[CT measurement of the thoracic density].

The purpose of this introducing study was to establish the normal lung density using computed tomography of the chest. If it is possible to analyze the density of normal lung parenchyma, it could be possible to estimate the quantity of effective ventilation capacity based on account of the CT number of given range. A cross section of the lung, however, is not homogeneous because it contents of vascular tissue, interstitial tissue, air and others which have widely variety densities. To estimate pulmonary function, it is necessary to know the exact CT number of only normal lung tissue. Mean values for varies tissues and areas in the thorax were assessed in 34 patients (21 males, 13 females, average age: 58 years, from August 1987 to June 1993), 18 case of lung cancer (10 preoperative, 8 postoperative), 5 metastatic lung cancer, 1 giant bulla, 1 aspergilloma, 1 pulmonary AV fistula, 8 case had no lung disease. The measured normal peripheral lung by radiographic appearance on CT images, vascular in the lung, bronchus, rib, muscle and fat structured chest wall, heart, liver, aorta, esophagus, and thymus. Density of normal peripheral lung tissue was measured in 6 points on each slices. These scores were compared left vs. right, slice number, and anterior vs. posterior. The CT numbers in this study following the no enhanced computed tomography scanner: GE9800 CT by using the regions of interest which limited in 0.01 cm 2 area. There was no significant difference between left and right lung, among different slices, although between anterior and posterior in the normal lung.(ABSTRACT TRUNCATED AT 250 WORDS)