Brain stem and cerebellar hyperintense lesions in migraine

Association between vertebral artery dominance and basilar artery curvature in migraineurs: an anatomical magnetic resonance imaging study

BACKGROUND AND PURPOSES

Numerous studies demonstrate a link between cerebrovascular alterations and migraine pathogenesis. We investigated the association between migraine and vertebral artery dominance (VAD), basilar artery (BA) curvature, and elongation.

MATERIALS AND METHODS

This cross-sectional MRI study included 74 migraine patients and 74 control subjects aged between 18 and 55 years. Diameters of the intracranial part of the vertebral artery (VA) and BA, height of the BA bifurcation, and total lateral displacement of the BA were measured. In addition, we investigated the directional relationship between VAD and BA curvature.

RESULTS

There were no statistically significant differences between the groups regarding VA and BA diameters and total lateral displacement of the BA. The height of the BA bifurcation was found to be significantly higher in migraine patients compared to controls (p = 0.002). The left-side VAD was more frequent in migraine patients compared to control subjects (60.8% (45/74) vs 41.9% (31/74), p = 0.001). In migraine patients, particularly those with aura (MwA) patients, with left-side VAD, the rate of BA displacement to the right side is significantly higher than those with right-side VAD or non-VAD (p = 0.022). Also, we found that total lateral displacement of the BA is correlated with VA asymmetry in patients with MwA (r = 0.538, p = 0.007).

CONCLUSION

VAD and its opposite-directional relationship with the lateral displacement of the BA may be associated with migraine pathophysiology. Together with aging, this association may contribute to changes in the vertebrobasilar system (VBS) geometry which may result in increased risk for posterior circulation infarction (PCI) in migraineurs.

Differentiation of hemispheric white matter lesions in migraine and multiple sclerosis with similar radiological features using advanced MRI

Background and aim

White matter hyperintensities (WMHs), presented on T2-weighted or fluid-attenuated inversion recovery magnetic resonance imaging (MRI) sequences, are lesions in the human brain that can be observed in both migraine and multiple sclerosis (MS).

Methods

Seventeen migraine patients and 15 patients with relapsing-remitting multiple sclerosis with WMHs, and 17 healthy subjects age-and sex-matched to the migraine group were prospectively enrolled and underwent conventional and advanced MRI studies with diffusion-and perfusion-weighted imaging and single voxel proton magnetic resonance spectroscopy.

Results

In both disease groups, elevated T2 relaxation time, apparent diffusion coefficient (ADC) values, and decreased N-acetyl-aspartate levels were found in the intralesional white matter compared to the contralateral normal-appearing white matter (NAWM), while there was no difference between the hemispheres of the control subjects. Migraine patients had the lowest intralesional creatine + phosphocreatine and myo-inositol (mI) values among the three groups, while patients with MS showed the highest intralesional T1 and T2 relaxation times, ADC, and mI values. In the contralateral NAWM, the same trend with mI changes was observed in migraineurs and MS patients. No differences in perfusion variables were observed in any groups.

Conclusion

Our multimodal study showed that tissue damage is detectable in both diseases. Despite the differences in various advanced MRI measures, with more severe injury detected in MS lesions, we could not clearly differentiate the two white matter lesion types.

Potential of focal cortical dysplasia in migraine pathogenesis

Focal cortical dysplasias are abnormalities of the cerebral cortex associated with an elevated risk of neurological disturbances. Cortical spreading depolarization/depression is a correlate of migraine aura/headache and a trigger of migraine pain mechanisms. However, cortical spreading depolarization/depression is associated with cortical structural changes, which can be classified as transient focal cortical dysplasias. Migraine is reported to be associated with changes in various brain structures, including malformations and lesions in the cortex. Such malformations may be related to focal cortical dysplasias, which may play a role in migraine pathogenesis. Results obtained so far suggest that focal cortical dysplasias may belong to the causes and consequences of migraine. Certain focal cortical dysplasias may lower the threshold of cortical excitability and facilitate the action of migraine triggers. Migraine prevalence in epileptic patients is higher than in the general population, and focal cortical dysplasias are an established element of epilepsy pathogenesis. In this narrative/hypothesis review, we present mainly information on cortical structural changes in migraine, but studies on structural alterations in deep white matter and other brain regions are also presented. We develop the hypothesis that focal cortical dysplasias may be causally associated with migraine and link pathogeneses of migraine and epilepsy.

Correlation between migraine and cerebral small vessel disease: A case-control study

BACKGROUND

Microcirculatory pathology is one of the pathophysiological theories of migraine, which may present as visually subclinical lesions. Image markers of cerebral small vessel disease (CSVD) have been investigated in elderly migraineurs. However, past studies looked at only part of image features, and the conclusions may have been hindered by confounding factors. The relationship between migraine and CSVD signs needs reliable demonstrations.

METHODS

We conducted a case-control study by recruiting episodic young migraineurs from a tertiary headache centre, with tension-type headache (TTH) and healthy controls. Distinct image features of microvascular damage and baseline characteristics across groups were assessed, and multivariate linear regression was performed to evaluate the risk factors for image abnormalities in migraineurs.

RESULTS

Forty-eight migraineurs, 32 TTHs and 49 healthy controls were included. The median age was 32 year-old. 58.7% of the participants were female. The Scheltens score and volume of white matter hyperintensities (WMHs) in migraineurs, and the number of Virchow-Robin spaces (VRSs) in both migraineurs and TTHs were different from those in normal controls. No lacunar infarct-like lesions (ILLs) or cerebral microbleeds (CMBs) were found. Age, education level (high level: β = -2.23, lobar WMHs), attack duration (long duration: β = 3.81, lobar WMHs) and attack frequency were independent risk factors for Scheltens score and volume of WMH in migraineurs. Migraine aura (β = -2.389), attack frequency and education level were correlated with the number of VRSs.

CONCLUSIONS

Migraine was associated with WMHs and VRSs. Aura, attack duration, attack frequency, age and education level were risk factors for image abnormalities of CVSD in migraineurs.

SIGNIFICANCE

This study provides a novel and comprehensive landscape of CSVD MRI features in young migraineurs, and it fills the blank of CMBs and VRSs which received less attention, with more persuasive, more reliable and stronger evidence of the association between CSVD and migraine. Our results also imply some new feature of TTH and the possible pathophysiology of the migraine course as well as new clues for the early management of migraine in terms of visual brain damage.

Neurite Damage in Patients with Migraine

We examined neurite orientation dispersion and density imaging in patients with migraine. We found that patients with medication overuse headache exhibited lower orientation dispersion than those without. Moreover, orientation dispersion in the body of the corpus callosum was statistically negatively correlated with migraine attack frequencies. These findings indicate that neurite dispersion is damaged in patients with chronic migraine. Our study results indicate the orientation preference of neurite damage in migraine.

Migraine in multiple sclerosis patients: potential links and treatment approach

INTRODUCTION

Migraine has been reported to be twice as prevalent in patients with multiple sclerosis (MS) compared to the non-MS population. However, prospective, controlled studies that could lead to robust conclusions are still lacking.

AREAS COVERED

Treatment of migraine in patients with MS can be challenging. Comorbidities need to be assessed and managed early, and preventive treatment should be initiated when indicated. Caution is warranted regarding the selection of the preventive medication since certain agents can magnify MS symptoms and particularly cognitive symptoms. This paper aims to discuss the association of MS and migraine, shed light on distinguishing points and red flags, as well as offer practical advice on the selection of treatment according to patients' characteristics.

