Cerebellar Blood Flow Research Articles

Diurnal variation of cerebral blood flow in healthy humans under normal entrained conditions.

The presence of a circadian cycle of cerebral blood flow may have implications for the occurrence of daily variations in cerebrovascular events in humans, but how cerebral blood flow varies throughout the day and its mechanism are still unclear. The study aimed to explore the diurnal variation of cerebral blood flow in healthy humans and its possible mechanisms. Arterial spin labelling images were collected at six time-points (09:00 hours, 13:00 hours, 17:00 hours, 21:00 hours, 01:00 hours, 05:00 hours) from 18 healthy participants (22-39 years old; eight females) to analyse diurnal variations in cerebral blood flow. Resting heart rate and blood pressure at six time-points and blood indicators (20-hydroxyeicosatetraenoic acid, epoxyeicosatrienoic acids, prostaglandin E2, noradrenaline and nitric oxide) related to cerebral vascular tone at two time-points (09:00 hours and 21:00 hours) were collected to analyse possible influences on diurnal variations in cerebral blood flow. From 21:00 hours to 05:00 hours, parietal cortical relative cerebral blood flow tended to increase, while frontal cortical and cerebellar relative cerebral blood flow tended to decrease. There was a time-dependent negative correlation between parietal cortical relative cerebral blood flow and resting heart rate, whereas there was a time-dependent positive correlation between cerebellar relative cerebral blood flow and resting heart rate. The change of parietal cortical relative cerebral blood flow was positively correlated with the change of nitric oxide. There was also a time-dependent positive correlation between mean arterial pressure and mean whole-brain cerebral blood flow. The findings indicated that parietal cortical relative cerebral blood flow and frontal cortical/cerebellar relative cerebral blood flow showed roughly opposite trends throughout the day. The diurnal variations in relative cerebral blood flow were regional-specific. Diurnal variation of nitric oxide and neurogenic regulation may be potential mechanisms for diurnal variation in regional relative cerebral blood flow.

Cerebellum and hippocampus abnormalities in patients with insomnia comorbid depression: a study on cerebral blood perfusion and functional connectivity.

Chronic insomnia disorder and major depressive disorder are highly-occurred mental diseases with extensive social harm. The comorbidity of these two diseases is commonly seen in clinical practice, but the mechanism remains unclear. To observe the characteristics of cerebral blood perfusion and functional connectivity in patients, so as to explore the potential pathogenesis and biological imaging markers, thereby improving the understanding of their comorbidity mechanism. 44 patients with chronic insomnia disorder comorbid major depressive disorder and 43 healthy controls were recruited in this study. The severity of insomnia and depression were assessed by questionnaire. The cerebral blood perfusion and functional connectivity values of participants were obtained to, analyze their correlation with questionnaire scores. The cerebral blood flow in cerebellum, vermis, right hippocampus, left parahippocampal gyrus of patients were reduced, which was negatively related to the severity of insomnia or depression. The connectivities of left cerebellum-right putamen and right hippocampus-left inferior frontal gyrus were increased, showing positive correlations with the severity of insomnia and depression. Decreased connectivities of left cerebellum-left fusiform gyrus, left cerebellum-left occipital lobe, right hippocampus-right paracentral lobule, right hippocampus-right precentral gyrus were partially associated with insomnia or depression. The connectivity of right hippocampus-left inferior frontal gyrus may mediate between insomnia and depression. Insomnia and depression can cause changes in cerebral blood flow and brain function. Changes in the cerebellar and hippocampal regions are the result of insomnia and depression. They reflect abnormalities in sleep and emotion regulation. That may be involved in the pathogenesis of comorbidity.

