Cerebellar Hyperperfusion Research Articles

Crossed cerebellar hyperperfusion during periictal and ictal periods revealed by 1.5-Tesla arterial spin labeling magnetic resonance perfusion images

Crossed cerebellar hyperperfusion during periictal and ictal periods revealed by 1.5-Tesla arterial spin labeling magnetic resonance perfusion images

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.

Specificities of arterial spin labeling (ASL) abnormalities in acute seizure

PurposeArterial spin labeling (ASL) is a non-invasive tool measuring cerebral blood flow (CBF) and is useful to assess acute neurological deficit. While acute stroke presents as hypoperfused vascular territory, epileptic activity causes cortical hyperperfusion. Other neurological conditions exhibit hyperperfusion, like migraine or secondary “luxury perfusion” in strokes. Our objectives were to evaluate the usefulness and potential specificities of ASL in acute seizure and correlate it with electroencephalogram. Materials and methodsAmongst a cohort of patients with neurological deficit, addressed for suspicion of stroke, we retrospectively reviewed 25 consecutive patients with seizures who underwent magnetic resonance imaging (MRI) with ASL and electroencephalography (EEG). We compared them with a control group of patients with migraine and stroke secondary re-perfusion, exhibiting ASL hyperperfusion. ResultsLateralized cortical hyperperfusion (high relative CBF) was observed in all patients. Good topographic correlation with EEG was found in 18 patients (72%). Eight (32%) had hyperperfusion of ipsilateral pulvinar, 5 (20%) had hyperperfused contralateral cerebellar hemisphere, 16 (64%) presented diffusion abnormalities and 20 (80%) had underlying epileptogenic lesions. Pulvinar hyperperfusion was not observed in the control group, nor were diffusion abnormalities in migrainous patients. Contralateral cerebellar hyperperfusion was observed in two migrainous patient, without associated pulvinar activation, whereas all patients with cerebellar hyperperfusion in the study group had associated pulvinar activation. ConclusionsElevated CBF can be observed in the epileptogenic zone, ipsilateral pulvinar and contralateral cerebellum (diaschisis) in seizure. These abnormalities seem specific when compared with other causes of hyperperfusion. Arterial spin labeling can be highly effective in the differential diagnosis of strokes.

Subcortical SISCOM hyperperfusion: Should we pay more attention to it?

PurposeDemonstrating cerebral blood flow changes during seizures, ictal-interictal single photon emission computed tomography (SPECT) with co-registration to MRI (SISCOM) reflects brain activation and its pathways of spread. To investigate subcortical ictal hyperperfusion patterns during focal seizures, we retrospectively reviewed SISCOM analysis of patients who became seizure-free after cortical resection. Our aim was to evaluate the relationship between epileptogenic zones and subcortical hyperperfusion. Method67 patients were identified as having SISCOM evaluation and having remained seizure-free for at least one year after surgical resection. SISCOM analysis was blindly reviewed for localization of basal ganglia (BG), thalamic (TN) and cerebellar (CH) hyperperfusion based on three different thresholds. Subcortical activation and epilepsy characteristics were then compared between patients. For a given region of interest and threshold, the sensitivity, specificity and positive and negative predictive value for correct lateralization of the epilepsy side was calculated. ResultsDepending on the threshold used, BG hyperperfusion was found in 37.3–73.9% of patients, TN hyperperfusion in 31.3–68.1% and CH hyperperfusion in 13.5–29%. For a threshold of 1.5, the best predictive positive value for correct lateralization of the epilepsy side was obtained with BG/CH coactivation (89%). For a threshold of 2.0 and 2.5, it was obtained with BG/TN coactivation (88%) and BG activation (82%), respectively. ConclusionSubcortical SISCOM hyperperfusion could offer additional clues in terms of lateralization.

Crossed Cerebellar and Contralateral Thalamic Hyperperfusion in Epilepsy.

Crossed Cerebellar and Contralateral Thalamic Hyperperfusion in Epilepsy.