EXPERT OPINION

A holistic approach including pharmacological and non-pharmacological modifications is required to treat migraine in patients with MS effectively. Anti-CGRP monoclonal antibodies are a promising option due to limited drug-to-drug interactions; however, larger prospective studies are required to draw robust conclusions on the concomitant use of anti-CGRPs with MS disease modifying treatments. Early migraine preventive treatment might be needed to reduce the burden of disease in patients with MS.

Advanced brain MRI may help understand the link between migraine and multiple sclerosis

BACKGROUND

There is a clinical association between migraine and multiple sclerosis.

MAIN BODY

Migraine and MS patients share similar demographics, with the highest incidence among young, female and otherwise healthy patients. The same hormonal constellations/changes trigger disease exacerbation in both entities. Migraine prevalence is increased in MS patients, which is further enhanced by disease-modifying treatment. Clinical data show that onset of migraine typically starts years before the clinical diagnosis of MS, suggesting that there is either a unidirectional relationship with migraine predisposing to MS, and/or a "shared factor" underlying both conditions. Brain imaging studies show white matter lesions in both MS and migraine patients. Neuroinflammatory mechanisms likely play a key role, at least as a shared downstream pathway. In this review article, we provide an overview of the literature about 1) the clinical association between migraine and MS as well as 2) brain MRI studies that help us better understand the mechanistic relationship between both diseases with implications on their underlying pathophysiology.

CONCLUSION

Studies suggest a migraine history predisposes patients to develop MS. Advanced brain MR imaging may shed light on shared and distinct features, while helping us better understand mechanisms underlying both disease entities.

CGRP, Migraine, and Brain MRI in CADASIL: A Pilot Study

BACKGROUND

Migraine is associated with neuroimaging differences in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). However, it is unknown if migraine-related disability (MRD) or if calcitonin gene-related peptide (CGRP), a vasoactive peptide important in migraine pathology, have radiographic implications. The aims of this study were to identify whether MRD or interictal serum CGRP levels impacted neuroimaging findings for those with CADASIL.

MATERIALS AND METHODS

A cross-sectional analysis was performed. The primary outcomes were neuroimaging differences associated with MRD among those with migraine or interictal serum CGRP levels of those with and without migraine. MRD was defined by 2 migraine disability scales (Migraine Disability Assessment, Headache Impact Test-6). Retrospective brain magnetic resonance imaging was reviewed (average 1.7 ± 2.0 y before enrollment). Rank-sum and χ 2 tests were used.

RESULTS

Those with migraine (n=25, vs. n=14 without) were younger [median 49 (25 to 82) y vs. 60 (31 to 82) y, P <0.007], had fewer cerebral microbleeds (0 to 31 vs. 0 to 50, P =0.02) and less frequently had anterior temporal lobe T2 hyperintensities [68% (17/25) vs 100% (14/14), P =0.02]. MRD scale outcomes had no significant radiographic associations. Interictal serum CGRP did not differ (migraine: n=18, 27.0±9.6 pg/mL vs. no migraine: n=10, 26.8±15.7 pg/mL, P =0.965).

CONCLUSIONS

Migraine may forestall microangiopathy in CADASIL, though possibly independent of severity as measured by MRD. Interictal serum CGRP did not differ in our cohort suggesting CGRP may not be vital to migraine pathophysiology in CADASIL. Larger studies are needed to account for age differences.

White Matter Lesions Identified by Magnetic Resonance in Women with Migraine: A Volumetric Analysis and Clinical Correlations

BACKGROUND

Repeated migraine attacks and aura could independently cause structural changes in the central nervous system. Our research aims to study the correlation of migraine type, attack frequency, and other clinical variables with the presence, volume and localization of white matter lesions (WML), in a controlled study.

METHODS

Sixty volunteers from a tertiary headache center were selected and divided equally into four groups: episodic migraine without aura (MoA), episodic migraine with aura (MA), chronic migraine (CM) and controls (CG). Voxel-based morphometry techniques were used to analyze WML.

RESULTS

There were no differences in WML variables between groups. There was a positive correlation between age and the number and total volume of WMLs, which persisted in the comparison categorized by size and brain lobe. Disease duration was positively correlated with the number and total volume of WML, and when controlled by age, the correlation maintained significance only for the insular lobe. Aura frequency was associated with frontal and temporal lobe WMLs. There was no statistically significant correlation between WML and other clinical variables.

CONCLUSION

Migraine overall is not a risk factor for WML. Aura frequency is, however, associated with temporal WML. Disease duration, in adjusted analyses that account for age, is associated with insular WML.

Migraine Type-Dependent Patterns of Brain Activation After Facial and Intranasal Trigeminal Stimulation

In migraine, the trigeminal nerve is intimately involved in the pathophysiology of the disease. We hypothesized that alterations in the sensory trigeminal activation in migraine would be reflected by EEG-derived event-related potentials (ERP). We aimed to investigate differences in the temporal and spatial processing of trigeminal stimuli between interictal migraine patients and healthy subjects. ERP to trigeminal stimuli were recorded at 128-channels to allow localization of their cortical sources with high temporal resolution. Seventeen patients with episodic migraine without aura, 17 subjects with episodic migraine with aura, and 17 healthy subjects participated in the study. The first branch of the trigeminal nerve was stimulated using intranasal chemical (CO₂), cutaneous electrical, and cutaneous mechanical (air puff) stimuli. Analyses were performed with regard to micro-state segmentation, ERP source localization, and correlation with the patients' clinical characteristics. Topographical assessments of EEG configurations were associated with the pathological condition. The source analysis revealed altered trigeminal-sensory response patterns in the precuneus, temporal pole, and cerebellum for both migraine groups during the interictal phase. The estimated current source density was positively correlated with migraine disease duration, indicating brain functional and structural changes as a consequence of the disease. Hyperactivity of the cerebellar posterior lobe was observed as a specific trigeminal response of migraine patients with aura. In conclusion, our results suggest the presence of brain changes accompanying the advancement of migraine as an expression of dysfunctional central pain processing. Hence, we identified EEG patterns in response to mechano-/chemosensory stimuli that can serve as biomarkers of migraine.

Cerebral Hemodynamics, Right-to-Left Shunt and White Matter Hyperintensities in Patients with Migraine with Aura, Young Stroke Patients and Controls

Background: Migraine with aura (MA) patients present an increased risk of cerebrovascular events. However, whether these patients present an increased white matter hyperintensities (WMHs) load compared to the general population is still under debate. Our study aimed to evaluate the relationship between cerebral hemodynamics, right-to-left shunt (RLS) and WMHs in MA patients, young patients with cryptogenic stroke or motor transient ischemic attack (TIA) and controls. Methods: We enrolled 30 MA patients, 20 young (<60 years) patients with cryptogenic stroke/motor TIA, and 10 controls. All the subjects underwent a transcranial Doppler bubble test to detect RLS and cerebral hemodynamics assessed by the breath holding index (BHI) for the middle (MCA) and posterior (PCA) cerebral arteries. Vascular risk factors were collected. The WMHs load on FLAIR MRI sequences was quantitatively assessed. Results: The stroke/TIA patients presented a higher prevalence of RLS (100%) compared with the other groups (p < 0.001). The MA patients presented a higher BHI compared with the other groups in the PCA (p = 0.010) and higher RLS prevalence (60%) than controls (30%) (p < 0.001). The WMHs load did not differ across groups. BHI and RLS were not correlated to the WMHs load in the groups. Conclusions: A preserved or more reactive cerebral hemodynamics and the presence of a RLS are likely not involved in the genesis of WMHs in MA patients. A higher BHI may counteract the risk related to their higher prevalence of RLS. These results need to be confirmed by further studies to be able to effectively identify the protective role of cerebral hemodynamics in the increased RLS frequency in MA patients.

