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Cerebral hypoperfusion is responsible for cognitive impairment in patients with severe carotid artery stenosis (CAS). The manifestation of reversed ophthalmic artery flow (ROAF) is not uncommon in patients with CAS, suggesting a state of intensified cerebral hypoperfusion. This study aimed to examine whether the presence of ROAF can exacerbate cognitive impairment in patients with severe unilateral CAS.One-hundred-and-two patients with CAS and 37 age-matched volunteers participated in this case-control study. Depending on the side of CAS and occurrences of ROAF, the patients were allocated to four groups: left CAS groups with ROAF (n=28) or without ROAF (n=22), and right CAS groups with ROAF (n=26) or without ROAF (n=26). All subjects underwent a battery of neuropsychological tests.All patients performed worse than the control group on most tests. No significant differences were observed between patient groups (ps0.05), except for inferior performance on psychomotor speed and visuospatial tests in the right ROAF group (ps0.03). Hierarchical regression analyses indicated strong contributions of estimated premorbid intelligence to performance on most tests (ps0.05). The severity of left and right CAS was distinctively associated with different functions. To a lesser extent, the severity of infarcts was also associated with impairment of psychomotor speed and some executive functions (ps0.05). The contributions of ROAF to performance on most tests were negligible.Patients with unilateral CAS may present with specific cognitive impairment relevant to the ipsilateral hemispheric functions. However, the manifestation of ROAF does not necessarily imply more extensive or severe cognitive impairment.

Healthcare expenditure in many developed countries has reached such an unprecedented level that it cannot be sustainable unless some change in medical practice is implemented. In this paper, we examine a computer-in-the-loop model for the transaction between care-providers and care-receivers by identifying tasks that can be offloaded from physicians to computers in light of the state of the art of computer technology, as well as its evolution with time. Currently a number of consumer electronics innovations have found their way into healthcare applications. We anticipate that healthcare will be continuously benefited by such a trend.

BACKGROUND AND PURPOSE: The roles of DTI and dynamic susceptibility contrast-enhanced–PWI in predicting the angiographic vascularity of meningiomas have not been studied. We aimed to investigate if these 2 techniques could reflect the angiographic vascularity of meningiomas. MATERIALS AND METHODS: Thirty-two consecutive patients with meningiomas who had preoperative dynamic susceptibility contrast-enhanced–PWI, DTI, and conventional angiography were retrospectively included. The correlations between angiographic vascularity of meningiomas, classified with a 4-point grading scale, and the clinical or imaging variables—age and sex of patient, as well as size, CBV, fractional anisotropy, and ADC of meningiomas—were analyzed. The meningiomas were dichotomized into high-vascularity and low-vascularity groups. The differences in clinical and imaging variables between the 2 groups were compared. Receiver operating characteristic curve analysis was used to determine the diagnostic performance of these variables. RESULTS: In meningiomas, angiographic vascularity correlated positively with CBV but negatively with fractional anisotropy. High-vascularity meningiomas demonstrated significantly higher CBV but lower fractional anisotropy as compared with low-vascularity meningiomas. In differentiating between the 2 groups, the area under the curve values were 0.991 for CBV and 0.934 for fractional anisotropy on receiver operating characteristic curve analysis. CONCLUSIONS: CBV and fractional anisotropy correlate well with angiographic vascularity of meningiomas. They may differentiate between low-vascularity and high-vascularity meningiomas.