A subtle connection between crossed cerebellar diaschisis and supratentorial collateral circulation in subacute and chronic ischemic stroke

ObjectivesIt has not been reported whether collateral circulation, a factor closely related to the prognosis of patients with cerebral infarction, is related to the occurrence of crossed cerebellar diaschisis(CCD) or not. Our research attempts to verify the relationship between the collateral circulation grade and the occurrence of CCD, mainly by means of CTA and CTP. Materials and methodsA total of 47 patients were divided into a CCD-positive (Kim et al., 2019) or a CCD-negative group Furlanis et al. (2018) by calculating the asymmetry index (AI) value (<10%) of bilateral cerebellar cerebral blood flow (CBF). A 4-scale grading method was used to evaluate collateral circulation in the supratentorial infarct area, and the four perfusion parameters of the supratentorial and subtentorial brain regions were analyzed and compared between the two groups. The extent of vascular lesions was evaluated by MR sequences including DWI and MRA. ResultsAmong the four perfusion parameters, except for CBV, were significantly different between the bilateral cerebellum in the CCD-positive group, but only TTP in the supratentorial cerebral infarction area was statistically different in the two groups. Moreover, the collateral circulation sore in the CCD-positive group was significantly lower than that in the CCD-negative group. But no statistical difference was found in the comparison of DWI positive rates between the two groups. ConclusionThe collateral score in the supratentorial infarct area is correlated with the occurrence of CCD,which may be used to explain the effect of CCD on the prognosis of patients.

Hyperperfusion in the cerebellum lobule VIIb in patients with epileptic seizures

BackgroundThe cerebellum plays an important role in motor control, however, its involvement in epilepsy has not been fully understood. Arterial spin labelling perfusion magnetic resonance image (ASL) is a noninvasive method to evaluate cerebral and cerebellar blood flow. We investigated cerebellar perfusion in patients with epileptic seizures using ASL.MethodsAdult patients with epileptic seizures who underwent ASL in three post labeling delay (PLD) conditions (1525, 1800, and 2500 msec) and conventional electroencephalography (EEG) on the same day were investigated. Clinical and EEG characteristics of them were retrospectively analyzed.ResultsSix patients (6 women, age; 36.2 ± 17.9 years (mean ± SD)) showed hyperperfusion in selective areas in the cerebellar paravermis of lobule VIIb. One patient with generalized epilepsy (tentative diagnosis of juvenile myoclonic epilepsy or epilepsy with myoclonic absences) showed unilateral hypoperfusion in PLD 1525 msec and hyperperfusion in PLD 1800 and 2500 msec at the area while EEG showed generalized spike-wave complexes. After successful treatment, these perfusion abnormalities disappeared. In two patients with focal epilepsy manifesting with asymmetrical motor symptoms, cerebellar hyperperfusion was found on the opposite side to the seizure focus estimated by seizure semiology. Besides hyperperfusion of the VIIb lobule, hypoperfusion at the same area was detected in shorter PLD condition in four patients and in longer PLD condition in one patient.ConclusionThe cerebellar paravermis of lobule VIIb can be a component of motor circuit and participate in epileptic network in humans. Cerebellar perfusion abnormalities can be associated with neurovascular coupling via capillary bed.

Changes in the amplitude of low-frequency fluctuations in specific frequency bands in major depressive disorder after electroconvulsive therapy.

