Khong Pek-Lan, Chan Godfrey C F, Lee So-Lun, Au Wing Y, Fong Daniel Y T, Tsang Kenneth W T, Ooi Gaik-Cheng
Department of Diagnostic Radiology, University of Hong Kong, Rm 406, Block K, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong SAR, China.
Radiology. 2003 Nov;229(2):507-12. doi: 10.1148/radiol.2292021805.
To describe and quantify thin-section computed tomographic (CT) features of the lung in patients with beta-thalassemia major (beta-TM) and determine the correlation between thin-section CT findings, pulmonary function test (PFT) results, and iron overload.
Forty-one patients with beta-TM (mean age, 24.5 years) underwent thin-section CT (during full inspiration and expiration) and PFTs. Two radiologists in consensus recorded the presence of focal bronchial and parenchymal abnormalities and air trapping. A semiquantitative air trapping score (ATS) was used, and patients were separated into air trapping-negative (ATS between 0 and 3) and air trapping-positive (ATS > 3) groups for statistical analysis. Iron overload was estimated by calculating the ratio of the signal intensity (SI) of the liver to the SI of paraspinous muscle by using magnetic resonance imaging in 27 patients (66%). We performed multiple logistic regression analysis to study the influence of age, PFT findings, and SI ratio on the presence of air trapping at CT and multivariate regression analysis to study the simultaneous influence of the presence of air trapping on obstructive PFT indexes.
Air trapping was the predominant thin-section CT finding and was seen in 10 (24%) of 41 patients. No patient had interstitial lung disease at CT, although 11 (27%) had a restrictive spirometric pattern. Simple logistic regression analysis revealed significant associations between ATS and forced expiratory volume in the first second (FEV1), FEV1/forced vital capacity (FVC), forced expiratory flow (FEF) in the midexpiratory phase (FEF25%-75%), FEF at 50% of the FVC (FEF50%), and FEF at 75% of the FVC (FEF75%) (P =.019,.030,.007,.034, and.021, respectively) but not between ATS and SI ratio. At multiple logistic regression analysis, only FEF25%-75% was significantly associated with ATS (P =.019, adjusted odds ratio = 0.86, R2 = 41.8%). Multivariate analysis revealed that ATS did not have a significant influence on lung function indexes (P =.104), although significant effects were found with FEV1, FEF25%-75%, FEF50%, and FEF75% when examined separately.
Air trapping may be present at expiratory thin-section CT in patients with beta-TM and is associated with reduced FEF25%-75% values but not hepatic iron overload.
描述和量化重型β地中海贫血（β-TM）患者肺部的薄层计算机断层扫描（CT）特征，并确定薄层CT表现、肺功能测试（PFT）结果与铁过载之间的相关性。
41例β-TM患者（平均年龄24.5岁）接受了薄层CT检查（在完全吸气和呼气时）及PFT。两名放射科医生达成共识，记录局灶性支气管和实质异常以及空气潴留的存在情况。采用半定量空气潴留评分（ATS），并将患者分为空气潴留阴性组（ATS在0至3之间）和空气潴留阳性组（ATS>3）进行统计分析。通过磁共振成像计算27例患者（66%）肝脏与椎旁肌信号强度（SI）之比来估计铁过载情况。我们进行多因素logistic回归分析以研究年龄、PFT结果和SI比在CT上对空气潴留存在的影响，并进行多变量回归分析以研究空气潴留的存在对阻塞性PFT指标的同时影响。
空气潴留是主要的薄层CT表现，41例患者中有10例（24%）出现。CT检查时无患者患有间质性肺疾病，尽管11例（27%）患者有限制性肺量计模式。简单logistic回归分析显示，ATS与第1秒用力呼气容积（FEV1）、FEV1/用力肺活量（FVC）、呼气中期用力呼气流量（FEF）（FEF25%-75%）、FVC 50%时的FEF（FEF50%）以及FVC 75%时的FEF（FEF75%）之间存在显著相关性（P分别为0.019、0.030、0.007、0.034和0.021），但与ATS和SI比之间无相关性。在多因素logistic回归分析中，只有FEF25%-75%与ATS显著相关（P = 0.019，调整比值比 = 0.86，R2 = 41.8%）。多变量分析显示，ATS对肺功能指标无显著影响（P = 0.104），尽管单独检查时FEV1、FEF25%-75%、FEF50%和FEF75%有显著影响。
β-TM患者在呼气时薄层CT可能出现空气潴留，且与FEF25%-75%值降低有关，但与肝脏铁过载无关。