BACKGROUND AND PURPOSE: Contrast leakage results in underestimation of the CBV of brain tumors. Our aim was to compare the diagnostic performance of DSC perfusion MR imaging without and with mathematic contrast-leakage correction in differentiating PCNSLs and glioblastomas. MATERIALS AND METHODS: Perfusion parameters—CBV, corrected CBV, and leakage coefficient—were measured in enhancing tumor portions and contralateral NAWM of 15 PCNSLs and 20 glioblastomas, respectively. The ratios of CBV and corrected CBV were calculated by dividing the tumor values by those obtained from contralateral NAWM. A paired t test was used to compare tumor K(2) and NAWM K(2), as well as tumor CBV ratios without and with leakage correction. Comparisons of CBV, corrected CBV, and K(2) between PCNSLs and glioblastomas were done by using a 2-sample t test. The diagnostic performance of DSC perfusion MR imaging without and with contrast-leakage correction was assessed with receiver operating characteristic curve analysis. RESULTS: PCNSLs and glioblastomas demonstrated higher K(2) than those in their contralateral NAWM. Corrected CBV ratios were significantly higher than the uncorrected ones for both tumors. PCNSLs had lower CBV ratios (P < .001), lower corrected CBV ratios (P < .001), and higher K(2) (P = .001) compared with glioblastomas. In differentiating between PCNSLs and glioblastomas, the area under the curve of the CBV ratio, corrected CBV ratio, and K(2) were 0.984, 0.940, and 0.788, respectively. CONCLUSIONS: PCNSL can be differentiated from glioblastoma with CBV ratios, corrected CBV ratios, and K(2). CBV without contrast-leakage correction seems to have the best diagnostic performance in differentiating the 2 tumors.

Cerebral vasoreactivity (CVR) can be assessed by functional MRI (fMRI) using hypercapnia challenges. In normal subjects, studies have shown temporal variability of CVR blood oxygenation level-dependent responses among different brain regions. In the current study, we analyzed the variability of BOLD CVR dynamics by fMRI with a breath-holding task in 17 subjects with unilateral carotid stenosis before they received carotid stenting. Great heterogeneity of CVR dynamics was observed when comparing BOLD responses between ipsilateral and contralateral hemispheres in each patient, especially in middle cerebral artery (MCA) territories. While some subjects (n=12) had similar CVR responses between either hemisphere, the others (n=5) had a poorly correlated pattern of BOLD changes between ipsilateral and contralateral hemispheres. In the latter group, defined as impaired CVR, post-stenting perfusion tended to be more significantly increased. Our data provides the first observation of divergent temporal BOLD responses during breath holding in patients with carotid stenosis. The development of collateral circulation and the derangement of cerebral hemodynamics can be detected through this novel analysis of the different patterns of BOLD changes. The results also help in prediction of robust increase of perfusion or hyperperfusion after carotid stenting.

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 2 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.

We aimed to assess whether intracranial carotid artery calcification (ICAC) evident on head computed tomography is a risk factor for symptomatic intracerebral hemorrhage (sICH) following tissue plasminogen activator (tPA) treatment for acute stroke.We classified 297 consecutive patients into 2 groups (no to mild ICAC and moderate to severe ICAC) according to ICAC severity. Outcome measures included detection of intracerebral hemorrhage and assessment using a modified Rankin scale (mRS) at 1 month and 1 year after stroke.ICH (any type) was significantly more common in patients with moderate to severe ICAC than in patients with no to mild ICAC (22.5% versus 12%; relative risk [RR], 1.67; 95% confidence interval [CI], 1.1-2.5; P.05). The moderate to severe ICAC group tended to have a higher percentage of sICH, but this association was not statistically significant (RR, 1.57; 95% CI, .75-3.3, P.05). Multivariate adjusted regression analysis revealed that moderate to severe ICAC was an independent risk factor for ICH following tPA treatment (odds ratio, 2.52; 95% CI, 1.07-5.94; P=.04). Dependent functional outcome (mRS score 3-6) at 1-month and 1-year follow-up was significantly associated with moderate to severe ICAC (RR, 1.56; 95% CI, 1.06-2.27; and RR, 1.56; 95% CI, 1.06-2.33; P.05). However, ICAC was not an independent factor of functional dependency at 1-month and 1-year follow-up in the final multivariate regression model.A significantly higher percentage of patients with moderate to severe ICAC developed ICH following tPA administration for stroke. ICAC severity is an independent risk factor for ICH events. ICAC severity can help predict short-term and long-term functional dependency in tPA-treated patients, although this can be confounded by other cardiovascular risk factors and stroke severity.

