Ting-Yu Chang

Rapid progression and brain atrophy in anti-AMPA receptor encephalitis

Anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor encephalitis is an anti-neuronal surface antigen autoimmune encephalitis that is rarely reported. Our study evaluated the first known patient who developed anti-AMPA receptor encephalitis during pregnancy. Initial brain MRI revealed bilateral limbic encephalitis. However, rapid brain atrophy on MRI with extensive hypometabolism of cerebral cortices, caudate nuclei and brain stem hypoperfusion on (18)F-FDG PET developed when clinically progressed. IgG index of serial CSF studies reflected the clinical improvements after plasmapheresis and plasma exchange. The clinical spectrum of anti-AMPA receptor encephalitis may be expanded from limited limbic involvement to extended central nervous system.

Dehydration is an independent predictor of discharge outcome and admission cost in acute ischaemic stroke

Our aim was to investigate the influence of admission dehydration on the discharge outcome in acute ischaemic and hemorrhagic stroke.

Plasticity of Circle of Willis: A Longitudinal Observation of Flow Patterns in the Circle of Willis One Week after Stenting for Severe Internal Carotid Artery Stenosis

Background and Purpose: The purpose of the present study was to assess whether the direction of flow via the circle of Willis (CoW) changed after stenting for severe internal carotid artery (ICA) stenosis. Methods: 65 patients (38 men, mean age 63.2 ± 8.4 years, range 44–82) with a symptomatic ICA occlusion were investigated. Magnetic resonance angiography was performed prior to and 1 week after carotid artery stenting (CAS). The pattern in the CoW was assessed. Results: One third of the subjects (35.38%) had a significantly altered flow pattern in the CoW after unilateral CAS, including blocked ipsilateral A1 segment collateral (n = 4), blocked contralateral A1 segment collateral (n = 5), blocked ipsilateral posterior communicating artery (PCoA) segment collateral (n = 4), blocked ipsilateral A1 segment and P1 segment collateral (n = 1), opening of ipsilateral A1 segment collateral (n = 5), opening of ipsilateral PCoA segment collateral (n = 3) and opening of ipsilateral P1 segment collateral (n = 1). Conclusions: CoW segmental hypoplasia is not a static feature. Willisian collateralization with recruitment of the CoW segment (A1, P1 and PCoA) may be blocked after CAS. CAS also leads to the opening of new willisian collateralization, either for relief of reperfusion pressure or for other hypoperfused areas.

Impact of silent ischemic lesions on cognition following carotid artery stenting.

Objective: The occurrence of silent ischemic lesions (SILs) is a common finding after carotid artery stenting (CAS). This study aimed to evaluate the impact of SILs on cognitive functioning following CAS. Methods: The retrospective study separated 131 patients with unilateral carotid stenosis into three groups: medication only, MRI-evaluated CAS and CT-evaluated CAS, and compared the sociodemographic factors, post-CAS images and Mini-Mental State Examination scores performed before and 6–12 months after enrollment. Results: Seven minor strokes occurred in the 99 patients receiving CAS. SILs were detected in 12 of 55 patients with diffusion-weighted MR imaging (DWI) and in 3 of 37 patients with CT 1 week after CAS. In patients with DWI follow-up, the frequency of SILs was 8, 24, 43 and 60% in patients with 0-, 1-, 2- and 3-vessel coronary artery disease (p = 0.006). The frequency of SILs on DWI was 0, 32 and 33% in patients with improved, unchanged, or deteriorated cognitive functioning (p = 0.02). Such an association was not observed if based on SILs on CT or manifesting stroke. Conclusion: The presence of coronary artery disease increases the risk for having post-CAS SILs, and the occurrence of SILs may be associated with cognitive changes after CAS.

Coexisting Diseases of Moyamoya Vasculopathy

BACKGROUND Several coexisting diseases have been reported in patients with moyamoya vasculopathy (MMV), but studies of quasi-moyamoya disease (quasi-MMD) are rare. This study aims to investigate the frequency of known coexisting diseases in patients with quasi-MMD and to compare quasi-MMD with moyamoya disease (MMD). METHODS Between 2000 and 2011, we retrospectively screened patients with International Classification of Diseases, Ninth Revision, code of 4375 (MMD) in the Health Information System of our hospital. The vascular images of each patient were confirmed by 2 neurologists and 1 neuroradiologist based on the diagnostic criteria of Japan Ministry of Health and Welfare. We excluded the patients with missing images and erroneous diagnosis. Demographics, coexisting diseases, laboratory data, treatment, and recurrent strokes were recorded. The eligible patients were divided into quasi-MMD and MMD groups according to the presence or absence of coexisting diseases. RESULTS MMV was found in 90 patients including 37 (41.1%) quasi-MMD and 53 (58.9%) MMD. Atherosclerosis (32.4%) and thyroid disease (29.7%) were the leading coexisting diseases in quasi-MMD. Patients with MMD became symptomatic in a bimodal age distribution, whereas patients with quasi-MMD became symptomatic in a single-peak distribution. The prognosis of recurrent strokes was similar between quasi-MMD and MMD based on Kaplan-Meier analysis. CONCLUSIONS A bimodal distribution of onset age was noted in MMD, whereas a single-peak distribution was found in quasi-MMD. Coexisting diseases were usually underevaluated but were more common than expected in patients with MMV. Atherosclerosis and thyroid diseases were the leading coexisting diseases in different preferential age.

