Association of Left Vertebral Artery Hypoplasia with Posterior Circulation Stroke and the Functional Outcome of Patients with Atrial Fibrillation-Related Cardioembolic Stroke.

BACKGROUND AND PURPOSE: A cardiogenic embolus could reach the posterior circulation through the right vertebral artery because of a relatively larger diameter in cases of left vertebral artery hypoplasia. Hence, we investigated whether left vertebral artery hypoplasia is associated with cardiac embolisms with atrial fibrillation in the posterior circulation and its functional outcomes. MATERIALS AND METHODS: In this monocentric retrospective study, patients with acute cardioembolic stroke with atrial fibrillation were enrolled and underwent CT or neck MRA, which visualized the aortic arch and subclavian arteries. The laterality and size of vertebral artery hypoplasia were recorded. Posterior circulation stroke, basilar artery occlusion, and the functional outcomes after 3 months were investigated. RESULTS: This study included 407 patients; the patients with left vertebral artery hypoplasia experienced a higher rate of posterior circulation stroke (19 versus 73; 42.2% versus 20.2%; P = .001) and basilar artery occlusion (5 versus 10; 11.1% versus 2.8%; P = .005) than the patients without left vertebral artery hypoplasia. Multivariate analysis revealed that left vertebral artery hypoplasia showed an association with lower odds of achieving a good functional outcome 3 months after the stroke (OR = 0.4; 95% CI, 0.2-0.9; P = .027). CONCLUSIONS: Patients with cardioembolic stroke and left vertebral artery hypoplasia had posterior circulation stroke, basilar artery occlusion, and poor functional outcomes after 3 months.

Carotid Plaque Composition Assessed by CT Predicts Subsequent Cardiovascular Events among Subjects with Carotid Stenosis.

BACKGROUND AND PURPOSE: Currently, the characteristics of carotid plaques are considered important factors for identifying subjects at high risk of stroke. This study aimed to test the hypothesis that carotid plaque composition assessed by CTA is associated with an increased risk of future major adverse cardiovascular events among asymptomatic subjects with moderate-to-severe carotid artery stenosis. MATERIALS AND METHODS: This single-center, retrospective cohort study included 194 carotid plaques from 176 asymptomatic subjects with moderate-to-severe carotid artery stenosis. The association of CTA-determined plaque composition with the risk of subsequent adverse cardiovascular events was analyzed. RESULTS: During a median follow-up of 41 months, the adverse cardiovascular event incidence among 194 carotid plaques was 19.6%. There were significant differences in plaque Hounsfield units (P < .001) and spotty calcium presence (P < .001) between carotid plaques from subjects with and without subsequent adverse cardiovascular events. Multivariable analysis revealed carotid plaque Hounsfield unit density (P < .001) and spotty calcium (P < .001) as independent predictors of subsequent adverse cardiovascular events. In association with moderate carotid artery stenosis, the plaque Hounsfield unit values were significantly lower among carotid plaques from subjects who experienced subsequent adverse cardiovascular events (P = .002), strokes (P = .01), and cardiovascular deaths (P = .04); the presence of spotty calcium was significantly associated with the occurrence of adverse cardiovascular events (P = .001), acute coronary syndrome (P = .01), and cardiovascular death (P = .04). CONCLUSIONS: Carotid plaque Hounsfield unit density and spotty calcium were independent predictors of a greater risk of adverse cardiovascular event occurrence.

White matter hyperintensities and recurrent stroke risk in patients with stroke with small-vessel disease.