BACKGROUNDMajor depressive disorder (MDD) tends to have a high incidence and high suicide risk. Electroconvulsive therapy (ECT) is currently a relatively effective treatment for MDD. However, the mechanism of efficacy of ECT is still unclear.AIMTo investigate the changes in the amplitude of low-frequency fluctuations in specific frequency bands in patients with MDD after ECT.METHODSTwenty-two MDD patients and fifteen healthy controls (HCs) were recruited to this study. MDD patients received 8 ECT sessions with bitemporal placement. Resting-state functional magnetic resonance imaging was adopted to examine regional cerebellar blood flow in both the MDD patients and HCs. The MDD patients were scanned twice (before the first ECT session and after the eighth ECT session) to acquire data. Then, the amplitude of low-frequency fluctuations (ALFF) was computed to characterize the intrinsic neural oscillations in different bands (typical frequency, slow-5, and slow-4 bands).RESULTSCompared to before ECT (pre-ECT), we found that MDD patients after the eighth ECT (post-ECT) session had a higher ALFF in the typical band in the right middle frontal gyrus, posterior cingulate, right supramarginal gyrus, left superior frontal gyrus, and left angular gyrus. There was a lower ALFF in the right superior temporal gyrus. Compared to pre-ECT values, the ALFF in the slow-5 band was significantly increased in the right limbic lobe, cerebellum posterior lobe, right middle orbitofrontal gyrus, and frontal lobe in post-ECT patients, whereas the ALFF in the slow-5 band in the left sublobar region, right angular gyrus, and right frontal lobe was lower. In contrast, significantly higher ALFF in the slow-4 band was observed in the frontal lobe, superior frontal gyrus, parietal lobe, right inferior parietal lobule, and left angular gyrus.CONCLUSIONOur results suggest that the abnormal ALFF in pre- and post-ECT MDD patients may be associated with specific frequency bands.

Exploring the relationship between soft and hard tissues: The example of vertebral arteries and transverse foramina.

Understanding how the brain is provided with glucose and oxygen is of particular interest in human evolutionary studies. In addition to the internal carotid arteries, vertebral arteries contribute significantly to the cerebral and cerebellar blood flow. The size of the transverse foramina has been suggested to represent a reliable proxy for assessing the size of the vertebral arteries in fossil specimens. To test this assumption, here, we statistically explore spatial relationships between the transverse foramina and the vertebral arteries in extant humans. Contrast computed tomography (CT) scans of the cervical regions of 16 living humans were collected. Cross‐sectional areas of the right and left transverse foramina and the corresponding vertebral arteries were measured on each cervical vertebra from C1 to C6 within the same individuals. The cross‐sectional areas of the foramina and corresponding arteries range between 13.40 and 71.25 mm2 and between 4.53 and 29.40 mm2, respectively. The two variables are significantly correlated except in C1. Using regression analyses, we generate equations that can be subsequently used to estimate the size of the vertebral arteries in fossil specimens. By providing additional evidence of intra‐ and inter‐individual size variation of the arteries and corresponding foramina in extant humans, our study introduces an essential database for a better understanding of the evolutionary story of soft tissues in the fossil record.

FDG PET/MRI for Visual Detection of Crossed Cerebellar Diaschisis in Patients With Dementia.

Depressed regional metabolism and cerebellar blood flow may be caused by dysfunction in anatomically separate but functionally related regions, presumably related to disruption of the corticopontine-cerebellar pathway. The purpose of this study was to evaluate the prevalence of crossed cerebellar diaschisis (CCD) in patients undergoing 18F-FDG PET/MRI for suspected neurodegenerative disease. In total, 75 patients (31 men, 44 women; mean age, 74 years) underwent hybrid FDG PET/MRI for clinical workup of neurodegenerative disease. Images were obtained with an integrated 3-T PET/MRI system. PET surface maps, fused T1-weighted magnetization-prepared rapid acquisition gradient echo and axial FLAIR/PET images were generated with postprocessing software. Two board-certified neuroradiologists and a nuclear medicine physician blinded to patient history evaluated for pattern of neurodegenerative disease and CCD. Qualitative assessment showed that 10 of 75 (7.5%) patients had decreased FDG activity in the cerebellar hemisphere contralateral to the supratentorial cortical hypometabolism consistent with CCD. Six of the 10 patients had characteristic imaging findings of frontotemporal dementia (three behavioral variant frontotemporal dementia, two semantic primary progressive aphasia, and one logopenic primary progressive aphasia), three had suspected corticobasal degeneration, and one had Alzheimer dementia. Our study results suggest that CCD occurs most commonly in frontotemporal dementia, particularly the behavioral variant, and in patients with cortico-basal degeneration. Careful attention to cerebellar metabolism may assist in the clinical evaluation of patients with cognitive impairment undergoing FDG PET/MRI as part of their routine dementia workup.

