Neuroimaging in cerebrovascular disorders: Measurement of cerebral physiology after stroke and assessment of stroke recovery*
Article Outline
Nuclear medicine imaging can play an important role in the diagnosis of stroke risk, the differential diagnosis of vascular and parenchymal cerebral abnormalities, and the understanding and management of poststroke recovery. Radionuclide brain-imaging methods can assess hemodynamic, vascular, and metabolic status before and after stroke. Several techniques, including vasodilatory stress imaging with regional cerebral blood flow (rCBF) single-photon emission computed tomography (SPECT), oxygen extraction methods with positron emission tomography (PET), and spectroscopic imaging with magnetic resonance spectroscopic imaging, offer ways to distinguish vascular from parenchymal dysfunction and to determine whether any observed abnormalities in cerebral blood flow are primary for secondary disease manifestations. The value of radionuclide imaging in assessing the efficacy of several interventional surgical procedures is presented. Data from several imaging modalities bearing on the controversial issue of luxury perfusion and reperfusion injury are analyzed, including some of the discrepancies between animal and human clinical data. Imaging evidence for white matter disease and microangiopathy is analyzed, including a quantitative rCBF pattern analysis that distinguishes between typical Alzheimer's disease and microangiopathy by using multivariate analysis of variance curve profile analysis, which shows results of significant differences in the circumferential cortical blood flow profiles at P=.01. Microangiopathy showed rCBF reduction in the frontal and frontotemporal regions as compared with the more typical reduction in posterior temporal-parietal rCBF diminution characteristic of Alzheimer's disease. Several functional neuroimaging approaches to the study of cerebral poststroke reorganization are analyzed in the context of 2 major models of recovery: the resolution of diaschisis and reorganization in spared brain. Research on these issues is presented with SPECT, PET, magnetic resonance imaging, and magnetic resonance spectroscopy. Data show how standard structural magnetic resonance imaging. 99mTc hexamethylpropylene amine oxime SPECT, PET imaging, and magnetic resonance spectroscopy can be used to identify the extent of permanent damage versus penumbral and remote effects of a stroke. The results of the analysis of the pure-diaschisis model show a high correlation between the rCBF brain SPECT defect volume in the cortex and the magnetic resonance spectroscopic imaging (MRSI) change in the white matter. There is a statistically significant positive correlation between the 2 (P<.01; r2=0.94). The increased creatine/N-acetyl aspartate and reduced rCBF are proposed to be due to an increase in the white matter creatine component due to diaschisis and the repair mechanisms associated with increased astrocytosis, in addition to a reduction of N-acetyl aspartate in diaschitic white matter. Xenon-133 dynamic SPECT is shown to be a quantitative and sensitive measure of cerebrovascular status and hemodynamic constraints in both spared and affected brain, providing evidence for reorganization and cerebral plasticity. Fluorine-18 PET and 31P spectroscopic imaging data show reorganizational changes in the contralesional hemisphere after stroke. The phosphocreatine-adenosine triphosphate ratio in the contralesional hemisphere was 38%±17% higher than in the ipsilateral hemisphere. The phosphocreatine-adenosine triphosphate ratio was highly correlated (r=0.88, P<.05) with increasing 18F-fluorodeoxyglucose uptake. These results showed that there is a parallel change in glucose metabolism and high-energy phosphate metabolism associated with poststroke recovery that is proposed to be due to cerebral reorganization in the contralateral premotor cortex. The value of these results on rehabilitation strategy, including possible criteria for the use of facilitatory versus compensatory approaches, is analyzed.
No full text is available. To read the body of this article, please view the PDF online.
References
- . Comparable studies of the incidence of stroke and its pathological types: Results from an international collaboration. International Stroke Incidence Collaboration. Stroke. 1997;28:491–499
- . tPA-associated reperfusion after acute stroke demonstrated by SPECT. Stroke. 1998;29:429–432
- Cerebral vasocapacitance and TIAs. Neurology. 1989;39:25–29
- Assessment of cerebral haemodynamic reserve. Correlation between PET parameters and CO2 reactivity measured by the intravenous xenon-133 injection technique. J Neurol Neurosurg Psychiatry. 1988;51:1045–1050
- Oxygen extraction fraction at maximally vasodilated tissue in the ischemic brain estimated from the regional CO2 responsiveness measured by positron emission tomography. J Cereb Blood Flow Metab. 1988;8:227–235
- The effect of acetazolamide on regional cerebral blood flow in patients with Alzheimer's disease or stroke as measured by single-photon emission computed tomography. Invest Radiol. 1989;24:99–103
- SPECT evaluation of brain perfusion reserve by the acetazolamide test using Tc-99m HMPAO. Clin Nucl Med. 1991;16:572–579
- . Brain single photon emission computed tomography: Newer activation and intervention studies. In: Semin Nucl Med. 21:1991;p. 40–57
