Decreased hemispheric water mobility in hemiplegic migraine related to mutation of CACNA1A gene

The Dawn and Advancement of the Knowledge of the Genetics of Migraine

Background: Migraine is a prevalent episodic brain disorder known for recurrent attacks of unilateral headaches, accompanied by complaints of photophobia, phonophobia, nausea, and vomiting. Two main categories of migraine are migraine with aura (MA) and migraine without aura (MO). Main body: Early twin and population studies have shown a genetic basis for these disorders, and efforts have been invested since to discern the genes involved. Many techniques, including candidate-gene association studies, loci linkage studies, genome-wide association, and transcription studies, have been used for this goal. As a result, several genes were pinned with concurrent and conflicting data among studies. It is important to understand the evolution of techniques and their findings. Conclusions: This review provides a chronological understanding of the different techniques used from the dawn of migraine genetic investigations and the genes linked with the migraine subtypes.

Familial Hemiplegic Migraine With Progressive Cerebellar Ataxia Caused by a p.Thr666Met CACNA1A Gene Mutation in a Chinese Family

Here, we describe the first case of familial hemiplegic migraine type 1 (FHM1) resulting from a T666M mutation in the CACNA1A gene of a Chinese individual. A 54-year-old female patient demonstrated extensive clinical manifestations, including transient paropsia, hemianesthesia, logaphasia, hemiplegia, migraine, fever, impaired consciousness, and progressive cerebellar ataxia. At admission, neurological examination showed a fever of 38.6°C, coma, bilateral pupillary constriction, left-sided deviation of both eyes, meningeal irritation, and bilateral positive Chaddock's sign. Brain magnetic resonance imaging (MRI) displayed only cerebellar atrophy. The pressure and white blood cells of the cerebrospinal fluid (CSF) were elevated. Her nine relatives also had similar clinical spectra. To further clarify the diagnosis, we conducted a genetic analysis on the family. The results of genetic testing showed that all seven living affected members carried the T666M mutation in the CACNA1A gene. This case report indicates that the diagnosis of FHM should be taken into account when a patient manifests migraine accompanied with hemiplegia, acute encephalopathy, and abnormal CSF. In addition, genetic testing is indispensable for the identification of some atypical attacks of hemiplegic migraine.

Encephalopathy in a Large Cohort of British Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Patients

Background and Purpose- Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic form of stroke usually presenting with migraine with aura, lacunar infarcts, and cognitive impairment. Acute encephalopathy is a less recognized presentation of the disease. Methods- Data collected prospectively from 340 consecutively recruited symptomatic patients with diagnosis of CADASIL seen in a British National CADASIL clinic was retrospectively reviewed and original clinical records and imaging obtained. An encephalopathic event was defined as an acute event of an altered state of consciousness in a patient with CADASIL, manifesting with signs of brain dysfunction, which warranted hospital admission in the absence of any other cause. Clinical characteristics, risk factors, and outcome of encephalopathic presentations were studied. Results- A total of 35 of 340 (10.3%) participants had a history of 50 encephalopathic events which was the first hospital presentation of CADASIL in 33 (94.3%) patients. Most commonly reported features during episodes were visual hallucinations (44%), seizures (22%), and focal neurological deficits (60%).Complete recovery within 3 months was reported in 48(96%) episodes. In 62% of episodes, there was a history of migraine or migraine aura directly preceding the encephalopathy. In 2 out of 15 cases where magnetic resonance imaging during episodes was available, unilateral focal cortical swelling was seen. A past history of migraine was independently associated with encephalopathy (odds ratio=12.3 [95% CI, 1.6-93.7]; P=0.015). Conclusions- In up to 10% of CADASIL patients, a reversible encephalopathy is the first presentation leading to diagnosis. The strong association with migraine suggests a shared pathogenesis. Focal cortical swelling may be seen on magnetic resonance imaging during the acute episode.

Pathophysiological mechanisms of migraine and epilepsy: Similarities and differences

Migraine and epilepsy are episodic disorders with distinct features, but they have some clinical and pathophysiological overlaps. We review here clinical overlaps between seizures and migraine attacks, activities of neuronal networks observed during seizures and migraine attacks, and molecular and cellular mechanisms of migraine identified in genetic forms, focusing on genetic variants identified in hemiplegic migraine and their functional effects. Epilepsy and migraine can be generated by dysfunctions of the same neuronal networks, but these dysfunctions can be disease-specific, even if pathogenic mutations target the same protein. Studies of rare monogenic forms have allowed the identification of some molecular/cellular dysfunctions that provide a window on pathological mechanisms: we have begun to disclose the tip of the iceberg.