BACKGROUND AND PURPOSE: White matter hyperintensities (WMH) are a predictor of stroke among elderly individuals. This study aimed to evaluate the association between WMH severity and the risk of recurrent vascular events among Asian patients with ischaemic stroke with small-vessel disease (SVD) including micro/macrobleeds and lacunes. METHODS: Data from participants (n = 1454) in the PICASSO (PreventIon of CArdiovascular Events in iSchemic Stroke Patients with High Risk of Cerebral HemOrrhage) trial were reviewed. The severity of WMH in baseline brain magnetic resonance imaging scans was assessed using the Fazekas scale. The association between WMH severity and stroke (ischaemic or hemorrhagic) and major vascular events (MVEs) (a composite of stroke/myocardial infarction/vascular death) was assessed. RESULTS: Study patients had a significant burden of SVD: Fazekas score 0 (n = 2), 1 (n = 426), 2 (n = 650) and 3 (n = 376) [median Fazekas score 2 (mean follow-up, 1.9 ± 1.3 years)]. The stroke incidence rate per 100 personyears was 2.6 in the Fazekas 0-1 group, 3.6 in the Fazekas 2 group and 7.0 in the Fazekas 3 group, and the rates for MVEs were 3.3, 4.3 and 7.6, respectively. Compared with the Fazekas 0-1 group, the Fazekas 3 group was associated with a higher risk of stroke [adjusted hazard ratio (HR), 2.15; 95% confidence interval (CI), 1.19-3.88; P = 0.011], ischaemic stroke (adjusted HR, 2.11; 95% CI, 1.07-4.15; P = 0.031), hemorrhagic stroke (adjusted HR, 3.72; 95% CI, 1.09-12.70; P = 0.036) and MVEs (adjusted HR, 2.09; 95% CI, 1.20-3.66; P = 0.010). CONCLUSION: Advanced WMH in Asian patients with ischaemic stroke with SVD burden was associated with an increased risk of recurrent vascular events. It may exert an effect as a prognostic indicator in high risk of recurrent vascular events.

Comparison of High-Resolution MR Imaging and Digital Subtraction Angiography for the Characterization and Diagnosis of Intracranial Artery Disease.

BACKGROUND AND PURPOSE: High-resolution MR imaging has recently been introduced as a promising diagnostic modality in intracranial artery disease. Our aim was to compare high-resolution MR imaging with digital subtraction angiography for the characterization and diagnosis of various intracranial artery diseases. MATERIALS AND METHODS: Thirty-seven patients who had undergone both high-resolution MR imaging and DSA for intracranial artery disease were enrolled in our study (August 2011 to April 2014). The time interval between the high-resolution MR imaging and DSA was within 1 month. The degree of stenosis and the minimal luminal diameter were independently measured by 2 observers in both DSA and high-resolution MR imaging, and the results were compared. Two observers independently diagnosed intracranial artery diseases on DSA and high-resolution MR imaging. The time interval between the diagnoses on DSA and high-resolution MR imaging was 2 weeks. Interobserver diagnostic agreement for each technique and intermodality diagnostic agreement for each observer were acquired. RESULTS: High-resolution MR imaging showed moderate-to-excellent agreement (interclass correlation coefficient = 0.892-0.949; κ = 0.548-0.614) and significant correlations (R = 0.766-892) with DSA on the degree of stenosis and minimal luminal diameter. The interobserver diagnostic agreement was good for DSA (κ = 0.643) and excellent for high-resolution MR imaging (κ = 0.818). The intermodality diagnostic agreement was good (κ = 0.704) for observer 1 and moderate (κ = 0.579) for observer 2, respectively. CONCLUSIONS: High-resolution MR imaging may be an imaging method comparable with DSA for the characterization and diagnosis of various intracranial artery diseases.

Risk of stroke and transient ischaemic attack after herpes zoster.

We assessed the association of herpes zoster (HZ) with stroke/transient ischaemic attack (TIA) in the general population according to age with controlling risk factors for stroke, using a nationwide representative cohort. The study was based on a prospective dynamic cohort consisting of 1 million Koreans representing all age groups, genders and geographical areas in the Korea Health Insurance Database. New events of stroke/TIA and HZ were identified using the diagnostic codes in the International Classification of Diseases, tenth revision. The risk for stroke/TIA after HZ was compared with HZ-free stroke/TIA individuals according to age group. A total of 766 179 adults were followed up for 11 years from 2003. The incidence of the first-diagnosed HZ cases was 9.40 per 1000 person-years, and that of the first-diagnosed stroke/TIA cases was 9.77 per 1000 person-years. The risk for stroke/TIA was higher in patients who had previous HZ episodes than in those who had never experienced HZ (incidence rate ratio 1.90; 95% CI 1.85-1.95). In addition, this risk persisted for several years after HZ. The risk of stroke/TIA after HZ gradually decreased with age; adjusted hazard ratio (HR) 2.04 in 18- to 30-year-olds, HR 1.74 in 30- to 40-year-olds, HR 1.43 in 40- to 50-year-olds, HR 1.23 in 50- to 60-year-olds, HR 1.24 in 60- to 70-year-olds, and HR 1.29 in those >70 years old, after controlling risk factors for stroke/TIA. Our findings provide evidence that HZ carries an increased risk of stroke or TIA and that the effect of HZ on stroke decreases with increasing age.

