Hyun Jin Noh

Pathogenesis of cerebral microbleeds: In vivo imaging of amyloid and subcortical ischemic small vessel disease in 226 individuals with cognitive impairment

Cerebral microbleeds (CMBs) are a neuroimaging marker of small vessel disease (SVD) with relevance for understanding disease mechanisms in cerebrovascular disease, cognitive impairment, and normal aging. It is hypothesized that lobar CMBs are due to cerebral amyloid angiopathy (CAA) and deep CMBs are due to subcortical ischemic SVD. We tested this hypothesis using structural magnetic resonance imaging (MRI) markers of subcortical SVD and in vivo imaging of amyloid in patients with cognitive impairment.

The Relationship between Hippocampal Volume and Cognition in Patients with Chronic Primary Insomnia

Background and Purpose Differences in hippocampal volume (HV) were compared between chronic primary insomniacs (PIs) and good sleepers (GSs), and the relationship between HV and memory function in PIs was investigated to clarify the effect of chronic sleep deprivation on brain structure and cognition. Methods Twenty PIs (mean age, 50 years; 18 females) and 20 age-, gender-, and education-matched GSs were enrolled. Brain magnetic resonance imaging (MRI) was performed on a 1.5-T MRI scanner. Left and right HV and intracranial volume (ICV) were measured manually. Nighttime polysomnography and neuropsychological testing were also applied to all subjects. Group differences in HV were analyzed and the relationships between HV and sleep questionnaire data, nighttime polysomnography, and neuropsychological findings were evaluated. Results Compared to GSs, PIs exhibited significantly increased sleep latency and arousal index and a decreased percentage of REM sleep in nighttime polysomnography, as well as impaired verbal and visual memory, and frontal lobe function. Absolute HV and ICV did not differ significantly between PIs and GSs. In the PIs, right and left HVs were negatively correlated with the duration of insomnia and the arousal index, and positively correlated with the recognition of visual memory. In addition, free recall in verbal memory was positively correlated with left HV in PIs. Conclusions These findings suggest that chronic sleep deprivation impairs memory and frontal lobe function, and that a long duration of insomnia and poor sleep quality contribute to a bilateral reduction in HV.

Multiphasic perfusion computed tomography as a predictor of collateral flow in acute ischemic stroke: comparison with digital subtraction angiography.

Background: Assessing collateral status is important in acute ischemic stroke. The purpose of this study was to compare multiphasic perfusion computed tomography (MPCT) with digital subtraction angiography (DSA) in predicting leptomeningeal collateral flow in acute middle cerebral artery (MCA) infarction. Methods: Consecutive patients underwent MPCT and DSA for acute MCA infarction that presented within 6 h of symptom onset. We included patients who showed MCA occlusion in the same location on both modalities and assessed the agreement rate and correlation between the MPCT and DSA collateral grades. Results: Of 54 patients, 44 (81.5%) had proximal MCA (M1) occlusions and 10 (18.5%) had distal MCA (M2) occlusions based on MPCT and DSA. The ĸ-coefficients were 0.87 and 0.81 in the MPCT and DSA collateral grade systems, respectively. Forty-four patients (81.5%) belonged to the same category in both collateral-grading systems. MPCT collateral grades correlated positively with those of DSA (Spearman’s correlation coefficient 0.827, p < 0.001). Conclusion: Our data show that MPCT can predict leptomeningeal collateral flow in acute ischemic stroke. Based on collateral status assessed by MPCT, different therapeutic approaches might be warranted.

Dual Therapy with Cidofovir and Mirtazapine for Progressive Multifocal Leukoencephalopathy in a Sarcoidosis Patient

Background: Progressive multifocal leukoencephalopathy (PML) is a demyelinating central nervous system disease caused by JC virus (JCV) reactivation in immunocompromised patients. The disease course of PML is often progressive, fatal and at present, there are few reports on successful treatment outcomes. Case Report: A 45-year-old man with systemic sarcoidosis presented with rapidly progressive dementia and right hemiparesis. The patient was diagnosed with PML as confirmed via brain biopsy and JCV PCR. With a combination treatment of cidofovir and mirtazapine, there was significant improvement of neurological symptoms without measurable functional deficit. Conclusion: This case suggests that dual therapy with cidofovir and mirtazapine might be an effective treatment option in PML patients with sarcoidosis.