Fatal Cerebral Edema With Status Epilepticus in Children With Dravet Syndrome: Report of 5 Cases

Dravet syndrome (DS) is a well-recognized developmental and epileptic encephalopathy associated with SCN1A mutations and 15% mortality by 20 years. Although over half of cases succumb to sudden unexpected death in epilepsy, the cause of death in the remainder is poorly defined. We describe the clinical, radiologic, and pathologic characteristics of a cohort of children with DS and SCN1A mutations who developed fatal cerebral edema causing mass effect after fever-associated status epilepticus. Cases were identified from a review of children with DS enrolled in the Epilepsy Genetics Research Program at The University of Melbourne, Austin Health, who died after fever-associated status epilepticus. Five children were identified, all of whom presented with fever-associated convulsive status epilepticus, developed severe brain swelling, and died. All had de novo SCN1A mutations. Fever of 40°C or greater was measured in all cases. Signs of brainstem dysfunction, indicating cerebral herniation, were first noted 3 to 5 days after initial presentation in 4 patients, though were apparent as early as 24 hours in 1 case. When MRI was performed early in a patient's course, focal regions of cortical diffusion restriction were noted. Later MRI studies demonstrated diffuse cytotoxic edema, with severe cerebral herniation. Postmortem studies revealed diffuse brain edema and widespread neuronal damage. Laminar necrosis was seen in 1 case. Cerebral edema leading to fatal brain herniation is an important, previously unreported sequela of status epilepticus in children with DS. This potentially remediable complication may be a significant contributor to the early mortality of DS.

Adult-Onset Hemiplegic Migraine with Cortical Enhancement and Oedema

We present genetically identical twin patients who experienced late-onset migraine with visual and somatosensory auras and later developed hemiplegic migraines associated with severe cortical oedema and enhancement. Both positron emission tomography and electroencephalography showed an increase in activity contralateral to the hemiplegic side. Brain biopsy during the attack showed reactive astrogliosis and microgliosis. Mutations in CACNA1A, ATP1A2, SLC1A3 and NOTCH3 were ruled out by sequencing. This report shows the clinical and genetic evaluation of a severe form of familial hemiplegic migraine as well as the evolution of the imaging changes.

Diffusion- and Perfusion-Weighted MR Imaging in Persistent Migrainous visual Disturbances

Pathological changes on diffusion-weighted MR scans had been described in hemiplegic migraine and perfusion changes had been demonstrated in typical migraine aura with radio-isotope studies and, more recently, MR perfusion imaging. However, there is relatively little knowledge of the pathophysiology of long-lasting migraine aura and its possibly variant phenotype, visual snow. Our aim was to investigate with advanced MR techniques whether patients with long-lasting visual disturbance showed regional alterations in cerebral water diffusion and perfusion. We have studied four patients using MR perfusion and MR diffusion imaging. Two patients had typical visual aura and two had a primary persistent visual disturbance (visual snow phenomenon). All patients had normal conventional structural MR imaging. MR diffusion-weighted images were acquired with a b-value of up to 1000 s/mm2. From the diffusion weighted images we generated maps of apparent diffusion coefficient (ADC), which were inspected visually and used for ADC measurements of predefined regions of interest, which included the visual, frontal, insular and temporal cortices. MR perfusion imaging was performed using a bolus tracking technique with dynamic susceptibility-weighted images. Colour coded maps of relative cerebral blood volume, mean transit time and bolus arrival time were generated, as well as time-signal intensity curves over the anterior, middle and posterior cerebral artery territories. The maps of the ADC and above perfusion parameters appeared symmetrical in all patients with no evidence of decreased water diffusion or cerebral perfusion in the occipital regions, or elsewhere. There was no statistically significant difference between the ADC measurements of the primary visual cortices and other cortical regions. Our findings suggest that regional changes in cerebral water diffusion and perfusion do not play an important part in the pathophysiology of persistent migraine aura or primary persistent visual disturbance.

Magnetic Resonance Imaging of Pediatric Neurologic Emergencies

Although computed tomography is often the first line of imaging in the emergency setting, magnetic resonance imaging (MRI) is of increasing importance in the evaluation of central nervous system emergencies in the pediatric population. As such, it is necessary to understand the indications for which MRI may be necessary. This article reviews the unique pathophysiologic entities affecting the pediatric population and the associated MRI findings. Specifically, utility of emergent MRI and characteristic appearances of traumatic brain injury, traumatic spinal injury, nonaccidental trauma, arterial ischemic stroke, cerebral sinovenous thrombosis, stroke mimics, and central nervous system infections are described.

Recurrent steroid-responsive cerebral vasogenic edema in status migrainosus and persistent aura

Background

Status migrainosus (SM) and persistent aura (PA) without infarction are complications of migraine. Although several patients have been reported to have reversible brain lesions associated with complications of migraine, their nature and pathophysiology remain unclear.