High resolution MRI difference between moyamoya disease and intracranial atherosclerosis.

BACKGROUND AND PURPOSE: Along with intracranial atherosclerotic disease (ICAD), moyamoya disease (MMD) is the most common cause of middle cerebral artery (MCA) occlusion in Asians. Although they have differing vascular wall pathologies, conventional angiographic evaluation methods cannot easily differentiate MMD from ICAD in certain situations, such as in young patients with atherosclerotic risk factors. High resolution magnetic resonance imaging (HR-MRI) findings for the diseased segments of MCAs in MMD and symptomatic ICAD were compared to further elucidate differences in arterial wall changes. METHODS: Angiographically confirmed patients, 12 MMD and 20 ICAD, who suffered a stroke due to MCA occlusion were recruited and underwent HR-MRI. The size of the outer diameter and other stenotic vessel wall characteristics revealed by HR-MRI, including enhancement, eccentricity and other lesion patterns, were analyzed by two independent reviewers in a blind fashion. RESULTS: MMD patients were younger than ICAD patients (32.92 ± 11.08 years vs. 51.85 ± 11.97 years; mean ± SD) and displayed a smaller outer diameter in the stenotic portion (1.61 ± 0.43 mm for MMD vs. 3.03 ± 0.53 mm for ICAD, P < 0.0001). Eccentric lesions (three of 12 in MMD vs. 19 of 20 in ICAD, P < 0.0001) and focal enhancements in diseased areas (two of seven in MMD vs. 13 of 17 in ICAD, P = 0.061) were less common in MMD cases. CONCLUSIONS: Our HR-MRI findings show that MMD is associated with smaller, concentric occlusive lesions which are rarely enhanced compared with symptomatic ICAD, consistent with the results of previous pathological reports. HR-MRI may therefore have utility in differentiating MMD from ICAD.

Stroke recurrence patterns are predicted by the subtypes and mechanisms of the past, non-cardiogenic stroke.

BACKGROUND AND PURPOSE: The association between past stroke subtypes and recurrent stroke subtypes in non-cardiogenic stroke remains unknown. METHODS: Patients with ischaemic stroke who had a past history of large-artery disease (LAD) or small-artery disease (SAD) subtypes were assessed. LAD was subdivided into intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS). LAD stroke mechanisms were categorized as artery-to-artery embolism, in situ thrombotic occlusion and local branch occlusion, while SAD was subdivided into lacunar infarction (LI) and branch atheromatous disease (BAD) on the basis of magnetic resonance imaging findings. The relationship between past and current strokes was analyzed. RESULTS: Among the 202 patients enrolled, the LAD group (n = 111) had 64 and 47 patients with ICAS and ECAS, and the SAD group (n = 91) had 63 and 28 patients with LI and BAD, respectively, at the time of past stroke. Patients with LAD developed LAD-associated strokes most often (n = 99, 89.2%), and patients with SAD developed SAD most often (n = 69, 75.8%; P < 0.001). Patients with ICAS were more likely to develop ICAS later (n = 46, 79.3%), whereas those with ECAS developed ECAS more often (n = 31, 75.6%; P < 0.001). Patients with ICAS presenting with artery-to-artery embolism more often developed artery-to-artery embolism later (n = 26, 72.2%), whereas those with local branch occlusion developed recurrent local branch occlusion most often (n = 10, 66.7%, P = 0.005). In the SAD group, patients with BAD developed LAD more frequently than the LI group (n = 11, 39.3% vs. n = 9, 14.3%, P = 0.022). CONCLUSIONS: The subtypes and mechanisms of recurrent stroke are significantly influenced by those of the past stroke.

Age- and weight-adjusted warfarin initiation nomogram for ischaemic stroke patients.