Immediate Regression of Leukoaraiosis after Carotid Artery Revascularization

Background: Leukoaraiosis (LA) affects cognition after stroke and reversal of LA may improve cognitive performance. We aimed to determine the impact of cerebral perfusion and circle of Willis (CoW) flow patterns on the extent of LA after carotid artery revascularization. Methods: LA was scored on fluid-attenuated inversion recovery magnetic resonance (MR) images at the levels of the centrum semiovale and frontal horns in both cerebral hemispheres of 62 contiguous patients (men/women = 38/24, mean age = 63.2 ± 8.4 years, range 44–82) before and after unilateral carotid artery revascularization. The pre- and poststenting differences in LA scores, CoW flow pattern on MR angiography, and MR perfusion parameters were analyzed. Results: The total LA score decreased from 9.87 ± 0.65 to 8.33 ± 0.72 after stenting (p = 0.03). The CoW was complete in 21 subjects and incomplete in 41 subjects. The incomplete CoW group had a higher preoperative LA load and higher cerebral interhemispheric asymmetry index, both of which decreased significantly postoperatively. Conclusions: CoW anomalies may contribute to LA in patients with carotid artery stenosis, and restoration of cerebral perfusion by carotid artery revascularization can reduce LA severity.

Intracerebral Hemorrhage after Thrombolytic Therapy in Acute Ischemic Stroke Patients with Renal Dysfunction

Purpose: One complication of thrombolysis is intracranial hemorrhage (ICH). We investigated whether treatment with tissue plasminogen activator (t-PA) for ischemic infarction results in a higher risk of ICH in patients with kidney dysfunction, who are predisposed to treatment complications due to their bleeding tendency. Methods: A total of 297 patients given thrombolytic therapy for ischemic stroke were classified into 2 groups on the basis of their estimated renal glomerular filtration rate (eGFR). The outcome measures included the incidence of ICH and modified Rankin scale scores at 1 month and 1 year. Results: ICH was more common in the renal dysfunction group (23 vs. 12.5%). Nevertheless, multivariate logistic regression showed that the odds of ICH were not high in the group with low eGFR. Also, eGFR values <60 ml/min/1.73 m2 did not predict the odds for functional dependence or death at 1 month and 1 year. Conclusion: After adjusting for confounding factors, the odds ratio for ICH was not higher in intravenous t-PA-treated stroke patients with renal dysfunction. A trend to the occurrence of ICH among these patients, however, was noted. Renal dysfunction does not predict the odds for functional dependence or death at 1 month and 1 year.

Graph theoretical analysis of functional networks and its relationship to cognitive decline in patients with carotid stenosis

Significant carotid stenosis compromises hemodynamics and impairs cognitive functions. The interplay between these changes and brain connectivity has rarely been investigated. We aimed to discover the changes of functional connectivity and its relation to cognitive decline in carotid stenosis patients. Twenty-seven patients with unilateral carotid stenosis (≥60%) and 20 age- and sex-matched controls underwent neuropsychological tests and resting-state functional magnetic resonance imaging. The patients also received perfusion magnetic resonance imaging. The relationships between cognitive function and functional networks among the patients and controls were evaluated. Graph theory was applied on resting-state functional magnetic resonance imaging network analysis, which revealed that the hemispheres ipsilateral to the stenosis were significantly impaired in “degree” and “global efficiency.” The neuropsychological performances were positively correlated with degree, clustering coefficient, local efficiency, and global efficiency, and negatively correlated with characteristic path length, modularity, and small-worldness in the patients, whereas these relationships were not observed in the controls. In this study, we identified the networks that were impaired in the affected hemispheres in patients with carotid stenosis. Specific indices (global efficiency, characteristic path length, and modularity) were highly correlated with neuropsychological performance in our patients. Analysis of brain connectivity may help to elucidate the relationship between hemodynamic impairment and cognitive decline.

Correlation between the flow pattern of the circle of Willis and segmental perfusion asymmetry after carotid artery revascularization

Background:  To correlate cerebral perfusion and flow patterns after carotid artery revascularization within the circle of Willis (CoW).

Associations between Circle of Willis Morphology and White Matter Lesion Load in Subjects with Carotid Artery Stenosis

Background: Various cerebral pathological changes have been reported to cause leukoaraiosis (LA). We hypothesized that circle of Willis (CoW) anomalies may contribute to LA in severe carotid artery stenosis victims through impaired cerebral autoregulation. We conducted a retrospective review on cerebral magnetic resonance (MR) patterns in patients with severe symptomatic carotid artery stenosis and compared white matter lesion (WML) load between subjects with and without complete CoW. Methods: LA on fluid attenuation inversion recovery (FLAIR) MR images at the levels of the centrum semiovale and frontal horns in both cerebral hemispheres were scored in 106 patients with unilateral carotid artery stenosis (64 men and 42 women; mean age 68.7 ± 9.2 years, range 44–82). Subjects were divided into groups of complete and incomplete CoW according to cerebral MR angiography. Differences in the LA scores between the groups of complete and incomplete CoW were further analyzed. Results: Compared with those with incomplete configuration of the CoW, subjects with a complete CoW demonstrated a decreased WML load at the level of the centrum semiovale (2.78 ± 1.17 vs. 5.62 ± 2.12, p = 0.02) and frontal horns (2.21 ± 0.79 vs. 4.22 ± 1.83, p = 0.01). Conclusion: Our results support the importance of a complete CoW since it may protect from WML in case of carotid stenosis.