Progressive amnestic cognitive impairment in a middle-aged patient with developmental language disorder: a case report

BackgroundDevelopmental disorder and dementia in older adults have been considered unrelated clinical entities because their timing of diagnosis differs greatly; however, recent studies have suggested an association between them. This case describes a middle-aged patient with language disorder exhibiting progressive amnestic cognitive impairment.Case PresentationA 44-year-old Japanese man with long-term language dysfunction presented for his first-ever medical evaluation at age 36 years. Although his conversational ability had been impaired since childhood, he was able to graduate from secondary school and gain unskilled employment. At age 36 years, however, his workplace environment became more stressful, which led to behavioral problems that necessitated medical consultation. He consulted two psychiatrists in vain. At age 44 years, the third attending psychiatrist examined him in detail. The major component of his language disorder was amnestic cognitive impairment in the language domain as shown by logical memory subtests of the Wechsler Memory Scale–Revised. Magnetic resonance imaging showed normal findings for his age and no small vessel disease. Global cerebral hypoperfusion versus cerebellar blood flow was shown on (123I) iodoamphetamine single-photon emission computed tomography, and amyloid-β deposition was negative on positron emission tomography with 11C-Pittsburgh compound B. Pathologic tau accumulation was negative on 18F-THK5351 positron emission tomography imaging. Laboratory tests show no infections, no vitamin deficiencies, and no other diseases that may cause dementia. Clinical features, results of neurocognitive tests and neuroimaging studies showed no well-known neurodegenerative diseases. Collectively, he was diagnosed with language disorder based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Over a 2-year follow-up period, amnestic cognitive impairment in visual and language domains progressed in parallel with global cerebral hypoperfusion.ConclusionThis case suggests a possible link between language disorder as defined by Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria and progressive amnestic cognitive impairment in middle age, which may ultimately lead to dementia, derived from a neurodegenerative disease.

Cerebellar Blood Flow and Gene Expression in Crossed Cerebellar Diaschisis after Transient Middle Cerebral Artery Occlusion in Rats.

Crossed cerebellar diaschisis (CCD) is a state of hypoperfusion and hypometabolism in the contralesional cerebellar hemisphere caused by a supratentorial lesion, but its pathophysiology is not fully understood. We evaluated chronological changes in cerebellar blood flow (CbBF) and gene expressions in the cerebellum using a rat model of transient middle cerebral artery occlusion (MCAO). CbBF was analyzed at two and seven days after MCAO using single photon emission computed tomography (SPECT). DNA microarray analysis and western blotting of the cerebellar cortex were performed and apoptotic cells in the cerebellar cortex were stained. CbBF in the contralesional hemisphere was significantly decreased and this lateral imbalance recovered over one week. Gene set enrichment analysis revealed that a gene set for “oxidative phosphorylation” was significantly upregulated while fourteen other gene sets including “apoptosis”, “hypoxia” and “reactive oxygen species” showed a tendency toward upregulation in the contralesional cerebellum. MCAO upregulated the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in the contralesional cerebellar cortex. The number of apoptotic cells increased in the molecular layer of the contralesional cerebellum. Focal cerebral ischemia in our rat MCAO model caused CCD along with enhanced expression of genes related to oxidative stress and apoptosis.

Differences in cerebellar perfusion between Parkinson's disease and multiple system atrophy