OBJECTIVES: Specific guidelines for initial dosing of warfarin in ischaemic stroke patients have not been developed. Therefore, we have developed an age- and weight-adjusted warfarin initiation nomogram (AW-WIN) for ischaemic stroke patients and then evaluated the efficacy and safety of AW-WIN compared with physician-determined warfarin dosing (PDWD). METHODS: The age- and weight-adjusted warfarin initiation nomogram was administered to 104 acute ischaemic stroke patients between January 2008 and February 2009. A historical control group (PDWD) of 96 patients was selected from comparable patients who were discharged with warfarin during the previous year. Time-to-therapeutic international normalized ratios (INRs) and the incidence of excessive anticoagulation were compared in the AW-WIN and PDWD groups. RESULTS: The general characteristics, risk factors, and stroke mechanism of the AW-WIN and PDWD groups did not differ significantly. The mean time to INR ≥ 2.0 was significantly shorter in the AW-WIN than in the PDWD group (4.9 ± 0.7 vs. 6.2 ± 0.8 days, P = 0.0008). After adjustment for potential confounding variables, the AW-WIN group reached target INR faster than the PDWD group (hazard ratio, 1.76; 95% confidence interval, 1.26-2.45; P = 0.001). The time-to-therapeutic INR ≥1.7 was shorter (P = 0.0002), the proportion of patients with therapeutic INR (2-3) at 5 days was higher (P = 0.002), and the rate of excessive anticoagulation of ≥3.5 INR during hospitalization was lower (P = 0.024) in the AW-WIN than in the PDWD group. CONCLUSIONS: AW-WIN reduces the time to target INR and the risk of excessive anticoagulation. AW-WIN may be an efficient and safe method of anticoagulation during the acute phase of ischaemic stroke.

Poststroke depression and emotional incontinence: factors related to acute and subacute stages.

OBJECTIVES: To investigate the characteristics and prevalence of poststroke depression (PSD) and poststroke emotional incontinence (PSEI) and the factors related to these conditions at admission and 3 months after stroke. METHODS: We evaluated 508 consecutive patients with acute ischemic stroke for PSD and PSEI at admission and 3 months later. PSD was evaluated using the Beck Depression Inventory, and PSEI was evaluated using Kim's criteria. Blood samples were collected and genotyped for the promoter region of the serotonin transporter protein (5-HTTLPR) and the number of tandem repeats within intron 2 (STin2 VNTR). Perceived social support (the ENRICHD Social Support Inventory) was also measured. RESULTS: PSD and PSEI were present in 13.7% and 9.4% of patients, respectively, at admission and in 17.7% and 11.7%, respectively, at 3 months after stroke. Multivariate analyses showed that PSD at admission was associated with the NIH Stroke Scale score at admission (p < 0.001), whereas PSD at 3 months was associated with the presence of microbleeds (p < 0.01) and perceived low social support (p < 0.001). In contrast, only lesion location (p = 0.022) was associated with PSEI at admission, whereas modified Rankin Scale score (p = 0.019), STin2 VNTR (p = 0.040), and low social support (p = 0.042) were related to PSEI 3 months after stroke. CONCLUSIONS: Diverse factors such as neurologic dysfunction, lesion location, microbleeds, genetic traits, and social support are differently related to acute and subacute emotional disturbances. Strategies to prevent or manage these problems should consider these differences.

Isolated lateral thalamic infarction: the role of posterior cerebral artery disease.

BACKGROUND AND PURPOSE: Lateral thalamic infarction (LTI) is usually caused by small vessel disease (SVD), i.e., occlusion of the deep perforator. However, focal atherosclerotic posterior cerebral artery disease (PCAD) may produce LTI via thrombotic occlusion of the perforator. We aimed to investigate the prevalence of PCAD in LTI and differences in clinical and imaging findings between LTIs associated with PCAD and SVD. METHODS: We retrospectively evaluated 58 consecutive patients with isolated LTI who underwent diffusion-weighted imaging (DWI) and MR angiography (MRA) within 7 days after stroke onset. Patients were divided into two groups: those with PCAD and those with SVD. Clinical syndromes were divided into pure sensory stroke (PSS) and sensory stroke plus (SS-plus), i.e., the concomitant presence of motor dysfunction or ataxia. Clinical and imaging findings were compared between these two groups. RESULTS: Of the 58 patients, 13 (22.4%) had PCAD. PSS was more frequently associated with SVD than with PCAD (57.8% vs. 23.1%, P=0.032). Initial DWI lesion volume (cm³) was significantly larger in PCAD than in patients with SVD (0.38±0.13 vs. 0.33±0.22, P=0.025). Among the 23 patients (39.7%) who underwent follow-up DWI, patients with PCAD showed a significantly greater increase in subacute lesion volume than those with SVD (P=0.019). Although National Institutes of Health Stroke Scale scores did not differ at admission (P=0.185), they were significantly higher at discharge in PCAD than in patients with SVD (P=0.012). CONCLUSIONS: Our data suggest that PCAD is an important cause of LTI, being related to SS-plus, larger lesion volume, and worse clinical outcomes.

