Effect of small deep hemispheric infarction on the ipsilateral cortical blood flow in man

Evidence of cerebral hypoperfusion in scleroderma patients

OBJECTIVES

To investigate regional cerebral blood flow by (99m)Tc-hexamethylpropylenamineoxime (HMPAO) single photon emission computed tomography (SPECT) in a series of 40 patients (mean age 58.5+/-11.5 yr) affected by systemic sclerosis (SSc) in comparison with age-matched healthy controls.

METHODS

Subjects affected by concomitant severe pathologies that might interfere with the interpretation of the SPECT results were excluded. SPECT findings were correlated with the severity of peripheral microvascular involvement, as assessed by nailfold videocapillaroscopy (NVC). Whenever possible, patients underwent magnetic resonance imaging (MRI) of the brain.

RESULTS

Twenty-one SSc patients (52%) showed hypoperfusion in two or more regions of interest (ROIs) at the SPECT analysis. MRI was available in 14 of these patients, and was shown to be altered in eight of them (57%). One patient with both abnormal SPECT and abnormal MRI was affected by mild cognitive impairment. Transcranial Doppler sonography was normal in all but one of these patients with hypoperfusion. Nineteen patients exhibited a normal brain SPECT scan, but the MRI was shown to be altered in 3/12 of them (25%). No significant differences were found between the group of SSc patients showing hypoperfusion and those showing a normal SPECT scan regarding age, the duration of disease, the presence of vascular risk factors or damage of other organs typically involved in the disease, and the severity of peripheral microvascular involvement (NVC).

CONCLUSIONS

Focal or diffuse cerebral hypoperfusion was found in more than half of the neurologically asymptomatic SSc patients studied, paralleling the incidence of altered brain MRI. The hypoperfusion was not linked to ageing and possibly reflects the cerebral location of the microangiopathic process characterizing the disease.

Intelligence after stroke in childhood: review of the literature and suggestions for future research

Review of published clinical and neuropsychologic outcome studies reveals limited information about intellectual functioning after childhood stroke. The extant data are supplemented here by analysis of intelligence quotient (IQ) results obtained from 38 children in an ongoing study of unilateral middle cerebral artery ischemic stroke. Evidence so far indicates that, after stroke, mean IQ falls significantly below the population mean but remains within the average range. There is no significant difference between hemispheric side of injury; the Verbal and Performance IQ lateralization profile widely recognized in adults with unilateral injury is not apparent in younger children, and there is only a trend toward this profile in older children. The effects of a number of other variables, including sex, site of stroke, and longitudinal assessment, are also considered. Although the generally minor effect of stroke on IQ is encouraging, a number of children do require extra help on return to school. Some suggestions for future research are highlighted in order to encourage further consideration of the issues raised here.

Effects of thalamic hemorrhage on cortical hemodynamic parameters assessed by perfusion MR imaging: preliminary report

Thalamic lesions may induce a diffuse hypometabolism and subsequent decrease of cortical cerebral blood flow (rCBF) and cerebral blood volume (rCBV). Up to now PET was used to assess these changes. However this latter method cannot be applied routinely to stroke patients because it is expensive and not currently available. The purpose of this preliminary study was to evaluate the effects of 'pure metabolic depression' induced by thalamic stroke on rCBV and rCBF by using a non invasive method perfusion-MRI. Two patients experienced aphasia, with motor and sensory impairment related to thalamic hemorrhage. Four weeks later, dynamic T2*-weighted echo planar imaging was used to produce perfusion-MR images during an intravenous bolus injection of gadopentetate dimeglumine. A decrease of cortical rCBV and rCBF mainly confined to sensorimotor cortex was observed in both cases ipsilateral to the lesion. Although a sequential assessment of this abnormalities is needed in a larger series of patients in order to establish relevant correlations with neurological status, this preliminary study indicates that perfusion-MRI might be a practical and promising tool in the assessment of cortical rCBV and rCBF changes.

