容积百分比的差值[RVC-860～-950,(17.66±22.36)％]、呼气相与吸气相CT平均肺密度比值(MLDex/in,0.93 ±0.06)、呼气相与吸气相CT全肺容积比(LVeex/im,0.71 ±0.14)与FEV1％、FEV1/FVC呈负相关(r=-0.48～-0.69,P＜0.01);CT评估肺气肿参数[EI,(18.43±13.60)％]和空气潴留评估参数(RVC-860 ～-950、MLDex/in、LVeex/in)与RV/TLC呈正相关(r=0.41 ～0.66,P＜0.01).随后一元线性回归分析表明,CT肺气肿评估参数(EI 、Perc1、Perc15)和CT空气潴留评估参数(RVC-860～-950、MLDeex/in、LVeex/in)的变化与常规PFT参数间具有关联性(R2值0.27 ～O.66,P＜0.01);进一步将CT肺气肿与空气潴留参数两两结合成CT肺功能模型,进行多元线性回归分析(R2=0.66～0.85,P＜0.01),较单独分析时明显提高.结论 COPD患者CT肺气肿和空气潴留参数二者分别与PFT具有线性相关性,能够有效反映患者肺功能变化.CT肺气肿参数和空气潴留参数组成相关模型联合分析,与PFT相关性更好,更精确地反映了COPD患者肺功能的变化.     

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。     

长期吸烟者肺小气道损害的功能性HRCT与肺功能测定对照研究

目的：探讨功能性HRCT及肺功能测定对长期吸烟者肺小气道损害的临床诊断价值。方法：非吸烟组25例和吸烟组45例，行吸气末和呼气末HRCT扫描与肺功能测定，并分析其结果。结果：吸烟组中30例HRCT表现为小叶中心型肺气肿、全小叶型肺气肿、间隔旁型肺气肿、肺实质微结节、磨玻璃样密度影、小叶间隔线、空气潴留；这30例中肺功能测定正常27例，阻塞型通气功能障碍3例。非吸烟组19例行肺功能测定，结果全部正常；HRCT有阳性表现5例。结论：吸气末和呼气末HRCT先于肺功能测定发现吸烟对肺小气道的损害。     

MSCT肺容积的测量与肺功能的相关性初探

目的:探讨多层螺旋CT肺容积评估的价值,并分析其与肺功能试验(PFT)指标的关系.方法:志愿者15例,均在1周内完成PFT及CT检查.采用多层螺旋256排PHILIPS_Brilliance iCT,于最大吸气末和最大呼气末分别扫描全肺,用Lung Density肺定量软件测定全肺容积.结果:MSCT肺容积指标中的平均最大吸气末容积Vin:5169.5cm3,PET所得的肺总量TLC:5671.5cm3,Vin与TLC相关性r=0.87,P＜0.01；MSCT肺容积指标中的最大呼气末容积Vex:3109.7cm3,PET所得的残气量RV:3149.0cm3,Vex与RV的相关性r=0.88,P＜0.01；(Vin-Vex):2059.8 cm3,肺活量VC:2540.2cm3,VC与(Vin-Vex)的相关性r=0.87,P＜0.01.结论:MSCT肺容积指标与PFT指标有很好的相关性,可用于肺功能状况的评估.     

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。     

呼吸双相定量CT对慢性阻塞性肺疾病临床症状与肺功能评价

【摘要】目的：探讨呼吸双相CT定量参数对慢性阻塞性肺疾病（COPD）临床症状与肺功能的影响。方法：205例患者行呼吸双相肺部CT,测量肺密度参数包括肺气肿指数（EI）、空气潴留（AT）、平均肺密度（MLD）,容积参数为全肺容积（TLC）。患者于检查当日填写COPD评估测试（CAT）,并行肺功能检查,包括FEV1/ FVC、FEV1％及RV/TLC。分析CT定量参数与CAT评分、肺功能指标相关性并进行多元线性回归分析。结果：CT肺密度参数与CAT评分（r=0.220～0.293,P=0.000～0.005)和各项肺功能指标(r=0.320～0.730,P<0.001）均有显著相关性。EI与CAT评分的相关系数大于其它CT参数,是CAT评分独立影响因素(P<0.001);呼气相MLD、TLC和AT与肺功能相关系数分别高于吸气相MLD、TLC和EI。回归分析AT对各项肺功能指标贡献(P<0.001)均＞EI。结论：吸气相EI是症状评分独立影响因素,呼气相CT定量参数较吸气相对肺功能影响更大,呼吸双相定量CT可更好地反映COPD临床与肺功能状况。     

