Crossed cerebellar hypoperfusion in hyperacute ischemic stroke

Out of the core: the impact of focal ischemia in regions beyond the penumbra

The changes in the necrotic core and the penumbra following induction of focal ischemia have been the focus of attention for some time. However, evidence shows, that ischemic injury is not confined to the primarily affected structures and may influence the remote areas as well. Yet many studies fail to probe into the structures beyond the penumbra, and possibly do not even find any significant results due to their short-term design, as secondary damage occurs later. This slower reaction can be perceived as a therapeutic opportunity, in contrast to the ischemic core defined as irreversibly damaged tissue, where the window for salvation is comparatively short. The pathologies in remote structures occur relatively frequently and are clearly linked to the post-stroke neurological outcome. In order to develop efficient therapies, a deeper understanding of what exactly happens in the exo-focal regions is necessary. The mechanisms of glia contribution to the ischemic damage in core/penumbra are relatively well described and include impaired ion homeostasis, excessive cell swelling, glutamate excitotoxic mechanism, release of pro-inflammatory cytokines and phagocytosis or damage propagation via astrocytic syncytia. However, little is known about glia involvement in post-ischemic processes in remote areas. In this literature review, we discuss the definitions of the terms "ischemic core", "penumbra" and "remote areas." Furthermore, we present evidence showing the array of structural and functional changes in the more remote regions from the primary site of focal ischemia, with a special focus on glia and the extracellular matrix. The collected information is compared with the processes commonly occurring in the ischemic core or in the penumbra. Moreover, the possible causes of this phenomenon and the approaches for investigation are described, and finally, we evaluate the efficacy of therapies, which have been studied for their anti-ischemic effect in remote areas in recent years.

Reduced cerebral blood flow and cognitive dysfunction following isolated cerebellar infarction: two case reports

Cognitive impairment in focal cerebellar disorders has been widely recognized and is described as cerebellar cognitive affective syndrome (CCAS). However, the relationship between CCAS and crossed cerebello-cerebral diaschisis (CCD) has rarely been discussed. The present report describes the uncommon phenomenon of CCD in two cases with isolated cerebellar infarction, and discuss its contribution to cognitive impairment. Cognitive performance was examined using the CCAS scale and a battery of neuropsychological assessments. Moreover, the relative distribution of cerebral and cerebellar blood flow was measured using three-dimensional arterial spin labeling imaging. Case 1 showed deficits in general cognition and had impaired language, episodic memory, and executive function. Case 2 showed deficits in general cognition at baseline, and cognitive deterioration of visuospatial abilities, language, episodic memory, and executive function was observed at the 3-month follow-up. Both cases met the diagnosis criteria of CCAS. Reduced cerebral blood flow was observed in the cerebral hemisphere contralateral to the cerebellar infarction at baseline in Case 1, and at the 3-month follow-up in Case 2. The present report describes cognitive decline after isolated cerebellar infarction in combination with contralateral cerebral hypoperfusion, as measured using quantitative arterial spin labeling. One possible mechanism involves the functional depression of cerebello-cerebral pathways.

Effects of Cerebellar Transcranial Direct Current Stimulation in Patients with Stroke: a Systematic Review

BACKGROUND

The cerebellum is involved in regulating motor, affective, and cognitive processes. It is a promising target for transcranial direct current stimulation (tDCS) intervention in stroke.

OBJECTIVES

To review the current evidence for cerebellar tDCS (ctDCS) in stroke, its problems, and its future directions.

METHODS

We searched the Web of Science, MEDLINE, CINAHL, EMBASE, Cochrane Library, and PubMed databases. Eligible studies were identified after a systematic literature review of the effects of ctDCS in stroke patients. The changes in assessment scale scores and objective indicators after stimulation were reviewed.

RESULTS

Eleven studies were included in the systematic review, comprising 169 stroke patients. Current evidence suggests that anode tDCS on the right cerebellar hemisphere does not appear to enhance language processing in stroke patients. Compared with the sham group, stroke patients showed a significant improvement in the verb generation task after cathodal ctDCS stimulation. However, with regard to naming, two studies came to the opposite conclusion. The contralesional anodal ctDCS is expected to improve standing balance but not motor learning in stroke patients. The bipolar bilateral ctDCS protocol to target dentate nuclei (PO10h and PO9h) had a positive effect on standing balance, goal-directed weight shifting, and postural control in stroke patients.

CONCLUSIONS

ctDCS appears to improve poststroke language and motor dysfunction (particularly gait). However, the evidence for these results was insufficient, and the quality of the relevant studies was low. ctDCS stimulation parameters and individual factors of participants may affect the therapeutic effect of ctDCS. Researchers need to take a more regulated approach in the future to conduct studies with large sample sizes. Overall, ctDCS remains a promising stroke intervention technique that could be used in the future.