Case

We report on a 38-year-old male who presented with nine episodes of SM and PA over eight years. Serial neuroimaging studies including brain magnetic resonance imaging (MRI), blood flow single photon emission tomography (SPECT),18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) and11 C-flumazenil PET (FMZ-PET) demonstrated cerebral vasogenic edema (CVE) with hypoperfusion and hypometabolism in the area, anatomically corresponding to the area with PA. SM and PA were effectively controlled by corticosteroid therapy. Follow-up MRI revealed complete reversibility of the CVE, which was supported by normal FMZ-PET and FDG-PET findings.

Conclusion

We have described a patient with transient brain lesions associated with complications of migraine who was diagnosed with fully reversible and steroid responsive CVE.

Repeated encephalopathy and hemicerebral atrophy in a patient with familial hemiplegic migraine type 1

We herein describe a case of a 38-year-old man with familial hemiplegic migraine with a T666M mutation in the electrical potential-dependent calcium ion channel (CACNA1A) gene. His migraine was accompanied by hemiparesis and impaired consciousness. Brain magnetic resonance imaging revealed abnormalities in the right cortical hemisphere. Single-photon emission computed tomography demonstrated a decrease in iomazenil uptake and an increase in (99m)Tc-ethyl cysteinate dimer uptake at the ipsilateral site. Positron emission tomography showed a decrease in 18F-fluorodeoxyglucose uptake in the same area, which later showed atrophic changes. The patient's brain atrophy ceased after treatment with sodium valproate. This case suggests that the progression of brain atrophy can be prevented with adequate prophylaxis.

Hemiconvulsion-hemiplegia-epilepsy syndrome: current understandings

Hemiconvulsion-Hemiplegia (HH) syndrome is an uncommon consequence of prolonged focal febrile convulsive seizures in infancy and early childhood. It is characterized by the occurrence of prolonged clonic seizures with unilateral predominance occurring in a child and followed by the development of hemiplegia. Neuroradiological studies showed unilateral edematous swelling of the epileptic hemisphere at the time of initial status epilepticus (SE). This acute phase is followed by characteristic cerebral hemiatrophy with subsequent appearance of epilepsy, so called Hemiconvulsion-Hemiplegia-Epilepsy (HHE) syndrome. The etiologies and the underlying mechanisms remain to be understood. Using a review of the literature, we summarized the data of the last 20 years. It appears that idiopathic HH/HHE syndrome is the most common reported form. The basic science data suggest that immature brain is relatively resistant to SE-induced cell injury. Several factors might contribute to the pathogenesis of HH/HHE syndrome: 1. prolonged febrile seizure in which inflammation may worsen the level of cell injury; 2. inflammation and prolonged ictal activity that act on blood-brain-barrier permeability; 3. predisposing factors facilitating prolonged seizure such as genetic factors or focal epileptogenic lesion. However, these factors cannot explain the elective involvement of an entire hemisphere. We draw new hypothesis that may explain the involvement of one hemisphere such as maturation of brain structure such as corpus callosum or genetic factors (CACNA1A gene) that are specifically discussed. An early diagnosis and a better understanding of the underlying mechanisms of HHE are needed to improve the outcome of this condition.

Sporadic hemiplegic migraine presenting as acute encephalopathy

A 10-year-old boy with psychomotor developmental delay and cerebellar vermis atrophy developed right hemiplegia with vomiting, unconsciousness, convulsions, and late-onset fever. Slow delta activity was noted over the left hemisphere on electroencephalography, and neuroimaging revealed swelling of the left temporo-occipital cerebral cortex with restricted diffusivity, successive transient cortical atrophy, and hyperperfusion over the left cerebral hemisphere. Interleukin-6 was elevated in the cerebrospinal fluid. The acute symptoms resolved completely within 3 weeks after onset, but hypoperfusion persisted in the left posterior cortex thereafter. Another episode with transient left hemiplegia appeared 7 months later, followed by recurrence of migraine attacks. Analysis of the CACNA1A gene revealed a mutation of c.1997 C>T (p.T666M). None of his family members had migraine. This case represents an unusual evolution of sporadic hemiplegic migraine with manifestations of acute encephalopathy, for which the role of migraine-related inflammatory process is assumed.