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     

薄层CT对具有COPD高危因素肺功能正常者的肺实质形态及量化评估

目的 总结具有慢性阻塞性肺疾病(COPD)高危因素肺功能正常者的肺部CT形态学特点,评价CT容积量化参数与肺功能指标的相关性,进一步探索有无肺气肿者的临床指标、CT征象间的差异.方法 对35例具有COPD高危因素的肺功能正常者进行薄层CT及肺功能检查.评价肺部CT征象(间隔旁型肺气肿、小叶中心型肺气肿、全小叶型肺气肿、小叶中心型肺结节、线样肺不张、磨玻璃样密度影、间质性炎症、马赛克征和支气管扩张或管壁增厚)的发生率.CT容积定量参数有双肺总容积(TLV),阈值＜-950 HU的肺气肿容积(EV950)和肺气肿指数(EI950).将EI950＜3％时,定义为无明显肺气肿.Spearman相关分析评价CT容积参数与肺功能指标的相关性;有、无显著肺气肿2组间的临床指标、CT征象的比较运用t检验或Fisher精确检验.结果 35例COPD高危者的CT征象中,出现率最高的前3个征象依次是间隔旁型肺气肿18例(51.43％)、线样肺不张13例(37.14％)和小叶中心型肺气肿11例(31.43％).肺功能指标肺总量(TLC)与CT容积参数TLV具有中度正相关性(r=0.435,P＜0.05).对有、无肺气肿2组间的临床指标及CT征象的比较,发现仅第1秒率(FEV1/FVC)在2组间存在差异.结论 COPD高危者的CT征象具有一定的特点,以间隔旁型肺气肿、线样肺不张和小叶中心型肺气肿为主;且不同程度肺气肿的高危者具有相似的CT形态学特点.     

64层螺旋CT肺容积成像在慢性阻塞性肺疾病中的诊断价值

目的 探讨64层螺旋CT肺容积扫描诊断慢性阻塞性肺疾病(COPD)的临床价值.资料与方法 COPD组87例,对照组29例,进行64层螺旋CT肺容积扫描和常规肺功能检查,两次检查时间间隔小于30d,研究CT肺容积参数与肺功能实验室指标之间的相关性,并采用ROC曲线分析CT肺容积参数对COPD诊断和分级的临床价值.结果 CT容积扫描获取的肺气肿容积比例与肺功能分级、RV(实际/预计％)、TLC(实际/预计％)、RV/TLC(％)、FEV1(实际/预测％)和FEV1/VC MAX(％)之间均存在显著相关(r分别为0.560,0.309,0.246,0.280,-0.522,-0.599,P均＜0.01):ROC曲线分析结果显示,全肺肺气肿容积比例、右肺肺气肿容积比例和左肺肺气肿容积比例诊断COPD的曲线下面积分别为0.863、0.822和0.917(P均＜0.01),差异有统计学意义.结论 CT测量的肺气肿容积与肺总容积之比和肺功能分级相关,对诊断COPD有预测意义.     

无症状非吸烟者肺HRCT定量分析及其与肺功能的相关性研究

目的探讨健康成人随年龄的变化,吸呼气相HRCT肺密度指标的变化及其与肺功能的相关性。方法对63例无症状非吸烟者进行肺吸气末与呼气末HRCT扫描,其中32例进行肺功能测试。将所有受试者按年龄分为5组,分别测定各组的HRCT定量指标,进行分析。所测肺功能与定量指标进行相关性分析。结果随着年龄的增长,各肺野及全肺的呼气相CT平均肺密度及差值均随着年龄的增加而逐渐降低,有极显著统计学意义(P<0.01)。用力肺活量(FVC)、1 s用力呼气容积(FEV1)、肺总量(TLC)与吸气相各个肺野及全肺的平均肺密度均有极显著的相关性(P<0.01);残气容积(RV)与吸气相中肺野平均肺密度极显著相关(P<0.01),与上、下肺野及全肺则为显著相关(P<0.05)。结论无症状非吸烟者随年龄增长,吸呼气相HRCT肺密度定量指标发生了变化,能够评价肺功能指标的一些轻微改变。     

Quantitative assessment of peripheral airway obstruction on paired expiratory/inspiratory thin-section computed tomography in chronic obstructive pulmonary disease with emphysema