Crossed Cerebellar Diaschisis Worsens the Clinical Presentation in Acute Large Vessel Occlusion

INTRODUCTION

Initial NIHSS in anterior large vessel occlusion (LVO) correlates partially with the hypoperfusion volume. We aimed at assessing the contribution of crossed cerebellar diaschisis (CCD) from the hypoperfused territory on LVO initial clinical deficit.

METHODS

CCD was retrospectively identified by brain CT perfusion imaging (CTP) in patients with anterior LVO treated by mechanical thrombectomy from January 2017 to July 2021. CCD was defined by CTP parameter alteration in the contralateral cerebellar hemisphere to the LVO. NIHSS, clinical/perfusion variables, and CCD were included in regression models to assess their interrelationships.

RESULTS

206 patients were included. CCD was present in 90 patients (69%). NIHSS scores were higher on admission and at stroke discharge among patients with CCD (17.90 ± 6.1 vs. 11.4 ± 8.4, p < 0.001; 9.6 ± 7.7 vs. 6.6 ± 7.9, p = 0.049; respectively). Patients with a CCD had higher stroke volumes (118.2 ± 60.3 vs. 69.3 ± 59.7, p < 0.001) and lower rate of known atrial fibrillation (22% vs. 41%, p = 0.021). On multivariable logistic regression, CCD independently worsened the initial NIHSS (OR 4.85 [2.37-7.33]; p < 0.001).

CONCLUSION

CCD is found in 69% of LVO on admission CTP, correlates with stroke volumes, and independently worsens initial NIHSS.

Investigating the Association of Wallerian Degeneration and Diaschisis After Ischemic Stroke With BOLD Cerebrovascular Reactivity

Introduction

Wallerian degeneration and diaschisis are considered separate remote entities following ischemic stroke. They may, however, share common neurophysiological denominators, since they are both related to disruption of fiber tracts and brain atrophy over time. Therefore, with advanced multimodal neuroimaging, we investigate Wallerian degeneration and its association with diaschisis.

Methods

In order to determine different characteristics of Wallerian degeneration, we conducted examinations on seventeen patients with chronic unilateral ischemic stroke and persisting large vessel occlusion, conducting high-resolution anatomical magnetic resonance imaging (MRI) and blood oxygenation-level dependent cerebrovascular reactivity (BOLD-CVR) tests, as well as Diamox ¹⁵(O)–H₂O–PET hemodynamic examinations. Wallerian degeneration was determined using a cerebral peduncle asymmetry index (% difference of volume of ipsilateral and contralateral cerebral peduncle) of more than two standard deviations away from the average of age-matched, healthy subjects (Here a cerebral peduncle asymmetry index > 11%). Diaschisis was derived from BOLD-CVR to assess the presence of ipsilateral thalamus diaschisis and/or crossed cerebellar diaschisis.

Results

Wallerian degeneration, found in 8 (47%) subjects, had a strong association with ipsilateral thalamic volume reduction (r² = 0.60) and corticospinal-tract involvement of stroke (p < 0.001). It was also associated with ipsilateral thalamic diaschisis (p = 0.021), No cerebral peduncular hemodynamic differences were found in patients with Wallerian degeneration. In particular, no CBF decrease or BOLD-CVR impairment was found.

Conclusion

We show a strong association between Wallerian degeneration and ipsilateral thalamic diaschisis, indicating a structural pathophysiological relationship.

Crossed cerebellar diaschisis: risk factors and prognostic value in focal cortical dysplasia by 18F-FDG PET/CT

PURPOSE

Crossed cerebellar diaschisis (CCD) has been widely studied in hemispheric stroke but is less characterized in epilepsy. In this study, we used 18F-FDG PET/CT to investigate the risk factors for CCD and its prognostic value for intractable epilepsy caused by focal cortical dysplasia (FCD).

METHODS

One hundred medically intractable epilepsy patients pathologically diagnosed with FCD postoperatively were included and classified into two groups: CCD+ and CCD-. PET/CT images were analyzed qualitatively by visual assessment and semi-quantitatively using the absolute asymmetry index (|AI|). Clinical factors, including age, sex, body mass index (BMI), age at seizure onset, epilepsy duration, seizure type, seizure frequency, electroencephalography (EEG) and brain magnetic resonance imaging (MRI), were retrospectively assessed from medical records. Follow-up outcomes were evaluated according to the Engel classification at 3, 6, 12, 24 and 36 months postoperatively.