Impaired quantitative cerebral blood flow in scleroderma patients

Systemic Sclerosis (SSc) is a multisystem disease characterised by proliferation of vascular tissue, obliterative microvascular lesions and diffuse organ fibrosis. Despite widespread vascular disease, Central Nervous System complaints are only infrequently reported and it is uncertain whether they merely derive from systemic complications or whether they may be also caused by a primary vascular process within the brain. Regional cerebral blood flow (rCBF) was quantitatively measured by the 133Xenon clearance technique in twenty-seven consecutive SSc patients without relevant systemic complications and with different severity of vascular involvement, as staged by nailfold capillary videomicroscopy (NCV). Absolute, percent, and asymmetry rCBF values were compared (z-statistics) with age- and sex-matched healthy controls. Cerebral MRI and Mini-Mental State Examination (MMSE) were also performed. Doppler sonography of neck vessels and Transcranial Doppler sonography (TCD) were performed in patients presenting rCBF reduction. Cerebral hypoperfusion was found in the 52% of patients, i.e.: in 33% of patients with the 'early' NCV pattern, in 56% of patients with the 'active' pattern, and in 67% of patients with the 'late' NCV pattern. Thirty percent were the MRIs showing focal and/or diffuse signal abnormalities in the white matter of both hemispheres with the highest rate (44%) in the 'late' NCV pattern. MMSE disclosed mild dementia in one patient in the 'late' NCV group and some mistakes in 6 more patients, in the 'active' or 'late' NCV groups, whereas TCD failed to find significant stenosis of Willis' arteries. Cerebral hypoperfusion is shown for the first time in a substantial part of SSc patients without either neurological symptoms or relevant systemic complications. It is suggested that the rCBF reduction might be related to the systemic scleroderma microangiopathy although, probably due to the paucity of connective tissue in cerebral vessels, the vast majority of patients remains in a subclinical phase.

Abulia from unilateral capsular genu infarction: report of two cases

We report two cases of capsular genu infarction in patients showing pure abulia without motor weakness. One case is left-sided infarction, and another is right-sided. Single photon emission computed tomography (SPECT) examination in both disclosed hypoperfusion in the ipsilateral frontal cortex at the infarction. In one case, reversion of frontal hypoperfusion was observed later. We considered that the frontal hypoperfusion was due to trans-synaptic hypofunction of thalamo-frontal projections from the deep-seated capsular genu lesion and that it resulted in the pure abulia without neurological deficits.

Accuracy of 133-xenon regional cerebral blood flow and quantitative electroencephalography in systemic lupus erythematosus

OBJECTIVE

Comparative assessment of sensitivity and specificity of regional Cerebral Blood Flow (rCBF) by 133-Xenon inhalation and quantitative Electroencephalography (qEEG) in patients with Neuropsychiatric Systemic Lupus Erythematosus (NP-SLE).

METHODS

Sixty-two combined rCBF and qEEG examinations were performed in fifty-two SLE patients. Group A: 27 SLE patients without NP-SLE; group B: 17 patients with florid (within 1 month) NP-SLE; group C: 12 patients previous NP-SLE examined in the remission phase (four patients of which already considered in group B). The study also included data deriving from two sets of examinations in ten patients who were observed twice, in different phases of the clinical course of NP-SLE.

RESULTS

In comparison to healthy controls, rCBF lower (p < .001) in group B only, whereas qEEG showed similar increases of both delta and theta relative powers together with a reduction of alpha relative power in groups A-C. As compared to group A, sensitivity and specificity in detecting cerebral abnormalities in group B were 76% and 78% for rCBF, and 59% and 44% for qEEG, respectively. In the ten patients examined twice, rCBF was consistent with clinical course in 90% of cases and qEEG in 60%.

CONCLUSION

Total accuracy in detecting cerebral functional abnormalities during florid NP-SLE is better by rCBF than by qEEG. rCBF and, in selected cases, qEEG examinations are reliable markers of NP-SLE.