Variable manifestations of familial hemiplegic migraine associated with reversible cerebral edema in children

Three children with familial hemiplegic migraine presented with right-sided weakness, speech difficulty, altered mental status, and gait abnormalities. These persistent aura signs were accompanied by left-sided slowing and cerebral dysfunction, documented by electroencephalograms. Cranial magnetic resonance imaging revealed cortical edema restricted to the left cerebral hemisphere. Follow-up electroencephalogram and imaging studies produced normal results 1-4 months afterward. However, cognitive changes persisted. Genetic testing demonstrated variable results: one child manifested a CACNA1A mutation compatible with familial hemiplegic migraine type 1, whereas another demonstrated an ATP1A2 sequence alteration. No known mutations were evident in the third child, with minor head trauma thought to precipitate the familial hemiplegic migraine. These findings demonstrate the variable clinical and genetic heterogeneity of childhood familial hemiplegic migraine.

Pathophysiological role of omega pore current in channelopathies

In voltage-gated cation channels, a recurrent pattern for mutations is the neutralization of positively charged residues in the voltage-sensing S4 transmembrane segments. These mutations cause dominant ion channelopathies affecting many tissues such as brain, heart, and skeletal muscle. Recent studies suggest that the pathogenesis of associated phenotypes is not limited to alterations in the gating of the ion-conducting alpha pore. Instead, aberrant so-called omega currents, facilitated by the movement of mutated S4 segments, also appear to contribute to symptoms. Surprisingly, these omega currents conduct cations with varying ion selectivity and are activated in either a hyperpolarized or depolarized voltage range. This review gives an overview of voltage sensor channelopathies in general and focuses on pathogenesis of skeletal muscle S4 disorders for which current knowledge is most advanced.

Late cytotoxic edema in 2 children with hemiplegia: hemiplegic migraine or stroke?

Hemiplegic migraine (HM) is a rare variant of migraine with aura, characterized by migrainous headache and fully reversible motor deficit within 24 hours. Both sporadic and familial forms of HMs are genetically heterogenous with little information on neuroimaging during and after acute attacks. We report 2 cases of children with presumed HM and late cytotoxic edema.

Diffusion MRI at 25: exploring brain tissue structure and function

Diffusion MRI (or dMRI) came into existence in the mid-1980s. During the last 25 years, diffusion MRI has been extraordinarily successful (with more than 300,000 entries on Google Scholar for diffusion MRI). Its main clinical domain of application has been neurological disorders, especially for the management of patients with acute stroke. It is also rapidly becoming a standard for white matter disorders, as diffusion tensor imaging (DTI) can reveal abnormalities in white matter fiber structure and provide outstanding maps of brain connectivity. The ability to visualize anatomical connections between different parts of the brain, non-invasively and on an individual basis, has emerged as a major breakthrough for neurosciences. The driving force of dMRI is to monitor microscopic, natural displacements of water molecules that occur in brain tissues as part of the physical diffusion process. Water molecules are thus used as a probe that can reveal microscopic details about tissue architecture, either normal or in a diseased state.

Enhanced subcortical spreading depression in familial hemiplegic migraine type 1 mutant mice

Familial hemiplegic migraine type 1, a monogenic migraine variant with aura, is linked to gain-of-function mutations in the CACNA1A gene encoding Ca(V)2.1 channels. The S218L mutation causes severe channel dysfunction, and paroxysmal migraine attacks can be accompanied by seizures, coma, and hemiplegia; patients expressing the R192Q mutation exhibit hemiplegia only. Familial hemiplegic migraine knock-in mice expressing the S218L or R192Q mutation are highly susceptible to cortical spreading depression, the electrophysiological surrogate for migraine aura, and develop severe and prolonged motor deficits after spreading depression. The S218L mutants also develop coma and seizures and sometimes die. To investigate underlying mechanisms for these symptoms, we used multielectrode electrophysiological recordings, diffusion-weighted magnetic resonance imaging, and c-fos immunohistochemistry to trace spreading depression propagation into subcortical structures. We showed that unlike the wild type, cortical spreading depression readily propagated into subcortical structures in both familial hemiplegic migraine type 1 mutants. Whereas the facilitated subcortical spread appeared limited to the striatum in R192Q, hippocampal and thalamic spread was detected in the S218L mutants with an allele-dosage effect. Both strains exhibited increased susceptibility to subcortical spreading depression and reverberating spreading depression waves. Altogether, these data show that spreading depression propagates between cortex, basal ganglia, diencephalon, and hippocampus in genetically susceptible brains, which could explain the prolonged hemiplegia, coma, and seizure phenotype in this variant of migraine with aura.

Sporadic hemiplegic migraine with seizures and transient MRI abnormalities

Hemiplegic migraines are characterised by attacks of migraine with aura accompanied by transient motor weakness. There are both familial and sporadic subtypes, which are now recognised as separate entities by the International Classification of Headache Disorders, edition II (ICHD-II). Sporadic hemiplegic migraine is a rare variant of migraine, We report a case of sporadic hemiplegic migraine and seizures with MRI features suggestive of cortical hyper intensity and edema on T2 and FLAIR images with no restriction pattern on diffusion and these changes completely resolving over time, suggesting that these changes are due prolonged neuronal depolarization and not of ischemic origin.