RESULTS

Of the 100 patients, 77 (77.0%) were classified as CCD-, and 23 (23.0%) were classified as CCD + . CCD+ patients had a higher number of lobes involved on PET (3.61 ± 2.16 vs 2.26 ± 1.01, P < 0.001) than CCD- patients. CCD- patients showed more negative MRI results than CCD + patients (P = 0.02). At 12 months postoperatively, 70.7% (29/41) of CCD- patients and 30.8% (4/13) of CCD + patients presented a favourable prognosis (P = 0.02). Significant differences in the average |AI| values in the posterior frontal and anterior temporal lobes were found between CCD+ and CCD- patients (P < 0.05).

CONCLUSION

The number of lobes involved on PET, structural anomalies on MRI, the |AI| values in the posterior frontal and anterior temporal lobes may be predisposing factors for CCD. CCD occurrence may help predict the prognosis of FCD patients at 12 months postoperatively.

Detection of Crossed Cerebellar Diaschisis by Intravoxel Incoherent Motion MR Imaging in Subacute Ischemic Stroke

Intravoxel incoherent motion has received extensive attention in brain studies for its potential as a non-invasive magnetic resonance perfusion method. However, studies on intravoxel incoherent motion imaging and crossed cerebellar diaschisis detection are relatively scarce. The aim of our study was to evaluate the feasibility of using intravoxel incoherent motion imaging in crossed cerebellar diaschisis diagnosis in subacute ischemic stroke patients by comparing results from intravoxel incoherent motion imaging, single-photon emission computed tomography, and arterial spin-labeling perfusion methods. In total, 39 patients with subacute ischemic stroke who underwent intravoxel incoherent motion, arterial spin-labeling, and single-photon emission computed tomography scanning were enrolled. Intravoxel incoherent motion-derived perfusion-related parameters including fast diffusion coefficient, vascular volume fraction, arterial spin-labeling-derived cerebral blood flow as well as single-photon emission computed tomography-derived cerebral blood flow of bilateral cerebellum were measured. A crossed cerebellar diaschisis-positive result was considered present with an asymmetry index ≥10% of single-photon emission computed tomography. In the crossed cerebellar diaschisis-positive group, fast diffusion coefficient, arterial spin-labeling-derived cerebral blood flow, and computed tomography-derived cerebral blood flow of the contralateral cerebellum decreased compared with those of the ipsilesional cerebellum; whereas vascular volume fraction significantly increased. The National Institutes of Health Stroke Scale score and infarct volume in the crossed cerebellar diaschisis-positive group were significantly higher than those in the crossed cerebellar diaschisis-negative group. A positive correlation was detected between the fast diffusion coefficient-based asymmetry index and the single-photon emission computed tomography-based asymmetry index, fast diffusion coefficient-based asymmetry, and arterial spin-labeling based asymmetry index; whereas the vascular volume fraction-based asymmetry index value had a negative correlation with the single-photon emission computed tomography-based asymmetry index and arterial spin-labeling based asymmetry index. Furthermore, the area under the receiver operating characteristic curve value of the arterial spin-labeling-based asymmetry index was 0.923. The fast diffusion coefficient derived from the intravoxel incoherent motion could be valuable for the assessment of crossed cerebellar diaschisis in supratentorial stroke patients.

BOLD cerebrovascular reactivity as a novel marker for crossed cerebellar diaschisis

Objective

To study blood oxygen level–dependent cerebrovascular reactivity (BOLD-CVR) as a surrogate imaging marker for crossed cerebellar diaschisis (CCD).

Methods

Twenty-five participants with symptomatic unilateral cerebrovascular steno-occlusive disease underwent a BOLD-CVR and an acetazolamide challenged (15O)-H2O-PET study. CCD and cerebellar asymmetry index were determined from PET and compared to BOLD-CVR quantitative values. Neurologic status at admission and outcome after 3 months were determined with NIH Stroke Scale (NIHSS) and modified Rankin Scale (mRS) scores.

Results

For both the BOLD-CVR and PET examination, a significant cerebellar asymmetry index was found for participants exhibiting CCD (CCD+ vs CCD−: for BOLD-CVR 13.11 ± 9.46 vs 1.52 ± 4.97, p < 0.001; and for PET 7.31 ± 2.75 vs 1.68 ± 2.98, p < 0.001). The area under the curve for BOLD-CVR was 0.89 (95% confidence interval: 0.75–1.0) with 0.91 sensitivity and 0.81 specificity to detect CCD. Participants exhibiting CCD were in poorer clinical condition at baseline (CCD+ vs CCD−: NIHSS 7 vs 1, p = 0.003; mRS 3 vs 1, p = 0.001) and after 3-month follow-up (NIHSS 2 vs 0, p = 0.02; mRS 1 vs 0, p = 0.04). Worse performance on both scores showed an agreement with a larger BOLD-CVR cerebellar asymmetry index. This was not found for PET.