Cerebro-Cerebellar Networks in Migraine Symptoms and Headache

The cerebellum is associated with the biology of migraine in a variety of ways. Clinically, symptoms such as fatigue, motor weakness, vertigo, dizziness, difficulty concentrating and finding words, nausea, and visual disturbances are common in different types of migraine. The neural basis of these symptoms is complex, not completely known, and likely involve activation of both specific and shared circuits throughout the brain. Posterior circulation stroke, or neurosurgical removal of posterior fossa tumors, as well as anatomical tract tracing in animals, provided the first insights to theorize about cerebellar functions. Nowadays, with the addition of functional imaging, much progress has been done on cerebellar structure and function in health and disease, and, as a consequence, the theories refined. Accordingly, the cerebellum may be useful but not necessary for the execution of motor, sensory or cognitive tasks, but, rather, would participate as an efficiency facilitator of neurologic functions by improving speed and skill in performance of tasks produced by the cerebral area to which it is reciprocally connected. At the subcortical level, critical regions in these processes are the basal ganglia and thalamic nuclei. Altogether, a modulatory role of the cerebellum over multiple brain regions appears compelling, mainly by considering the complexity of its reciprocal connections to common neural networks involved in motor, vestibular, cognitive, affective, sensory, and autonomic processing—all functions affected at different phases and degrees across the migraine spectrum. Despite the many associations between cerebellum and migraine, it is not known whether this structure contributes to migraine initiation, symptoms generation or headache. Specific cerebellar dysfunction via genetically driven excitatory/inhibitory imbalances, oligemia and/or increased risk to white matter lesions has been proposed as a critical contributor to migraine pathogenesis. Therefore, given that neural projections and functions of many brainstem, midbrain and forebrain areas are shared between the cerebellum and migraine trigeminovascular pathways, this review will provide a synopsis on cerebellar structure and function, its role in trigeminal pain, and an updated overview of relevant clinical and preclinical literature on the potential role of cerebellar networks in migraine pathophysiology.

Basilar artery curvature is associated with migraine with aura in the Northern Manhattan Study

INTRODUCTION

Genetic and imaging studies demonstrate a link between vascular morphology and migraine with aura (MA). We examined the relationship between basilar artery (BA) curvature and MA in a population-based cohort of stroke-free participants.

METHODS

This cross-sectional study included participants from the MRI substudy of the Northern Manhattan Study. Participants had structured migraine assessments at enrollment and underwent brain MR angiography. BA curvature was defined as the sum of the total BA horizontal deviation from midline at the distal tip, mid-pons, and vertebrobasilar junction, and was the primary independent variable in logistic regression analyses. BA measurements were obtained blinded to migraine status. We compared groups of all migraine vs no migraine, migraine without aura (MwoA) vs no migraine, and MA vs no migraine.

RESULTS

Of 880 participants, 146 had MwoA and 32 had MA. Average BA curvatures were 15.2 ± 8.9 mm in non-migraineurs, 15.8 ± 9.3 mm in MwoA, and 18.5 ± 11.4 mm in MA. In an adjusted model, greater BA curvature was associated with MA (OR 1.042 per mm, 95% CI 1.006-1.080) but not with MwoA (OR 1.014 per mm, 95% CI 0.993-1.035), when compared to non-migraineurs.

CONCLUSIONS

Greater BA curvature was associated with MA. Given aura typically originates from the occipital cortex, understanding the physiopathology of this association may provide clues to migraine's underlying mechanisms and relationship with stroke.

Migraine

Migraine is a common, chronic, disorder that is typically characterized by recurrent disabling attacks of headache and accompanying symptoms, including aura. The aetiology is multifactorial with rare monogenic variants. Depression, epilepsy, stroke and myocardial infarction are comorbid diseases. Spreading depolarization probably causes aura and possibly also triggers trigeminal sensory activation, the underlying mechanism for the headache. Despite earlier beliefs, vasodilation is only a secondary phenomenon and vasoconstriction is not essential for antimigraine efficacy. Management includes analgesics or NSAIDs for mild attacks, and, for moderate or severe attacks, triptans or 5HT_1B/1D receptor agonists. Because of cardiovascular safety concerns, unreliable efficacy and tolerability issues, use of ergots to abort attacks has nearly vanished in most countries. CGRP receptor antagonists (gepants) and lasmiditan, a selective 5HT1_F receptor agonist, have emerged as effective acute treatments. Intramuscular onabotulinumtoxinA may be helpful in chronic migraine (migraine on ≥15 days per month) and monoclonal antibodies targeting CGRP or its receptor, as well as two gepants, have proven effective and well tolerated for the preventive treatment of migraine. Several neuromodulation modalities have been approved for acute and/or preventive migraine treatment. The emergence of new treatment targets and therapies illustrates the bright future for migraine management.

White Matter Lesions in Migraine

Migraine, the third most common disease worldwide, is a well-known independent risk factor for subclinical focal deep white matter lesions (WMLs), even in young and otherwise healthy individuals with no cardiovascular risk factors. These WMLs are more commonly seen in migraine patients with transient neurologic symptoms preceding their headaches, the so-called aura, and those with a high attack frequency. The pathophysiology of migraine-related deep white matter hyperintensities remains poorly understood despite their prevalence. Characteristic differences in their distribution related to chronic small vessel ischemic disease compared with that of common periventricular WMLs in the elderly suggest a different underlying mechanism. Both ischemic and inflammatory mechanisms have been proposed, as there is increased cerebral vulnerability to ischemia in migraineurs, whereas there is also evidence of blood-brain barrier disruption with associated release of proinflammatory substances during migraine attacks. An enhanced susceptibility to spreading depolarization, the electrophysiological event underlying migraine, may be the mechanism that causes repetitive episodes of cerebral hypoperfusion and neuroinflammation during migraine attacks. WMLs can negatively affect both physical and cognitive function, underscoring the public health importance of migraine, and suggesting that migraine is an important contributor to neurologic deficits in the general population.

Structural and Functional Brain Changes in Migraine

Migraine is a prevalent primary headache disorder and is usually considered as benign. However, structural and functional changes in the brain of individuals with migraine have been reported. High frequency of white matter abnormalities, silent infarct-like lesions, and volumetric changes in both gray and white matter in individuals with migraine compared to controls have been demonstrated. Functional magnetic resonance imaging (MRI) studies found altered connectivity in both the interictal and ictal phase of migraine. MR spectroscopy and positron emission tomography studies suggest abnormal energy metabolism and mitochondrial dysfunction, as well as other metabolic changes in individuals with migraine. In this review, we provide a brief overview of neuroimaging studies that have helped us to characterize some of these changes and discuss their limitations, including small sample sizes and poorly defined control groups. A better understanding of alterations in the brains of patients with migraine could help not only in the diagnosis but may potentially lead to the optimization of a targeted anti-migraine therapy.

Exploring EEG Spectral Patterns in Episodic and Chronic Migraine During the Interictal State: Determining Frequencies of Interest in the Resting State

Objective

The analysis of particular (electroencephalographic) EEG frequency bands has revealed new insights relative to the neural dynamics that, when studying the EEG spectrum as a whole, would have remained hidden. This study is aimed at characterizing spectral resting state EEG patterns for assessing possible differences of episodic and chronic migraine during the interictal period. For that purpose, a novel methodology for analyzing specific frequencies of interest was performed.

