Kume N, Hayashida K, Iwama T, Cho I, Matsunaga N
Department of Radiology, National Cardiovascular Center, Osaka, Japan.
Eur J Nucl Med. 1998 Dec;25(12):1637-42. doi: 10.1007/s002590050342.
Superficial temporal artery - middle cerebral artery (STA-MCA) bypass surgery might improve the cerebral blood flow (CBF) but fail to reduce the risk of post-surgical events such as ischaemic stroke. In this study, we studied retrospectively whether the risk of post-surgical events corresponded to the change in resting CBF and/or the change in vasoreactivity observed before and after STA-MCA surgery using N-isopropyl-I-123-p-iodoamphetamine (123I-IMP) brain single-photon emission tomography (SPET). 123I-IMP brain SPET images obtained at rest and following acetazolamide challenge both before and after STA-MCA surgery were studied in 30 patients. Resting CBF was estimated semiquantitatively using the resting count ratios of the middle cerebral artery (MCA) area to the cerebellum. Acetazolamide c hallenge was assumed to result in an average increase in flow of 40% in the cerebellum. The vasoreactive response was then estimated as the ratio of the change in counts (acetazolamide - rest) to the resting cerebellar counts multiplied by 1.4. We classified 14 patients (50.5 +/- 19.3 years) into group I, who h a change in their resting CBF from before to after surgery of >10%, and 16 patients (54.0 +/- 18.8 years) into group II, who had a change in their resting CBF from before to after surgery of ¿leq10%. Oxygen-15 positron emission tomography (PET) studies were performed in five patients from group I and five patients from group II. One post-surgical event occurred in group I while there were eight post-surgical events in group II (P<0.05). Resting CBF improved by 20.4% +/- 7.5% in group I and by 0.9% +/- 6.9% in group II patients after surgery (P<0.001). No significant difference in the improvement in vasoreactivity was observed between group I patients (32.6% +/- 17.7%) and group II patients (24.6% +/- 15.6%) following surgery. Patients in the group I PET subset showed normalization of oxygen extraction fraction (OEF) from 0.59 +/- 0.09 before surgery to 0.46 +/- 0.06 after surgery (P<0.05), while patients in the group II PET subset showed no statistical difference in OEF before surgery (0.58 +/- 0.14) and after surgery (0.54 +/- 0.05). We conclude that the outcome of STA-MCA bypass surgery can be predicted by the improvement in resting CBF but not by the improvement in vasoreactivity.
颞浅动脉-大脑中动脉（STA-MCA）搭桥手术可能会改善脑血流量（CBF），但未能降低术后诸如缺血性中风等事件的风险。在本研究中，我们回顾性研究了使用N-异丙基-I-123-对碘安非他明（123I-IMP）脑单光子发射断层扫描（SPET），术后事件的风险是否与STA-MCA手术前后静息CBF的变化和/或血管反应性的变化相对应。对30例患者术前和术后静息及乙酰唑胺激发后获得的123I-IMP脑SPET图像进行了研究。使用大脑中动脉（MCA）区域与小脑的静息计数比半定量估计静息CBF。假定乙酰唑胺激发可使小脑血流量平均增加40%。然后将计数变化（乙酰唑胺-静息）与静息小脑计数乘以1.4的比值作为血管反应性反应进行估计。我们将14例患者（50.5±19.3岁）分为I组，其术后静息CBF较术前变化>10%，16例患者（54.0±18.8岁）分为II组，其术后静息CBF较术前变化≤10%。对I组的5例患者和II组的5例患者进行了氧-15正电子发射断层扫描（PET）研究。I组发生1例术后事件，而II组发生8例术后事件（P<0.05）。术后I组患者静息CBF改善20.4%±7.5%，II组患者改善0.9%±6.9%（P<0.001）。术后I组患者（32.6%±17.7%）和II组患者（24.6%±15.6%）的血管反应性改善无显著差异。I组PET亚组患者的氧摄取分数（OEF）从术前的0.59±0.09恢复正常至术后的0.46±0.06（P<0.05），而II组PET亚组患者术前（0.58±0.14）和术后（0.54±0.05）的OEF无统计学差异。我们得出结论，STA-MCA搭桥手术的结果可通过静息CBF的改善来预测，而不能通过血管反应性的改善来预测。