Conclusions

BOLD-CVR demonstrates similar sensitivity to detect CCD as compared to (15O)-H2O-PET in patients with symptomatic unilateral cerebrovascular steno-occlusive disease. Furthermore, participants exhibiting CCD had a poorer baseline neurologic performance and neurologic outcome at 3 months.

Classification of evidence

This study provides Class II evidence that BOLD-CVR identifies CCD in patients with symptomatic unilateral cerebrovascular steno-occlusive disease.

Crossed cerebellar diaschisis in post-treatment glioma patients: A comparative study of arterial spin labelling and dynamic susceptibility contrast

OBJECTIVES

To assess crossed cerebellar diaschisis (CCD) in post-treatment glioma patients, and to compare the performance of arterial spin labelling (ASL) and dynamic susceptibility contrast (DSC) in detecting CCD.

METHODS AND MATERIALS

This retrospective study included 130 patients who had both DSC and ASL. Among them, 16 had underwent fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT). We investigated the relationship between CCD and the location and size of supratentorial lesions, and compared PET diagnostic performance with that of ASL and DSC. We assessed the inter-methods agreement for ASL and DSC, and performed quantitative analysis by calculating the asymmetry index (AI) between bilateral cerebellum and exploring how the AI values for ASL-CBF, DSC-rCBF, and DSC-rCBV maps correlated with each other.

RESULT

Supratentorial lesions affecting the corona radiata (P < 0.001), basal ganglia (P < 0.001), and insula (P = 0.046) were significantly associated with the occurrence of CCD. Lesion size was significantly larger (P = 0.005) in the CCD positive group. With PET as a reference, ASL-CBF and DSC-rCBF maps exhibited the best diagnostic performance compared with the other DSC-generated maps (diagnostic accuracy = 83.3% for both, area under curve (AUC) of ASL = 0.967, AUC of rCBF = 0.983), although differences were not statistically significant. The κ value for the inter-methods (ASL and DSC) agreement in detecting CCD was 0.893, while the degree of perfusion asymmetry was more significant in ASL- than DSC-generated maps. Bland-Altman plots showed that the AI for ASL-CBF was moderately correlated with those for DSC-rCBF and DSC-rCBV.

CONCLUSIONS

CCD can present in post-treatment glioma patients and is detectable on MR-perfusion images including ASL-CBF, DSC-rCBF, and DSC-rCBV maps.

Pathological factors contributing to crossed cerebellar diaschisis in cerebral gliomas: a study combining perfusion, diffusion, and structural MR imaging

PURPOSE

To investigate imaging features of crossed cerebellar diaschisis (CCD) in cerebral gliomas, and its underlying pathophysiological mechanisms.

METHODS

Thirty-three pre-surgical patients with cerebral gliomas and 33 healthy controls underwent arterial spin-labeling, diffusion tensor imaging, and high-resolution T1-weighted imaging using MRI, in order to estimate cerebral blood flow (CBF), white matter integrity, and lesion volume, respectively. Asymmetry indices of CBF in the cerebellum were used for evaluating the level of CCD in the patients. These indices were correlated with clinical variables (lesion size and position, tumor histological grade, and CBF asymmetry) and diffusion tensor imaging parameters (fractional anisotropy and number of fibers in the cortico-ponto-cerebellar pathway and across the cerebral hemispheres), respectively.

RESULTS

The patients showed decreased CBF in the cerebellar hemisphere contralateral to the supratentorial tumor, and increased CBF asymmetry in the cerebellum (both P < 0.05). CCD levels in high-grade gliomas were higher than those of low-grade gliomas (P < 0.05). CCD levels were negatively correlated with the size of the supratentorial lesions, and positively correlated with FA asymmetry in the cerebral fibers (both P < 0.05).

CONCLUSIONS

CCD in cerebral gliomas was specifically associated with tumor histological grade, lesion size, and white matter impairments in the hemisphere ipsilateral to the tumor. The findings implicated that observing CCD might have potential for assisting grading diagnosis of cerebral gliomas.

Detection of crossed cerebellar diaschisis in hyperacute ischemic stroke using arterial spin-labeled MR imaging

Background and purpose

Arterial spin-labeling (ASL) was recently introduced as a noninvasive method to evaluate cerebral hemodynamics. The purposes of this study were to assess the ability of ASL imaging to detect crossed cerebellar diaschisis (CCD) in patients with their first unilateral supratentorial hyperacute stroke and to identify imaging or clinical factors significantly associated with CCD.