Introduction: Chronic hydrocephalus is a common complication that can occur after aneurysmal subarachnoid haemorrhage (SAH). The purpose of this study was to investigate clinical risk factors that could predict the occurrence of shunt-dependent chronic hydrocephalus after aneurysmal SAH. Methods: Eighty-eight consecutive patients who underwent either surgery or transarterial endovascular embolization as a treatment for cerebral aneurysm within 72 h -after experiencing SAH from March 2005 to July 2006 were studied retrospectively to assess the risk factors that might predict shunt-dependent chronic hydrocephalus. Clinical and demographic factors were examined, including age, sex, initial admission mean arterial blood pressure (MABP), blood sugar level at admission, fever frequency, initial external ventricular drainage (EVD), Fisher grade, Hunt and Hess grade, intraventricular haemorrhage (IVH) and treatment methods to define predictors of shunt-dependent hydrocephalus. The length of hospital stay and modified Rankin scale recorded 6 months after SAH were also evaluated; these parameters were compared between the shunt-dependent and non-shunt-dependent groups. Results: Of the 88 patients, 22 (25%) underwent shunt placement to treat their chronic hydrocephalus. The average length of hospital stay was 33.9 days for the shunt-treated group and 14 days for the non-shunt-treated group. The non-shunt-treated group scored an average of 1.05 on the modified Rankin scale compared with 2.77 for the shunt-treated group. A univariate analysis revealed that several admission variables were associated with long-term shunt-dependent hydrocephalus: (1) increased age (p = 0.023); (2) initial admission MABP (p = 0.027); (3) a high Fisher grade (p = 0.031); (4) a poor admission Hunt and Hess grade (p = 0.030); (5) the presence of IVH (p = 0.029), and (6) initial EVD (p < 0.0001). The factor most commonly associated with shunt-dependent hydrocephalus over the course of hospital days was fever frequency (p < 0.0001). Conclusions: Chronic hydrocephalus after aneurysmal SAH has a multifactorial aetiology. Understanding the risk factors that predict the occurrence of chronic hydrocephalus may help neurosurgeons to expedite permanent cerebrospinal fluid diversion, which could decrease both the cost and length of hospital stay and prevent further complications.

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.

Introduction: Clinical research of cervicocranial fibromuscular dysplasia (FMD) is rare in Asian populations. Our study reviewed Taiwanese ischemic stroke patients with cervicocranial FMD and compared them with previous reports. Methods: Between 2000 and 2011, we collected 19 consecutive cervicocranial FMD patients who received demographic registration, a blood test for excluding vasculitis, and comprehensive angiography. Cerebral ultrasound, vascular images and clinical outcomes (Barthel index, modified Rankin scale, recurrent stroke, or death) were monitored during follow-up. Results: Of the 19 patients, 16 (84%) had carotid FMD, while 7 (37%) had vertebral FMD. Only 2 investigated patients (13%) had renal FMD and 1 (5%) had cerebral aneurysm. 14 (74%) presented acute arterial dissection. All patients received medical treatment and had neither recurrent stroke nor dissection during follow-up. In the literature review of 225 FMD patients, 3.6% had recurrent stroke during follow-up, and some reported surgical procedure or angioplasty could give a good clinical outcome in progressing ischemia irrelevant to the cause of stenosis. Conclusion: In Taiwanese cervicocranial FMD patients, arterial dissection was one of the most common clinical presentations. Most of our patients had isolated involvement of the cervicocranial artery and carried a favorable outcome under medical treatment.

We explored the role of variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene as factors for atherothrombotic stroke (ATS). A HapMap-based haplotype-tagging single nucleotide polymorphism (htSNP) association study was conducted in an isolated Taiwanese population. Multivariate logistic regression analyses revealed that patients with the GG/CG genotype of rs4293222 and the AA/AG genotype of rs4360791 had a 1.61-fold (odds ratio [OR] = 1.61; 95% confidence interval [CI] = 1.02–2.56, p = 0.042) and a 1.69-fold (OR = 1.69; 95% CI = 1.00–2.86, p = 0.047) increased risk of ATS, compared with patients with the CC/GG genotype, respectively. The most common haplotype allele, GTA, was used as a reference when analyzing the association between the haplotypes related to rs4293222, rs10507391, rs12429692 and ATS. The combined frequencies of all minor variant alleles of the three selected htSNP were associated with a 44% decreased risk of ATS (OR = 0.56; 95% CI = 0.37–0.84, p = 0.005). This study provides preliminary evidence suggesting that genetic polymorphisms of ALOX5AP are associated with ATS.

