Crausman R S, Lynch D A, Mortenson R L, King T E, Irvin C G, Hale V A, Newell J D
Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206, USA.
Chest. 1996 Jan;109(1):131-7. doi: 10.1378/chest.109.1.131.
To assess quantitative high-resolution CT (quantitative CT) as a diagnostic and prognostic tool in pulmonary lymphangioleiomyomatosis.
Spirometry, lung volumes, diffusing capacity, exercise physiology, and expiratory high-resolution CT (HRCT) examinations were performed on a cohort of ten patients with the diagnosis of lymphangioleiomyomatosis (LAM) referred to a tertiary care center. HRCT examinations were also done on ten normal control subjects. A thresholding technique was used to quantitatively assess the amount of abnormal cystic parenchyma present on each of the two images obtained for each subject with LAM and for each normal control subject. This numeric index of cystic parenchyma, the quantitative CT index, was then examined (1) as a diagnostic measure to distinguish the subjects with LAM from the normal control subjects and (2) as a prognostic measure to assess disease severity in the subjects with LAM. Linear regression of the quantitative CT index against physiologic indexes of pulmonary function and exercise performance was analyzed to determine the relationship between this radiologic assessment of disease severity and functional impairment.
The quantitative CT index was significantly greater for the LAM patients, 37.2 +/- 6.9 (SEM), compared with the control group, 0.8 +/- 0.2 (p = 0.0001). Linear regression analysis demonstrated significant linear correlation between the quantitative CT index and measures of airflow (FEV1, r = -0.90, p = 0.0005), air trapping (residual volume, r = 0.70, p = 0.02), diffusing capacity (diffusing capacity for carbon monoxide, r = -0.76, p = 0.01), gas exchange (alveolar to arterial oxygen gradient) at rest, r = 0.69, p = 0.007, and at maximum exercise, r = 0.79, p = 0.007) and exercise performance (maximum workload, r = -0.84, p = 0.002), and oxygen utilization (oxygen utilization at maximum exercise, r = -0.76, p = 0.01).
Quantitative CT techniques can distinguish subjects with LAM from normal controls. Further, the quantitative CT index correlates well with physiologic measurements of airflow, lung volumes, diffusing capacity, and exercise performance and, thus, may provide a useful measure of disease severity.
评估定量高分辨率CT（定量CT）作为肺淋巴管平滑肌瘤病的诊断和预后工具的价值。
对转诊至三级医疗中心的10例诊断为淋巴管平滑肌瘤病（LAM）的患者进行了肺量计检查、肺容积测定、弥散功能测定、运动生理学检查和呼气高分辨率CT（HRCT）检查。还对10名正常对照者进行了HRCT检查。采用阈值技术定量评估LAM患者和正常对照者每人所获两张图像上存在的异常囊性实质的量。然后对这个囊性实质的数值指标，即定量CT指标进行了如下研究：（1）作为区分LAM患者和正常对照者的诊断指标；（2）作为评估LAM患者疾病严重程度的预后指标。分析定量CT指标与肺功能和运动表现的生理指标之间的线性回归，以确定这种疾病严重程度的影像学评估与功能损害之间的关系。
LAM患者的定量CT指标显著高于对照组，分别为37.2±6.9（标准误）和0.8±0.2（p = 0.0001）。线性回归分析表明，定量CT指标与气流指标（第一秒用力呼气容积，r = -0.90，p = 0.0005）、气体潴留（残气量，r = 0.70，p = 0.02）、弥散功能（一氧化碳弥散量，r = -0.76，p = 0.01）、静息时气体交换（肺泡 - 动脉血氧梯度），r = 0.69，p = 0.007，以及最大运动时气体交换（r = 0.79，p = 0.007）、运动表现（最大工作量，r = -0.84，p = 0.002）和氧利用（最大运动时氧利用，r = -0.76，p = 0.01）之间存在显著的线性相关性。
定量CT技术能够区分LAM患者和正常对照者。此外，定量CT指标与气流、肺容积、弥散功能和运动表现的生理测量结果具有良好的相关性，因此可能为疾病严重程度提供一种有用的测量方法。