OBJECTIVES: We examined the hypothesis that paired inspiratory/expiratory computed tomography (CT) scans in a limited-lung area that excludes emphysema may provide a more accurate evaluation of peripheral airway obstruction in patients with chronic obstructive pulmonary disease (COPD) with emphysema. MATERIALS AND METHODS: This study included 32 patients with COPD. The cross-sectional area between -500 and -1024 HU was segmented as whole-lung. The relative areas (RA) less than -950 HU for the whole-lung (RA<-950) were segmented as emphysema, and pixels less than -900 HU for the whole-lung (RA<-900) were segmented to evaluate air trapping. Next, the cross-sectional area between -500 and -950 HU that excludes emphysema was segmented as limited-lung, and pixels between -900 and -950 HU for the limited-lung (RA900-950) were segmented. The changes in RA<-900 (RA<-900-change) and RA900-950 (RA900-950-change) between inspiration and expiration were calculated. Correlations between CT measurements and the results of pulmonary function tests (PFT) were evaluated. RESULTS: There was no significant difference between the mean inspiratory RA<-950 and expiratory RA<-950 (P = 0.245), but the mean expiratory RA900-950 decreased significantly compared with the mean inspiratory RA900-950 (P < 0.001). The correlation coefficients between PFT parameters and the RA900-900-change in the limited-lung without emphysema were higher than that of the RA<-900-change in the whole-lung. CONCLUSIONS: The paired inspiratory/expiratory CT measurements in the limited-lung without emphysema correlated more closely with the PFTs. Our observations suggest that paired inspiratory/expiratory CT scans in the limited-lung excluding emphysema are sensitive for the evaluation of airway obstruction in COPD with emphysema.     

肺气肿HRCT肺密度与肺功能的相关性研究

目的：探讨HRCT肺密度的测定与肺功能的相关性。方法：通过对39例确诊慢性阻塞性肺疾病患者进行深吸气后全肺HRCT检查和同期进行的肺功能检查结果进行对照,分析肺密度与肺功能的相关性和肺气肿患者的各肺叶之间的分部的均匀程度。结果：39例患者的平均肺密度与肺功能的检验有显著意义的相关性,P值〈0．05;各肺叶之间的肺密度显示为不均匀分布。结论：HRCT局部肺密度测定与肺气肿的诊断指标存在显著相关性;可简单量化性地诊断及进行肺功能分析。中度肺气肿病灶在肺内呈现不均匀分布。     

吸烟人群肺部MDCT形态和容积量化评估及与肺功能的相关性研究

目的 分析吸烟人群肺部多排螺旋CT(MDCT)形态学特点,测量CT肺容积量化参数,研究二者与肺功能检查(PFT)指标的相关性.方法 选取59例吸烟者,其中14例为慢性阻塞性肺疾病(COPD)患者,另纳入39例不吸烟者作为对照组.所有受试者接受MDCT双气相扫描及PFT.分析并比较3组人群中与吸烟相关的11种肺部CT征象.测量肺气肿指数(EI)和平均肺密度(MLD).分析上述参数与PFT指标的相关性.结果 ①小叶中心型肺气肿、间隔旁型肺气肿、支气管扩张或管壁增厚的评分及发生率在3组间存在统计学差异(P均＜0.01).②吸烟COPD患者间隔旁型肺气肿与一氧化碳弥散量(DLCO)/肺泡容积(VA),支气管扩张或管壁增厚与DLCO实测值与预计值比值[DLCO SB(％P)]、DLCO与VA比值的实测值与预计值之比[DLCO/VA(％P)],EI与25％最大呼气量实测值与预计值的比值[MEF25％(％P)]、DLCO SB(％ p)、DLCO/VA(％P)均呈负相关.吸烟非COPD者小叶中心型肺气肿与第1秒用力呼气量与用力肺活量的比值(FEV1/FVC)、MEF25％(％P)、50％最大呼气量实测值与预计值的比值[MEF5％(％P)]、DLCO SB(％P)及DLCO/VA(％P),间隔旁型肺气肿与DLCO SB(％P)、DLCO/VA(％P),支气管扩张或管壁增厚与DLCO/VA(％P),EI与FEV1/FVC、MEF5％(％P)均呈负相关,MLD与FEV1(％P)、MEF25％ (％P)呈正相关.结论 MDCT可用于分析吸烟人群的肺部形态异常,其形态学特点及容积量化参数对肺功能有很好的预测价值.     

HRCT肺小血管面积定量测量与COPD小气道功能的相关性研究

目的 探讨高分辨率CT (HRCT)肺小血管面积与肺截面积比值(%CSA)与慢性阻塞性肺疾病(COPD)患者肺部小气道功能的相关性。方法 选取我院收治入院的连续性COPD患者105例,同时纳入年龄、性别相匹配健康对照组100例。所有纳入者均接受胸部HRCT扫描及肺功能检查。分析所有纳入者的主要小气道肺功能指标(MMEF%、MEF50.00%及MEF25.00%)及脉冲震荡指标IOS(Z5、R5、R20、Fres、X5)。采用Image图像处理软件测量分析基于HRCT的%CSA参数,包括肺小血管截面积<5 mm²(%CSA_<5)及5～10 mm²(%CSA_5-10)。应用独立样本t检验比较COPD组与对照组间肺功能及HRCT参数的差异;采用Spearman相关性分析COPD组%CSA与肺功能小气道指标、IOS指标之间的相关性;最后利用ROC曲线评价%CSA指标评估COPD患者小气道功能障碍的诊断效能。结果 COPD组患者小气道肺功能指标(MMEF%、MEF50.00%及MEF25.00%)...     