Sulcal Effacement on Fluid Attenuation Inversion Recovery Magnetic Resonance Imaging in Hyperacute Stroke Association With Collateral Flow and Clinical Outcomes

Background and Purpose— The clinical significance of sulcal effacement has been widely investigated in CT studies, but the results are controversial. In this study, we evaluated the presence of perisylvian sulcal effacement (PSE) on fluid attenuation inversion recovery MRI and hypothesized that PSE may be related to collateral flow status together with hyperintense vessels on fluid attenuation inversion recovery in hyperacute stroke. In addition, we investigated whether an association between PSE and clinical outcome could be found in these patients. Methods— Consecutive patients with acute middle cerebral artery infarcts within 6 hours of symptom onset were included. All patients had internal carotid artery or middle cerebral artery occlusion and underwent MRI including FLAIR. The presence of PSE and hyperintense vessels on fluid attenuation inversion recovery and the collateral status and occurrence of early recanalization (ER) on conventional angiography were evaluated. Results— Of 139 patients, 79 (56.8%) had PSE. Multivariate testing revealed PSE was independently associated with collateral status. The association between hyperintense vessels and collaterals was different depending on PSE. Compared to PSE-positive and ER-negative patients, PSE-negative and ER-negative patients (odds ratio, 4.11; 95% confidence interval, 1.12–15.17) and PSE-negative and ER-positive patients (odds ratio, 34.62; 95% confidence interval, 5.75–208.60), but not PSE-positive and ER-positive patients, were more likely to experience favorable clinical outcomes (modified Rankin Scale score ⩽2 at 3 months). Conclusions— PSE is independently associated with collateral status in patients with acute middle cerebral artery stroke. Moreover, PSE in conjunction with recanalization status can predict clinical outcomes in these patients.

Characterization of the Infarct Pattern Caused by Vulnerable Aortic Arch Atheroma: DWI and Multidetector Row CT Study

Background: Aortic arch atheroma (AAA) has been accepted as a possible embolic source in patients with ischemic stroke, especially cryptogenic stroke. However, despite its well-known role as a risk factor for stroke, research focused on the mechanism or characteristics of stroke caused by AAA is insufficient. In this study, we aimed to evaluate clinical and radiological characteristics including lesion pattern on DWI in acute stroke patients associated with vulnerable AAA detected by multidetector row computed tomography (MDCT). Methods: From September 2008 through May 2011, patients who presented with acute ischemic stroke and underwent MDCT were found in a prospective stroke registry. Patients without evident stroke etiology were included and classified by presence of vulnerable AAA. Vulnerable AAA was defined as (i) at least 6 mm thick adjacent to the aortic wall; (ii) ulcerated plaque, or (iii) soft plaque. Soft plaque was defined as the presence of clearly visualized area of hypoattenuation (<80 Hounsfield units) suggestive of thrombus. The patients without vulnerable AAA were classified as no/simple AAA group. The characteristics of diffusion-weighted MRI (DWI) lesions were analyzed in terms of the number and size of the lesions, and the involved vascular territories. Results: A total of 63 cryptogenic stroke patients were included in this study. Vulnerable AAA was observed in 15 (23.8%) patients. The patients with vulnerable AAA were older than those with no/simple AAA (p = 0.026). DWI analysis revealed that the vulnerable AAA group had a greater chance of having multiple and small lesions in multiple vascular territories that were mainly located in cortical and border-zone regions than the no/simple AAA group. Multiple logistic regression analysis showed that age (odds ratio 1.17; 95% confidence interval 1.02–1.34) and multiple small lesions in multiple vascular territories (odds ratio 33.18; 95% confidence interval 4.26–258.45) were independently associated with vulnerable AAA. Conclusion: Vulnerable AAA is independently associated with a DWI pattern characterized by multiple small scattered lesions in multiple vascular territories in conjunction with age. It may help determine stroke mechanism quickly and easily, and provide more information about the pathomechanism of vulnerable AAA-related stroke.

