应用单光子发射计算机断层扫描脑血流灌注显像评价颈内动脉球囊闭塞试验后大脑耐受性

Evaluation of brain tolerability with SPECT perfusion imaging during temporary internal carotid artery occlusion

目的评估单光子发射计算机断层扫描（SPECT）脑血流灌注显像在球囊闭塞试验（BOT）中的评价效用。方法31例颈内动脉瘤患者接受了暂时性BOT。在闭塞球囊排空前5min．大约740MBq锝标双半胱乙脂（99mTc-ECD）静脉注入，随后进行单光子发射计算机断层扫描。所得图像进行视觉分析、分级f正常、轻度、中度和重度灌注减低）并计算患侧／健侧（L／N）感兴趣区内放射性计数比值。结果SPECT提示了24例受试者在暂时性球囊闭塞后出现了异常灌注，而只有4例出现了神经症状。正常血流灌注组L／N比值范围为0．98＋0．03（7例），轻度血流灌注减低组L／N比值范围为0．89±0．03（11例），中度血流灌注减低组L／N比值范围为0．81±0．03（7例），重度血流灌注减低组L／N比值范围为0．66±0．04（6例），各组间的差异有统计学意义（P=0．000）。结论BOT联合负荷SPECT评价颈内动脉闭塞后的大脑耐受性是一种易行、客观、敏感的方法，所得初步结果需更多病人数量来证实。

Objective To evaluate the usefulness of brain single photon emission computed tomography （SPECT） during temporary carotid balloon occlusion testing. Methods Temporary balloon occlusion testing was performed on 31 patients with internal carotid artery aneurysms. During the balloon occlusion, 99mTc- ethylcysteinate dimer （ECD） was injected intravenously about 5 min before balloon deflation, followed by SPECT data acquisition. SPECT images were visually evaluated, and the severity ofhypoperfusion on the occluded side was classified using 4 grades （normal, mild, moderate, and severe）. The count ratio of the occluded side to the contra-lateral side （L/N ratio） was also analyzed. Results SPECT after temporary occlusion showed mild, moderate or severe hypoperfusion in 24 patients, whereas neurologic deterioration was observed in only 4 patients. The L/N ratios were 0.98±0.03 in normal perfusion（7 patients）, 0.89±0.03 in mild hypoperfusion（l 1 patients）, 0.81±0.03 in moderate hypoperfusion（7 patients）, and 0.66±0.04 in severe hypoperfusion（6 patients）（P=-0.000）. Conclusion SPECT is a useful, convenient, sensitive way to detect cerebral hypoperfusion during carotid occlusion.