IntroductionObjective biomarkers are required for differential diagnosis of Parkinson's disease (PD), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). ObjectiveWe aimed to determine if cerebellar blood flow, measured using N-isopropyl-[123I] p-iodoamphetamine single photon emission computed tomography (123I -IMP-SPECT), was useful for differentiating between PD, MSA and PSP. MethodsTwenty-four patients with PD, seventeen patients with MSA with predominant parkinsonian features (MSA-P), sixteenth patients with MSA with predominant cerebellar ataxia (MSA-C) and eight patients with PSP were enrolled. Twenty-seven normal controls' data were used for the calculation of z score. All patients underwent 123I -IMP-SPECT, and data were analyzed using a three-dimensional-stereotactic surface projection program. ResultsCerebellar perfusion in MSA-P (MSA-P vs PD, P = .002; MSA-P vs PSP, P < .001) and MSA-C (MSA-C vs PD, P < .001; MSA-C vs PSP, P < .001) were significantly decreased compared with PD or PSP. There was no significant difference in perfusion between PD and PSP groups (P = .061). The area under the receiver operating characteristic curve for cerebellar perfusion between MSA-P and PD was 0.858. ConclusionOur findings revealed that cerebellar perfusion by 123I-IMP-SPECT was useful for differentiating between PD and MSA-P.

Abstract WP195: Cerebellar Magnetic Stimulation for Long-Lasting Dizziness After Brainstem Stroke

Introduction: Brainstem stroke sometimes causes long-lasting dizziness. A cerebellar control disorder of the vestibulo-ocular reflex (VOR) has been postulated as a mechanism of dizziness in such patients. We conducted a proof-of-principle cohort study to assess the potential efficacy of cerebellar repetitive transcranial magnetic stimulation (rTMS) as treatment for long-lasting post-brainstem stroke dizziness. Methods: We first applied cerebellar rTMS in healthy volunteers (n=11) and showed that cerebellar intermittent theta burst stimulation (iTBS) affected vestibulocerebellar neural activity. Then, we enrolled 11 patients with long-lasting post-brainstem stroke dizziness (lateral medullary infarction, 9; lateral pontine infarction, 1; and lateral pontine hemorrhage, 1), applied cerebellar rTMS (iTBS for 5 days), and followed these patients up for clinical symptoms (Dizziness Handicap Inventory [DHI]), signs (nystagmus), and VOR gain. Results: After rTMS, DHI scores were significantly reduced with disappearance or attenuation of the ipsilesional nystagmus characteristic of the long-lasting post-brainstem stroke dizziness. Reduction in the absolute VOR gain was also associated with reduced DHI scores. Relative cerebellar blood flow to the brainstem, measured in 4 patients, was increased. However, the effects of cerebellar rTMS did not always persist. Conclusion: Our study showed the potential efficacy of cerebellar rTMS for treatment of long-lasting post-brainstem stroke dizziness. Further large-scale randomized studies are warranted to confirm our findings.

Transcranial magnetic stimulation for diplopia in a patient with spinocerebellar ataxia type 6: a case report

A 62-year-old Japanese male with spinocerebellar ataxia type 6(SCA6) was admitted to our hospital for exacerbation of ataxia. We administered single-pulse transcranial magnetic stimulation (TMS) over the hand motor area (40 single pulses, about 0.3Hz at 100% of RMT) and over the cerebellum (20 single pulses, about 0.5Hz at 50% of RMT) with a circular coil once a day for one session, and for five sessions a week for 2 weeks (10 sessions). This therapy was performed for 2 courses, separated by a rest period of about 2 weeks (total 20 sessions) to reduce ataxia. After the initiation of TMS, since diplopia unexpectedly improved, we started a quantitative assessment of diplopia by counting the number of fixation spots that he observed in his visual field. This assessment suggested that TMS had an immediate and cumulative effect on diplopia. We also delivered more localized stimulation only over the motor cortex with a Figure-8 coil, and diplopia improved immediately. Additionally, we administered a sham stimulation before the real stimulation over the motor cortex and the cerebellum. The sham stimulation improved diplopia, and greater improvement was observed with subsequent real stimulation. We also used a Hess chart examination and video recordings of binocular gross appearance to elucidate the changes in ocular movement objectively. These examinations did not reveal any obvious oculomotor changes. The improved diplopia in this case suggests that there could have been improvement of something other than oculomotor movement or oculomotor improvement that was so slight that we could not detect it with our assessment. We speculate that TMS over the motor cortex may increase cerebellar blood flow and/or stimulation might affect the region around the motor cortex.

