Brainstem 1H-MR spectroscopy in episodic and chronic migraine

The pathogenesis of evolution from episodic migraine (EM) to chronic migraine (CM) has not yet been clearly determined. Some studies revealed that dysfunction of the brainstem may play a role. We aimed to determine the brainstem ¹H-MR spectroscopic (MRS) findings in episodic and chronic migraine. We recruited patients with EM, CM and controls. Patients with CM were divided into subgroups with and without medication overuse (MO). The ¹H-MRS metabolite ratios at the periaqueductal gray (PAG) and bilateral dorsal pons were measured and compared with those in controls. A total of 19 patients with EM, 53 patients with CM (with MO n = 30, without MO n = 23) and 16 control subjects completed the study. Patients with EM had the highest N-acetylaspartate (NAA)/creatine (Cr) ratio at the dorsal pons (right, P = 0.014; left, P = 0.034) in comparison with those of CM and controls. The latter two groups did not differ. Among migraine patients, NAA/Cr ratios at dorsal pons were inversely correlated with headache frequency (right, r = −0.350, P = 0.004; left, r = −0.284, P = 0.019) and intensity (right, r = −0.286, P = 0.019; left, r = −0.244, P = 0.045), but not disease duration. In contrast, the metabolite ratios did not differ at the PAG among the study groups. Of note, MO was not associated with brainstem MRS ratios in patients with CM. The increased NAA/Cr levels may suggest neuronal hypertrophy at the dorsal pons in EM. A progressive dysfunction of this region may occur from EM to CM since the levels declined with increasing headache frequency and intensity.     

Multiple diffusivities define white matter degeneration in amnestic mild cognitive impairment and Alzheimer's disease

Different diffusivity measurements in diffusion-tensor imaging (DTI) could be helpful for detecting the distinct mechanisms of white matter degeneration in Alzheimer's disease (AD). However, few studies have explored the changes of white matter in amnestic mild cognitive impairment (aMCI) and AD by whole-brain voxel-wise analyses of all diffusivity indices. The association between grey matter atrophy and white matter damage measured by distinct diffusivities is still uncertain. Structural magnetic resonance imaging and DTI with four diffusivity indices, comprising fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity, were performed in 30 normal controls, 26 mild AD patients, and 40 aMCI patients with isolated memory impairment. T1 voxel-based morphometry and DTI tract-based spatial statistics were applied to compare the grey and white matter changes in the 3 groups. In contrast to the lack of significant white matter change presenting in aMCI patients, extended white matter degeneration over entire cerebral networks was exhibited in mild AD patients. Both axonal degradation and demyelination contributed to the white matter degeneration in AD; nevertheless, demyelination essentially involved the frontal portion of cerebral networks. Axonal degradation and demyelination over the temporal region were associated with the contiguous grey matter atrophy. However, only the severity of demyelination over the frontal region was correlated with the degree of atrophy over adjacent frontal grey matter. Our results suggest that different mechanisms of white matter damage demonstrate discrete regional distribution in AD. Demyelination may independently correlate with contiguous grey matter over the frontal region.     

Is vasospasm requisite for posterior leukoencephalopathy in patients with primary thunderclap headaches?

Primary thunderclap headache (TCH) is sometimes associated with cerebral vasospasm. However, the role of vasospasm in relation to the development of reversible or irreversible posterior leukoencephalopathy among patients with primary TCH has never been fully addressed. This paper includes a report on a 51-year-old woman with primary TCH complicated with posterior leukoencephalopathy and a literature review of 16 further patients with the same illness. Their magnetic resonance or conventional angiographic findings were clearly described. Our review found that all these 17 patients showed evidence of cerebral vasospasm. Eleven (65%) of them developed permanent ischaemic infarctions, almost exclusively located at the watershed zones. We suggest that the presence of vasospasm might be requisite for posterior leukoencephalopathy as well as for permanent infarctions in these patients. Therefore, searching for any clue of vasospasm is mandatory in treatment of patients with primary TCH. Absence of an accompanying vasospasm might predict a good outcome.     

