Abstract
Local cerebral perfusion pressure (CPP) is a primary factor controlling cerebral circulation and previous studies have indicated that the ratio of cerebral blood flow (CBF) to cerebral blood volume (CBV) can be used as an index of the local CPP. In this study, we investigated whether the CBF/CBV ratio differs among different brain structures under physiological conditions, by means of 15O positron emission tomography. Nine healthy volunteers (5 men and 4 women; mean age, 47.0 ± 1.2 years) were studied by H2 15O bolus injection for CBF measurement and by C15O inhalation for CBV measurement. The CBF/CBV ratio maps were created by dividing the CBF images by the CBV images after anatomical normalization. Regions of interest were placed on the CBF/CBV maps and comparing the regions. The mean CBF/CBV ratio was highest in the cerebellum (19.3 ± 5.2/min), followed by the putamen (18.2 ± 3.9), pons (16.4 ± 4.6), thalamus (14.5 ± 3.3), cerebral cortices (13.2 ± 2.4), and centrum semiovale (11.5 ± 2.1). The cerebellum and putamen showed significantly higher CBF/CBV ratios than the cerebral cortices and centrum semiovale. We created maps of the CBF/CBV ratio in normal volunteers and demonstrated higher CBF/CBV ratios in the cerebellum and putamen than in the cerebral cortices and deep cerebral white matter. The CBF/CBV may reflect the local CPP and should be studied in hemodynamically compromised patients and in patients with risk factors for small-artery diseases of the brain.
Keywords: cerebral perfusion pressure, cerebral blood flow, cerebral blood volume, H215O, C15O
References
- [1].Powers WJ. Cerebral hemodynamics in ischemic cerebrovascular disease. Ann Neurol. 1991;29:231–240. doi: 10.1002/ana.410290302. [DOI] [PubMed] [Google Scholar]
- [2].Derdeyn CP, Videen TO, Yundt KD, Fritsch SM, Carpenter DA, Grubb RL, et al. Variability of cerebral blood volume and oxygen extraction: stages of cerebral haemodynamic impairment revisited. Brain. 2002;125:595–607. doi: 10.1093/brain/awf047. [DOI] [PubMed] [Google Scholar]
- [3].Gibbs JM, Wise RJ, Leenders KL, Jones T. Evaluation of cerebral perfusion reserve in patients with carotid-artery occlusion. Lancet. 1984;1:310–314. doi: 10.1016/S0140-6736(84)90361-1. [DOI] [PubMed] [Google Scholar]
- [4].Sette G, Baron JC, Mazoyer B, Levasseur M, Pappata S, Crouzel C. Local brain haemodynamics and oxygen metabolism in cerebrovascular disease. Positron emission tomography. Brain. 1989;112(Pt4):931–951. doi: 10.1093/brain/112.4.931. [DOI] [PubMed] [Google Scholar]
- [5].Schumann P, Touzani O, Young AR, Morello R, Baron JC, MacKenzie ET. Evaluation of the ratio of cerebral blood flow to cerebral blood volume as an index of local cerebral perfusion pressure. Brain. 1998;121(Pt7):1369–1379. doi: 10.1093/brain/121.7.1369. [DOI] [PubMed] [Google Scholar]
- [6].Ibaraki M, Miura S, Shimosegawa E, Sugawara S, Mizuta T, Ishikawa A, et al. Quantification of cerebral blood flow and oxygen metabolism with 3-dimensional PET and 15O: validation by comparison with 2-dimensional PET. J Nucl Med. 2008;49:50–59. doi: 10.2967/jnumed.107.044008. [DOI] [PubMed] [Google Scholar]
- [7].Mintun MA, Raichle ME, Martin WR, Herscovitch P. Brain oxygen utilization measured with O-15 radiotracers and positron emission tomography. J Nucl Med. 1984;25:177–187. [PubMed] [Google Scholar]
