Reproducibility of measurements of cerebral infarct volume on CT scans

Follow-up infarct volume on fluid attenuated inversion recovery (FLAIR) imaging in distal medium vessel occlusions: the role of cerebral blood volume index

BACKGROUND

Distal medium vessel occlusions (DMVOs) contribute substantially to the incidence of acute ischemic strokes (AIS) and pose distinct challenges in clinical management and prognosis. Neuroimaging techniques, such as Fluid Attenuation Inversion Recovery (FLAIR) imaging and cerebral blood volume (CBV) index derived from perfusion imaging, have significantly improved our ability to assess the impact of strokes and predict their outcomes. The primary objective of this study was to investigate relationship between follow-up infarct volume (FIV) as assessed by FLAIR imaging in patients with DMVOs.

METHODS

This prospectively collected, retrospective reviewed cohort study included patients from two comprehensive stroke centers within the Johns Hopkins Medical Enterprise, spanning August 2018-October 2022. The cohort consisted of adults with AIS attributable to DMVO. Detailed imaging analyses were conducted, encompassing non-contrast CT, CT angiography (CTA), CT perfusion (CTP), and FLAIR imaging. Univariable and multivariable linear regression models were employed to assess the association between different factors and FIV.

RESULTS

The study included 79 patients with DMVO stroke with a median age of 69 years (IQR, 62-77 years), and 57% (n = 45) were female. There was a negative correlation between the CBV index and FIV in a univariable linear regression analysis (Beta =  - 16; 95% CI,  - 23 to  - 8.3; p < 0.001) and a multivariable linear regression model (Beta =  - 9.1 per 0.1 change; 95% CI,  - 15 to  - 2.7; p = 0.006). Diabetes was independently associated with larger FIV (Beta = 46; 95% CI, 16 to 75; p = 0.003). Additionally, a higher baseline ASPECTS was associated with lower FIV (Beta =  - 30; 95% CI,  - 41 to  - 20; p < 0.001).

CONCLUSION

Our findings underscore the CBV index as an independent association with FIV in DMVOs, which highlights the critical role of collateral circulation in determining stroke outcomes in this patient population. In addition, our study confirms a negative association of ASPECTS with FLAIR FIV and identifies diabetes as independent factor associated with larger FIV. These insights pave the way for further large-scale, prospective studies to corroborate these findings, thereby refining the strategies for stroke prognostication and management.

How Do Quantitative Tissue Imaging Outcomes in Acute Ischemic Stroke Relate to Clinical Outcomes?

BACKGROUND AND PURPOSE

Infarct volume and other imaging markers are increasingly used as surrogate measures for clinical outcome in acute ischemic stroke research, but how improvements in these imaging surrogates translate into better clinical outcomes is currently unclear. We investigated how changes in infarct volume at 24 hours alter the probability of achieving good clinical outcome (modified Rankin Scale [mRS] 0-2).

METHODS

Data are from endovascular thrombectomy patients from the randomized controlled ESCAPE-NA1 (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischaemic Stroke) trial. Infarct volume at 24 hours was manually segmented on non-contrast computed tomography or diffusion-weighted magnetic resonance imaging. Probabilities of achieving good outcome based on infarct volume were obtained from a multivariable logistic regression model. The probability of good outcome was plotted against infarct volume using linear spline regression.

RESULTS

A total of 1,099 patients were included in the analysis (median final infarct volume 24.9 mL [interquartile range: 6.6-92.2]). The relationship between total infarct volume and good outcome probability was nearly linear for infarct volumes between 0 mL and 250 mL. In this range, a 10% increase in the probability of achieving mRS 0-2 required a decrease in infarct volume of approximately 34.0 mL (95% confidence interval: -32.5 to -35.6). At infarct volumes above 250 mL, the probability of achieving mRS 0-2 probability was near zero. The relationships of tissue-specific infarct volumes and parenchymal hemorrhage volume generally showed similar patterns, although variability was high.

CONCLUSION

There seems to be a near-linear association between total infarct volume and probability of achieving good outcome for infarcts up to 250 mL, whereas patients with infarct volumes greater than 250 mL are highly unlikely to have a favorable outcome.

Hypochlorous acid derived from microglial myeloperoxidase could mediate high-mobility group box 1 release from neurons to amplify brain damage in cerebral ischemia-reperfusion injury