Neuroradiological findings in atypical teratoid/rhabdoid tumor of the central nervous system

PURPOSE: To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) findings of atypical teratoid tumor/rhabdoid tumor (AT/RT) of the central nervous system (CNS). MATERIAL AND METHODS: Twenty cases of CNS AT/RT have been found over the past 23 years in our hospital; these involving 11 boys and 9 girls whose mean age at diagnosis was 5.5 years. Their clinical data, the CT, and MRI findings were reviewed retrospectively. RESULTS: AT/RT was located in the cerebellum in 15 cases. Four cases arose from the supratentorial region, while only one occurred primarily in the lumbar spinal cord. Almost all cases revealed heterogeneous intensity and heterogeneous enhancement. Peripheral cystic components were common. Survival time ranged from 2 months to 3 years, with a mean survival of 11.6 months. CONCLUSION: Most cases of AT/RT are located in the cerebellum. The radiologic manifestations are non-specific. The diagnosis mainly depends on the pathologic findings. However, AT/RT should still remain in the differential diagnosis of brain tumors in young children, especially those located in the cerebellar hemisphere and with eccentric cysts.     

Endovascular embolization of recurrent traumatic carotid-cavernous fistulas managed previously with detachable balloons

BACKGROUND: This study investigated the causes of recurrent traumatic carotid-cavernous fistulas (RTCCFs) after detachable balloon embolization and evaluated the selection of embolic materials for endovascular treatment of the RTCCFs. METHODS: Over a 10-year period, 116 patients underwent transarterial balloon embolization with occlusion of the fistulas and preservation of the parent arteries. In 15 patients, 18 RTCCFs developed. The causes of RTCCFs included premature balloon deflation and migration (n = 13) or bony fragment puncture of balloons (n = 5). A second or third embolization involved balloons (n = 6), balloons with coils (n = 2), and N-butyl-2-cyanoacrylate with coils (n = 7), or balloon, coils, and N-butyl-2-cyanoacrylate (n = 3). RESULTS: In this study, 17 RTCCFs were successfully occluded after repeat embolization with preservation of parent arteries. One case resulted in recurrent epistaxis. The recurrent fistula and parent artery were occluded with balloons. No significant complications or recurrent fistulas occurred after the last embolization (mean follow-up period, 16 months). CONCLUSIONS: Balloon puncture or premature deflation and migration occasionally cause RTCCFs. Sacrifice of the parent artery rarely is needed. Transarterial embolization remains the best approach, with balloons used first, then coils, N-butyl-2-cyanoacrylate, or both.     

Repetitive phenomena in dementia

OBJECTIVE: Both repetitive talk and behaviors (repetitive phenomena) are common in demented patients and are bothersome to their caregivers and families. The purpose of this preliminary report was to explore these repetitive phenomena in demented patients admitted to a geropsychiatric ward. METHOD: The sample population consisted of 141 demented patients. Patients' caregivers were asked if patients had presented a repetitive fixed pattern of physical action or talk since the onset of dementia. RESULTS: Of the 141 demented patients included in the study, seventy-nine had repetitive phenomena. Patients with these phenomena had various presentations and developed them in the early stage of dementia. CONCLUSIONS: Repetitive phenomena are widespread in dementia, especially for older patients, and may be an early sign of dementia. The characteristics of repetitive phenomena and some likely underlying mechanisms are discussed.     

Posterior cranial fossa tumours in childhood

We reviewed clinical and CT findings in 133 posterior cranial fossa tumours in children. All had histological diagnosis, apart from 20 cases of brain stem glioma. The majority were intra-axial tumours, including 53 medulloblastomas (40%), 31 cerebellar astrocytomas (23%), 28 brain stem gliomas (21%), 14 ependymomas (11%), and single cases of ganglioglioma, haemangioblastoma and teratoma. Extra-axial tumours formed only 3%, including 2 chordomas and 2 schwannomas. The clinical data and CT findings are reviewed. Cerebellar astrocytoma involved the sexes equally, while medulloblastoma, brain stem glioma, and ependymoma were more common in males. Most cerebellar astrocytomas were in the midline, and presumably arose from the vermis. The frequency of calcification was similar to that in previous reports, being highest in ependymoma (69%), followed my medulloblastoma (29%), cerebellar astrocytoma (17%), and brain stem glioma (8%).