Materials and methods

We reviewed 204 consecutive patients who underwent MRI less than 8 hours after the onset of stroke symptoms. The inclusion criteria were supratentorial abnormality in diffusion-weighted images in the absence of a cerebellar or brain stem lesion, bilateral supratentorial infarction, subacute or chronic infarction, and MR angiography showing vertebrobasilar system disease. For qualitative analysis, asymmetric cerebellar hypoperfusion in ASL images was categorized into 3 grades. Quantitative analysis was performed to calculate the asymmetric index (AI). The patients’ demographic and clinical features and outcomes were recorded. Univariate and multivariate analyses were also performed.

Results

A total of 32 patients met the inclusion criteria, and 24 (75%) presented CCD. Univariate analyses revealed more frequent arterial occlusions, higher diffusion-weighted imaging (DWI) lesion volumes and higher initial NIHSS and mRS scores in the CCD-positive group compared with the CCD-negative group (all p < .05). The presence of arterial occlusion and the initial mRS scores were related with the AI (all p < .05). Multivariate analyses revealed that arterial occlusion and the initial mRS scores were significantly associated with CCD and AI.

Conclusion

ASL imaging could detect CCD in 75% of patients with hyperacute infarction. We found that CCD was more prevalent in patients with arterial occlusion, larger ischemic brain volumes, and higher initial NIHSS and mRS scores. In particular, vessel occlusion and initial mRS score appeared to be significantly related with CCD pathophysiology in the hyperacute stage.

Crossed cerebellar diaschisis in patients with acute middle cerebral artery infarction: Occurrence and perfusion characteristics

We aimed to investigate the overall prevalence and possible factors influencing the occurrence of crossed cerebellar diaschisis after acute middle cerebral artery infarction using whole-brain CT perfusion. A total of 156 patients with unilateral hypoperfusion of the middle cerebral artery territory formed the study cohort; 352 patients without hypoperfusion served as controls. We performed blinded reading of different perfusion maps for the presence of crossed cerebellar diaschisis and determined the relative supratentorial and cerebellar perfusion reduction. Moreover, imaging patterns (location and volume of hypoperfusion) and clinical factors (age, sex, time from symptom onset) resulting in crossed cerebellar diaschisis were analysed. Crossed cerebellar diaschisis was detected in 35.3% of the patients with middle cerebral artery infarction. Crossed cerebellar diaschisis was significantly associated with hypoperfusion involving the left hemisphere, the frontal lobe and the thalamus. The degree of the relative supratentorial perfusion reduction was significantly more pronounced in crossed cerebellar diaschisis-positive patients but did not correlate with the relative cerebellar perfusion reduction. Our data suggest that (i) crossed cerebellar diaschisis is a common feature after middle cerebral artery infarction which can robustly be detected using whole-brain CT perfusion, (ii) its occurrence is influenced by location and degree of the supratentorial perfusion reduction rather than infarct volume (iii) other clinical factors (age, sex and time from symptom onset) did not affect the occurrence of crossed cerebellar diaschisis.

Correlation of Asymmetry Indices Measured by Arterial Spin-Labeling MR Imaging and SPECT in Patients with Crossed Cerebellar Diaschisis

BACKGROUND AND PURPOSE

Crossed cerebellar diaschisis, not only a secondary result of supratentorial infarction but also an indicator of clinical outcomes, has frequently been reported on PET and SPECT but has been rarely described with arterial spin-labeling MR imaging. The purpose of this study was to determine the ability of arterial spin-labeling MR imaging to evaluate crossed cerebellar diaschisis compared with that of SPECT. To our knowledge, this is the first study to validate arterial spin-labeling in crossed cerebellar diaschisis by using SPECT as a reference standard.

MATERIALS AND METHODS

This study included 16 patients in whom crossed cerebellar diaschisis was shown on SPECT and 10 control subjects in whom crossed cerebellar diaschisis was not shown on SPECT. During the qualitative analysis, asymmetric cerebellar perfusion on arterial spin-labeling was divided into 1 of the following 3 grades by 2 blinded observers: the affected cerebellum was isointense compared with the unaffected cerebellum (grade I), it was slightly hypointense (grade II), or it was markedly hypointense (grade III). In the quantitative analysis, asymmetry indices were calculated by using SPECT and arterial spin-labeling images. For statistical analysis, κ statistics, the interobserver correlation coefficient, the independent t test, Pearson correlation, and linear regression analysis were used.