Myeloperoxidase (MPO) plays critical role in the pathology of cerebral ischemia-reperfusion (I/R) injury via producing hypochlorous acid (HOCl) and inducing oxidative modification of proteins. High-mobility group box 1 (HMGB1) oxidation, particularly disulfide HMGB1 formation, facilitates the secretion and release of HMGB1 and activates neuroinflammation, aggravating cerebral I/R injury. However, the cellular sources of MPO/HOCl in ischemic brain injury are unclear yet. Whether HOCl could promote HMGB1 secretion and release remains unknown. In the present study, we investigated the roles of microglia-derived MPO/HOCl in mediating HMGB1 translocation and secretion, and aggravating the brain damage and blood-brain barrier (BBB) disruption in cerebral I/R injury. In vitro, under the co-culture conditions with microglia BV cells but not the single culture conditions, oxygen-glucose deprivation/reoxygenation (OGD/R) significantly increased MPO/HOCl expression in PC12 cells. After the cells were exposed to OGD/R, MPO-containing exosomes derived from BV2 cells were released and transferred to PC12 cells, increasing MPO/HOCl in the PC12 cells. The HOCl promoted disulfide HMGB1 translocation and secretion and aggravated OGD/R-induced apoptosis. In vivo, SD rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus different periods of reperfusion. Increased MPO/HOCl production was observed at the reperfusion stage, accomplished with enlarged infarct volume, aggravated BBB disruption and neurological dysfunctions. Treatment of MPO inhibitor 4-aminobenzoic acid hydrazide (4-ABAH) and HOCl scavenger taurine reversed those changes. HOCl was colocalized with cytoplasm transferred HMGB1, which was blocked by taurine in rat I/R-injured brain. We finally performed a clinical investigation and found that plasma HOCl concentration was positively correlated with infarct volume and neurological deficit scores in ischemic stroke patients. Taken together, we conclude that ischemia/hypoxia could activate microglia to release MPO-containing exosomes that transfer MPO to adjacent cells for HOCl production; Subsequently, the production of HOCl could mediate the translocation and secretion of disulfide HMGB1 that aggravates cerebral I/R injury. Furthermore, plasma HOCl level could be a novel biomarker for indexing brain damage in ischemic stroke patients.

Effects of intensive blood pressure lowering on cerebral ischaemia in thrombolysed patients: insights from the ENCHANTED trial

Background

Intensive blood pressure lowering may adversely affect evolving cerebral ischaemia. We aimed to determine whether intensive blood pressure lowering altered the size of cerebral infarction in the 2196 patients who participated in the Enhanced Control of Hypertension and Thrombolysis Stroke Study, an international randomised controlled trial of intensive (systolic target 130-140 mm Hg within 1 h; maintained for 72 h) or guideline-recommended (systolic target <180 mm Hg) blood pressure management in patients with hypertension (systolic blood pressure >150 mm Hg) after thrombolysis treatment for acute ischaemic stroke between March 3, 2012 and April 30, 2018.

Methods

All available brain imaging were analysed centrally by expert readers. Log-linear regression was used to determine the effects of intensive blood pressure lowering on the size of cerebral infarction, with adjustment for potential confounders. The primary analysis pertained to follow-up computerised tomography (CT) scans done between 24 and 36 h. Sensitivity analysis were undertaken in patients with only a follow-up magnetic resonance imaging (MRI) and either MRI or CT at 24-36 h, and in patients with any brain imaging done at any time during follow-up. This trial is registered with ClinicalTrials.gov, number NCT01422616.

Findings

There were 1477 (67.3%) patients (mean age 67.7 [12.1] y; male 60%, Asian 65%) with available follow-up brain imaging for analysis, including 635 patients with a CT done at 24-36 h. Mean achieved systolic blood pressures over 1-24 h were 141 mm Hg and 149 mm Hg in the intensive group and guideline group, respectively. There was no effect of intensive blood pressure lowering on the median size (ml) of cerebral infarction on follow-up CT at 24-36 h (0.3 [IQR 0.0-16.6] in the intensive group and 0.9 [0.0-12.5] in the guideline group; log Δmean -0.17, 95% CI -0.78 to 0.43). The results were consistent in sensitivity and subgroup analyses.

Interpretation

Intensive blood pressure lowering treatment to a systolic target <140 mm Hg within several hours after the onset of symptoms may not increase the size of cerebral infarction in patients who receive thrombolysis treatment for acute ischaemic stroke of mild to moderate neurological severity.

Funding

National Health and Medical Research Council of Australia; UK Stroke Association; UK Dementia Research Institute; Ministry of Health and the National Council for Scientific and Technological Development of Brazil; Ministry for Health, Welfare, and Family Affairs of South Korea; Takeda.

Lesion size and long-term cognitive outcome after pediatric stroke: A comparison between two techniques to assess lesion size

BACKGROUND

There is little consensus on how lesion size impacts long-term cognitive outcome after pediatric arterial ischemic stroke (AIS). This study, therefore, compared two techniques to assessed lesion size in the chronic phase after AIS and determined their measurement agreement in relation to cognitive functions in patients after pediatric stroke.

METHODS

Twenty-five patients after pediatric AIS were examined in the chronic phase (>2 years after stroke) in respect to intelligence, memory, executive functions, visuo-motor functions, motor abilities, and disease-specific outcome. Lesion size was measured using the ABC/2 formula and segmentation technique (3D Slicer). Correlation analysis determined the association between volumetry techniques and outcome measures in respect to long-term cognitive outcome.

RESULTS

The measurements from the ABC/2 and segmentation technique were strongly correlated (r = 0.878, p < .001) and displayed agreement in particular for small lesions. Lesion size from both techniques was significantly correlated with disease-specific outcome (p < .001) and processing speed (p < .005) after controlling for age at stroke and multiple comparison.