Crossed cerebellar hyperperfusion after MELAS attack followed up by whole brain continuous arterial spin labeling perfusion imaging

Crossed cerebellar hyperperfusion (CCH) is detected in patients with epilepsy by brain perfusion studies including single photon emission computed tomography and positron emission tomography. In addition, brain perfusion can be studied with arterial spin labeling (ASL), which is a non-invasive MRI perfusion method that quantitatively measures cerebral blood flow per unit tissue mass. We followed up a 47-year-old patient with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) by continuous arterial spin labeling technique, which showed crossed cerebellar hyperperfusion after acute stroke-like episode. This cerebellar hyperperfusion normalized in the follow-up.

Brain activation patterns of versive, hypermotor, and bilateral asymmetric tonic seizures

Patients who have seizure onset from different brain regions can produce seizures that appear clinically indistinguishable from one another. These clinically stereotypic manifestations reflect epileptic activation of specific networks. Several studies have shown that ictal perfusion single photon emission computed tomography (SPECT) can reveal propagated ictal activity. We hypothesize that the pattern of hyperperfusion may reflect neuronal networks that generated specific ictal symptomatology. All patients were identified who were injected with (99m)Tc-hexamethyl-propylene-amine-oxime (HMPAO) during versive seizures (n = 5), bilateral asymmetric tonic seizures (BATS; n = 5), and hypermotor seizures (n = 7) in the presurgical epilepsy evaluation between 2001 and 2005. The SPECT ictal–interictal difference image pairs of each subgroup were compared with image pairs of 14 controls using statistical parametric mapping (SPM 2) to identify regions of significant hyperperfusion. Hyperperfused regions with corrected cluster-level significance p < 0.05 were considered significant. We have identified a distinct ictal perfusion pattern in each subgroup. In versive seizure subgroup, prominent hyperperfusion was present in the frontal eye field opposite to the direction of head version. In addition, there was associated caudate and crossed cerebellar hyperperfusion. The BATS subgroup showed pronounced hyperperfusion supplementary sensorimotor area ipsilateral to the epileptogenic region, bilateral basal ganglia, and contralateral cerebellar hemisphere. The hypermotor seizure subgroup demonstrated two clusters of significant hyperperfusion: one involving bilateral frontomesial regions, cingulate gyri, and caudate nuclei, and another involving ipsilateral anteromesial temporal structures, frontoorbital region, insula, and basal ganglia. We have identified distinct hyperperfusion patterns for specific ictal symptomatology. Our findings provide further insight into understanding the anatomic basis of seizure semiology.

Neuromagnetic crossed cerebellar activation during seizures arising from the motor cortex

Event Abstract Back to Event Neuromagnetic crossed cerebellar activation during seizures arising from the motor cortex Ismail Mohamed1*, Hiroshi Otsubo2, Paul Ferrari3, Carter Snead2 and Douglas Cheyne4 1 University of Calgary, Department of Pediatrics, Alberta Children's Hospital, Canada 2 Hospital for Sick Children, Neurology Division, Canada 3 Hospital for Sick Children, Program in Neurosciences and Mental Health, United States 4 University of Toronto, Program in Neurosciences and Mental Health, Hospital for Sick Children, and Department of Medical Imaging, Canada Crossed cerebellar hyperperfusion is a relatively rare phenomenon observed in ictal SPECT /PET scans performed during seizures arising predominantly from the frontal lobe [1]. The phenomenon is thought to originate from the spread of ictal discharges through efferent projections to the contralateral cerebellar hemisphere. We report on the neuromagnetic correlates of crossed cerebellar activation in a child with seizures arising from the motor cortex. The child is a 4 ½ year old right handed boy with seizures since 1.5 years of age. His seizures consisted of left body, face and limb twitching. MEG recordings were performed utilizing whole head 151-channel axial gradiometer system (VSM MedTech Ltd) located inside a magnetically shielded room. Two typical electroclinical seizures were captured during MEG recording. MEG analysis of ictal data was performed utilizing an event-related beamformer (ERB) [2]. We computed mean source power in the 20-100 Hz frequency band over consecutive two seconds intervals starting from the magnetic seizure onset time. Based on the peak source locations as determined with the ERB, we created time series of source activity or ‘virtual sensors’ for each of the peak locations in the 20-100 Hz band. Results: Seizures lasted 26 and 53 seconds. The maximum source activity was seen over the right precentral gyrus at the onset of both seizures. Contralateral cerebellar activation was noted at the onset and peaked after 12 seconds in both seizures. Invasive video-EEG monitoring captured seizures arising from the right Rolandic region including the hand and face motor areas and concordant with the ERB seizure onset localization. Conclusion: ERB analysis of ictal MEG data demonstrated the neuromagnetic evidence and time course of crossed cerebellar activation during seizures arising from the motor cortex in a child with intractable epilepsy.