RESULTS

Almost all the diagnoses of crossed cerebellar diaschisis on SPECT were noted on arterial spin-labeling in both qualitative and quantitative analyses with good interobserver agreement (κ = 0.961; interobserver correlation coefficient, 0.806). The mean asymmetry index of arterial spin-labeling (26.06 ± 9.00) was significantly larger than that for SPECT (15.28 ± 5.34; P < .001). There was a significant positive correlation between the asymmetry indices obtained for SPECT and those for arterial spin-labeling (r = 0.77 [95% CI, 0.443-0.916]; P < .001). The relationship of asymmetry indices between SPECT and arterial spin-labeling (x, y) was calculated as y = 6.2131 + 1.2986x (R(2) = 0.592; P < .001).

CONCLUSIONS

Arterial spin-labeling can be a noninvasive alternative to SPECT for evaluating crossed cerebellar diaschisis.

Corticopontocerebellar Connectivity Disruption in Congenital Hemiplegia

BACKGROUND

Crossed cerebellar diaschisis is the disruption of functional connectivity between cerebrum and cerebellum after hemispheric unilateral brain lesions. In adults and to a lesser extent in children, crossed cerebellar diaschisis has been largely investigated by functional connectivity and demonstrated to influence paretic hand function.

OBJECTIVE

We aim to demonstrate a disruption in structural corticopontocerebellar (CPC) connectivity in children with congenital brain lesions and examine its correlation with paretic hand motor function.

METHODS

Thirty-six children (Manual Ability Classification System: I, n = 21; II, n = 15) with unilateral brain lesions and 18 controls were analyzed in a case-control study, and diffusion magnetic resonance imaging data were acquired at 3T. High angular resolution diffusion imaging probabilistic tractography was employed for the region of interest-based reconstruction of CPC tracts. To identify statistical differences in structural cerebrocerebellar connectivity between case and control groups, an asymmetry index based on the number of streamlines of CPC tracts was used. In the case group, the correlation between asymmetry index and hand function measures was also determined.

RESULTS

Projections through the middle cerebellar peduncle to the contralateral cerebral cortex showed greater asymmetry in children with congenital unilateral brain lesion compared to controls (P = .03), thus indicating a disruption of structural cerebrocerebellar connectivity. The degree of asymmetry index showed a correlation (P < .03; r = -0.31) with impaired hand abilities in bimanual tasks.

CONCLUSIONS

Disruption of structural cerebrocerebellar connectivity is present in patients with congenital unilateral brain injury and might be related to impaired hand function in bimanual skills, with potential implication in tailoring early intervention strategies.

Crossed cerebellar diaschisis detected by arterial spin-labeled perfusion magnetic resonance imaging in subacute ischemic stroke

BACKGROUND

Crossed cerebellar diaschisis (CCD) was a common radiological phenomenon manifested as reduced blood flow and metabolism in the cerebellar hemisphere contralateral to a supratentorial cerebral lesion. The hypoperfusion and hypometabolism in the contralateral cerebellum in CCD was traditionally detected by positron emission tomography (PET) and single-photon emission computed tomography (SPECT). The present prospective study aimed to assess the detection of CCD in subacute stage ischemic stroke by arterial spin-labeling (ASL) perfusion technique with a 3.0-T magnetic resonance imaging (MRI) scanner.

METHODS

ASL images were obtained from 46 patients with supratentorial ischemic stroke at subacute stage. Regional cerebral blood flow values in the cerebellar hemispheres were measured on a region of interest basis.

RESULTS

Twenty-four of 46 (52%) patients showed CCD phenomenon by ASL-MRI method, which was in line with the PET/SPECT series. Infarctions in basal ganglia areas are prone to cause CCD.

CONCLUSIONS

With advantages in easy acquisition and no radiation, ASL-MRI seems to be an ideal tool for the detection and follow-up of CCD.

Apparent diffusion coefficient evaluation for secondary changes in the cerebellum of rats after middle cerebral artery occlusion

Supratentorial cerebral infarction can cause functional inhibition of remote regions such as the cerebellum, which may be relevant to diaschisis. This phenomenon is often analyzed using positron emission tomography and single photon emission CT. However, these methods are expensive and radioactive. Thus, the present study quantified the changes of infarction core and remote regions after unilateral middle cerebral artery occlusion using apparent diffusion coefficient values. Diffusion-weighted imaging showed that the area of infarction core gradually increased to involve the cerebral cortex with increasing infarction time. Diffusion weighted imaging signals were initially increased and then stabilized by 24 hours. With increasing infarction time, the apparent diffusion coefficient value in the infarction core and remote bilateral cerebellum both gradually decreased, and then slightly increased 3–24 hours after infarction. Apparent diffusion coefficient values at remote regions (cerebellum) varied along with the change of supratentorial infarction core, suggesting that the phenomenon of diaschisis existed at the remote regions. Thus, apparent diffusion coefficient values and diffusion weighted imaging can be used to detect early diaschisis.

