Matsuda H, Kinuya K, Higashi S, Kawasaki Y, Sumiya H, Shuke N, Hisada K, Yamashita J, Yamaguchi N
Department of Nuclear Medicine, Kanazawa University School of Medicine.
Kaku Igaku. 1991 Jul;28(7):701-9.
Fundamental and clinical evaluation was performed on 99mTc-ECD, a new agent for brain perfusion SPECT. Radiochemical purity reaches a plateau of approximately 98% at 30 min after reconstitution and remains stable up to 24 hours later. A biodistribution study showed approximately 5% injected dose in the brain, very slow brain washout of 5.6% per hour on the average, and rapid washout from the other organ mainly through the urinary system. Brain ECD distribution was determined within 2 min postinjection and remained stable for up to 1 hour. Three hours later, slight but significant changes in brain distribution were observed, that were relative reduction of cerebral cortical activity and gray to white matter activity ratio, and relative elevation of white matter and thalamic activities. Comparative studies of ECD images with IMP and HMPAO images revealed that radioactivity contrast between affected and unaffected areas was less prominent in ECD than in IMP in cerebral and cerebellar cortical lesions, more prominent in ECD than in IMP in striatal and thalamic lesions, and somewhat more prominent in ECD than in HMPAO in both lesions. Imaging around 1 hour postinjection seems to be more appropriate than immediate postinjection imaging because of the clearance of the extracranial radioactivity and somewhat better radioactivity contrast between affected and unaffected areas.
对脑灌注单光子发射计算机断层扫描（SPECT）的新型显像剂99mTc-ECD进行了基础和临床评估。重新配制后30分钟，放射化学纯度达到约98%的平稳状态，并在24小时后保持稳定。生物分布研究显示，脑内放射性约为注射剂量的5%，平均每小时脑内放射性清除率为5.6%，且主要通过泌尿系统从其他器官快速清除。脑内ECD分布在注射后2分钟内即可确定，并在长达1小时内保持稳定。3小时后，观察到脑内分布有轻微但显著的变化，即大脑皮质活性及灰质与白质活性比相对降低，白质和丘脑活性相对升高。ECD图像与IMP和HMPAO图像的对比研究显示，在大脑和小脑皮质病变中，ECD图像上患侧与健侧之间的放射性对比不如IMP图像明显；在纹状体和丘脑病变中，ECD图像上的放射性对比比IMP图像更明显；在这两种病变中，ECD图像上的放射性对比比HMPAO图像略更明显。由于颅外放射性的清除以及患侧与健侧之间放射性对比略好，注射后约1小时成像似乎比注射后立即成像更合适。
