Kato S, Nakamoto T, Iizuka M
First Department of Internal Medicine, Dokkyo University School of Medicine, Tochigi Prefecture, Japan.
Chest. 1996 Jun;109(6):1439-45. doi: 10.1378/chest.109.6.1439.
To establish an early diagnosis and have a quantitative estimation of congestion or edema, pulmonary CT scans were performed to detect the increase of regional lung water volume of patients with congestive heart failure. CT scanning of the upper, middle, and lower lung fields at maximum inspiration and hemodynamic analysis to ensure a hemodynamically chronic stable condition after the heart failure therapy for 5 weeks by cardiac catheterization within 2 weeks before CT scanning were performed in 10 normal subjects and 25 patients with left-sided heart failure. Patients were divided into two groups according to the presence or absence of pulmonary congestion or edema on chest radiographs, and the mean pulmonary wedge pressure (mPWP). The pulmonary congestion group (14 patients) had pulmonary congestion or edema, and mPWP was greater than 13 mm Hg despite the heart failure therapy. The nonpulmonary congestion group (11 patients) had no pulmonary congestion or edema, and mPWP was lower than 10 mm Hg. Histograms of pulmonary CT numbers were graphed to a set region of interest (ROI) on transverse CT images in all subjects; then changes of pulmonary CT numbers when pulmonary congestion or edema occurred were estimated from those histograms. We found that when severe pulmonary congestion or edema occurred in 6 patients with severe left heart failure, the pulmonary CT numbers within the ROI rapidly increased from -650 to -750 Hounsfield units (HU). We defined the amount ratio between the pixels (pixel counts between -650 and -750 HU within these R0Is) and the pixels (pixel counts between -300 and -950 HU) of the CT number (which were all pixels composing these R0Is) x100(%) as "%PXL." %PXL showed a linear correlation with mPWP. Compared with the %PXL in the normal group, the %PXL in the pulmonary congestion group was significantly higher than that in the normal group (p<0.05, p<0.01, p<0.001) in all lung fields. Similarly, compared with the %PXL in the normal group, %PXL in the nonpulmonary congestion group was significantly higher than that in the normal group in the middle and lower lung fields (p<0.05, p<0.01) in the posterior field. From these results, we concluded that %PXL was a good index to identify abnormal water content usually not recognizable by routine chest radiograph in the lungs.
为了建立早期诊断并对充血或水肿进行定量评估，对充血性心力衰竭患者进行肺部CT扫描，以检测局部肺水含量的增加。对10名正常受试者和25名左侧心力衰竭患者在最大吸气时进行上、中、下肺野的CT扫描，并在CT扫描前2周内通过心导管检查进行血流动力学分析，以确保心力衰竭治疗5周后血流动力学处于慢性稳定状态。根据胸部X线片上是否存在肺充血或水肿以及平均肺楔压（mPWP）将患者分为两组。肺充血组（14例患者）存在肺充血或水肿，尽管进行了心力衰竭治疗，mPWP仍大于13 mmHg。非肺充血组（11例患者）无肺充血或水肿，mPWP低于10 mmHg。在所有受试者的横断CT图像上，将肺部CT值的直方图绘制到设定的感兴趣区域（ROI）；然后根据这些直方图估计肺充血或水肿发生时肺部CT值的变化。我们发现，6例严重左心衰竭患者发生严重肺充血或水肿时，ROI内的肺部CT值从-650亨氏单位（HU）迅速增加到-750 HU。我们将CT值（构成这些ROI的所有像素）中-650至-750 HU之间的像素数与-300至-950 HU之间的像素数之比×100（%）定义为“%PXL”。%PXL与mPWP呈线性相关。与正常组的%PXL相比，肺充血组在所有肺野中的%PXL均显著高于正常组（p<0.05、p<0.01、p<0.001）。同样，与正常组的%PXL相比，非肺充血组在中、下肺野的后野中的%PXL显著高于正常组（p<0.05、p<0.01）。根据这些结果，我们得出结论，%PXL是识别肺部常规胸部X线片通常无法识别的异常含水量的良好指标。