Functional circulation images by angio-CT in the assessment of small deep cerebral infarctions

We analyzed circulation time (rABCT) and vascular volume density images obtained by angio-computerized tomography (angio-CT) in 63 patients with small deep cerebral infarctions. Abnormalities in the rABCT image were found in 88% of the patients and in the vascular volume image in 48%. Two groups with different clinical pictures were picked out by rABCT changes: one with major-vessel involvement, the other with small-vessel involvement. The perfusional changes found were mainly due to altered vascular canalization rather than to altered vasomotility. The hemodynamic theory could explain the spatial relations between perfusion changes and CT hypodense areas without needing assumptions linking blood flow and metabolism.

Prognosis and MRI after ischemic stroke of the basal ganglia

The clinical courses and long-term prognoses in 16 young patients with infarctions of the basal ganglia were evaluated and the recent magnetic resonance imaging findings in 9 of them were examined. Only 5 of 14 patients (35%) had motor sequelae, 4 had hemiparesis, and 1 had gait disturbance. Secondary dystonia occurred in 1 patient. Magnetic resonance imaging disclosed a circumscribed lesion in the basal ganglia, as reflected by T2 high- and T1 low-intensity signals, in all patients. The abnormal region on T2-weighted images usually was more extensive than that observed on T1-weighted ones. The hemiplegic patients each had an area of abnormal intensity in the internal capsule or corona radiata with relatively high signals on the T2- and proton-density-weighted images. Mild to moderate asymmetric atrophy of the midbrain on the side ipsilateral to the stroke lesion was observed in 8 of 9 patients. The mechanism involved may be remote transsynaptic neuronal death of the substantia nigra, as well as Wallerian degeneration of the pyramidal tract.

Right motor neglect associated with dynamic aphasia, loss of drive and amnesia: case report and cerebral blood flow study

A 30-year-old right-handed man had right motor neglect, amnesia, aphasia and loss of drive following bilateral thalamic and subthalamic infarctions. Serial resting cerebral blood flow (CBF) measurements with either Xenon 133 inhalation or positron emission tomography at 1, 8 and 10 months post-onset showed a widespread and long-lasting low CBF in the cortex. An additional CBF measurement, during motor tasks, showed a marked interhemispheric asymmetry in the pattern of activation: whereas left hand movement resulted in a CBF increase in contralateral superior rolandic and prerolandic areas, no significant regional CBF changes were seen during right hand movement, despite recovery from motor neglect. This loss of CBF increase in cortical motor and premotor areas during voluntary movement of the previously neglected side points to a disruption of cortico-subcortical pathways subserving motor activation. The pathophysiology of aphasia, loss of drive and amnesia as well as their relationships to motor neglect, may also be discussed on the basis of thalamo-cortical disconnections.

Sneddon syndrome: cerebral perfusion studies by Tc99m HM-PAO and SPECT

Sneddon syndrome is a non-inflammatory, non-atherosclerotic disease involving small and medium-sized arteries of the brain and of the skin. The arteriographic examination is often negative despite progressive impairment of the neurological status. In 3 patients with Sneddon syndrome cerebral perfusion was assessed with single photon emission computerized tomography (SPECT) and technetium99 m-hexamethylpropylenamineoxime (Tc99 HM PAO). A correlation between clinical and SPECT finding was found, with significant focal reduction of regional cerebral blood flow (rCBF) in the two more severely affected patients.

Manic-depressive and pure manic states after brain lesions

Although mania is a rare complication of brain lesions, recent reports have emphasized the importance of lesion location and genetic predisposition in these patients. In the present study we compared patients who developed a bipolar affective disorder (i.e., mania and depression) after a brain lesion with patients who only developed mania. Although no significant between-group differences were found on demographic variables, the manic-depressed group showed significantly more impairments on the Mini Mental State Exam than the mania only group. All the bipolar patients had subcortical lesions (mainly right head of the caudate and right thalamus), while patients with unipolar mania had significantly higher frequency of cortical involvement (mainly right orbitofrontal and basotemporal cortices). It is suggested that subcortical and cortical right hemisphere lesions may produce different neurochemical and/or remote metabolic brain changes that may underlie the production of either a bipolar disease or a unipolar mania.