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.

BACKGROUND AND PURPOSE: Many authors have reported the increase in vertebral body height after vertebroplasty; if the fractured vertebrae are mobile, we should be able to demonstrate their mobility in radiographs. The purpose of this study was to discover the diagnostic value of dynamic radiographs and the percentage of mobile vertebrae in painful VCFs. MATERIALS AND METHODS: From September 2005 to September 2008, 105 patients underwent surgery to treat 144 painful osteoporotic VCFs. The indications for surgery were severe pain and MR imaging−confirmed active edematous lesions. Preoperative sitting lateral radiographs of the fractured vertebrae were compared with supine cross-table (with a bolster beneath) lateral radiographs to determine the presence or absence of dynamic mobility. Kyphotic angle and anterior vertebral body height were measured. RESULTS: The patients9 ages ranged from 62 to 90 years. There were 19 men and 86 women. The total number of mobile VCFs was 126 (87.5%). One hundred four (99%) patients had at least 1 mobile VCF. The average anterior vertebral height in sitting lateral radiographs was 13.53 ± 6.80 mm and increased to 22.01 ± 6.13 mm in supine cross-table with bolster lateral radiographs. The average vertebral body height increase was 8.48 ± 5.36 mm. CONCLUSIONS: Dynamic (sitting and supine with bolster) radiographs can be valuable in diagnosing painful vertebrae in VCFs. The sensitivity was 0.88 in this study.

Low density lipoprotein is transcytosed across the blood-brain barrier mediated by low density lipoprotein receptor (LDLR). LDLR in the brain is mainly expressed on capillary endothelial cells and is therefore considered to be an important susceptibility gene in modifying the stroke presentation. A HapMap-based haplotype-tagging single nucleotide polymorphism association study was conducted in an isolated Taiwanese population. Two hundred and ninety-two unrelated patients with cerebral infarction, 76 patients with small vessel occlusion (SVO) disorder and 216 with non-SVO disorder were enrolled. For rs2738446, under the dominant model, the odds ratios (ORs) associated with the CC genotype were computed, with GG + CG carriers considered as the reference group. Homozygote CC carriers had a two-fold increased risk of SVO disorder [OR=2.0, 95% confidence interval (CI)=1.08-3.70, p=0.025). For rs2738450, under the dominant model, the ORs associated with the CC genotype were computed, with AA + AC carriers considered as the reference group. Homozygote CC carriers had a 1.85-fold increased risk of SVO disorder (OR=1.85, 95% CI=1.01-3.33, p=0.04). When analysing the association between the haplotype related to rs2738446 and rs2738450 and SVO disorder, the most common haplotype allele CC was used as the reference, and the GA haplotype allele was associated with a 48% decreased risk of SVO disorder (OR=0.52; 95% CI=0.29-0.93, p=0.029). Haplotype-based analysis of LDLR in Taiwanese patients with cerebral infarction provided preliminary evidence suggesting that genetic polymorphisms of LDLR can modify the stroke presentation.

The aim of this study is to identify the risk factors of extracranial carotid atherosclerosis in patients with first-ever ischemic stroke.A total of 541 consecutive first-ever ischemic stroke patients were enrolled in the present study. We examined clinical and laboratory factors that were potentially relevant to extracranial carotid artery atherosclerosis. The degree of carotid stenosis was diagnosed based on B-mode ultrasonography.The sample contained 325 men and 216 women. Among these patients, 80% had a50% carotid stenosis and 20% had aor = 50% carotid stenosis. Multiple logistic regression analysis revealed that age (odds ratio = 2.15, 95% CI = 1.06-1.11, P0.001) and smoking (odds ratio = 1.52, 95% CI = 1.17-3.54, P = 0.012) were significantly associated withor = 50% carotid stenosis.In the present study, age and smoking are found to be the independent risk factors for carotid atherosclerosis. The identification of these risk factors may improve our knowledge in the primary prevention of ischemic stroke in Taiwan.

