Remote Effects of Focal Lesions on Cerebral Flow and Metabolism

Pawlik, G.; Herholz, Karl; Beil, Curt; Wagner, Rainer; Wienhard, K.; Heiss, Wolf‐Dieter

doi:10.1007/978-3-642-70720-9_6

Cited by 23 publications

(4 citation statements)

References 35 publications

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“…Unfortunately, the dysfunctional zone is typically much larger than the epileptogenic zone or, in cases with a gross morphological abnormality, the epileptogenic lesion. To date, it has remained unclear whether that widespread metabolic depression is due to functional deactivation or neuronal degeneration, as it is known from various acute lesions causing deafferentation (34,35), or whether it rather reflects secondary epileptic damage to the areas of most frequent seizure spread. As long as the intended surgical procedure is a large en bloc resection, the problem of precise intralobar localization may be clinically irrelevant.…”

Section: Discussionmentioning

confidence: 99%

PET and functional testing in temporal lobe epilepsy

Fink

Kessler

Pawlik

et al. 1994

Acta Neurologica Scandinavica

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Thirty‐seven patients with severe temporal lobe epilepsy were studied interictally with [18F]fluorodeoxyglucose‐PET in each of three conditions: resting, during emotional speech, and while performing a visual recognition task. In the resting state, each patient exhibited regional hypometabolism in agreement with his epileptic EEG focus, but that area was typically very large. The zone of maximum dysfunction was significantly better demarcated on activated scans showing an increase in whole‐brain metabolism averaging 18%. Concurrently, the midtemporal‐focus metabolic contrast was improved by 27%. This effect was more consistently produced by the speech paradigm that also induced significant amygdala recruitment and revealed the individual hemispheric speech dominance. Psychological trait factors played a role only for unspecific global activation.

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Section: Discussionmentioning

confidence: 99%

PET and functional testing in temporal lobe epilepsy

Fink

Kessler

Pawlik

et al. 1994

Acta Neurologica Scandinavica

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“…This was obviously due to some neutonally mediated effect, since a primary vascular cause could be excluded owing to the remote vascular territory. Further remote effects were reductions in CBF and metabolism in ipsilateral cortex and basal ganglia [29]. Their cause was less clear since selective ischaemic neuronal loss [30] or inadequate blood supply could also affect these areas, yet similar effects have also been observed in non-ischaemic lesions such as brain tumours and intracerebral haematomas, and they therefore seem to be more closely related to the site than to the nature of the primary lesion [31].…”

Section: Deactivation Of Remote Tissue (Diaschisis)mentioning

confidence: 99%

“…A study of the correlation between FDG-PET and post-mortem findings in a patient with multiple brain infarcts concluded that degeneration of fibre tracts as well as microscopic infarcts not apparent on gross examination may contribute to metabolic inactivations [32]. Infarcts of the parietal and frontal lobes most often cause significant reductions of CBF and metabolism in the ipsilateral basal ganglia and the contralateral cerebellum [29,33,34], consistent with damage of cortico-ponto-cerebellar pathways as the most likely mechanism.…”

Section: Deactivation Of Remote Tissue (Diaschisis)mentioning

confidence: 99%

Assessment of pathophysiology of stroke by positron emission tomography

Heiss¹,

Herholz²

1994

Eur J Nucl Med

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In stroke patients, multitracer positron emission tomography (PET) permits the assessment of acute changes in regional cerebral blood flow (rCBF), blood volume (rCBV), oxygen consumption (rCMRO2) and glucose metabolism (rCMRgl), which are the initial steps in the complex molecular and biochemical process leading to ischaemic cell damage. While early infarcts exhibit low flow and oxygen consumption, increased oxygen extraction fraction (OEF) due to preserved metabolism at reduced flow suggests viability of tissue. However, most initially "viable" tissue will be metabolically deranged and will become necrotic in the further course; only in a few instances do these tissue compartments recover to normal function. Increased glucose uptake at reduced oxygen supply induces non-oxidative glycolysis with noxious lactacidosis, whereas hyperperfusion beyond the metabolic demand is of controversial effect. In subacute or chronic states after ischaemia reduced flow can be compensated by increased blood volume; when perfusional reserve is exhausted, oxygen extraction increases. Such findings may guide therapeutic decisions and predict the severity of permanent deficits. Functional deactivation of tissue remote from the lesion is found regularly as a sign of damaged connecting pathways. Flow and metabolic studies during the performance of specific tasks help to detect alternative functional loops and may yield prognostic information. Repeat studies in the course of stroke are employed for the evaluation of therapeutic strategies targeted to improve reperfusion or to effect metabolic or biochemical alterations. In the future PET may gain additional clinical importance when patients are selected for elective treatment according to the prevailing pathophysiological pattern.

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“…As reviewed by Reivich [ 18], in studies using positron emission tomography (PET) and single photon emission computed tomography (SPECT), the interruption of this cerebro-ponto-cerebellar pathway is thought to cause a remote metabolic depression within the cerebellum that is most likely due to transneuronal loss of excitatory input, for which the term crossed cerebellar diaschisis (CCD) was coined by Baron et al in 1980 [1]. Since then the topographical [11][12][13], temporal [5,11], functional [7] and clinical correlates [11] of CCD have been investigated mainly in supratentorial stroke [10,11,20] and tumours [9,12]. However, only limited studies exist about CCD in infratentorial lesions [14].…”

Section: Introductionmentioning

confidence: 99%

Diaschisis of specific cerebellar lobules: pontine haematoma studied with high-resolution PET and MRI

et al. 1996

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Cerebellar glucose metabolism was studied in one patient with a hemipontine haematoma in order to investigate remote metabolic effects within the cerebellar lobules. In the patient, who suffered a circumscribed hemipontine haemorrhage, and in three normal subjects cerebellar glucose metabolisms was studied using 18F-2-fluoro-2-deoxy-D-glucose and high-resolution positron emission tomography (PET). Regions of interest were placed on sagittal brain slices of co-registered magnetic resonance images for quantitative evaluation of glucose metabolism in each cerebellar lobule. Interruption of corticopontine fibres caused inactivation of pontine nuclei with subsequent contralateral cerebellar diaschisis, mainly in the anterior lobe and the posterior portion of the quadrangular lobule. Damage within the ponto-cerebellar part of the cortico-ponto-cerebellar pathway, e.g. pontine nuclei and crossing ponto-cerebellar fibres from contralateral pontine nuclei, led to ipsi- and contralateral cerebellar diaschisis within the semilunar, gracile and biventral lobules. High-resolution PET is capable of demonstrating bilateral diaschisis involving specific cerebellar lobules to a different degree that is consistent with the pontine anatomy of the cortico-ponto-cerebellar pathway and with the location of the haemorrhagic lesion.

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Remote Effects of Focal Lesions on Cerebral Flow and Metabolism

Cited by 23 publications

References 35 publications

PET and functional testing in temporal lobe epilepsy

PET and functional testing in temporal lobe epilepsy

Assessment of pathophysiology of stroke by positron emission tomography

Diaschisis of specific cerebellar lobules: pontine haematoma studied with high-resolution PET and MRI

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