Methods

Eighty-seven patients with migraine (45 with episodic and 42 with chronic migraine) and 39 age- and sex-matched controls performed a resting-state EEG recording. Spectral measures were computed using conventional frequency bands. Additionally, particular frequency bands were determined to distinguish between controls and migraine patients, as well as between migraine subgroups.

Results

Frequencies ranging from 11.6 Hz to 12.8 Hz characterized migraine as a whole, with differences evident in the central and left parietal regions (controlling for false discovery rate). An additional band between 24.1 Hz and 29.8 Hz was used to discriminate between migraine subgroups. Interestingly, the power in this band was positively correlated with time from onset in episodic migraine, but no correlation was found for chronic migraine.

Conclusions

Specific frequency bands were proposed to identify the spectral characteristics of the electrical brain activity in migraine during the interictal stage. Our findings support the importance of discriminating between migraine subgroups to avoid hiding relevant features in migraine.

Is ischemia associated with the formation of White matter lesions in migraine?

OBJECTIVE

White matter lesions (WMLs) are more common in migraine patients than in the normal population. Ischemia/hypoxia and oxidative stress are considered to play a role in WMLs formation. This study aimed to investigate ischemia-modified albumin (IMA), ferroxidase and thiol/disulfide homeostasis in migraineurs with and without WMLs.

PATIENTS AND METHODS

Sixty-two migraineurs with WML, 59 migraineurs without WML and 61 controls were included in the study. All participants underwent brain MRI. WMLs was evaluated according to the Fazekas scale. IMA, ferroxidase, total thiol, native thiol and disulfide measurements were carried out in all participants.

RESULTS

The IMA levels were higher in the migraine groups compared to the control group (p < 0.001) and in the WML group compared to non-WML (p < 0.001). The total and native thiol levels were higher in the non-WML group compared to the control and WML groups (p < 0.001 for both). The disulfide levels were similar between the control and non-WML groups, but they were significantly lower in the WML group compared to the control and non-WML groups. There was no significant difference between the groups in terms of the ferroxidase levels (p = 0.092). The thiol/disulfide, IMA and ferroxidase levels were not significantly correlated with the frequency and duration of attacks, severity of pain and disability due to migraine.

CONCLUSION

Increased serum IMA levels in migraineurs point to the role of ischemia/hypoxia, and increased total thiol and decreased disulfide levels indicate an oxidant/antioxidant imbalance in migraine. Ischemia/hypoxia may play a role in WMLs formation in migraine.

Advanced Imaging in the Evaluation of Migraine Headaches

The use of advanced imaging in routine diagnostic practice appears to provide only limited value in patients with migraine who have not experienced recent changes in headache characteristics or symptoms. However, advanced imaging may have potential for studying the biological manifestations and pathophysiology of migraine headaches. Migraine with aura appears to have characteristic spatiotemporal changes in structural anatomy, function, hemodynamics, metabolism, and biochemistry, whereas migraine without aura produces more subtle and complex changes. Large, controlled, multicenter imaging-based observational trials are needed to confirm the anecdotal evidence in the literature and test the scientific hypotheses thought to underscore migraine pathophysiology.

Absent increase in vertebral artery blood flow during l-arginine infusion in hypertensive men

Endothelial dysfunction is observed in the peripheral vasculature of hypertensive patients, but it is unclear how the cerebral circulation is affected. More specifically, little is known about the impact of human hypertension on vertebral artery (VA) endothelial function. This study evaluated whether the endothelial function of the VA is impaired in hypertensive men. For 13 male hypertensive subjects (46 ± 3 yr) and eight age-matched male controls (46 ± 4 yr), blood pressure (BP; photoplethysmography), VA, and common carotid (CC) blood flow (duplex ultrasound) were determined at rest and during 30 min of intravenous l-arginine (30 g; a precursor of nitric oxide) or isotonic saline infusion. Controls and hypertensive subjects demonstrated a similar resting CC (601 ± 30 vs. controls 570 ± 43 ml/min; P = 0.529) and VA blood flow (119 ± 11 vs. controls 112 ± 9 ml/min; P = 0.878). During administration of l-arginine, CC blood flow increased similarly between groups (hypertensive 12 ± 3%, controls 13 ± 2%; P = 0.920). In contrast, the increase in VA blood flow was nonexistent in the hypertensive subjects (0.8 ± 3% vs. controls: 16 ± 4%; P = 0.015) with no significant change in BP. Both CC and VA flow returned to near-resting values within 30 min after the infusion, and for four hypertensive subjects and three controls, time-control experiments using 0.9% saline did not affect VA or CC blood flow significantly. The results demonstrate endothelial dysfunction in the posterior cerebral circulation of middle-aged hypertensive men.

Headache in transient ischemic attacks

Background

Headache is a common feature in acute cerebrovascular disease but no studies have evaluated the prevalence of specific headache types in patients with transient ischemic attacks (TIA). The purpose of the present study was to analyze all headaches within the last year and the last week before TIA and at the time of TIA.

Methods

Eligible patients with TIA (n = 120, mean age 56.1, females 55%) had focal brain or retinal ischemia with resolution of symptoms within 24 h without presence of new infarction on MRI with DWI (n = 112) or CT (n = 8). All patients were evaluated within one day of admission by a single neurologist. As a control group we used patients (n = 192, mean age 58.7, females 64%) admitted with diagnoses “lumbago”, “lumbar spine osteochondrosis” or “gastrointestinal ulcer”.

Results

One-year prevalence of migraine without aura was significantly higher in TIA patients than in controls: 20.8% and 7.8% respectively (p = 0.002, OR 3.1, 95% CI 1.6–6.2). 22 patients (18.3%) had sentinel or warning headache within the last week before TIA. At the time of TIA a new type of headache was observed in 16 patients (13.3%). No controls had a new type of headache. 12 of these 16 patients had migraine-like headache, 8 patients had tension-type-like headache and one patient thunderclap headache. Posterior circulation TIA was associated with headaches within last week before TIA and at the time of TIA much more frequently than anterior circulation TIA.

Conclusions

The one year prevalence of migraine was significantly higher in TIA patients than in controls and so was the prevalence of headache within the last week before TIA and at the time of TIA. A previous headache that worsens and a new type of headache can be a warning of impending TIA.

White matter hyperintensities and headache: A population-based imaging study (HUNT MRI)

Objective

To examine the relationship between white matter hyperintensities and headache.

Methods

White matter hyperintensities burden was assessed semi-quantitatively using Fazekas and Scheltens scales, and by manual and automated volumetry of MRI in a sub-study of the general population-based Nord-Trøndelag Health Study (HUNT MRI). Using validated questionnaires, participants were categorized into four cross-sectional headache groups: Headache-free (n = 551), tension-type headache (n = 94), migraine (n = 91), and unclassified headache (n = 126). Prospective questionnaire data was used to further categorize participants into groups according to the evolution of headache during the last 12 years: Stable headache-free, past headache, new onset headache, and persistent headache. White matter hyperintensities burden was compared across headache groups using adjusted multivariate regression models.

Results

Individuals with tension-type headache were more likely to have extensive white matter hyperintensities than headache-free subjects, with this being the case across all methods of white matter hyperintensities assessment (Scheltens scale: Odds ratio, 2.46; 95% CI, 1.44–4.20). Migraine or unclassified headache did not influence the odds of having extensive white matter hyperintensities. Those with new onset headache were more likely to have extensive white matter hyperintensities than those who were stable headache-free (Scheltens scale: Odds ratio, 2.24; 95% CI, 1.13–4.44).