- [8].Phelps ME, Huang SC, Hoffman EJ, Kuhl DE. Validation of tomographic measurement of cerebral blood volume with C-11-labeled carboxyhemoglobin. J Nucl Med. 1979;20:328–334. [PubMed] [Google Scholar]
- [9].Herscovitch P, Markham J, Raichle ME. Brain blood flow measured with intravenous H2(15)O. I. Theory and error analysis. J Nucl Med. 1983;24:782–789. [PubMed] [Google Scholar]
- [10].Kanno I, Iida H, Miura S, Murakami M, Takahashi K, Sasaki H, et al. A system for cerebral blood flow measurement using an H215O autoradiographic method and positron emission tomography. J Cereb Blood Flow Metab. 1987;7:143–153. doi: 10.1038/jcbfm.1987.37. [DOI] [PubMed] [Google Scholar]
- [11].Iida H, Kanno I, Miura S, Murakami M, Takahashi K, Uemura K. Error analysis of a quantitative cerebral blood flow measurement using H2(15)O autoradiography and positron emission tomography, with respect to the dispersion of the input function. J Cereb Blood Flow Metab. 1986;6:536–545. doi: 10.1038/jcbfm.1986.99. [DOI] [PubMed] [Google Scholar]
- [12].Ibaraki M, Ito H, Shimosegawa E, Toyoshima H, Ishigame K, Takahashi K, et al. Cerebral vascular mean transit time in healthy humans: a comparative study with PET and dynamic susceptibility contrast-enhanced MRI. J Cereb Blood Flow Metab. 2007;27:404–413. doi: 10.1038/sj.jcbfm.9600337. [DOI] [PubMed] [Google Scholar]
- [13].Ito H, Kanno I, Takahashi K, Ibaraki M, Miura S. Regional distribution of human cerebral vascular mean transit time measured by positron emission tomography. Neuroimage. 2003;19:1163–1169. doi: 10.1016/S1053-8119(03)00156-3. [DOI] [PubMed] [Google Scholar]
- [14].Ibaraki M, Shinohara Y, Nakamura K, Miura S, Kinoshita F, Kinoshita T. Interindividual variations of cerebral blood flow, oxygen delivery, and metabolism in relation to hemoglobin concentration measured by positron emission tomography in humans. J Cereb Blood Flow Metab. 2010;30:1296–1305. doi: 10.1038/jcbfm.2010.13. [DOI] [PMC free article] [PubMed] [Google Scholar]
- [15].Okazawa H, Yonekura Y, Fujibayashi Y, Yamauchi H, Ishizu K, Nishizawa S, et al. Measurement of regional cerebral plasma pool and hematocrit with copper-62-labeled HSA-DTS. J Nucl Med. 1996;37:1080–1085. [PubMed] [Google Scholar]
- [16].Yamauchi H, Fukuyama H, Nagahama Y, Okazawa H, Konishi J. A decrease in regional cerebral blood volume and hematocrit in crossed cerebellar diaschisis. Stroke. 1999;30:1429–1431. doi: 10.1161/01.STR.30.7.1429. [DOI] [PubMed] [Google Scholar]
- [17].Cremer JE, Seville MP. Regional brain blood flow, blood volume, and haematocrit values in the adult rat. J Cereb Blood Flow Metab. 1983;3:254–256. doi: 10.1038/jcbfm.1983.35. [DOI] [PubMed] [Google Scholar]
- [18].Kinoshita T, Okudera T, Tamura H, Ogawa T, Hatazawa J. Assessment of lacunar hemorrhage associated with hypertensive stroke by echo-planar gradient-echo T2*-weighted MRI. Stroke. 2000;31:1646–1650. doi: 10.1161/01.STR.31.7.1646. [DOI] [PubMed] [Google Scholar]
- [19].Kato H, Izumiyama M, Izumiyama K, Takahashi A, Itoyama Y. Silent cerebral microbleeds on T2*-weighted MRI: correlation with stroke subtype, stroke recurrence, and leukoaraiosis. Stroke. 2002;33:1536–1540. doi: 10.1161/01.STR.0000018012.65108.86. [DOI] [PubMed] [Google Scholar]