The Almirall European Headache Awards 2009

The Almirall European Headache Awards (AEHA) were organized in conjunction with the European Headache Federation. The awards were held in 2009, aiming to share clinical experience and best practice in headache-related disease management. 56 unusual and challenging cases of headache from 5 European countries (Belgium, France, Italy, Portugal and Spain) were judged by a Scientific Committee including expert representatives from participating countries, acting as reviewers. Three cases were selected from each country. The 15 resulting cases were presented to the Scientific Committee in Madrid, Spain in November 2009 and awards were given to the top 5 presentations. This article presents details of these cases, including the award winning entries. They have been categorized into four main groups: (a) headaches in rare syndromes; (b) secondary headaches to infectious/autoimmune causes or post-trauma/mass occupation; (c) headache in unresolved cases; and (d) other relevant cases. First prize was awarded to a case involving a 55-year-old male with familial thrombocytopenia and a unilateral neuralgiform headache secondary to trigeminal vascular contact, and which was successfully treated with carbamazepine. Conclusions from the meeting include: rare syndromes do occur and require appropriate treatment to improve outcomes; concomitant diseases may impair adequate diagnosis and should be investigated; physicians should be cautious and treat possible serious underlying disease, whilst accurately clarifying the correct diagnosis; neurological examination and complementary tests may be required; consideration should be given to possible rare medication events; and some cases may remain without a clear cause or diagnosis and symptoms should be treated whilst investigations continue.

Brain apparent water diffusion coefficient magnetic resonance image during a prolonged visual aura

BACKGROUND

Reversible changes in brain magnetic resonance imaging (MRI) weighted in diffusion-weighted images (DWI) and apparent water diffusion coefficient (ADC) maps have been reported in acute stroke, epilepsy, eclampsia, and hypoglycemia, but they are contradictory regarding to migraine aura.

OBJECTIVE

A 41-year-old woman with known basilar migraine for 5 years consulted about a persistent visual aura (visual snow phenomenon) plus bilateral paresthesias in the extremities for 4 days. The headache was treated with success with 10 mg of wafer rizatriptan and 600 mg of ibuprophen.

METHODS

The neurologic and ophthalmologic examination were normal. An urgent brain MRI detected no lesions in T1, T2, fluid-attenuated inversion recovery, and DWI, but an abnormal signal appeared in the left occipital lobe in ADC and (r)ADC maps. The brain MRI angiography, carotid ultrasound study, transesophageal echocardiography, 24-hour cardiac Holter monitoring, and thrombophilia study were normal.

RESULTS

A new brain MRI 8 days after did not show any previous lesion in the same sequences.

CONCLUSIONS

We present a patient with migraine and transitory abnormal signals in the ADC map of an occipital region during persistent visual aura. The clinical-radiological relationship is congruent. Some similar cases have showed these MRI signals during the aura, suggesting cytotoxic edema, without ischemic lesions in the MRI controls. Theses ADC images probably appear in complex auras.

Clinical and neuroimaging evidence of interictal cerebellar dysfunction in FHM2

We used multimodal magnetic resonance (MR) techniques [brain diffusion-weighted magnetic resonance imaging, diffusion-weighted imaging (DWI), proton MR spectroscopy (MRS), 1H-MRS; and skeletal muscle phosphorous MRS, 31P-MRS] to investigate interictal brain microstructural changes and tissue energy metabolism in four women with genetically determined familial hemiplegic migraine type 2 (FHM2), belonging to two unrelated families, compared with 10 healthy women. Brain DWI revealed a significant increase of the apparent diffusion coefficient median values in the vermis and cerebellar hemispheres of FHM2 patients, preceding in two subjects the onset of interictal cerebellar deficits. 31P-MRS revealed defective energy metabolism in skeletal muscle of FHM2 patients, while brain 1H-MRS showed a mild pathological increase in lactate in the lateral ventricles of one patient and a mild reduction of cortical N-acetyl-aspartate to creatine ratio in another one. Our MRS results showed that a multisystem energy metabolism defect in FHM2 is associated with microstructural cerebellar changes detected by DWI, even before the onset of cerebellar symptoms.

Cortical spreading edema in persistent visual migraine aura

We present imaging evidence of the spreading of cortical edema with reversibly restricted water diffusion from the left occipital to the temporoparietal cortex in persistent visual migraine aura in a 58-year-old man. The right-sided visual field defect lasting for 15 days was associated with discoupling of glucose metabolism and blood flow and the decreased apparent diffusion coefficient also suggested cytotoxic edema. At 8 weeks no signs were present, and magnetic resonance imaging became normal; therefore, long-lasting restricted cortical water diffusion, even if coupled with hypometabolism and edema, can be reversible in persistent visual migraine aura.