Conclusions

Having tension-type headache or developing headache in middle age was linked to extensive white matter hyperintensities. These results were similar across all methods of assessing white matter hyperintensities. If white matter hyperintensities treatment strategies emerge in the future, this association should be taken into consideration.

White matter hyperintensities in migraine: Clinical significance and central pulsatile hemodynamic correlates

Background The role of central pulsatile hemodynamics in the pathogenesis of white matter hyperintensities in migraine patients has not been clarified. Methods Sixty patients with migraine (20-50 years old; women, 68%) without overt vascular risk factors and 30 demographically-matched healthy controls were recruited prospectively. Cerebral white matter hyperintensities volume was determined by T1-weighted magnetic resonance imaging with CUBE-fluid-attenuated-inversion-recovery sequences. Central systolic blood pressure, carotid-femoral pulse wave velocity, and carotid augmentation index were measured by applanation tonometry. Carotid pulsatility index was derived from Doppler ultrasound carotid artery flow analysis. Results Compared to the controls, the migraine patients had higher white matter hyperintensities frequency (odds ratio, 2.75; p = 0.04) and greater mean white matter hyperintensities volume (0.174 vs. 0.049, cm³, p = 0.04). Multivariable regression analysis showed that white matter hyperintensities volume in migraine patients was positively associated with central systolic blood pressure ( p = 0.04) and carotid-femoral pulse wave velocity ( p < 0.001), but negatively associated with carotid pulsatility index ( p = 0.04) after controlling for potential confounding factors. The interaction effects observed indicated that the influence of carotid-femoral pulse wave velocity ( p = 0.004) and central systolic blood pressure ( p = 0.03) on white matter hyperintensities formation was greater for the lower-carotid pulsatility index subgroup of migraine patients. White matter hyperintensities volume in migraine patients increased with decreasing carotid pulsatility index and with increasing central systolic blood pressure or carotid-femoral pulse wave velocity. Conclusions White matter hyperintensities are more common in patients with migraine than in healthy controls. Increased aortic stiffness or central systolic blood pressure in the presence of low intracranial artery resistance may predispose patients with migraine to white matter hyperintensities formation.

Cortical Spreading Depression Closes Paravascular Space and Impairs Glymphatic Flow: Implications for Migraine Headache

Functioning of the glymphatic system, a network of paravascular tunnels through which cortical interstitial solutes are cleared from the brain, has recently been linked to sleep and traumatic brain injury, both of which can affect the progression of migraine. This led us to investigate the connection between migraine and the glymphatic system. Taking advantage of a novel in vivo method we developed using two-photon microscopy to visualize the paravascular space (PVS) in naive uninjected mice, we show that a single wave of cortical spreading depression (CSD), an animal model of migraine aura, induces a rapid and nearly complete closure of the PVS around surface as well as penetrating cortical arteries and veins lasting several minutes, and gradually recovering over 30 min. A temporal mismatch between the constriction or dilation of the blood vessel lumen and the closure of the PVS suggests that this closure is not likely to result from changes in vessel diameter. We also show that CSD impairs glymphatic flow, as indicated by the reduced rate at which intraparenchymally injected dye was cleared from the cortex to the PVS. This is the first observation of a PVS closure in connection with an abnormal cortical event that underlies a neurological disorder. More specifically, the findings demonstrate a link between the glymphatic system and migraine, and suggest a novel mechanism for regulation of glymphatic flow.SIGNIFICANCE STATEMENT Impairment of brain solute clearance through the recently described glymphatic system has been linked with traumatic brain injury, prolonged wakefulness, and aging. This paper shows that cortical spreading depression, the neural correlate of migraine aura, closes the paravascular space and impairs glymphatic flow. This closure holds the potential to define a novel mechanism for regulation of glymphatic flow. It also implicates the glymphatic system in the altered cortical and endothelial functioning of the migraine brain.

Relationship between white matter hyperintensities and retinal nerve fiber layer, choroid, and ganglion cell layer thickness in migraine patients

Aim

To compare the relationship between white matter hyperintensities (WMH) on brain magnetic resonance imaging and retinal nerve fiber layer (RNFL), choroid, and ganglion cell layer (GCL) thicknesses in migraine patients and healthy subjects. We also assessed the role of cerebral hypoperfusion in the formation of these WMH lesions.

Methods

We enrolled 35 migraine patients without WMH, 37 migraine patients with WMH, and 37 healthy control subjects examined in the Neurology outpatient clinic of our tertiary center from May to December 2015. RFNL, choroid, and GCL thicknesses were measured by optic coherence tomography.

Results

There were no differences in the RFNL, choroid, or GCL thicknesses between migraine patients with and without WMH ( p > 0.05). Choroid layer thicknesses were significantly lower in migraine patients compared to control subjects ( p < 0.05), while there were no differences in RFNL and GCL thicknesses ( p > 0.05).

Conclusions

The ‘only cerebral hypoperfusion’ theory was insufficient to explain the pathophysiology of WMH lesions in migraine patients. In addition, the thinning of the choroid thicknesses in migraine patients suggests a potential causative role for cerebral hypoperfusion and decreased perfusion pressure of the choroid layer.

Retinal Nerve Fibre Layer Thickness of Migraine Patients with or without White Matter Lesions

The aim of this study was to determine whether retinal nerve fibre layer (RNFL) thickness is correlated with cerebral white matter lesions (WML) in migraine patients. Forty migraine and 40 healthy subjects were included in this study. The difference in RNFL thickness between the control and a migraine group with WML and a migraine group without WML were investigated using analysis of variance (ANOVA). A Tukey post hoc test was conducted to determine from which group the difference originated. Lower RNFL thicknesses were observed in the migraine patient group where WML was detected using magnetic resonance imaging (MRI), compared with the control group and with the migraine group with no WML. Statistically significant difference was found between the three groups in terms of RNFL thickness. Although there was a statistically significant difference between the control and the migraine group with WML detected with MRI, no statistically significant difference was found in terms of RNFL thickness between the control and the migraine group with no WML related to Tukey post hoc test. Moreover, there was a statistically significant difference between migraine patients with WML and patients without WML in terms of retinal nerve fibre layer thickness. The results indicate that reduction in RNFL detected via optical coherence tomography may be related to cerebral WML in migraine patients. Further studies by neurologists and ophthalmologists are necessary to determine the clinical relevance of the relation between RNFL and cerebral WML.

Neuropsychological assessment in migraine patients: a descriptive review on cognitive implications

Migraine is considered a disabling disorder with highly prevalence in population. Recent studies report that migraine patients have a cognitive decline associated to structural brain alterations. We search on PubMed and Web of Science databases and screening references of included studies and review articles for additional citations. From 519 studies identified, only 16 met the inclusion criteria. All studies were conducted on 1479 migraineurs (190 non-migraine headache and 11,978 controls subject) and examined the association between migraine and cognitive impairment. The results are discordant. Indeed, while cognitive deficits during the attack of migraine are now recognized, only few studies confirmed the presence of cognitive impairment in migraine patients. Given the prevalence of migraine in the population (especially among women), and the early age of the population, an association between migraine and cognitive impairment could have substantial public health implications. Future studies should determine if specific migraine characteristics, for example, attack frequency, may impact the association between migraine and cognitive decline.

