Shimosegawa E, Hatazawa J, Aizawa Y, Shouji Y, Hachiya T, Murakami M
Department of Radiology and Nuclear Medicine, Research Institute of Brain and Blood Vessels, Akita, Japan.
J Nucl Med. 1997 May;38(5):791-6.
Discordant findings of 99mTc-methyl cysteinate dimer (99mTc-ECD) brain distribution have been reported when brain tissue is supplied by excess blood flow. We evaluated changes in 99mTc-ECD brain activity in the opposing pathological state, in which cerebral blood flow (CBF) is more profoundly impaired than metabolism, and analyzed the relationship of 99mTc-ECD activity with CBF and metabolism to investigate the dominant regulating factor on 99mTc-ECD distribution.
Twelve patients with unilateral intracranial steno-occlusive diseases were evaluated using dynamic and static 99mTc-ECD SPECT. Relative 99mTc-ECD activities and the retention ratio of the affected and unaffected cortices were compared with CBF and oxygen metabolism obtained by PET. Change in the relationships until 1 hr after tracer injection were also analyzed.
Relative 99mTc-ECD activity was significantly correlated with CBF, and the highest correlation was obtained for the first minute of imaging (r = 0.674, p < 0.0010. Fifteen minutes after injection, the correlation coefficient with CBF decreased, whereas higher correlation was observed with the parameter of oxygen metabolism (r = 0.758-0.815, p < 0.001). Changes in the retention ratio were dependent on changes in oxygen metabolism, and the retention ratio for the high oxygen extraction fraction (OEF) area was the same as that for the normal OEF area.
In addition to CBF, brain distribution on 99mTc-ECD SPECT images is affected by brain metabolism, especially on delayed images after injection. The degree of discrepancy between CBF and metabolism should be considered when interpreting images of the misery perfusion state.
当脑组织由过多血流供应时，已报道了99mTc-半胱氨酸二聚体（99mTc-ECD）脑分布的不一致结果。我们评估了在相反病理状态下99mTc-ECD脑活性活性的变化，在该状态下脑血流量（CBF）比代谢更严重受损，并分析了99mTc-ECD活性与CBF和代谢的关系，以研究对99mTc-ECD分布的主要调节因素。
对12例单侧颅内狭窄闭塞性疾病患者进行了动态和静态99mTc-ECD SPECT评估。将患侧和未患侧皮质的相对99mTc-ECD活性和滞留率与PET获得的CBF和氧代谢进行比较。还分析了注射示踪剂后1小时内关系的变化。
相对99mTc-ECD活性与CBF显著相关，在成像的第一分钟相关性最高（r = 0.674，p < 0.001）。注射后15分钟，与CBF的相关系数下降，而与氧代谢参数的相关性更高（r = 0.758 - 0.815，p < 0.001）。滞留率的变化取决于氧代谢变化，高氧摄取分数（OEF）区域的滞留率与正常OEF区域相同。
除了CBF外，99mTc-ECD SPECT图像上的脑分布还受脑代谢影响，尤其是在注射后的延迟图像上。在解释灌注不良状态的图像时，应考虑CBF与代谢之间的差异程度。