Arterial spin labeling MR imaging for the clinical detection of cerebellar hypoperfusion in patients with spinocerebellar degeneration

PurposeThe aim of this study was to evaluate the clinical utility of arterial spin labeling (ASL) magnetic resonance imaging (MRI) for the detection of cerebellar hypoperfusion in patients with spinocerebellar degeneration (SCD). MethodsRegional cerebral blood flow (CBF) were obtained from ASL and 123I-IMP single-photon emission computed tomography (SPECT) images by volume-of-interest analysis in patients with SCD (n = 16). Regional CBF were also measured by ASL in age-matched controls (n = 19) and by SPECT in separate controls (n = 17). The cerebellar CBF values were normalized to the CBF values for the whole gray matter (nCBF) in ASL and SPECT. ResultsThe mean cerebellar nCBF measured by ASL was lower in patients with SCD (0.70 ± 0.09) than in the controls (0.91 ± 0.05) (p < 0.001), which was consistent with the comparison using SPECT (0.82 ± 0.05 vs. 0.98 ± 0.05, p < 0.001). The cerebellar nCBF measured by ASL significantly correlated with that determined by SPECT in patients (r = 0.56, p < 0.001). ConclusionsASL imaging showed decreased cerebellar blood flow, which correlated with that measured by SPECT, in patients with SCD. These findings suggest the clinical utility of noninvasive MRI with ASL for detecting cerebellar hypoperfusion in addition to atrophy, which would aid the diagnosis of SCD.

Effects of cerebellar magnetic stimulation on chronic post-lateral medullary infarction dizziness: A proof-of-principle cohort study

Background and purposeLateral medullary infarction (LMI) sometimes causes long-lasting dizziness. Although the precise mechanism of chronic post-LMI dizziness is unknown, a cerebellar control disorder of the vestibulo-ocular reflex (VOR) has been reported in such patients. We conducted a proof-of-principle cohort study to assess the potential efficacy of cerebellar repetitive transcranial magnetic stimulation (rTMS) as treatment for chronic post-LMI dizziness. MethodsWe first applied cerebellar rTMS in healthy volunteers (n = 11) and showed that cerebellar intermittent theta burst stimulation (iTBS) affected vestibulocerebellar neural activity. Then, between September and December 2015, we enrolled six patients (aged≥20 years) with chronic post-LMI dizziness (duration≥6 months), applied cerebellar rTMS (iTBS for 5 days), and followed these patients up for up to 25 months for clinical symptoms (Dizziness Handicap Inventory [DHI]), signs (nystagmus), and VOR gain. ResultsFour of the six patients completed the study without complications. After rTMS, DHI scores were reduced (mean pre-rTMS DHI score minus post-rTMS DHI score was 13.0 [P = 0.036]) with disappearance of the ipsilesional nystagmus characteristic of the post-LMI dizziness. Reduction in the absolute VOR gain (mean pre- rTMS gain minus post-rTMS gain in the ipsilesional direction was 0.135 [P = 0.036] and that in the contralesional direction was 0.137 [P = 0.031]) were also associated with reduced DHI scores. Relative cerebellar blood flow to the brainstem was increased in four of five patients. The effects of cerebellar rTMS did not always persist, and three of four patients elected to undergo more than one rTMS series. The repeat cerebellar rTMS treatments had same beneficial effects. ConclusionOur study showed, for the first time, the potential efficacy of cerebellar rTMS for treatment of chronic post-LMI dizziness. The short duration of the cerebellar rTMS effects can be compensated for by repeating the rTMS treatment every few months. Further large-scale randomized studies are warranted to confirm our findings.

