Velazquez M, Haller J, Amundsen T, Schuster D P
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri.
J Nucl Med. 1991 Apr;32(4):719-25.
We evaluated the accuracy, reproducibility, and linearity of lung water concentration (LWC) measurements using positron emission tomography (PET) in anesthetized supine dogs. First, we evaluated whether errors in attenuation correction, which might occur during the development of pulmonary edema, significantly affect LWC and pulmonary blood flow (PBF) measurements obtained with PET. In 10 animals, PET scans of LWC and PBF were obtained before and after oleic acid induced lung injury. Changes in LWC and PBF after injury were underestimated by 12%-25% if the postinjury LWC scan was reconstructed using attenuation data obtained prior to injury, before lung density had changed, instead of attenuation data obtained after lung injury. Next, in four other dogs, we did not administer oleic acid, but instead instilled progressive amounts of autologous plasma into the left caudal lobe and obtained LWC measurements after each. Changes in LWC were linearly related to the amount of plasma instilled (r = 0.99). The average coefficient of variation for LWC in the control right lobe was 4 +/- 2% and the average percent change between measurements was 1.5% +/- 5.8%. The correlation of regional LWC determined gravimetrically after the last scan, when corrected for differences in regional lung density, with LWC determined by PET, was excellent (r = 0.92). We conclude that when the correct attenuation scan is used for emission scan reconstruction. PET measurements of LWC are accurate, linear, and reproducible.
我们在麻醉的仰卧位犬中，使用正电子发射断层扫描（PET）评估了肺水浓度（LWC）测量的准确性、可重复性和线性。首先，我们评估了在肺水肿发展过程中可能出现的衰减校正误差是否会显著影响PET获得的LWC和肺血流量（PBF）测量值。在10只动物中，在油酸诱导肺损伤前后进行了LWC和PBF的PET扫描。如果损伤后LWC扫描使用损伤前、肺密度未改变时获得的衰减数据，而不是损伤后获得的衰减数据进行重建，损伤后LWC和PBF的变化会被低估12%-25%。接下来，在另外4只犬中，我们没有给予油酸，而是向左尾叶逐渐注入自体血浆，并在每次注入后测量LWC。LWC的变化与注入的血浆量呈线性相关（r = 0.99）。对照右叶LWC的平均变异系数为4±2%，测量值之间的平均百分比变化为1.5%±5.8%。在最后一次扫描后通过重量法测定的区域LWC，在校正区域肺密度差异后，与PET测定的LWC的相关性极佳（r = 0.92）。我们得出结论，当使用正确的衰减扫描进行发射扫描重建时，PET对LWC的测量是准确、线性且可重复的。