Motor hemiplegia and the cerebral organization of movement in man. II. The myth of the human extrapyramidal system

Following a brief review of the concept of extrapyramidal system, clinical and anatomic evidence is presented against its relative prominence in man. It is proposed that the greatest part of those structures traditionally labeled as extrapyramidal effects its respective functional activities by way of the pyramidal tracts themselves. Such structures, centered around the basal nuclei, the cerebellum and possibly, the limbic areas of the prosencephalon are, according to the present suggestion, indeed, pre pyramidal. This model is based upon the clinical analysis of patients and agrees with more than one century of anatomic verifications in human brains, favoring the notion of the singularity of the human brain.

Infarct of the anterior limb of the right internal capsule causing left motor neglect: case report and cerebral blood flow study

A sixty-nine year old hypertensive man had left motor neglect following an infarct of the anterior limb of the right internal capsule. He also had left auditory extinction on verbal dichotic listening and a sligh constructional apraxia. Regional cerebral blood flow (CBF) was measured at rest with Xenon 133 inhalation and was found to be slightly decreased in a diffuse fashion. Motor activation of the right hand resulted in an increase of CBF in the contralateral superior rolandic area, whereas no such increase was found during motor activation of the left hand. This lack of cortical CBF increase on contralateral motor activation is interpreted as a consequence of the failure of some corticosubcortical connexions involved in motor arousal. The specifically dynamic appearance of regional CBF abnormalities, i.e. during selective activation as opposed to rest measurements, is consistent with the functional character of neglect.

Remote effects of subcortical cerebrovascular lesions: a SPECT cerebral perfusion study

The remote effects of small unilateral cerebrovascular lesions confined to subcortical structures were evaluated by single photon emission computerized tomography (SPECT) and a CBF tracer, I-123 HIPDM. A CBF study was performed in 34 patients presenting with subcortical stroke either in the acute or in the chronic stages. Twenty-one of the 34 patients showed areas of cortical hypoperfusion ipsilateral to the subcortical lesion. In 14 patients, asymmetry of perfusion was also observed at the cerebellar level, perfusion being significantly reduced in the cerebellar hemisphere contralateral to the lesion. There was no correlation between the degree and extension of these remote effects and the type of stroke (ischemic or hemorrhagic), the patency of cerebral arteries, or the size and site of the lesion by transmissive computerized tomography (TCT). Subcortical hematomas showed a correlation between occurrence of remote effects and time interval from the onset of stroke, occurring more frequently in the acute phase. A correlation was observed between cortical and cerebellar remote effects and the severity of clinical presentation. The causes of remote effects are still unclear and have been extensively debated. Our data indicate that there is a relationship of remote effect to the neurological status. It is possible to show, by noninvasive, low-cost methods, remote CBF effects after stroke that may contribute to the assessment of brain functional impairment.

Amine accumulation in Parkinson's disease and other disorders

Amine accumulation in the axons of degenerating, amine-containing neurones is a natural component of neurone death in many species, including man. While it is becoming increasingly clear that this phenomenon may have functional significance in animal models of Parkinson's Disease, its potential importance in the clinical syndrome has been pretermitted. There are several reasons for this. Failure to sample tissue which contains accumulated amines, the masking of accumulation by adjacent depleted tissues and the degradation of accumulated amines in post-mortem tissues from Parkinsonian brains could account for the low incidence of detection of accumulation in this disorder. Increased levels of amines have been detected in the brains of patients with other conditions including cerebral infarction, Alzheimer's Disease and Huntington's Chorea. These increases have been attributed previously to enhanced aminergic activity, rather than a stage in the degenerative process, as our hypothesis suggests. In addition to the potential importance of amine accumulation in the pathophysiology of various clinical syndromes, a more thorough investigation of this phenomenon in animal models would seem essential since they are used routinely to both describe the basic principles of dopamine function and to evaluate therapeutic possibilities in Parkinson's Disease.