Sporadic hemiplegic migraine: report of a case with clinical and radiological features

A case of visual hallucination, headache and left hemiparesis is reported. The patient had a history of recurrent attacks of similar semiology for the previous 15 years. MRI brain revealed a cortical hyperintensity on T2W, FLAIR and diffusion weighted imaging (DWI) in the right cerebral hemisphere with a normal ADC (apparent diffusion coefficient) map and MR angiogram. Detailed workup for MELAS was negative. A diagnosis of sporadic hemiplegic migraine was made and he was managed conservatively. He made a gradual complete recovery over 2 weeks. He was discharged on flunarizine for prophylaxis and has remained asymptomatic over the ensuing 4 months. This interesting condition is reviewed and discussed herein.

Familial hemiplegic migraine with prolonged aura and multimodality imaging: a case report

We report a case of familial hemiplegic migraine with prolonged aura where multimodality imaging showed hemispheric cytotoxic edema along with evidence of hypometabolism in the affected hemisphere while there was no evidence of hypoperfusion of the affected hemisphere demonstrating that neuronal depression is a more plausible explanation in its pathogenesis.

Cerebral and cerebellar ADC values during a migraine attack

INTRODUCTION

We investigated the diffusion-weighted MRI changes, apparent diffusion coefficient (ADC) values, and conventional MRI findings in specific brain areas during migraine attacks in patients with and without aura.

METHODS

Included in the study were 22 patients (2 male, 20 female) aged between 17 and 49 years who were diagnosed as having migraine according to the diagnostic criteria of the International Headache Society. Also included in the study were 18 age- and sex-matched healthy volunteers. Hyperintense lesions were evaluated in conventional MR images. Heavily diffusion-weighted images, ADC maps, and segmented ADC maps generated for regional ADC (rADC) measurements, were also studied. ADC values from specific brain areas were used with appropriate region of interests (ROI).

RESULTS

Migraine with aura was diagnosed in 13 patients and migraine without aura was diagnosed in 9 patients. A total of 23 hyperintense lesions within the periventricular white matter and deep white matter were detected in five patients (21.8%). All of these hyperintense lesions were seen in migraine patients with aura. In only one patient did a hyperintense lesion show an increased diffusion pattern on diffusion-weighted images and ADC maps. One hyperintense lesion was detected in the control group (5.5%). There was no significant difference in ADC values between the migraine and control groups.

CONCLUSION

T2-weighted hyperintense lesions were significantly more frequent in migraine patients especially in those with aura than in the control group. No diffusion alterations in diffusion-weighted images were detected in the infra- and supratentorial brain areas during migraine attacks in patients with and without aura.

Imaging abnormalities in sporadic hemiplegic migraine on conventional MRI, diffusion and perfusion MRI and MRS

Prolonged hemiparetic migraine aura can cause diagnostic confusion and be mistaken for ischaemic stroke occurring during the course of a migraine--'migrainous infarction'. We report a case of prolonged hemiparesis occurring during the course of a migraine attack. Though initially confused with migrainous infarction, we suggest with sequential magnetic resonance imaging, magnetic resonance angiography, diffusion, perfusion images and magnetic resonance spectroscopy that the hemiplegia was not of vascular origin and that the patient had sporadic hemiplegic migraine. We hypothesize that the mechanisms of sporadic hemiplegic migraine probably lie at a cellular level, similiar to familial hemiplegic migraine.

Imaging Findings of Migraine

Increasingly sophisticated neuroimaging techniques have allowed researchers to begin to define functional and anatomical characteristics of migraine. This paper reviews current knowledge and techniques employed. Assessing present-day knowledge limitations it concludes that with parallel advances in the technology of imaging and the pathophysiologic understanding of migraine, a reliable biomarker may be discovered in the future.

Familial hemiplegic migraine presenting as recurrent encephalopathy in a Native Indian family

BACKGROUND

Familial hemiplegic migraine (FHM) is an autosomal dominant disorder, which can result from mutations in the CACNA1A (FHM1) and ATP1A2 (FHM2) genes. Typically, FHM presents with an aura of hemiplegia accompanied by a moderate-to-severe headache. FHM can be associated with other neurological findings including coma and seizures.

METHODS

We describe the clinical and genetic features of a two-generation, seven-member Native Indian family with recurrent encephalopathy and FHM.

RESULTS

Two of the three affected family members presented initially with encephalopathy, the third family member presented with classic episodes of migraine and hemiparesis. The CACNA1A gene locus was excluded in this family by haplotype analysis and no mutations were identified in the coding region of the ATP1A2 gene by direct sequencing.