Incidental Lesions Suggesting Multiple Sclerosis

PURPOSE OF REVIEW

Neurologists are frequently asked to consult on patients with incidentally observed anomalies on brain MRI that may be suggestive of multiple sclerosis (MS). The identification of such findings has important clinical management implications. This review provides an overview and practical clinical approach options for clinicians.

RECENT FINDINGS

An increase in the number of brain MRI studies performed annually is expected to result in detection of a corresponding greater number of unanticipated anomalies. A disproportionate number of patients referred to neurologists for this reason have punctate subcortical T2 hyperintensities that appear nonspecific in origin rather than having imaging features concerning for MS. However, in some instances, the MRI characteristics appear to be typical for demyelination. When these features are observed, efforts should be pursued to identify an accurate explanation for the preclinical findings through rigorous clinical evaluation, paraclinical testing, and utilization of longitudinal imaging.

SUMMARY

The identification of subjects with incidental T2 hyperintensities highly suggestive of MS is important for patient counseling and management. Continued neurologic evaluations and reassessment of the original clinical impression are recommended to ensure accurate interpretation of the available data.

Serum L-arginine and dimethylarginine levels in migraine patients with brain white matter lesions

Background/Aim

Migraine is a risk factor for the formation of silent brain white matter lesions (WMLs) that are possibly ischemic in nature. Although dysfunction of the L-arginine/nitric oxide (NO) pathway has been associated with oxidative stress and endothelial dysfunction in migraine, its role in WML development has not been specifically investigated. Thus, this prospective study aimed to measure the serum concentrations of the NO substrate L-arginine, the NO synthase inhibitor asymmetric dimethylarginine (ADMA), and the L-arginine transport regulator symmetric dimethylarginine (SDMA) in migraine patients in a headache-free period.

Methods

All participants underwent MR imaging to assess for the presence of WMLs on fluid-attenuated inversion recovery imaging. Altogether 109 migraine patients (43 with lesions, 66 without lesions) and 46 control individuals were studied. High-performance liquid chromatography was used to quantify L-arginine, ADMA and SDMA serum concentrations. Migraine characteristics were investigated, and participants were screened for risk factors that can lead to elevated serum ADMA levels independent of migraine.

Results

Migraine patients and controls did not differ in regard to vascular risk factors. Migraineurs with WMLs had a longer disease duration ( p < 0.001) and a higher number of lifetime headache attacks ( p = 0.005) than lesion-free patients. Higher L-arginine serum levels were found in both migraine subgroups compared to controls ( p < 0.001). Migraine patients with WMLs showed higher ADMA concentrations than lesion-free patients and controls ( p < 0.001, for both). In migraineurs, the presence of WMLs, aura and increasing age proved to be significant predictors of increased ADMA levels ( p = 0.008, 0.047 and 0.012, respectively). SDMA serum levels of lesional migraineurs were higher than in nonlesional patients ( p < 0.001). The presence of lesions and increasing age indicated an increased SDMA level ( p = 0.017 and 0.001, respectively). Binary logistic regression analysis showed that ADMA level ( p = 0.006), increasing age ( p = 0.017) and the total number of lifetime migraine attacks ( p = 0.026) were associated with an increased likelihood of exhibiting WMLs. There was no significant effect of age on ADMA and SDMA concentrations in controls.

Conclusions

Elevated ADMA levels may impact the pathogenesis of migraine-related WMLs by influencing cerebrovascular autoregulation and vasomotor reactivity. Higher SDMA concentrations may indirectly influence NO synthesis by reducing substrate availability. Elevated L-arginine serum levels might reflect an increased demand for NO synthesis.

Migraine with aura and risk of silent brain infarcts and white matter hyperintensities: an MRI study

A small number of population-based studies reported an association between migraine with aura and risk of silent brain infarcts and white matter hyperintensities in females. We investigated these relations in a population-based sample of female twins. We contacted female twins ages 30–60 years identified through the population-based Danish Twin Registry. Based on questionnaire responses, twins were invited to participate in a telephone-based interview conducted by physicians. Headache diagnoses were established according to the International Headache Society criteria. Cases with migraine with aura, their co-twins, and unrelated migraine-free twins (controls) were invited to a brain magnetic resonance imaging scan performed at a single centre. Brain scans were assessed for the presence of infarcts, and white matter hyperintensities (visual rating scales and volumetric analyses) blinded to headache diagnoses. Comparisons were based on 172 cases, 34 co-twins, and 139 control subjects. Compared with control subjects, cases did not differ with regard to frequency of silent brain infarcts (four cases versus one control), periventricular white matter hyperintensity scores [adjusted mean difference (95% confidence interval): −0.1 (−0.5 to 0.2)] or deep white matter hyperintensity scores [adjusted mean difference (95% confidence interval): 0.1 (−0.8 to 1.1)] assessed by Scheltens’ scale. Cases had a slightly higher total white matter hyperintensity volume compared with controls [adjusted mean difference (95% confidence interval): 0.17 (−0.08 to 0.41) cm ³ ] and a similar difference was present in analyses restricted to twin pairs discordant for migraine with aura [adjusted mean difference 0.21 (−0.20 to 0.63)], but these differences did not reach statistical significance. We found no evidence of an association between silent brain infarcts, white matter hyperintensities, and migraine with aura.

The Prevalence of Magnetic Resonance Imaging Hyperintensity in Migraine Patients and Its Association with Migraine Headache Characteristics and Cardiovascular Risk Factors

OBJECTIVES

To determine the frequency of hyperintense foci in migraine patients and the relationship with migraine headache characteristics and cardiovascular risk factors.

METHODS

Ninety patients with migraine headache (70 without aura and 20 with aura) were enrolled and interviewed. Information on their headache (severity, frequency, and mean disease duration) and other related data was obtained by completing a clinical checklist. Subsequently, brain magnetic resonance imaging (MRI) was performed and each patient was then evaluated for hyperintense lesions.

RESULTS

Of the 90 patients, 29 (32%) had silent hyperintense lesions on their MRI. The mean age of the patients with hyperintense foci was 41 years while those with no lesions was 33 years (p<0.010). Supratentorial hyperintense lesions represented the majority of lesions in the patients (n=46, 63%). Moreover, 56.3% of the lesions (n=41) were located within the right hemisphere. Cardiovascular risk factors such as smoking, serum cholesterol, oral contraceptive pills use, and body mass index (BMI) were not significantly different in these two groups (p>0.050). The lesions were found significantly more frequently in the patients who experienced chronic migraine (p=0.032).

CONCLUSION

Our study adds weight to the theory that disease duration has a key role in the formation of hyperintense brain lesions. Certain cardiovascular risk factors such as sex, smoking, serum cholesterol, and BMI, do not affect the presence or absence of such lesions, suggesting that the relationship between migraine and these lesions may be directly due to the effects of migraine itself.

Intracranial abnormalities and headache: A population-based imaging study (HUNT MRI)

Background

Most studies on intracranial abnormalities among headache sufferers were performed in selected clinical populations. The aim of this study was to evaluate the relationship between intracranial abnormalities and headache among middle-aged adults in the general population.

Methods

Participants in a large epidemiological study (the HUNT 3 study; 2006–2008) who answered a headache questionnaire and participated in a population-based imaging study of the head (HUNT MRI; 2007–2009) were included ( n = 864; age, 50–65 at enrollment). Based on the responses to the HUNT 3 questionnaire, respondents were categorized as having migraine, tension-type headache, or unclassified headache. Logistic regression was used to compare the occurrence of intracranial abnormalities between groups.

