Schuster D P, Marklin G F, Mintun M A, Ter-Pogossian M M
J Comput Assist Tomogr. 1986 Sep-Oct;10(5):723-9. doi: 10.1097/00004728-198609000-00002.
Regional lung density (LD) and lung water (LW) measurements were made with positron transmission and emission tomography (PET) in normal and edematous lung in supine dogs in vivo. A comparison was also made of LD measurements by PET and X-ray CT (used by others to noninvasively assess pulmonary edema). Mean LW was 0.25 +/- 0.06 ml water/ml lung and the mean LD (PET) was 0.32 +/- 0.06 g/ml lung (average ratio of LW to LD was 0.795 +/- 0.041). The LD measurements ranged from 0.25 +/- 0.06 in anterior portions of lung to 0.43 +/- 0.11 g/ml in posterior areas, but the ratio of LW to LD was similar throughout the lung. The LW and LD measurements obtained in both normal and edematous portions of lung were strongly correlated (r = 0.886). Values for LD by PET were consistently higher than values obtained for LD by X-ray CT. These differences are probably due to beam-hardening effects with CT and partial-volume averaging and scattered radiation effects with PET. Nevertheless, PET-LD measurements may be a satisfactory method for following acute changes in LW or for normalizing other PET-derived data.
在仰卧位的正常和水肿犬体内，采用正电子发射断层扫描（PET）测量局部肺密度（LD）和肺水（LW）。还比较了PET和X射线CT（其他人用于无创评估肺水肿）测量LD的结果。平均LW为0.25±0.06毫升水/毫升肺，平均LD（PET）为0.32±0.06克/毫升肺（LW与LD的平均比值为0.795±0.041）。LD测量值在肺前部为0.25±0.06，在后部为0.43±0.11克/毫升，但LW与LD的比值在整个肺中相似。在肺的正常和水肿部分获得的LW和LD测量值高度相关（r = 0.886）。PET测量的LD值始终高于X射线CT测量的LD值。这些差异可能是由于CT的束硬化效应以及PET的部分容积平均和散射辐射效应。尽管如此，PET-LD测量可能是跟踪LW急性变化或使其他PET衍生数据标准化的一种令人满意的方法。