Aberrant resting-state cerebellar blood flow in major depression

BackgroundAbnormal cortical cerebral blood flow and gray matter volume have been frequently reported in patients with major depressive disorder (MDD). In contrast, although the role of the cerebellum in MDD pathophysiology has attracted considerable interest more recently, studies investigating both functional and structural aspects of cerebellar integrity are scarce. MethodsIn this study, we used structural and functional magnetic resonance imaging (MRI) to investigate cerebellar volume and regional cerebellar blood flow (rCBF) at rest in clinically acute MDD patients (n = 22) and healthy controls (n = 18). We acquired high-resolution structural images at 3 T together with perfusion images obtained with continuous arterial spin labeling. Cerebellar structure and function were investigated using cerebellum-optimized analysis techniques. ResultsMarkedly increased rCBF was found in bilateral cerebellar areas VIIa and VIIIb (p < 0.05 family-wise-error [FWE] corrected). Significant differences in cerebellar volume between patients and controls were not found (p < 0.05, FWE-corrected). Left cerebellar area VIIa perfusion was significantly associated with depressive symptoms, as measured by the Hamilton Depression Rating Scale. LimitationsPotential limitations of this study include the modest sample size, the cross-sectional design, the lack of task-related imaging and the heterogeneity of drug treatment. ConclusionsThe data suggest contributions of “affective” cerebellar regions to MDD pathophysiology and symptom expression. While cerebellar perfusion at rest is compromised in MDD, cerebellar volume seems to be less affected.

Early Imaging Prediction of Malignant Cerebellar Edema Development in Acute Ischemic Stroke.

Malignant cerebellar edema (MCE) is a life-threatening complication of acute ischemic stroke that requires timely diagnosis and management. Aim of this study was to identify imaging predictors in initial multiparametric computed tomography (CT), including whole-brain CT perfusion (WB-CTP). We consecutively selected all subjects with cerebellar ischemic WB-CTP deficits and follow-up-confirmed cerebellar infarction from an initial cohort of 2635 patients who had undergone multiparametric CT because of suspected stroke. Follow-up imaging was assessed for the presence of MCE, measured using an established 10-point scale, of which scores ≥4 are considered malignant. Posterior circulation-Acute Stroke Prognosis Early CT Score (pc-ASPECTS) was determined to assess ischemic changes on noncontrast CT, CT angiography (CTA), and parametric WB-CTP maps (cerebellar blood flow [CBF]; cerebellar blood volume; mean transit time; time to drain). Fisher's exact tests, Mann-Whitney U tests, and receiver operating characteristics analyses were performed for statistical analyses. Out of a total of 51 patients who matched the inclusion criteria, 42 patients (82.4%) were categorized as MCE- and 9 (17.6%) as MCE+. MCE+ patients had larger CBF, cerebellar blood volume, mean transit time, and time to drain deficit volumes (all with P<0.001) and showed significantly lower median pc-ASPECTS assessed using WB-CTP (CBF, cerebellar blood volume, mean transit time, time to drain; all with P<0.001) compared with MCE- patients, while median pc-ASPECTS on noncontrast CT and CTA was not significantly different (both P>0.05). Receiver operating characteristics analyses yielded the largest area under the curve values for the prediction of MCE development for CBF (0.979) and cerebellar blood volume deficit volumes (0.956) and pc-ASPECTS on CBF (0.935), whereas pc-ASPECTS on noncontrast CT (0.648) and CTA (0.684) had less diagnostic value. The optimal cutoff value for CBF deficit volume was 22 mL, yielding 100% sensitivity and 90% specificity for MCE classification. WB-CTP provides added diagnostic value for the early identification of patients at risk for MCE development in acute cerebellar stroke.

Unilateral fetal-type circle of Willis anatomy causes right–left asymmetry in cerebral blood flow with pseudo-continuous arterial spin labeling: A limitation of arterial spin labeling-based cerebral blood flow measurements?

