SPECT肺灌注显像与CT扫描诊断放射性肺损伤的对比研究

目的 通过动物实验比较单光子发射计算机断层成像术（SPECT）肺灌注显像与CT扫描在诊断放射性肺损伤方面的应用价值.方法 16只新西兰白兔右肺单次照射40 Gy制作放射性肺损伤模型,照射前随机选取2只实验兔肺CT扫描和SPECT肺灌注显像,照射后6周和12周分别行肺CT扫描和SPECT肺灌注显像,12周后观察肺病理变化.结果 照射前实验兔肺CT和SPECT肺灌注显像无异常.6周时1只实验兔右肺CT出现毛玻璃样影像,左肺无明显异常,其余实验兔CT无异常;SPECT肺灌注显像未见放射性稀疏缺损区.12周时2只实验兔肺CT中右肺出现局部斑片样改变,左肺纹理增多,其余14只兔两肺纹理增多;SPECT肺灌注显像右肺均呈现放射性稀疏缺损,SPECT肺灌注显像和肺CT阳性检出率分别为100%（16/16）、12.5%（2/16）,两组比较差异有统计学意义（P=0.0000）.12周时病理学显示,两组实验兔右肺大量炎症细胞浸润和成纤维细胞增生,左肺少量炎症细胞浸润和轻度肺泡充血.结论 SPECT肺灌注显像诊断放射性肺损伤较CT敏感度高.

Comparative study of CT and SPECT lung perfusion imaging in the diagnosis of radiation-induced pulmonaryinjury

Objective To compare the application value of Single Photon Emission Computed Tomography （SPECT） lung perfusion imaging and CT in the diagnosis of radiation-induced pulmonary injury by animal experiment. Methods The right lungs of 16 New Zealand white rabbits were exposed to 40Gy light for a single time to establish the radiation-induced lung injured rabbit models.2 experimental rabbits were randomly chosen to undergo CT scanning and SPECT lung perfusion imaging before being radiated. In week 6 and week 6 after radiation, the lung CT and SPECT lung perfusion imaging were performed on them respectively.12 weeks after radiation, pathological pulmonary characteristics of rabbits were observed. Results Before rabbits were radiated, the image effect of lung CT and SPECT lung perfusion imaging showed no significant difference. However, in week 6, CT showed that there was ground-glass-like image in the right lung of one experimental rabbit but no abnormality in its left lung and both lungs of other rabbits. SPECT lung perfusion imaging showed no radioactive sparse defects area in lungs of all the rabbits. In week 12,CT showed that the right lungs of 2 rabbits had local patchy change and the texture of their left lungs in- creased. Other 14 rabbits had also increased texture on both lungs.SPECT lung perfusion imaging showed that all of the rabbits＇ right lungs had radioactive sparse defects. The positive rate of SPEC were 100%（16/16）and 12.5% （2/16） respectively, so the difference between the T lung perfusion imaging and CT two groups had statistical significance（ P =0.0000）. In week 12, pathology showed that there were large amount of inflammatory cell infiltration and fibroblast proliferation in the right lungs of all the experimental rabbits and a small amount of inflammatory cell infiltration and mild alveolar congestion in their left lungs.Conclusion SPECT lung perfusion imaging has a higher sensitivity than CT in diagnosing radiation-induced pulmonary injury.