Hisaka Igarashi

Prevalence of migraine in Japan: a nationwide survey.

This study presents the first nationwide survey of migraine in Japan. A representative sample of 4029 subjects aged 15 years or older was selected from the Japanese population according to the quota method. A combination of telephone interview and mailed questionnaire methods was used. Diagnosis of migraine was based on the International Headache Society (IHS) Classification. The overall prevalence of migraine in the past year was 8.4%; 5.8% was migraine without aura and 2.6% was migraine with aura. Significant correlation was found between the prevalence of migraine and such variables as gender, age and district of residence. Doctor attendance rate was very low and 69.4% with migraine had never consulted a physician for headache. Yet, 74.2% complained that migraine headache impaired their daily activity significantly. Only 11.6% were aware that their headache was migraine and 56.9% were using only the over-the-counter drugs. The study revealed a comparably high prevalence of migraine in the general population of Japan compared with other countries. A genetic factor was speculated as the cause of regional difference in migraine prevalence.

Regional Cerebral Blood Volume and Hematocrit Measured in Normal Human Volunteers by Single-Photon Emission Computed Tomography

Single-photon emission computed tomography (SPECT) was used for the measurement of regional cerebral blood volume (CBV) and hematocrit (Hct) in normal healthy human volunteers (mean age 30 ± 8 years). Regional cerebral red blood cell (RBC) volume and plasma volume were determined separately and their responses to carbon dioxide were investigated. Ten right-handed healthy volunteers were the subjects studied. SPECT scans were performed following intravenous injection of the RBC tracer (99mTc-labeled RBC) and plasma tracer (99mTc-labeled human serum albumin) with an interval of 48 h. Regional cerebral Hct was calculated as the regional ratio between RBC and plasma volumes and then was used for calculating CBV. Mean regional CBV in the resting state was 4.81 ± 0.37 ml/100 g brain, significantly greater in the left hemisphere compared with the right by 3.8% (p < 0.01). Mean regional RBC volumes (1.50 ± 0.09 ml/100 g brain) were less than mean regional plasma volumes (3.34 ± 0.28 ml/100 g brain), and mean regional cerebral Hcts were 31.3 ± 1.8%, which was 75.9 ± 2.1% of the large-vessel Hct. During 5% CO2 inhalation, increases in plasma volume (2.48 ± 0.82%/mmHg Paco2) were significantly greater than for RBC volume (1.46 ± 0.48%/mmHg Paco2). Consequently, the cerebral-to-large-vessel Hct ratio was reduced to 72.4 ± 2.2%. Results emphasize the importance of cerebral Hct for the measurement of CBV and indicate that regional cerebral Hcts are not constant when shifted from one physiological state to another.

Magnetic Resonance Imaging of the Brain in Patients with Migraine

Magnetic resonance imaging (MRI) was studied in 91 patients with migraine and in 98 controls. Risk factors known to cause MRI lesions were carefully examined. In 36 patients with migraine (39.6%), small foci of high intensity on T2-weighted and proton-density-weighted images were seen in the white matter. Of patients with migraine who were less than 40 years old and without any risk factor, 29.4% showed lesions on MRI; this was significantly higher than the 11.2% for the group of age-matched controls (n = 98). The lesions were distributed predominantly in the centrum semiovale and frontal white matter in young patients, but extended to the deeper white matter at the level of basal ganglia in the older age group. The side of the MRI lesions did not always correspond to the side of usual aura or headache. Migraine-related variables such as type of migraine, frequency, duration or intensity of headache or consumption of ergotamine showed no significant correlation with the incidence of MRI abnormalities. Our data indicated that migraine may be associated with early pathologic changes in the brain.

The similarities and differences of migraine with aura and migraine without aura : a preliminary study

A preliminary study was undertaken to provide clinical evidence to support the hypothesis that: “Migraine with aura, migraine without aura and aura alone are the same condition, which differ in degree rather than pathophysiology.” At the City of London Migraine Clinic, 50 patients consecutively attending the clinic with a past or present history of migraine with aura were questioned. Of the 50 patients questioned 36 (70%) had a combination of migraine with aura, migraine without aura and/or aura alone; i.e. 70% had had more than one type of migraine attack. The duration, severity and frequency of attacks did not differ between migraine with and migraine without aura. Conclusion-the results support the hypothesis that migraine with and migraine without aura, and aura alone are not separate conditions, because: (1) most patients suffer from more than one type of migraine attack; (2) there are no significant differences in the characteristics of the migraine attacks in the different groups; (3) there are no significant differences in the characteristics of the subjects.