CONCLUSIONS

This emphasizes the genetic and clinical heterogeneity in familial hemiplagic migraine FHM and highlights the need to consider the diagnosis of FHM in cases of recurrent encephalopathy.

A G301R Na+/K+ -ATPase mutation causes familial hemiplegic migraine type 2 with cerebellar signs

Familial hemiplegic migraine (FHM) is an autosomal dominant subtype of migraine with hemiparesis during the aura. In over 50% of cases the causative gene is CACNA1A (FHM1), which in some cases produces a phenotype with cerebellar signs, including ataxia and nystagmus. Recently, mutations in ATP1A2 on chromosome 1q23 encoding a Na+/K+ -ATPase subunit were identified in four families (FHM2). We now describe an FHM2 pedigree with a fifth ATP1A2 mutation coding for a G301R substitution. The phenotype was particularly severe and included hemiplegic migraine, seizure, prolonged coma, elevated temperature, sensory deficit, and transient or permanent cerebellar signs, such as ataxia, nystagmus, and dysarthria. A mild crossed cerebellar diaschisis during an attack further supported the clinical evidence of a cerebellar deficit. This is the first report suggesting cerebellar involvement in FHM2. A possible role for CACNA1A in producing the phenotype in this family was excluded by linkage studies to the FHM1 locus. The study of this family suggests that the absence of cerebellar signs may not be a reliable indicator to clinically differentiate FHM2 from FHM1.

Imaging of postthalamic visual fiber tracts by anisotropic diffusion weighted MRI and diffusion tensor imaging: principles and applications

Diffusion weighted MRI offers the possibility to study the course of the cerebral white matter tracts. In the present manuscript, the basics, the technique and the limitations of diffusion tensor imaging and anisotropic diffusion weighted MRI are presented and their applications in various neurological and neurosurgical diseases are discussed with special emphasis on the visual system. A special focus is laid on the combination of fiber tract imaging, anatomical imaging and functional MRI for presurgical planning and intraoperative neuronavigation of lesions near the visual system.

Migraine-Associated Seizures With Recurrent and Reversible Magnetic Resonance Imaging Abnormalities

Migraine and epilepsy are highly comorbid, but the nature of their association remains unclear. Exceptionally, reversible brain magnetic resonance imaging (MRI) abnormalities following migraine and seizures have been reported. There are no descriptions, however, of patients with recurrent brain MRI changes. We report a patient with repeated episodes of migraine-with-aura-associated seizures (migralepsy) and recurrent and reversible brain MRI abnormalities. Location of the abnormalities was always consistent with the neurologic deficits. The possibility that transient brain MRI abnormalities in a patient with migraine with aura followed by seizures may be due to migralepsy should be borne in mind to avoid misdiagnosis and potentially aggressive procedures.

Serial MRI in a case of familial hemiplegic migraine

We report MRI findings in a patient with familial hemiplegic migraine (FHM) with repeated episodes of hemiparesis. FHM is caused by a penetrant autosomal dominant genetic mutation; several mutations have been genotyped, involving brain-expressed ion channels. We found cerebral oedema, dilatation of intracerebral vessels and decreased water diffusion contralateral to the hemiparesis, not respecting vascular territories, with subsequent complete resolution of both clinical and imaging abnormalities. These results are thought to be consistent with an underlying primary neuronal pathology with secondary vascular effects, as opposed to the traditional, primarily vascular, model of migraine aetiology.

MR diffusion tensor imaging: recent advance and new techniques for diffusion tensor visualization

Recently, diffusion tensor imaging is attracting the biomedical researchers for its application in depiction of fiber tracts based on diffusion anisotropy. In this paper, we briefly describe the basic theory of diffusion tensor MR imaging, the determination process of diffusion tensor, and the basic concepts of diffusion tensor visualization techniques. Several results of clinical application in our institute are also introduced. Finally, the limitations, advantages and disadvantages of the techniques are discussed for further application of diffusion tensor visualization.

Multimodal functional imaging of prolonged neurological deficits in a patient suffering from familial hemiplegic migraine

The case of a patient with familial hemiplegic migraine (FHM) suffering from prolonged right sided hemiparesis and aphasia that persisted for more than 10 days is reported. The symptoms were accompanied by slowing of the magnetoencephalogram over the left hemisphere, which normalized parallel to the clinical improvement. Positron emission tomography obtained on the 6th day revealed glucose-hypometabolism (hemispheric difference > or =10%) in left hemisphere's fronto-basal cortex, caudate nucleus, and thalamus. In contrast, magnetic resonance imaging including perfusion and diffusion weighted imaging was normal and did not show significant alterations of cortical perfusion or water mobility during the episode. We hypothesize that this finding provides evidence for a primary neuronal dysfunction causing the prolonged neurological deficits in FHM.