Results

Intracranial abnormalities were more common in headache sufferers than in headache-free individuals (29% vs. 22%, respectively; p = 0.041). Adjusted multivariate analyses revealed that those with tension-type headache had higher odds of having minor abnormalities (odds ratio, 2.13; 95% confidence interval = 1.18–3.85). This association disappeared when those with only white matter hyperintensities were removed from the analysis.

Conclusions

Headache sufferers had increased odds of minor intracranial abnormalities. The increased odds were primarily related to the presence of white matter hyperintensities.

Changes of migraine-related white matter hyperintensities after 3 years: a longitudinal MRI study

OBJECTIVE/BACKGROUND

The aim of this longitudinal study was to investigate changes of migraine-related brain white matter hyperintensities 3 years after an initial study. Baseline quantitative magnetic resonance imaging (MRI) studies of migraine patients with hemispheric white matter hyperintensities performed in 2009 demonstrated signs of tissue damage within the hyperintensities. The hyperintensities appeared most frequently in the deep white matter of the frontal lobe with a similar average hyperintensity size in all hemispheric lobes. Since in this patient group the repeated migraine attacks were the only known risk factors for the development of white matter hyperintensities, the remeasurements of migraineurs after a 3-year long follow-up may show changes in the status of these structural abnormalities as the effects of the repeated headaches.

METHODS

The same patient group was reinvestigated in 2012 using the same MRI scanner and acquisition protocol. MR measurements were performed on a 3.0-Tesla clinical MRI scanner. Beyond the routine T1-, T2-weighted, and fluid-attenuated inversion recovery imaging, diffusion and perfusion-weighted imaging, proton magnetic resonance spectroscopy, and T1 and T2 relaxation time measurements were also performed. Findings of the baseline and follow-up studies were compared with each other.

RESULTS

The follow-up proton magnetic resonance spectroscopy studies of white matter hyperintensities showed significantly decreased N-acetyl-aspartate (median values 8.133 vs 7.153 mmol/L, P=.009) and creatine/phosphocreatine (median values 4.970 vs 4.641 mmol/L, P=.015) concentrations compared to the baseline, indicating a more severe axonal loss and glial hypocellularity with decreased intracellular energy production. The diffusion values, the T1 and T2 relaxation times, and the cerebral blood flow and volume measurements presented only mild changes between the studies. The number (median values 21 vs 25, P<.001) and volume (median values 0.896 vs 1.140 mL, P<.001) of hyperintensities were significantly higher in the follow-up study. No changes were found in the hemispheric and lobar distribution of hyperintensities. An increase in the hyperintensity size of preexisting lesions was much more common than a decrease (median values 14 vs 5, P=.004). A higher number of newly developed hyperintensities were detected than disappeared ones (130 vs 22), and most of them were small (<.034 mL). Small white matter hyperintensities in patients with a low migraine attack frequency had a higher chance to disappear than large white matter hyperintensities or white matter hyperintensities in patients with a high attack frequency (coefficient: -0.517, P=.034).

CONCLUSIONS

This longitudinal MRI study found clinically silent brain white matter hyperintensities to be predominantly progressive in nature. The absence of a control group precludes definitive conclusions about the nature of these changes or if their degree is beyond normal aging.

Migraine and cerebral blood flow in the general population

INTRODUCTION

Observations that migraine increases risk of cardiovascular disease and ischemic brain changes may suggest sustained vascular differences between migraineurs and controls. In a population-based setting, we compared cerebral blood flow between migraineurs in the attack-free period and controls.

METHODS

Between 2006 and 2008, 2642 participants, aged 45-65, from the Rotterdam Study completed a migraine questionnaire and had complete usable MRI data. Participants were classified into controls (N = 2033), probable migraine (N = 153), or migraine (N = 456). Using 2D phase contrast MRI, we performed a cross-sectional analysis of the effect of migraine on total cerebral blood flow (tCBF), parenchymal cerebral blood flow (pCBF), and blood flow in each intracranial arterial using linear regression. Additionally, we performed stratified analysis of subtypes of migraine.

RESULTS

Compared with controls, migraineurs had higher pCBF (1.07 ml/min/100 ml, 95% CI 0.08; 2.05). In particular, migraineurs had significantly higher blood flow in the basilar artery (4.70 ml/min, 95% CI 0.77; 8.62).

DISCUSSION

Migraineurs in the attack-free period have higher pCBF, particularly basilar artery flow, compared to controls, supporting the notion of sustained vascular differences between these groups outside of migraine attacks.

Migraine and stroke: in search of shared mechanisms

BACKGROUND

Migraine, particularly with aura, increases the risk for ischemic stroke, at least in a subset of patients. The underlying mechanisms are poorly understood and probably multifactorial.

METHODS

We carried out an extended literature review of experimental and clinical evidence supporting the association between migraine and ischemic stroke to identify potential mechanisms that can explain the association.

RESULTS

Observational, imaging and genetic evidence support a link between migraine and ischemic stroke. Based on clinical and experimental data, we propose mechanistic hypotheses to explain the link, such as microembolic triggers of migraine and enhanced sensitivity to ischemic injury in migraineurs.

DISCUSSION

We discuss the possible practical implications of clinical and experimental data, such as aggressive risk factor screening and management, stroke prophylaxis and specific acute stroke management in migraineurs. However, evidence from prospective clinical trials is required before modifying the practice in this patient population.

Ischaemic cavities in the cerebellum: an ex vivo 7-tesla MRI study with pathological correlation

BACKGROUND

Small cerebellar cavities (≤15 mm) are often observed coincidentally in ageing subjects and have also been associated with migraine. Although generally assumed to be of ischaemic origin, descriptive imaging studies are sparse and imaging findings have not been correlated with histopathology. We aimed to investigate whether small ischaemic cavities in the cerebellum show characteristic infarct patterns that might be helpful for diagnostic imaging.

METHODS

We examined 40 whole postmortem cerebella with 7-tesla MRI ex vivo for the presence of small ischaemic cavities. The scan protocol included a T2-, T2*- and fluid-attenuated inversion recovery-weighted sequence for all specimens. We investigated to which degree small ischaemic cavities affect the cortical, juxtacortical and/or deep subcortical regions of the cerebellum. In a subset of the cavities identified, we correlated the imaging data with histopathological findings. This was performed by cutting the particular cerebellar specimen into 5-mm-thick slices. Serial sections were performed if cavities remained unidentified macroscopically.

RESULTS

Twenty-two cavities were seen on ex vivo MRI in 8 out of 40 examined cerebella. Twenty out of 22 cerebellar cavities were located in the cortex, and only 2 in the deep white matter, with no cavities located in the juxtacortical white matter. None of the 20 cerebellar cortical cavities showed extension into the juxtacortical white matter on MRI, although in 1 cortical cavity some surrounding gliosis was seen to extend into the juxtacortical white matter. Nine out of 22 cavities were sampled for pathological correlation, including 7 cerebellar cortical cavities and both cavities or lacunes in the deep white matter. Three out of 7 cortical and both the deep cavities were histopathologically verified as cavities of ischaemic origin, while the remaining cortical cavities could not be retrieved upon histopathologic examination. Some microscopic gliosis was seen to extend into the juxtacortical white matter of all confirmed cortical cavities.

CONCLUSION

Knowledge of typical infarct patterns may facilitate the detection and characterisation of cerebellar ischaemic cavities in vivo. Cerebellar cortical cavities appeared to be much more common than deep cavities and presented on imaging as a full-thickness defect in the cerebellar cortex without extension in the adjacent white matter.