Ultrasonic plaque echolucency and emboli signals predict stroke in asymptomatic carotid stenosis.

OBJECTIVES: Better methods are required to identify patients with asymptomatic carotid stenosis (ACS) at risk of future stroke. Two potential markers of high risk are echolucent plaque morphology on carotid ultrasound and embolic signals (ES) in the ipsilateral middle cerebral artery on transcranial Doppler ultrasound (TCD). We explored the predictive value of a score based on these 2 measures in the prospective, observational, international multicenter Asymptomatic Carotid Emboli Study. METHODS: A total of 435 recruited subjects with ACS ≥70% had baseline ultrasound images and TCD data available. Subjects were prospectively followed up for 2 years. RESULTS: A total of 164 (37.7%) plaques were graded as echolucent. Plaque echolucency at baseline was associated with an increased risk of ipsilateral stroke alone (hazard ratio [HR] 6.43, 95% confidence interval [CI] 1.36-30.44, p = 0.019). A combined variable of plaque echolucency and ES positivity at baseline was associated with a markedly increased risk of ipsilateral stroke alone (HR 10.61, 95% CI 2.98-37.82, p = 0.0003). This association remained significant after controlling for risk factors, degree of carotid stenosis, and antiplatelet medication. CONCLUSIONS: Plaque morphology assessed using a simple, and clinically applicable, visual rating scale predicts ipsilateral stroke risk in ACS. The combination of ES detection and plaque morphology allows a greater prediction than either measure alone and identifies a high-risk group with an annual stroke risk of 8%, and a low-risk group with a risk of <1% per annum. This risk stratification may prove useful in the selection of patients with ACS for endarterectomy.

Effect of cilnidipine vs losartan on cerebral blood flow in hypertensive patients with a history of ischemic stroke: a randomized controlled trial.

OBJECTIVES: The aim of this study was to compare the effects of antihypertensive agents on cerebral blood flow (CBF) in hypertensive patients with previous ischemic stroke. MATERIALS AND METHODS: In this double-blind, multi-center, non-inferiority trial, 196 patients were randomized to cilnidipine 10-20 mg or losartan 50-100 mg once daily for 4 weeks. Baseline and follow-up CBF as measured by single photon emission computed tomography were obtained in 167. The primary endpoint was the global CBF change. The secondary endpoints were the CBF change in the hemisphere ipsilateral to the index stroke, non-impairment of global CBF and blood pressure (BP) reduction. RESULTS: Global CBF increased significantly in the cilnidipine arm (9.0 +/- 29.6%, P = 0.0071) and the losartan arm (11.4 +/- 31.4%, P = 0.0012), and these changes were not different between the two groups (P = 0.607). However, the estimated difference in percentage global CBF change between the two groups was -2.43% (97.5% CI, -13.06% to 8.21%), which crossed the predetermined non-inferiority margin of -8.6%. Ipsilesional hemispheric CBF change, non-impairment of global CBF and BP reduction were similar in the two groups. CONCLUSIONS: This trial failed to prove the non-inferiority of cilnidipine to losartan regarding global CBF change. Both the treatments, however, increase the global CBF despite BP lowering.

Addition of cilostazol reduces biological aspirin resistance in aspirin users with ischaemic stroke: a double-blind randomized clinical trial.

BACKGROUND AND PURPOSE: Biological aspirin resistance (AR) has been recognized as an important cause of clinical AR. Recent studies have reported the beneficial effects of cilostazol for the prevention of cardiovascular diseases. This study investigated whether addition of cilostazol to aspirin in ischaemic stroke patients can reduce AR. METHODS: In this double-blind multicenter trial, 244 aspirin users with ischaemic stroke were randomly assigned to receive cilostazol 100 mg twice daily or to placebo. Antiplatelet function was assessed using the VerifyNow Aspirin system. The primary end-point was the incidence of AR, which was measured as aspirin resistance unit (ARU) > or =550 after 4-week treatment. RESULTS: The incidence of AR after treatment in cilostazol group was not significantly different from that in placebo (8.8% vs. 10.9%, P = 0.578). However, AR decreased from 12.8% to 8.8% in cilostazol group, whereas it was not changed in the placebo group. The mean ARU after treatment were also lower in the cilostazol group (456.9 +/- 56.0 vs. 470.7 +/- 67.2, P = 0.081). Cilostazol addition did not prolong bleeding time. CONCLUSIONS: Although this was a negative study, our findings disclosed a trend toward enhanced antiplatelet effects when cilostazol was added to aspirin in ischaemic stroke patients. Combination of aspirin and cilostazol might be a treatment option in the ischaemic stroke patients with AR.