- A simple test to assess cerebrovascular reserve capacity using transcranial Doppler sonography and acetazolamide. Stroke. 1990;21:1306–1311
- . Interventions and functional brain imaging. In: Semin Nucl Med. 21:1991;p. 153–158
- . Evaluation of the cerebral vasodilatory capacity by the acetazolamide test before EC-IC bypass surgery in patients with occlusion of the internal carotid artery. Stroke. 1986;17:1291–1298
- Cerebral perfusion reserve determined by Tc-99m HMPAO Diamox brain SPECT in unilateral carotid artery stenosis: Comparison of regional cerebral blood flow pre-and post-angioplasty. J Cereb Blood Flow Metab. 1997;17:S196
- Comparison of technetium-99m-ECD to xenon-133 SPECT in normal controls and in patients with mild to moderate regional cerebral blood flow abnormalities. J Nucl Med. 1993;34:754–761
- Xenon SPECT sensitivity to cerebrovascular status in baseline and Diamox stress studies. J Cereb Blood Flow Metab. 1997;17:S199
- Mental rotation and phonological tasks investigated with a new xenon rCBF SPECT method. Neuroimage. 1997;5:S128
- Preoperative risk stratification with Tc-99m HMPAO SPECT test balloon occlusion of patients requiring carotid occlusion. J Nucl Med. 2002;43:248P
- Dementia rating scale performance: A comparison of vascular and Alzheimer's dementia. J Clin Exp Neuropsychol. 2000;22:445–454
- . Anterior choroidal artery infarction presenting as a progressive cognitive deficit. Clin Nucl Med. 2000;25:187–190
- Decreased capacity for mental effort after single supratentorial lacunar infarct may affect performance in everyday life. J Neurol Neurosurg Psychiatry. 1998;65:697–702
- Cerebral white matter lesions, retinopathy, and incident clinical stroke. JAMA. 2002;288:67–74
- Tc-99m HMPAO SPECT distinguishes microangiopathic diaschisis from cortical dementia. J Cereb Blood Flow Metab. 1995;15:S810
- . Early postischemic hyperperfusion: Pathophysiologic insights from positron emission tomography. J Cereb Blood Flow Metab. 1999;19:467–482
- . 99mTc-bicisate reliably images CBF in chronic brain diseases but fails to show reflow hyperemia in subacute stroke: Report of a multicenter trial of 105 cases comparing Xe-133 and Tc-99m-bicisate (ECD, neurolite) measured by SPECT on same day. J Cereb Blood Flow Metab. 1994;14:S44–S48
- . Interventions and functional brain imaging. In: Semin Nucl Med. 21:1991;p. 153–158
- . Diaschisis. In: Pribram KH editors. Brain and Behaviour I: Mood States and Mind. Baltimore, MD: Penguin; 1969;p. 27–36
- . Diaschisis. Stroke. 1986;17:817–830
- Tc-99m hexamethylpropylene amine oxime SPECT and X-ray CT in acute cerebral ischaemia. J Neurol. 1990;237:475–497
- Assessment of cerebral haemodynamic reserve: Correlation between PET parameters and CO2 reactivity measured by the intravenous xenon-133 injection technique. J Neurol Neurosurg Psychiatry. 1988;51:1045–1050
- Positron imaging in ischemic stroke disease. Ann Neurol. 1984;15:S126–S130
- . Thresholds in cerebral ischemia: The ischemic penumbra. Stroke. 1981;12:723–725
- . Positron tomography in cerebral ischemia: A review. Neuroradiology. 1985;27:509–516
- Pathophysiologic study of chronic infarcts: The importance of the peri-infarct area. Stroke. 1987;18:21–29
- PET studies of cortical diaschisis in patients with motor hemi-neglect. J neurol Sci. 1991;104:135–142
- Local glucose utilization in acute focal cerebral ischemia: Local dysmetabolism and diaschisis. Neurology. 1977;27:1042–1048
- (in press) . F-18 FDG brain PET and thallium-201 early and delayed SPECT in distinguishing atypical cerebral tumor from cerebral infarction. Clin Nucl Med. 2003;28:
- . The minor hemisphere as a source of aphasic speech. Arch Neurol. 1971;25:302–306
- Evidence for right hemisphere involvement in recovery from aphasia. Arch Neurol. 1988;45:1025–1029
- Preserved speech abilities and compensation following prefrontal damage. In: Proc Natl Acad Sci USA. 93:1996;p. 1249–1253
- Role of the nondominant hemisphere and undamaged area during word repetition in post-stroke aphasics. Stroke. 1996;27:897–903
- Neural substrates for the effects of rehabilitative training on motor recovery after ischemic infarct. Science. 1996;272:1791–1794
- . Increasing behavioral plasticity following central nervous system damage in monkeys and man: A method with potential application to human developmental motor disability. In: Julesz B, Kovacs I editor. Maturational Windows and Adult Cortical Plasticity. Redwood City, CA: Addison-Wesley; 1995;p. 201–215
- Brain SPECT: 1994 update. In: Freeman LM editors. Nuclear Medicine Annual 1994. New York, NY: Raven Press; 1994;p. 1–54
- . A method of analysis of SPECT blood flow image data for comparison with computed tomography. Clin Nucl Med. 1989;14:192–196
- Prognostication of recovery following stroke using the comparison of CT and Tc-99m HM-PAO SPECT. J Nucl Med. 1990;31:61–66
- Regional cerebral blood flow and magnetic resonance spectroscopic imaging findings in diaschisis from stroke. Stroke. 2002;33:1243–1248
- Post-stroke cerebral reorganization in human brain identified by 31P MR spectroscopic imaging and F-18 FDG PET. In: Proc Int Soc Magn Reson Med. 10:2002;p. 1030
* Supported in part by Grants R01 HD32100 (J.M.M.) and R01 HD 35536 to (G.D.) from the National Institutes of Health.
PII: S0001-2998(03)80006-5
doi:10.1053/snuc.2003.127293
© 2003 Published by Elsevier Inc.