Long term outcome and predictors of ischemic stroke recurrence in adult moyamoya disease

OBJECTIVE We sought to identify the clinical outcome and predictors for ischemic stroke recurrence in adults with symptomatic moyamoya disease (MMD). METHODS We analyzed 104 adult MMD patients with ischemic stroke or TIA registered at our institution. All patients underwent digital subtraction angiography and single photon emission computed tomography to measure disease severity and cerebral vascular reserve (CVR). A Cox regression model was used to identify predictors of recurrent ischemic stroke. RESULTS Fifty-nine patients were non-surgically treated and 45 patients were surgically treated. In the non-surgical group, the Kaplan-Meier estimate of ischemic stroke recurrence was 1.6% in the first year and 11.8% in the 5th year. Hypertension (hazard ratio [HR]=0.07, 95% confidence interval [CI] 0.01-0.99), diabetes (HR=35.16, 95% CI 2.61-474.16), presence of steno-occlusive lesion in posterior cerebral arteries (HR=17.53, 95% CI 2.02-152.43), and extended or global decreased CVR (HR=13.62, 95% CI 1.55-119.84) were independent predictors of recurrence. In the surgical group, the Kaplan-Meier estimate of ischemic stroke recurrence was 24.4% in the first year and 24.4% in the 5th year. Half of the recurred patients experienced recurrent ischemic strokes postoperatively. Diabetes was the only predictor of recurrent ischemic stroke (HR=6.17, 95% CI 1.31-29.14). CONCLUSIONS In non-surgically treated MMD, PCA stenosis and CVR were identified as predictors of ischemic stroke recurrence. Diabetes was an independent predictor of recurrent ischemic stroke in both non-surgical and surgically treated MMD groups.

Role of High-Resolution Magnetic Resonance Imaging in the Diagnosis of Primary Angiitis of the Central Nervous System

BACKGROUND Primary angiitis of the central nervous system (PACNS) is a rare disorder and is often difficult to diagnose due to the lack of a confirmatory test. PACNS can generally be diagnosed based on typical angiographic findings. We describe herein a patient diagnosed with PACNS despite the presence of normal findings on conventional angiography. CASE REPORT A 44-year-old man with a recent history of ischemic stroke in the right posterior cerebral artery territory developed acute-onset vertigo. Diffusion-weighted imaging revealed an acute infarction within the left posterior inferior cerebellar artery. His medical history was unremarkable except for hyperlipidemia; the initial examination revealed mild gait imbalance. During the 10 days of hospital admission, the patient experienced four recurrent ischemic strokes within the posterior circulation territory (occipital lobe, pons, and cerebellum). He was diagnosed with recurrent cerebral infarctions due to PACNS. The basilar artery exhibited no demonstrable luminal stenosis, but there were direct imaging signs of central nervous system angiitis including wall thickening and contrast enhancement. High-dose intravenous steroid therapy followed by oral prednisolone was administered. There was no further stroke recurrence and follow-up imaging of the arterial walls showed normalization of their characteristics. CONCLUSIONS The present case emphasizes the importance of wall imaging in the diagnosis and treatment of PACNS.

T-D-022 RELATIONSHIP BETWEEN COGNITIVE FUNCTION AND HIPPOCAMPAL VOLUMES IN PATIENTSWITH PRIMARY INSOMNIA

Introduction and Objectives: To investigate the relationship between cognitive function and hippocampal volumes in patients with primary insomnia (PI). Materials and Methods: We enrolled 20 female patients with PI and 20 good sleepers (GS) (mean age 50.8 yrs) matched by age and educational status. Patients were diagnosed with PI according to ICSD-2 criteria and all of them reported subjective memory decline. All subjects had undergone night polysomnography, neuropsychological tests, and brain MRI (1.5T). The hippocampal volumes (HV) were manually measured bilaterally. HV was corrected for intracranial volume. Results: Mean insomnia duration was 7.2 yrs, mean education period was 11.8 yrs, mean number of sleep-aid pills was 2.1, and mean duration of taking sleep pills was 3.7 yrs in PI. Mean HV of right hemisphere was 3265.2±255.1 mm3 in PI and 3151.3±295.7 mm3 in GS (p=0.185) and that of left side was 3000.3±214.7 mm3 in PI and 2897.4±390.5 mm3 in GS (p=0.265). Right HV was significantly correlated with insomnia duration (r=0.885) and duration of taking sleep medication (r=0.488) and left HV was negatively correlated with insomnia duration (r=0.536) and duration of taking sleep medication (r=0.539). PI showed significant impairment for attention, frontal lobe function, and non-verbal/verbal memory compared to GS. Recognition in the non-verbal memory test was positively correlated with right (r=0.913) and left HV (r=0.969). Short delay free recall in the verbal memory test was positively correlated with left HV (r=0.759). Conclusion: Although there was no significant difference in HV and ICV between PI and GS, long insomnia duration had negative influence on HV. PI had impaired cognitive function compared to GS and HV was positively correlated with memory function in PI. Chronic insomnia may deteriorate daytime cognitive impairment in PI, which was related to the HV.