Magnetic resonance angiogram evidence of vasospasm in familial hemiplegic migraine

We report a case of familial hemiplegic migraine in an 11-year-old girl who presented with coma and left hemiparesis. Magnetic resonance imaging showed reversible vasospasm and evidence of oligemia, bringing new information regarding neurovascular changes in familial hemiplegic migraine.

Diffusion-weighted magnetic resonance imaging during the aura of pseudomigraine with temporary neurologic symptoms and lymphocytic pleocytosis

A typical feature of pseudomigraine with temporary neurologic symptoms and lymphocytic pleocytosis (PMP) is the long duration of aura symptoms. To determine if these prolonged auras cause early ischemic parenchymal changes, we performed diffusion-weighted magnetic resonance imaging during the aura of a patient with PMP and found no reduction of water diffusion.

Frequency and clinical context of decreased apparent diffusion coefficient reversal in the human brain

PURPOSE

To determine the probability that regions of decreased apparent diffusion coefficient (ADC) return to normal without persistent symptoms or T2 change and the settings in which these ADC reversals occur.

MATERIALS AND METHODS

Three hundred magnetic resonance (MR) imaging studies were selected at random from a database of 7,147 examinations to determine the probability of a pathologically decreased ADC. In cases with decreased ADC, the clinical history was recorded and, if available, follow-up MR imaging findings were evaluated. Five cases of ADC reversal became known during the same period and were evaluated to determine the initial ADC decrease, clinical outcome, and findings at follow-up imaging.

RESULTS

Findings in 116 of 300 MR imaging studies revealed regions of decreased ADC. In 49 of 116 studies, follow-up MR imaging examinations were performed at least 4 weeks after the onset of symptoms; ADC did not reverse. Five cases of ADC reversal were identified in the same period, giving an estimated 0.2%-0.4% probability of ADC reversal. Clinical settings were venous sinus thrombosis and seizure (n = 3), hemiplegic migraine (n = 1), and hyperacute arterial infarction (n = 1). Both white matter (n = 3) and gray matter (n = 3) regions were involved.

CONCLUSION

Reversal of ADC lesions is rare, occurs in complicated clinical settings, and can involve white or gray matter.

Delayed cerebral edema and fatal coma after minor head trauma: role of the CACNA1A calcium channel subunit gene and relationship with familial hemiplegic migraine

Trivial head trauma may be complicated by severe, sometimes even fatal, cerebral edema and coma occurring after a lucid interval ("delayed cerebral edema"). Attacks of familial hemiplegic migraine (FHM) can be triggered by minor head trauma and are sometimes accompanied by coma. Mutations in the CACNA1A calcium channel subunit gene on chromosome 19 are associated with a wide spectrum of mutation-specific episodic and chronic neurological disorders, including FHM with or without coma. We investigated the role of the CACNA1A gene in three subjects with delayed cerebral edema. Two subjects originated from a family with extreme FHM, and one subject was the previously asymptomatic daughter of a sporadic patient with hemiplegic migraine attacks. In all three subjects with delayed severe edema, we found a C-to-T substitution resulting in the substitution of serine for lysine at codon 218 (S218L) in the CACNA1A gene. The mutation was absent in nonaffected family members and 152 control individuals. Haplotype analysis excluded a common founder for both families. Neuropathological examination in one subject showed Purkinje cell loss with relative preservation of granule cells and sparing of the dentate and inferior olivary nuclei. We conclude that the novel S218L mutation in the CACNA1A calcium channel subunit gene is involved in FHM and delayed fatal cerebral edema and coma after minor head trauma. This finding may have important implications for the understanding and treatment of this dramatic syndrome.

Diffusion tensor imaging: concepts and applications

The success of diffusion magnetic resonance imaging (MRI) is deeply rooted in the powerful concept that during their random, diffusion-driven displacements molecules probe tissue structure at a microscopic scale well beyond the usual image resolution. As diffusion is truly a three-dimensional process, molecular mobility in tissues may be anisotropic, as in brain white matter. With diffusion tensor imaging (DTI), diffusion anisotropy effects can be fully extracted, characterized, and exploited, providing even more exquisite details on tissue microstructure. The most advanced application is certainly that of fiber tracking in the brain, which, in combination with functional MRI, might open a window on the important issue of connectivity. DTI has also been used to demonstrate subtle abnormalities in a variety of diseases (including stroke, multiple sclerosis, dyslexia, and schizophrenia) and is currently becoming part of many routine clinical protocols. The aim of this article is to review the concepts behind DTI and to present potential applications.