6Stern EJ, Webb WR. Dynamic imaging of lung morphology with ultrafast high resolution computed tomography[J]. Thorac Imaging, 1993, 8(2): 273 - 282.
7Lamers R J, Thelissen GR, Kessels AG, et al. Chronic obstructive pulmonary disease: evaluation with spirometricaily controlled CT lung densitometry[J]. Radiology, 1994, 193 (1): 109 - 113.
8Kalender WA,Rienmuller R,Siessler W,et al.Measurement of pulmonary parenchaymal attenuation:Use of spirometric gating with quantitative CT[J].Radiology,1990,175(1):265-268.
10Kinsella M,Muller NL,Abbound TR,et al.Quantitation of emphysema by computed tomography using a "density mask" program and correlation with pulmonary function tests[J].Chest,1990,97(2):315-321.