Crossed cerebellar hyperperfusion on ictal FDG PET in astrocytoma

Crossed cerebellar hyperperfusion (CCH) is a rare phenomenon and reflects the close anatomical and functional relationship between the frontal brain region and its mediated remote effect on the contralateral cerebellum via the corticopontocerebellar pathway. Although it is well documented on cerebral single photon emission tomography (SPECT) in patients with epilepsy, it is rarely observed in seizures originating from brain tumours. We report a 41-y-old man who whilst undergoing 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) for investigation of suspected glioma, developed a generalized seizure. The scan performed shortly after seizure onset demonstrated intense metabolic activity in the right superior frontal lobe and in the contralateral cerebellar hemisphere consistent with CCH.

Sequential MR imaging and SPECT studies in herpes simplex encephalitis with crossed cerebellar hyperperfusion

We report a case of herpes simplex encephalitis in which sequential MR imaging and SPECT studies showed interesting findings. SPECT in the acute stage showed wide increased uptake in the left cerebral hemisphere, as well as increased uptake in the contralateral right cerebellar hemisphere. T1-weighted images in the subacute stage showed hyperintense signals along the cerebral cortices, but T2*-weighted gradient-echo images did not show any signal decrease caused by the magnetic susceptibility effect of hemoglobin degradation. Sequential SPECT studies in addition to MR imaging facilitate precise understanding of the pathophysiology of herpes simplex encephalitis.

Cerebellitis in an Adult With Abnormal Magnetic Resonance Imaging Findings Prior to the Onset of Ataxia

Brain magnetic resonance imaging (MRI) findings during acute cerebellar ataxia in cases of postinfectious cerebellitis are frequently normal. This has resulted in the use of other imaging modalities, such as single-photon emission computed tomography, to aid diagnosis. To illustrate the chronologic occurrence of cerebellar ataxia, abnormal findings on MRI, and cerebral spinal fluid pleocytosis in an adult case of postinfectious cerebellitis. Case report. A patient with a 6-week history of occipital headaches and only mild tandem gait difficulty had abnormal MRI findings that were consistent with cerebellar inflammation. As cerebellar ataxia progressed in parallel with cerebral spinal fluid pleocytosis, MRI findings indicative of cerebellar inflammation resolved, while single-photon emission computed tomography showed cerebellar hyperperfusion. Recovery of neurologic function was accompanied by clearing of the pleocytosis and residual MRI-detected cerebellar atrophy. This case demonstrates that transient abnormalities can be detected by MRI before clinical manifestations of cerebellitis appear, while hyperperfusion detected by single-photon emission computed tomography is prolonged.

Cerebellar changes in partial seizures: clinical correlations of quantitative SPECT and MRI analysis.

To determine the frequency and patterns of periictal cerebellar hyperperfusion, whether it is associated with increased cerebellar atrophy, and whether cerebellar hyperperfusion and cerebellar atrophy are associated with predisposing clinical factors or with the outcome of epilepsy surgery. Periictal and interictal SPECT scans and volumetric brain magnetic resonance imaging (MRI) were quantitatively analyzed in 54 consecutive patients with medically refractory partial epilepsy. Their histories were reviewed and their postsurgical outcomes assessed. Significant periictal cerebellar hyperperfusion was found in 26 (48.1%) patients, of whom 18 had CCH, two had homolateral cerebellar hyperperfusion (HCH), and six had symmetrical bilateral hyperperfusion (BCH). No relation found between the site of the SPECT seizure localization and the presence or type of cerebellar hyperperfusion. CCH was more common when the injected seizure involved unilateral clonic motor activity (p < 0.05). A smaller MRI relative cerebellar volume (cerebellar volume/cerebral volume) was correlated with a greater seizure frequency (Rs = -0.30; p < 0.05) but not with the duration of epilepsy. There was no difference in the cerebellar volumes between the different patterns of cerebellar perfusion (p > 0.05). However, patients without a focal structural MRI lesion had significantly smaller cerebellar volumes (p < 0.05). In patients who underwent epilepsy surgery (n = 31), there was a trend for those without excellent outcomes to have smaller relative cerebellar volumes than did those with excellent outcome (10.6 vs. 11.8%; p = 0.08). Periictal changes in cerebellar perfusion, particularly CCH, are common in patients with intractable partial epilepsy. However, periictal hyperperfusion does not appear to be a major contributor to the development of cerebellar atrophy.