Headache and sleep: shared pathophysiological mechanisms

OBJECTIVE

The objective of the current article is to review the shared pathophysiological mechanisms which may underlie the clinical association between headaches and sleep disorders.

BACKGROUND

The association between sleep and headache is well documented in terms of clinical phenotypes. Disrupted sleep-wake patterns appear to predispose individuals to headache attacks and increase the risk of chronification, while sleep is one of the longest established abortive strategies. In agreement, narcoleptic patients show an increased prevalence of migraine compared to the general population and specific familial sleep disorders have been identified to be comorbid with migraine with aura.

CONCLUSION

The pathophysiology and pharmacology of headache and sleep disorders involves an array of neural networks which likely underlie their shared clinical association. While it is difficult to differentiate between cause and effect, or simply a spurious relationship the striking brainstem, hypothalamic and thalamic convergence would suggest a bidirectional influence.

Migraineurs without aura show microstructural abnormalities in the cerebellum and frontal lobe

The involvement of the cerebellum in migraine pathophysiology is not well understood. We used a biparametric approach at high-field MRI (3 T) to assess the structural integrity of the cerebellum in 15 migraineurs with aura (MWA), 23 migraineurs without aura (MWoA), and 20 healthy controls (HC). High-resolution T1 relaxation maps were acquired together with magnetization transfer images in order to probe microstructural and myelin integrity. Clusterwise analysis was performed on T1 and magnetization transfer ratio (MTR) maps of the cerebellum of MWA, MWoA, and HC using an ANOVA and a non-parametric clusterwise permutation F test, with age and gender as covariates and correction for familywise error rate. In addition, mean MTR and T1 in frontal regions known to be highly connected to the cerebellum were computed. Clusterwise comparison among groups showed a cluster of lower MTR in the right Crus I of MWoA patients vs. HC and MWA subjects (p = 0.04). Univariate and bivariate analysis on T1 and MTR contrasts showed that MWoA patients had longer T1 and lower MTR in the right and left pars orbitalis compared to MWA (p < 0.01 and 0.05, respectively), but no differences were found with HC. Lower MTR and longer T1 point at a loss of macromolecules and/or micro-edema in Crus I and pars orbitalis in MWoA patients vs. HC and vs. MWA. The pathophysiological implications of these findings are discussed in light of recent literature.

Differentiating white matter lesions in multiple sclerosis and migraine using monoexponential and biexponential diffusion measurements

PURPOSE

To compare the white matter lesions seen in multiple sclerosis and migraine using monoexponential and high b-value biexponential diffusion measurements.

MATERIALS AND METHODS

Diffusion-weighted images were acquired on a 3.0-Tesla magnetic resonance imaging system. Diffusion parameters were estimated using monoexponential (0-1000 s/mm(2) ) and biexponential (0-5000 s/mm(2) ) approaches from 15 multiple sclerosis patients, 15 patients with migraine and 15 healthy control subjects. The study was performed in accordance with the approval of the Regional Research Ethics Committee. The apparent diffusion coefficient (ADC) values were measured in the lesions and the normal-appearing white matter of patients and in the white matter of controls.

RESULTS

High lesional ADCmono values were detected in both patient groups without significant differences between the groups (10.72 and 9.86 × 10(-4) mm(2) /s for MS and migraine respectively, P = 0.2134). The biexponential measurements showed significantly higher ADCfast , ADCslow , and Pslow values in the migraine lesions than in the multiple sclerosis lesions (16.47 versus 14.29, 1.41 versus 0.76, and 20.34 versus 12.01 all values in 10(-4) mm(2) /s; P = 0.0344, P = 0.0019, P = 0.0021, respectively).

CONCLUSION

Biexponential diffusion analysis may help to differentiate multiple sclerosis-related white matter lesions from migraine-related ones.

Very small cerebellar infarcts: integration of recent insights into a functional topographic classification

BACKGROUND

Very small cerebellar infarcts (diameter <2 cm) are a frequent finding on MRI. With an increasing scientific interest in cerebral microinfarcts, very small infarcts in the cerebellum deserve more of our attention as well. The goal of the present article was to review infarct terminology and mechanisms, as well as to critically appraise the current classification system for very small cerebellar infarcts.

METHODS

A search strategy was designed to identify all relevant studies on very small cerebellar infarcts in the English language. This search was restricted to papers published up to February 21, 2013. Studies were initially identified from the MEDLINE/PubMed database using the search terms 'small cerebellar infarct', 'lacunar infarct', 'microinfarct', 'end zone infarct', 'border zone infarct', 'watershed infarct', 'territorial infarct', and 'nonterritorial infarct'. Furthermore, a similar search strategy was directed to identify all relevant articles on (descriptive and functional) neuroanatomy and neuroimaging of the cerebellum.

RESULTS

Very small cerebellar infarcts have been referred to as lacunar infarcts, as junctional, border zone or watershed infarcts, as nonterritorial infarcts, as very small territorial or end zone infarcts, or simply as (very) small cerebellar infarcts. Since the original clinicoradiological study on these small infarcts, the classification into border zones remains in common use. This classification is based upon the assumption that these infarcts occur secondary to low flow in between arterial perfusion territories, where flow is believed to be the lowest. Later studies, however, have suggested occlusion of small (end-) arteries as a prerequisite for the pathogenesis of even small cerebellar infarcts, with low flow merely as a potential contributor. Therefore, it is likely that infarcts may as well occur in a nonborder zone distribution. Moreover, the classification into border zones may be considered unreliable since the location of border zones is highly variable among individuals and is not known in a particular patient. Recently, a functional topographic organization has been found in the cerebellum with evidence for a motor-nonmotor dichotomy between the anterior and posterior lobe. Since the cerebellar lobes can be easily and reliably distinguished with both CT and MRI, we recommend the classification of very small cerebellar infarcts according to topographic location.

CONCLUSION

There are several fundamental concerns with the current classification of very small cerebellar infarcts according to border zones, which we would like to overcome by recommending a new classification system based on topography. This will allow for a reliable and reproducible way of classifying very small cerebellar infarcts and is expected to improve clinicoradiological correlation.

Migraine and structural changes in the brain: a systematic review and meta-analysis

OBJECTIVE

To evaluate the association between migraine without aura (MO) and migraine with aura (MA) and 3 types of structural brain abnormalities detected by MRI: white matter abnormalities (WMAs), infarct-like lesions (ILLs), and volumetric changes in gray and white matter (GM, WM) regions.

METHODS

PubMed as well as the reference lists of identified studies and reviews were used to identify potentially eligible studies through January 2013. Candidate studies were reviewed and eligible studies were abstracted. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated for WMAs and ILLs.

RESULTS

Six population-based and 13 clinic-based studies were identified. The studies suggested that structural brain changes, including WMAs, silent ILLs, and volumetric changes in GM and WM regions, were more common in migraineurs than in control groups. The results were strongest for MA. The meta-analysis of WMAs showed an association for MA (OR 1.68; 95% CI 1.07-2.65; p = 0.03) but not for MO (OR 1.34; 95% CI 0.96-1.87; p = 0.08). The association of ILLs was greater for MA (OR 1.44; 95% CI 1.02-2.03; p = 0.04) than for MO, but no association was found for MA (p = 0.52) and MO (p = 0.08) compared to controls.

CONCLUSION

These data suggest that migraine may be a risk factor for structural changes in the brain. Additional longitudinal studies are needed to determine the differential influence of migraine without and with aura, to better characterize the effects of attack frequency, and to assess longitudinal changes in brain structure and function.