Rapid appearance of new cerebral microbleeds after acute ischemic stroke.

BACKGROUND: It is unknown whether the development of cerebral microbleeds (MBs), small areas of signal loss on T2*-weighted gradient-echo imaging (GRE), follows a slow or a rapid process. We hypothesized that MBs may develop rapidly after certain critical events, such as strokes, and investigated the frequency, location, and factors associated with the formation of new MBs after acute ischemic stroke. METHODS: We retrospectively examined 237 consecutive acute ischemic stroke patients who underwent MRI within 24 hours and follow-up MRI during the week after symptom onset. We defined new MBs as MBs that newly appeared on follow-up GRE outside the infarcted area. We examined the association of new MBs with demographics, risk factors, laboratory data, baseline MBs, and small vessel disease (SVD; leukoaraiosis and lacunar infarctions). RESULTS: Seventy-five patients (31.6%) had baseline MBs, and 30 (12.7%) developed new MBs. Multiple logistic regression analysis indicated that the presence of baseline MBs (odds ratio [OR] 5.72, 95% confidence interval [CI] 2.12-15.42, p = 0.001) and severe SVD (OR 2.94, 95% CI 1.12-7.77, p = 0.03) independently predicted the development of new MBs. Of the 56 new MBs, 29 (51.8%) appeared in the lobar location, 17 (30.4%) appeared in the deep location, and 10 (17.9%) appeared in the infratentorial location. CONCLUSIONS: This study suggests that new microbleeds (MBs) can develop rapidly after acute ischemic stroke. Baseline MBs and severe small vessel disease are predictors for the development of new MBs. Further studies will be needed to investigate the clinical implications and mechanisms of these findings.

Age and body weight adjusted warfarin initiation program for ischaemic stroke patients.

BACKGROUND: Despite its proven effect, anticoagulation is not recommended to the acute ischaemic stroke due to the risk of bleeding complications. The purpose of this study is development of individualized warfarin initiation program for acute or subacute stroke patients. METHODS: Among stroke patients who regularly visited out-patient clinics, we included patients who have continuously taken the same dose of warfarin as the prothrombin time remained at target International Nomarlized Ratio (INR). We assessed potential variables that affect the maintenance dose of warfarin. Using these variables, we developed an individualized warfarin initiation program. RESULTS: The median warfarin maintenance dose (interquartile range) in the 321 included patients was 4 (3-5) mg per day. Age (adjusted R(2) = 0.221, P < 0.001) and body weight (added to age, adjusted R(2) = 0.238, P = 0.008) were significant predicting factors of the dose. We classified the maintenance doses into high (HG), standard, and low group (LG) based on the distribution of maintenance doses. Decision tree analysis categorized younger (or=55 kg) patients into HG, and very old (>or=80 years old) or low body weight (<55 kg among those >56 years old) patients into LG. We recommend 7 mg of warfarin as a standard initial dose, but 10 mg was recommended for HG patients and 5 mg for LG. CONCLUSION: We expect that this individualized program may reduce the time to target INR without excessive anticoagulation. Further prospective studies are needed to reveal the efficacy and safety of applying this program for acute stroke patients.

Basilar artery atherosclerotic disease is related to subacute lesion volume increase in pontine base infarction.

BACKGROUND: Although basilar artery atherosclerotic disease (BAD) is frequent in patients with pontine base infarction, it remains unknown whether BAD is related to the lesion size or clinical outcome. METHODS: We studied 56 patients with unilateral pontine base infarction who underwent (i) diffusion-weighted MRI within 48 h after stroke onset and (ii) follow-up MRI and MR angiography in the subacute stage. Neurologic progression was defined as increased National Institutes of Health Stroke Scale score by > or = 2 during admission. Clinical outcome was dichotomized as good and poor (> or = 3) according to the modified Rankin Scale at 1 month after stroke onset. RESULTS: Twenty-two patients (39%) had BAD and 15 patients (27%) had neurologic progression. Follow-up MRI performed at median 3.5 +/- 1.1 days after the initial MRI showed the lesion volume significantly increased (P < 0.001). The BAD was not significantly related to demographic characteristics, risk factors, initial and follow-up lesion volume, neurologic progression and clinical outcome, but was closely related to the subacute increase in lesion volume (P = 0.004 for 20% increase, P = 0.029 for 50% increase). CONCLUSIONS: BAD is related to subacute increase in lesion volume, but not to ultimate poor clinical outcome in patients with pontine base infarction.