Brain SPECT imaging and treatment with IVlg in acute post-infectious cerebellar ataxia: Case report

A 19 year-old man presented with pharyngitis and cervical lymphadenopathy, followed by vomitmg and acute cerebellar ataxia. Serologic studies were consistent with a recent Epstein-Barr virus infection. Although contrast-enhanced brain computed tomography and MRI scans were normal, brain perfusion single photon emission tomography (SPECT) examination using 99mTc-HMPAO, performed on the 15th day of illness, showed marked cerebellar hyperperfusion, suggesting a diagnosis of acute post-infectious cerebellitis. After treatment with intravenous human immunoglobulin (IVlg, 2 g kg-1 over three days), progressive neurologic improvement occurred over two weeks. A brain SPECT study repeated after two additional weeks demonstrated a normal perfusion pattern. We conclude that brain perfusion SPECr examination is useful in identifying post-infectious cerebellitis and in monitoring its clinical course. In addition, IVlg may be helpful in treating this condition. [Neural Res 1998; 20: 85–88].

Supplementary sensorimotor area epilepsy. Seizure localization, cortical propagation and subcortical activation pathways using ictal SPECT.

We studied clinical signs, EEGs and ictal cerebral blood flow by single-photon emission computed tomography (SPECT) in eight patients with intractable supplementary sensorimotor area (SSMA) seizures. SPECT scans were performed after injection of the regional cerebral blood flow tracer [99mTc]HMPAO (hexametylpropylene amine oxime) early in the ictal phase (2-5 s after seizure onset). Ictal SPECT demonstrated unilateral predominance of hyper-perfusion of the SSMA in all patients, concordant with either lateralizing clinical signs, lateralization of ictal scalp EEG or with the site of ictal onset of seizures, obtained from intracranial electrodes. Two distinctive cortical blood-flow propagation patterns were identified in SSMA seizures. The type I pattern consisted of primary involvement of the ipsilateral SSMA and dorsal premotor and motor cortex. The type II pattern consisted of bilateral but asymmetric mesial frontal propagation. Ictal contraversive head and eye movements were associated with a type I propagation pattern (P < 0.03). Activation of subcortical structures led to variable hyper-perfusion of the basal ganglia and thalamus. Contralateral cerebellar hyperperfusion was observed in all cases. We conclude that ictal SPECT is a useful method for seizure localization in patients with SSMA epilepsy. The observed heterogeneity of clinical features in SSMA epilepsy correlates with propagation to, and activation of, specific cortical structures, and is consistent with known anatomical interconnections between the SSMA, ipsilateral cortical and transcallosal cortical structures.

A serial study of regional cerebral blood flow before and after hemispherectomy in a child

Hemimegalencephaly (HME) is a severe unilateral brain malformation the prognosis of which may be improved by hemispherectomy. HME also provides a unique opportunity to compare normal and pathological hemispheric function in the same patient. We performed a serial functional cerebral imaging study in a child suffering from a neuropathologically confirmed left HME. He was hemispherectomized at 11 months because of intractable epilepsy; this led to cessation of seizures and dramatic psychomotor improvement. Regional cerebral blood flow (rCBF) was studied at 1, 7, 10, 12 and 25 months with single photon computed tomography (SPECT) using 133-Xenon and with simultaneous EEG recording. At one month of age SPECT was performed ictally. During left EEG discharges, rCBF was 40% higher on the left hemisphere than on the right, even in occipital and frontal regions, usually immature at this age. A crossed cerebellar hyperperfusion was also found. At 7 and 10 months, SPECT was performed interictally; rCBF was 45% lower in the left hemisphere than in the right. During follow-up, global and regional CBF values showed normal levels and normal maturation in the right hemisphere except for a mild and transient decrease observed one month after hemispherectomy. SPECT provides an additional procedure for studying hemispheric function in vivo. Serial SPECT imaging may be useful for the preoperative and postoperative evaluation in unilateral cerebral malformation.