Cerebrovascular reserve capacity (CVRC) is an important parameter for treatment decisions in chronic cerebrovascular diseases. It can be assessed by measuring the acetazolamide-induced change in regional cerebral blood flow using SPECT with ^99mTc-labeled hexamethylpropyleneamine oxime (^99mTc-HMPAO) or PET with ¹⁵O-water. Methods: Our database was searched for patients with moyamoya vasculopathy or atherosclerotic cerebrovascular disease who had undergone ¹⁵O-water PET after normal ^99mTc-HMPAO SPECT results with respect to CVRC. ¹⁵O-water PET was analyzed visually and quantitatively. Quantitative analysis was based on parametric CVRC maps generated by voxelwise image subtraction. Results: The search identified 18 patients (43 ± 15 y, 12 moyamoya vasculopathy). PET revealed impaired CVRC in 8 patients (44%). Quantitative analysis confirmed the positive visual findings in ¹⁵O-water PET and the negative findings in ^99mTc-HMPAO SPECT. Conclusion: ¹⁵O-water PET enables detection of impaired CVRC in a considerable fraction of symptomatic patients with stenoocclusion and negative ^99mTc-HMPAO SPECT.

脑血管储备能力（CVRC）是慢性脑血管疾病治疗决策的重要参数。可以通过使用^99m Tc标记的六甲基丙烯胺肟（^99m Tc-HMPAO）的SPECT或¹⁵ O-水的PET来测量乙酰唑胺诱导的局部脑血流变化来进行评估。方法：在我们的数据库中搜索关于CVRC的^99m Tc-HMPAO SPECT结果正常后经历¹⁵ O-water PET的烟雾病血管病或动脉粥样硬化性脑血管疾病的患者。¹⁵目视和定量分析O-水PET。定量分析基于通过体素图像减法生成的参数CVRC图。结果：该搜索确定了18例患者（43±15岁，烟雾病12例）。PET显示8例患者（44％）的CVRC受损。定量分析证实了¹⁵ O-水PET的阳性视觉结果和^99m Tc-HMPAO SPECT的阴性结果。结论： ¹⁵ O-水PET能够在相当一部分有狭窄闭塞和^99m Tc-HMPAO SPECT阴性的症状患者中检测CVRC受损。