Implication of augmented vasogenic leakage in the mechanism of persistent aura in sporadic hemiplegic migraine

The aim of this study is to report a possible implication of augmented vasogenic leakage in the mechanism of prolonged aura in sporadic hemiplegic migraine. A 35-year-old woman with sporadic hemiplegic migraine presented with headache followed by right arm weakness, right visual field defect, aphasia and confusion that persisted for 1 week. During the acute stage, focal hyperaemia was seen in the left cerebral hemisphere corresponding to persistent aura symptoms. Augmented vasogenic leakage was demonstrated on delayed enhanced fluid-attenuated inversion recovery image. Magnetic resonance angiography showed dilation of the left middle cerebral artery. During the convalescent stage, such abnormal findings were not seen. Based on these results, we speculate that augmented vasogenic leakage from the leptomeningeal vessels, probably associated with activation of the trigeminovascular system, may delay the recovery of hemiplegic migraine aura.

Cerebral blood flow and cerebral hematocrit in patients with cerebral ischemia measured by single-photon emission computed tomography

Abstract– Single‐photon emission computed tomography (SPECT) was used for the measurement of regional cerebral blood flow (CBF), cerebral blood volume (CBV) and cerebral hematocrit (Hct). CBF was measured using N‐isopropyl‐p‐I‐123‐Iodoamphetamine. CBV was measured by both RBC tracer (Tc‐99m RBC) and plasma tracer (Tc‐99m human serum albumin) and cerebral hematocrit (Hct) was calculated. In normals, the cerebral‐to‐large vessel Hct ratio was 75.9%. Isovolemic hemodilution in patients with high Hct tended to increase the cerebral‐to‐large vessel Hct ratio. Low CBF, high CBV and slow cerebral blood mean transit time (MTT by dynamic CT scanning) was seen during the acute stage of completed infarction and during the symptom‐free interval of TIA. Cerebral Hct was increased in the ischemic region of poor prognosis.

Regional cerebral blood flow during an attack of vertebrobasilar insufficiency.

Using technetium-99m-labeled hexamethylpropyleneamineoxime [( 99mTc]HM-PAO) and single-photon emission computed tomography, we measured changes in regional cerebral blood flow in a 58-year-old man during an attack of vertebrobasilar insufficiency. Angiography demonstrated compression of the left vertebral artery by the osteophytes of cervical spondylosis when the patient turned his head to the left. Measured in the orthostatic position while turning his head to the left during a typical attack of vertebrobasilar insufficiency, regional cerebral blood flow was significantly reduced in the left cerebellum and the right occipital region. Our study illustrates the capability of [99mTc]HM-PAO single-photon emission computed tomography to measure transient reductions in regional cerebral blood flow and to relate these changes to the pathophysiology of vertebrobasilar insufficiency.

Ataxic hemiparesis with reductions of ipsilateral cerebellar blood flow.

Regional cerebellar blood flow was measured in a patient with left-sided ataxic hemiparesis, using single-photon emission computed tomography and N-isopropyl-p-[123I]Iodoamphetamine. X-ray computed tomography revealed a small infarct in the paramedian portion of the right upper basis pontis. Blood flow was markedly reduced in the contralateral cerebellar hemisphere corresponding to the side of ataxia. The present study emphasizes the value of the three-dimensional functional imaging of the cerebellum to investigate the responsible lesion for ataxia and to study function of the cerebro-cerebellar circuits.

SPECT Measurements of Regional Cerebral Blood Flow, Blood Volume, and Hematocrit in Stroke

In the present study, single-photon emission computed tomography (SPECT) was used for the measurement of regional cerebral blood flow (CBF), blood volume (CBV), and cerebral hematocrit (Hct) in normal subjects and patients with occlusive cerebral vascular diseases. Using these three cerebral hemodynamic parameters, regional pathophysiology during the acute stages of cerebral infarction and transient ischemic attack (TIA) was investigated.