Correlation between crossed cerebellar diaschisis and clinical neurological scales

BACKGROUND

A common consequence of unilateral stroke is crossed cerebellar diaschisis (CCD), a decrease in regional blood flow (CBF) and metabolism (CMRglu) in the cerebellar hemisphere contralateral to the affected cerebral hemisphere. Former studies indicated a post-stroke time-dependent relationship between the degree of CCD and the clinical status of acute and sub-acute stroke patients, but no study has been performed in post-stroke patients.

OBJECTIVES

The objective of this investigation was to evaluate the quantitative correlation between the degree of CCD and the values of clinical stroke scales in post-stroke patients.

MATERIALS AND METHODS

We measured with positron emission tomography (PET) regional CBF and CMRglu values in the affected cortical regions and the contralateral cerebellum in ten ischaemic post-stroke patients. Based on these quantitative parameters, the degree of diaschisis (DoD) was calculated, and the DoD values were correlated with three clinical stroke scales [Barthel Index, Orgogozo Scale and Scandinavian Neurological Scale (SNS)].

RESULTS

There were significant linear correlations between all clinical stroke scales and the CCD values (Barthel Index and Orgogozo Scale: P < 0.001, for both CBF and CMRglu; SNS: P = 0.007 and P = 0.044; CBF and CMRglu, respectively).

CONCLUSIONS

The findings indicate that DoD can be used as a quantitative indicator of the functional impairments following stroke, i.e. it can serve as a potential surrogate of the severity of the damage.

Cerebellar dysfunction may play an important role in vascular dementia

The cerebellum has traditionally been seen as a brain area limited to the coordination of voluntary movement, gait, posture, speech, and motor functions. There are increasing evidence, however, proving that the cerebellum is implicated in processes associated with the control of cognition, behavior, and psychiatric illness. Furthermore, the fact that the cerebellum is reciprocally connected to a broad range of limbic structures including the amygdale and hippocampus, as well as the cerebral cortex including the prefrontal areas, provides a strong neuroanatomical argument in favor of cerebellar involvement in cognition regulation. Studies have already found the fact that after stroke, the cerebellum suffered from reduction in metabolism and blood flow in the cerebellar hemisphere contralateral to a destructive cerebral lesion. The notion of crossed cerebellar diaschisis (CCD) may contribute to the explanation of the phenomenon. Consequently, theoretically, stroke in any part of the brain including frontal lobe and hippocampus, will affect cerebellar function and the later then results in vascular dementia (VD). More recently, a few clinical trials found that electrical stimulation of fastigial nucleus (FNS) in cerebellum could improve symptom of VD, though the relationship between cerebellum and VD is unclear. Taken together, there seems to be sufficient empirical ground to assume that the cerebellum plays a role in the regulation of VD. The hypotheses of cerebellar role in VD, which will be discussed in this paper, if confirmed, may lead to the formulation of new pathogenesis and new therapeutic approaches to VD.

The cerebellum in emotion regulation: a repetitive transcranial magnetic stimulation study

Several lines of evidence suggest that the cerebellum may play a role in the regulation of emotion. The aim of this study was to investigate the hypothesis that inhibition of cerebellar function using slow repetitive transcranial magnetic stimulation (rTMS) would lead to increased negative mood as a result of impaired emotion regulation. In a randomized counterbalanced within-subjects design, 12 healthy young right-handed volunteers received 20 min of cerebellar, occipital, or sham 1 Hz rTMS on three separate days. Mood state inventories were acquired prior to and immediately after rTMS and after an emotion regulation task (ERT). In the ERT, participants were instructed to either look at aversive and neutral scenes, or to suppress the negative feelings experienced while watching aversive scenes during which the electroencephalogram (EEG) was recorded. Results showing no changes in baseline-corrected mood were observed immediately after rTMS. However, significant increases in baseline-corrected negative mood following the ERT were reported after cerebellar rTMS exclusively. No effects on the EEG during the ERT were observed. These findings provide support for the view that the cerebellum is implicated in the regulation of emotion and mood, and concur with evidence of cerebellar abnormalities observed in disorders associated with emotion dysregulation. In order to clarify the underlying biological mechanisms involved, more research is needed.

Crossed cerebellar diaschisis in acute stroke detected by dynamic susceptibility contrast MR perfusion imaging

BACKGROUND AND PURPOSE

Crossed cerebellar diaschisis (CCD), the decrease in blood flow and metabolism in the cerebellar hemisphere contralateral to a supratentorial stroke, is frequently reported on positron-emission tomography (PET) and single-photon emission CT (SPECT) but is rarely described with MR perfusion techniques. This study was undertaken to determine the frequency of CCD observed in acute stroke by retrospective review of a research data base of patients with acute stroke evaluated by diffusion-weighted (DWI) and dynamic contrast susceptibility perfusion MR imaging (PWI).