A gamma camera system for atraumatic rCBF measurement using a new super high sensitivity collimator

The purpose of this study is to develop a useful gamma camera system for atraumatic rCBF measurement by the 133Xe intravenous injection (i.v.) method. A super high sensitivity slant hole (SHS-SL) collimator was designed for this purpose. The gamma camera used with this collimator was able to move close to the patient's head and obtain satisfactory count rates (130 kcpm-178 kcpm in a hemisphere) with a low dosage (10 mCi) of 133Xe. To validate this rCBF measurement system three studies were carried out: a comparative evaluation was performed against the flow values with the intracarotid 133Xe injection (i.c.) method, reproducibility of flow values was assessed from two serial i.v. measurements, and flow values were compared with clinical severity of the patients. The comparative study showed good correlation in the hemispheric and regional values between the two methods; r values 0.98 and 0.64-0.93 for gray matter flow and 0.96 and 0.78-0.93 for initial slope index. In the reproducibility study, the variation coefficients in the hemispheric and regional values between the two serial measurements were 5.0% and 7.3%-14.2% for gray mater flow, 5.2% and 7.9%-12.9% for initial slope index. The reproducibility in this study was as good as those with the i.c. method reported previously. The hemispheric flow values from our gamma camera system correlated well with the clinical severity of cerebrovascular disease. These results show that the gamma camera system with the SHS-SL collimator is useful for atraumatic rCBF measurement.

Cerebral blood flow in acute and chronic ischemic stroke using xenon-133 inhalation tomography

Serial measurements of cerebral blood flow (CBF) were performed in 12 patients with acute symptoms of ischemic cerebrovascular disease. CBF was measured by xenon-133 inhalation and single photon emission computer tomography. Six patients had severe strokes and large infarcts on the CT scan. They showed in the acute phase (Days 1-3) very large low-flow areas, larger than the hypodense areas seen on the CT scan. The cerebral vasoconstrictor and vasodilator capacity was tested in the acute phase following aminophylline and acetazolamide, respectively. A preserved but reduced reactivity was seen at both tests in all 6 cases in the infarct and the peri-infarct areas. On Days 5-25, 4 of the patients had transitory increases (59-108%) of CBF, probably corresponding to lysis of an intracerebral embolic occlusion. The other 2 patients showed on Days 7-15 only a moderate CBF increase (appr. 20%), both had occlusion of the relevant internal carotid artery. In all 6 patients, CBF studies at 2 and 6 months resembled the acute phase, showing large areas with reduced flow. At the 6 months follow-up, the vasodilatory stress test was repeated, and all but one showed a preserved but reduced vasoreactivity in the infarct and peri-infarct tissue. Of the remaining 6 patients, one had a pontine infarct and one had no lesions on the CT scan, both having normal angiograms and CBF maps. Four patients had small deep or subcortical CT lesions, and showed a slight, but persistent CBF reduction of about 6-8% in the parietal region on the affected side. No changes in the flow pattern were seen at the vasoreactive studies. A likely explanation for the finding of superjacent low-flow areas is an intrahemispheric uncrossed diaschisis. This interpretation is discussed in relation to the peri-infarct low-flow area seen in the 6 cases with large infarcts.

Calcium antagonist (PY 108-068) treatment may further decrease flow in ischemic areas in acute stroke

The effect of the possible influence of a new calcium antagonist, PY 108-068, on regional CBF was studied in patients suffering acute ischemic stroke. The dosage was 1.5 + 2.5 mg intravenously in six patients (series 1) and 2.5 + 5.0 mg intravenously in five other patients (series 2). CBF was measured before and after treatment by xenon-133 inhalation and single-photon emission computed tomography (Tomomatic 64). In the first series, no changes in hemispheric CBF, MABP, or clinical symptoms were noted after treatment, but one patient showed an increase of CBF in part of the periinfarct area. In the second series, slight increases in mean hemispheric flow values were seen, but in three of the five patients CBF decreased even further in the ischemic area. MABP decreased by 13%, and the clinical symptoms were unchanged.