The accuracy of cerebral blood flow measurements using pseudo-continuous arterial spin labeling can be affected by vascular factors other than cerebral blood flow, such as flow velocity and arterial transit time. We aimed to elucidate the effects of common variations in vascular anatomy of the circle of Willis on pseudo-continuous arterial spin labeling signal. In addition, we investigated whether possible differences in pseudo-continuous arterial spin labeling signal could be mediated by differences in flow velocities. Two hundred and three elderly participants underwent magnetic resonance angiography of the circle of Willis and pseudo-continuous arterial spin labeling scans. Mean pseudo-continuous arterial spin labeling-cerebral blood flow signal was calculated for the gray matter of the main cerebral flow territories. Mean cerebellar gray matter pseudo-continuous arterial spin labeling-cerebral blood flow was significantly lower in subjects having a posterior fetal circle of Willis variant with an absent P1 segment. The posterior fetal circle of Willis variants also showed a significantly higher pseudo-continuous arterial spin labeling-cerebral blood flow signal in the ipsilateral flow territory of the posterior cerebral artery. Flow velocity in the basilar artery was significantly lower in these posterior fetal circle of Willis variants. This study indicates that pseudo-continuous arterial spin labeling measurements underestimate cerebral blood flow in the posterior flow territories and cerebellum of subjects with a highly prevalent variation in circle of Willis morphology. Additionally, our data suggest that this effect is mediated by concomitant differences in flow velocity between the supplying arteries.

頸部血管超音波で神経症状改善を伴う頭蓋内椎骨動脈の再開通を捉えた1例

An 85-year-old woman came to our hospital due to an inability to live independently from a decline in her activities of daily living. Neurologically, she showed no focal signs, but multiple acute ischemic lesions were evident in the posterior circulation on magnetic resonance imaging. Occlusion of the right intracranial vertebral artery (VA) and stenosis of the left intracranial VA were detected on magnetic resonance angiography (MRA). Carotid duplex ultrasonography (CUS) showed a flow pattern with occlusion of the right VA before the branching of the posterior inferior cerebellar artery. Based upon antegrade flow in the right intracranial VA as evaluated on transcranial color flow imaging, the distal VA territory might have been maintained via collateral flow. With antiplatelet therapy and intravenous injection of argatroban, the patient’s activity gradually improved to the same level as before admission. Recanalization of the right VA was seen on MRA and CUS at 14 days after admission. Reduced cerebellar blood flow due to VA occlusion was thought to be associated with the mechanism affecting her activity levels. Follow-up ultrasonography was useful for evaluating changes in intracranial hemodynamics in this patient who demonstrated neurological improvement.

The Mechanism of Ipsilateral Ataxia in Lacunar Hemiparesis: SPECT Perfusion Imaging

Background and Purpose: Although ataxic hemiparesis is a common lacunar syndrome, the precise mechanism underlying hemiataxia is not clear. We attempted to identify ataxia-related, cerebral blood flow changes in patients presenting with ataxic hemiparesis after acute capsular infarct. Methods: We used 99mTc-ECD brain perfusion single-photon emission computed tomography to evaluate regional cerebral blood flow in 12 patients with ataxic hemiparesis caused by capsular infarct, and we compared the regional blood flow of these patients with that of 11 patients with pure motor hemiparesis caused by similar lesions. Results: The ipsilateral red nucleus blood flow was significantly decreased in the ataxic hemiparesis patients, whereas the ipsilateral red nucleus blood flow was increased in the pure motor hemiparesis patients. Crossed cerebellar diaschisis (decreased contralateral cerebellar blood flow) was seen in ataxic hemiparesis patients; similarly, it was seen in pure motor hemiparesis patients. Conclusions: Our findings suggest that ataxia in hemiparetic patients with capsular infarct can be caused by ipsilateral red nucleus dysfunction secondary to cortico-rubral pathway disruption at the internal capsule. i 2014 S. Karger AG, Basel

Vertebral Artery Hypoplasia: Frequency and Effect on Cerebellar Blood Flow Characteristics

Vertebral Artery Hypoplasia: Frequency and Effect on Cerebellar Blood Flow Characteristics