MATERIALS AND METHODS

PWI scans of 301 consecutive patients with acute stroke and positive DWI abnormality from a research data base were reviewed. Contralateral cerebellar hypoperfusion was identified by inspection of time-to-peak (TTP) maps for asymmetry with an absence of cerebellar abnormalities on T2-weighted scans, DWI, or disease of the vertebrobasilar system on MR angiography. In a subset of the cases, quantitative analysis of perfusion scans was performed using an arterial input function and singular value decomposition (SVD) to generate cerebral blood flow (CBF) maps.

RESULTS

A total of 47 of 301 cases (15.61%) met the criteria of CCD by asymmetry of cerebellar perfusion on TTP maps. On quantitative analysis, there was corresponding reduction of CBF by 22.75 +/- 10.94% (range, 7.45% to 52.13%) of the unaffected cerebellar hemisphere).

CONCLUSIONS

MR perfusion techniques can be used to detect CCD, though the frequency presented in this series is lower than that commonly reported in the PET/SPECT literature. Nevertheless, with its role in acute stroke and noninvasive nature, MR perfusion may be a viable alternative to PET or SPECT to study the phenomenon and clinical consequences of supratentorial stroke with CCD.

Crossed cerebellar diaschisis in acute ischemic stroke: a study with serial SPECT and MRI

This study evaluated the relationship between crossed cerebellar diaschisis (CCD) and (1) lesion volume and location in the acute phase and 1 week after stroke onset and (2) clinical outcome. Twenty-two patients with cerebral ischemic stroke underwent single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) within 48 h and on day 8 from onset. Interhemispheric asymmetric indices (AI) on SPECT were calculated for medial, intermediate, and lateral zones of the cerebellum. Lesion volumes and locations were obtained from diffusion-weighted MRI. Neurological status and 3-month clinical outcome were evaluated. Within 48 h, lesion locations in the temporal association cortex and pyramidal tract of the corona radiata were independent determinants for the AI of the medial zone (R(2)=0.439). Lesion locations in the primary, premotor, and supplementary motor cortices, primary somatosensory cortex, and anterior part of the posterior limb of the internal capsule were determinants for the AI of the intermediate zone (R(2)=0.785). Lesions in the primary motor cortex, premotor, and supplementary motor cortices and in the genu of the internal capsule were determinants for the AI of the lateral zone (R(2)=0.746). On day 8, the associations were decreased. The AIs of the intermediate and lateral zones and lesion location in the parietal association cortex were independently associated with the 3-month clinical outcome (R(2)>0.555). Acute CCD is a result of functional deafference, while in the subacute phase, transneuronal degeneration might contribute to CCD. CCD in the intermediate and later zones is a better indicator than that in the medial zone.

Crossed cerebellar diaschisis in acute human stroke: a PET study of serial changes and response to supratentorial reperfusion

Crossed cerebellar diaschisis (CCD) is well described in the chronic phase of stroke, but few data describe acute CCD and its serial changes after reperfusion. Using positron emission tomography (PET), we studied acute CCD with respect to supratentorial perfusion and outcome measures. In 19 acute stroke patients receiving intravenous thrombolysis (<3 h), 15O-water PET assessed CCD and supratentorial hypoperfusion volume before thrombolysis, 3, 24 h and 14 days later. Infarct volume at day 14 and NIHSS score at 3 months were assessed. Supratentorial hypoperfusion decreased from 25 cm3 (median) before thrombolysis to 0.1 cm3 at day 14. Baseline CCD was 13.4% and decreased continuously to 6.1% after 14 days. The NIHSS score decreased from 11 to 4 pts after 3 months. Infarct volume was 1.1 cm3. Crossed cerebellar diaschisis correlated to the hypoperfusion volume within the first 24 h after stroke, but not later. Hypoperfusion correlated to outcome measures at the early stage only. In contrast, CCD correlated to outcome values at all four measurements. Reperfusion with recovery of CCD was seen in patients with small infarcts and good clinical outcome and vice versa. Our data suggest that (i) CCD occurs as early as 3 h after stroke and might be reversible; (ii) acute CCD is closely related to the volume of supratentorial hypoperfusion. At later time points, however, CCD is disconnected from supratentorial perfusion but strongly associated to outcome measures; (iii) CCD is not susceptible to non-nutritional reperfusion and adds valuable information to interpret supratentorial reperfusion patterns.