Value of air trapping in detection of small airways disease in smokers

Purpose: 
To test the hypothesis that diffuse and/or focal air trapping are sensitive indicators of airflow obstruction in smoker's small airways disease, when age, gender and presence of emphysematous lesions were allowed for. Material and Methods: 
Fifty-eight smokers and 34 never smokers, recruited from a randomized population study of men born in 1933, were investigated by HRCT and by extended pulmonary function tests, including a sensitive test for small airways disease (N₂ slope). Diffuse air trapping was evaluated by calculating a quotient of mean lung density at expiration and inspiration. Focal air trapping was scored visually by consensus. Results: 
Diffuse air trapping did not differ between non-emphysematous smokers and never smokers. Furthermore, diffuse air trapping correlated well to the quotient between the residual volume and total lung capacity (RV/TLC, p = 0.01) and was consequently higher in emphysematous smokers than in never smokers.
Focal air trapping was found as frequently in smokers without emphysema as in never smokers. Smokers with emphysema showed significantly less focal air trapping. Neither the N₂ slope nor any of the other lung function variables differed between those with and without focal air trapping among non-emphysematous smokers. Conclusion: 
Neither diffuse nor focal air trapping are sensitive indicators of smoker's small airways disease.     

肺气肿的诊断：CT和肺功能检查的比较

作者比较了１１７例的ＣＴ扫描（其中５０例同时加作了ＨＲＣＴ扫描）和肺功能检查在检出肺气肿上的能力。结果显示ＣＴ和肺功能检查对肺气肿的检出率分别为７８．２６％和４７．８２％，两者有极显著的差异。６６．６７％（１６／２４）肺功能检查无肺气肿的病例，ＣＴ都发现了肺气肿征象，说明ＣＴ在检出轻度、早期肺气肿上较肺功能检查敏感。在５０例常规ＣＴ和ＨＲＣＴ的比较中发现３５．８％常规ＣＴ正常的病例，在ＨＲＣＴ上都     

Expiratory CT in cigarette smokers: correlation between areas of decreased lung attenuation, pulmonary function tests and smoking history

The aim of this study was to determine the correlation between cigarette-smoke-related bronchial disease and air trapping as assessed by expiratory high-resolution CT (HRCT) scans. Thirty healthy subjects (11 non-smokers, 7 ex-smokers for > 2 years, 12 current smokers; age range 35–55 years) with a smoking history between 0 and 28.5 pack-years underwent pulmonary function tests (PFT) and HRCT in inspiration and expiration in supine and prone position. The extent of air trapping was scored in ventral and dorsal aspects of the upper, middle and lower lung portions. In 24 subjects (7 non-smokers, 7 ex-smokers, 10 current smokers) areas of focal air trapping were found, and were present significantly more often in dependent lung portions (p < 0.05) compared with non-dependent portions. No significant differences were found between apical and basal lung zones. Scores of focal air trapping were not significantly different between smokers and ex-smokers, but were significantly lower (p < 0.05) in non-smokers and showed a significant (p < 0.0005) correlation with pack-years. The degree of air trapping was also associated with several lung function tests, especially RV, DLCO, FRC, FEV1 and FEV1/VC. Air trapping is seen in smokers with normal PFT and correlates with the severity of the smoking history, independently of current smoking status. Received 4 August 1997; Revision received 12 January 1998; Accepted 14 January 1998     

Imaging of small airways disease.

High-resolution computed tomography (HRCT) is the most useful modality for imaging of small airways disease. Direct signs of small airways disease that appear on HRCT scans are the result of changes in the airway wall or lumen. Abnormal small airways can be seen as tubular, nodular, or branching linear structures on HRCT scans. Indirect signs of small airways disease result from changes in the lung parenchyma distal to the diseased small airway and include air trapping, subsegmental atelectasis, centrilobular emphysema, and air-space nodules. Diverse inflammatory and infectious processes, such as bronchiolitis obliterans (BO), bronchiolitis obliterans with organizing pneumonia (BOOP), smoking-related diseases, and asthma affect the small airways of the lungs. HRCT findings of BO include air trapping and bronchiectasis. The predominant findings of BOOP are consolidation and ground-glass attenuation. HRCT can show abnormalities such as small nodules and areas of ground-glass attenuation even in asymptomatic smokers, but emphysema predominates in smokers with moderate or severe obstructive disease. Patients with asthma can have thickened airway walls, plugged large and small airways, subsegmental atelectasis, and air trapping, but emphysema is rarely seen even in severe asthma patients. HRCT scans can often accurately depict disease processes in the small airways and can occasionally lead to a specific diagnosis from among several clinically relevant possibilities.     

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     

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.