肺气肿的CT肺功能成像:CT技术与肺功能检查的对照研究

目的　比较高分辨CT(HRCT)、CT肺功能成像及肺功能检查 (PFT)对肺气肿及阻塞性肺疾病 (COPD)的诊断效用。方法　阻塞性通气障碍组 37例 ,正常对照组 2 0名。所有入选者均在 1周内完成CT检查和PFT。比较HRCT视觉评分、CT肺功能成像参数与PFT结果的相关性和差异性。结果　 (1)CT检查发现 ,阻塞性通气障碍组 37例中有 2 3例有肺气肿征象归属肺气肿亚组。 (2 )HRCT视觉评估仅与PFT参数中一氧化碳弥散量 (DLCO)占预计值百分比存在相关性 (r =- 0 731,P <0 0 0 1)。 (3)肺气肿亚组的视觉分数与最大吸气末、呼气末各像素指数 (PI)存在相关性 ,其中分别与PI 950in、PI 950ex相关性最好 (r分别 =0 5 0 6、0 6 10 ,P均 <0 0 0 1)。 (4)利用PI 910in、PI 910ex分别对两组的肺功能进行分级 ,与一秒钟用力呼气容积 /用力肺活量 (FEV1/FVC)比值的分级结果比较 ,差异无显著性 (χ2 分别 =0 5 2 7、3 6 4 5 ,P分别 =0 913、0 30 2 ) ,采用PI 910in对肺气肿亚组分级与FEV1/FVC的分级结果比较 ,差异无显著性 (χ2 =2 5 9,P =0 4 5 9)。结论　HRCT诊断肺气肿较普通CT敏感 ,但受层厚和照射剂量的限制 ,不能用于对全肺的评估。CT肺功能成像结果客观 ,操作简单 ,与HRCT视觉评分及PFT结果相关性好 ,对早期肺气肿的诊

CT pulmonary functional imaging in emphysema: a correlative study of CT technique and pulmonary function test

OBJECTIVE: To compare the effectiveness of high resolution CT, CT pulmonary functional imaging, and pulmonary function test (PFT) in the quantitative evaluation of emphysema and obstructive pulmonary disease. METHODS: The study included 37 patients with obstructive ventilatory defect and 20 normal controls. CT and pulmonary function test were performed in all subjects in one week. Correlation between and differences among HRCT visual scoring, parameters of CT pulmonary functional imaging and the result of pulmonary function test were compared. RESULTS: (1) Emphysema was detected by CT in 23 of the 37 patients with obstructive ventilatory defect. (2) HRCT visual scoring was correlated only with D(L)CO% (r = -0.731, P < 0.001) among other pulmonary function parameters. (3) HRCT visual scoring in patients with enrphysema was correlated with pixel indices (PI) at full inspiration and expiration. Visual scoring showed the best correlation with PI(-910in) (r = 0.506, P < 0.001) and PI(-910ex) (r = 0.610, P < 0.001). (4) The grading of pulmonary function based on PI(-910in) and PI(-910ex) showed no difference from the grading by pulmonary function tests (chi(2) = 0.527, P = 0.913; chi(2) = 3.645, P = 0.302). The grading of emphysema based on PI(-910in) accorded with the grading by pulmonary function tests (chi(2) = 2.59, P = 0.459). CONCLUSIONS: HRCT is more sensitive than conventional CT in diagnosing emphysema. However, in terms of slice thickness and radiation dose, it cannot be used in the evaluation of both lungs. CT functional imaging is easily performed, and the results are objective and correlated with the result of HRCT visual scoring and PFTs. It may be, therefore, more useful in diagnosing early emphysema and evaluating lung function.