MRI evidence of reperfusion injury associated with neurological deficits after carotid revascularization procedures.

BACKGROUND AND PURPOSE: Some patients develop major neurological complications after carotid revascularization procedures, despite the lack of new infarcts or classical hyperperfusion syndrome. METHODS: In four patients who developed major neurological deficits after carotid revascularization procedures, but without evidence of new ischemic infarcts or hyperperfusion, we performed post-procedural MRI [diffusion-weighted image (DWI), perfusion-weighted image (PWI), pre-and post-contrast fluid-attenuated inversion recovery (FLAIR) image] immediately after and 1 day after the procedure. RESULTS: Post-gadolinium FLAIR images on 1 day after the procedures showed prominent leptomeningeal enhancements in the revascularized hemispheres. These radiological findings disappeared on follow-up FLAIR images accompanied by the clinical improvement over the following several days after the procedures. CONCLUSION: Reperfusion syndrome may be associated with transient severe neurological deficits after carotid revascularization in patients without new ischemic events or classical hyperperfusion syndrome.

High prevalence of unrecognized cerebral infarcts in first-ever stroke patients with cardioembolic sources.

BACKGROUND: With magnetic resonance imaging (MRI) analysis, we investigated the prevalence, clinical significance, and factors related to the presence of unrecognized cerebral infarcts in patients with first-ever ischaemic stroke. METHODS: We consecutively included patients who were admitted with first-ever stroke. Unrecognized cerebral infarct was defined as an ischaemic infarction or primary intracerebral hemorrhage on MRI irrelevant to the index stroke, without acute lesions on diffusion-weighted image. RESULTS: Of the total 203 patients, 78 (39.4%) patients were observed as having unrecognized cerebral infarct. Patients with high-risk cardioembolic sources (e.g., atrial fibrillation) more frequently had unrecognized stroke than those without (P = 0.008, 21/36 [58.3%] vs. 57/167 [34.1%]). On univariate analysis, male sex (P = 0.027) and cardioembolic source (P = 0.008) were associated with the presence of unrecognized cerebral infarcts. After adjustment for gender, age and risk factors, the presence of cardioembolic sources independently increased the risk of unrecognized cerebral infarct (P = 0.002, odds ratio 3.56, 95% confidence interval 1.58-8.02). Regarding clinical outcome at 3 months, the presence of unrecognized cerebral infarct was not associated with the poor clinical outcome. CONCLUSION: In our study, the presence of cardioembolic sources was an independent risk factor for the unrecognized cerebral infarct in patients with first-ever stroke.

Location of single subcortical infarction due to middle cerebral artery atherosclerosis: proximal versus distal arterial stenosis.

BACKGROUND: Atherosclerotic middle cerebral artery (MCA) disease may produce subcortical infarction either in the upper part (corona radiata, CR) or in the lower area (internal capsule, IC) of the pyramidal tract. The study aimed to see whether the location of MCA stenosis (proximal vs distal) determines the location of subcortical infarction. METHODS: 62 consecutive patients who developed an acute (<72 h) infarction either on the CR or IC confirmed by diffusion-weighted MRI due to corresponding focal MCA M1 stenosis assessed by MR angiography were studied. The distance between the MCA origin and the centre of stenotic portion (S) and that between the MCA origin and its bifurcation site (M) were measured. Based on the S/M ratio, stenotic lesions were divided into "proximal' and "distal'. The relationship between the location of arterial stenosis and the location of infarcts was analysed. RESULTS: Thirteen of 31 patients (41.9%) with proximal M1 stenosis had IC lesions, while 26 (83.9%) of 31 patients with distal stenosis had CR lesions (p = 0.025). The S/M ratio in patients with the CR infarcts (mean (SD) 0.65 (0.21) was significantly greater than in those with the IC infarcts (0.48 (0.23)) (p = 0.007). In addition, the National Institutes of Health Stroke Scale score at admission was higher in patients with proximal M1 stenosis than in those with distal stenosis (6 vs 3.5; p = 0.04). CONCLUSIONS: The results suggest that perforating arteries arising from the distal M1 segment are related to infarcts involving the upper part of pyramidal tract, while those from proximal segment are related to lower lesions.