Using a superconducting-wavelength-shifter X-ray source with a photon flux density of 10(11)-10(13) photons s(-1) mrad(-1) (0.1% bandwidth)(-1) (200 mA)(-1) in the energy range 5-35 keV, three hard X-ray beamlines, BL01A, BL01B and BL01C, have been designed and constructed at the 1.5 GeV storage ring of the National Synchrotron Radiation Research Center (NSRRC). These have been designed for structure-related research using X-ray imaging, absorption, scattering and diffraction. The branch beamline BL01A, which has an unmonochromatized beam, is suitable for phase-contrast X-ray imaging with a spatial resolution of 1 microm and an imaging efficiency of one frame per 10 ms. The main beamline BL01B has 1:1 beam focusing and a medium energy resolution of approximately 10(-3). It has been designed for small-angle X-ray scattering and transmission X-ray microscopy, used, respectively, in anomalous scattering and nanophase-contrast imaging with 30 nm spatial resolution. Finally, the branch beamline BL01C, which features collimating and focusing mirrors and a double-crystal monochromator for a high energy resolution of approximately 10(-4), has been designed for X-ray absorption spectroscopy and high-resolution powder X-ray diffraction. These instruments, providing complementary tools for studying multiphase structures, have opened up a new research trend of integrated structural study at the NSRRC, especially in biology and materials. Examples illustrating the performances of the beamlines and the instruments installed are presented.

This study presents amplifier-free all-optical 2R regeneration schemes based on a compact self-seeded Fabry-Perot laser diode (SSFP-LD) at 1.5 mum and a two-mode injection locked distributed feedback laser diode (TMIL DFB-LD) at 1.3 mum, respectively. The proposed 2R regenerator achieve straight line transmissions at 10 Gb/s over 60/76 km at 13/1.5 mum without any traditionally required optical amplifier. In addition, the amplified gain and regeneration performance is experimentally investigated.

BackgroundCoronary artery disease (CAD) may coexist with extracranial carotid artery stenosis (ECAS), but the influence of CAD on procedure-related complications after carotid artery stenting (CAS) has not been well investigated. The study aimed to determine the impact of CAD on the occurrence of peri-CAS cerebral ischemic lesions on diffusion-weighted imaging (DWI) scanning.MethodsCoronary angiography was performed within six months before CAS. DWI scanning was repetitively done within 1 week before and after CAS. Clinical outcome measures were stroke, angina, myocardial infarction and death within 30 days.ResultsAmong 126 patients (69.5±9.0 years) recruited for unilateral protected CAS, 33 (26%) patients had peri-CAS DWI-positive lesions. CAD was noted in 79% (26 in 33) and 48% (45 in 93) of patients with and without peri-CAS DWI-positive lesions (OR, 4.0; 95% CI, 1.6-10.0; P = .0018), and the number of concomitant CAD on coronary angiography was positively correlated with the risk for peri-CAS DWI-positive lesions (P = .0032). In patients with no CAD (n = 55), asymptomatic CAD (n = 41) and symptomatic CAD (n = 30), the occurrence rates of peri-CAS DWI-positive lesions were 13%, 41% and 30% (P = .0048), and the peri-CAS stroke rates were 2%, 7% and 0% (P = .2120).ConclusionsThe severity of morphological CAD and the presence of either symptomatic or asymptomatic CAD are associated with the occurrence of peri-CAS cerebral ischemic lesions.

In this report, we illustrate the design concept of the small-offset(1 mm) virtual channel-cut monochromator. The monochromator is specially designed for Sub-micron X-ray Diffraction Beamline at Taiwan Photon Source. It can offer a monochromatic beam with the resolving power better than 5000 in the range of 7keV-25 keV and allows the beamline to cycle between the polychromatic and monochromatic modes with a fixed spot of 100 nm at the sample position. Its adjustments and the thermal deformation are reduced as possible to increase the stability of the focal point. The finite element analysis of the thermal deformation shows rather simple cooling techniques can be used. Base on above design, we expect the positional stability of the focus can be kept in around 10nm.