CONCLUSION

The two techniques showed convergent validity and were both significantly correlated with long-term outcome after pediatric AIS. Compared to the time-consuming segmentation technique, ABC/2 facilitates clinical and research work as it requires relatively little time and is easy to apply.

Correlation between HbA1C and Infarct Volume in Acute Ischemic Stroke

BACKGROUND: Stroke is second leading cause of death worldwide. Chronic hyperglycemia can promote neuronal toxicity. The previous study shows that acute hyperglycemia is correlated with infarct volume of ischemic stroke. AIM: This study aims to investigate the correlation between hemoglobin A1C (HbA1C) and infarct volume on acute ischemic stroke. METHODS: This is a cross-sectional study in acute ischemic stroke patient in Dr. Moewardi General Hospital, Surakarta, Indonesia. Data of infarct volume were collected from head computed tomography (CT)-scan and calculated with A × B × C/2 formula. We also collected lipid and patients’ glycemic profile from patients’ blood laboratory result. Head CT-scan and laboratory data of participants analyzed with Pearson and Spearman’s rho test for parametric and non-parametric data, respectively. We also performed multivariate analysis to evaluate confounding covariates. p < 0.05 was considered as statistically significant. RESULTS: A total of 38 participants were included in this study, with mean infarct volume was 0.46 ± 0.64cc and mean HbA1C was 6.96 ± 2.69%. Bivariate analysis shows strong positive correlation between infarct volume and HbA1C with r = 0.898 (p < 0.001). Other variable that showed a significant correlation with infarct volume were diabetes mellitus history (r = 0.671; p < 0.001), random blood su gar (r = 0.466; p = 0.003), fasting blood sugar (r = 0.636; p < 0.001), 2-h postprandial glucose level (r = 0.646; p ≤ 0.001), high density lipoprotein (r = −0.354; p = 0.029), and triglyceride (r = 0.429; p = 0.007). Based on multivariate analysis, HbA1C regression coefficient on infarct volume was B = 0.222 (p < 0.001), indicating that HbA1C as one of the variables contributing to volume of infarct. CONCLUSIONS: There is a strong positive correlation between infarct volume and HbA1C, and HbA1C is variable contribute to the volume of infarct.

Use of the ABC/2 Method to Select Patients for Thrombectomy After 6 Hours of Symptom Onset

OBJECTIVE

To determine whether the ABC/2 method could accurately and reliably measure infarct volume and guide thrombectomy decision in acute stroke cases presenting with late or unknown onset.

METHODS

Four physicians who routinely use MRI for acute stroke imaging, blinded to the RAPID results, measured the diffusion-weighted imaging (DWI) infarct volume using the ABC/2 method. Measurements with ABC/2 (the index test) were compared with RAPID (the reference standard) to calculate sensitivity, specificity, and accuracy measures for various volume cutpoints. Thrombectomy decisions based on RAPID and raters' measurements using the criteria from the Diffusion-Weighted Imaging or Computerized Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake-Up and Late-Presenting Strokes Undergoing Neurointervention With Trevo (DAWN) trial criteria were compared. Interrater and intrarater agreement was measured using kappa statistics.

RESULTS

Accuracy with the ABC/2 method was greater than 80% for each rater and each volume cut point. Interrater and intrarater agreement was substantial to excellent for each volume cut point. Treatment decisions with ABC/2 volume estimations showed strong interrater and intrarater agreement, and led to similar thrombectomy decisions compared with RAPID in more than 85% of cases.

CONCLUSION

DWI infarct volume measurement using ABC/2 method shows strong accuracy and reliability and may be an acceptable alternative to RAPID software for the application of DAWN criteria for thrombectomy decision-making.

Intrascanner Reproducibility of an SPM-based Head MR-based Attenuation Correction Method

Recently, an exhaustive examination of 11 state of the art MR-based attenuation correction (AC) concluded that there are currently a few methods showing similar results compared to the gold-standard, CT-based AC. While the study presented a thorough portfolio of metrics to quantify accuracy (bias) and quality, it lacked one of the most important metrics to quantify robustness that is critical for its clinical applicability: intrascanner reproducibility (repeatability). In this work, we provide for the first time a study of the repeatability of one of the outperforming brain MR-based AC methods: the SPM-based pseudo-CT approach. 22 subjects undergoing 3 ¹⁸F-FDG PET/MRI visits within 2 months were retrospectively analyzed in this study. Pseudo-CT mu-maps were obtained from the coregistered MR images for all 3 visits and the PET data from visit 1 was reconstructed using all three mu-maps. Relative changes (RC), Intraclass correlation coefficient (ICC), Reproducibility coefficient (RDC_95%) and Bland-Altman Limits of Agreement (LoA) were used to measure repeatability. Voxel-based and ROI-based results showed that absolute RC for the reconstructed PET images are within ~2%. The brain cortex and the cerebellum were the regions with the largest variability (~3%). The differences across visits were not statistically significant (p=0.90). In conclusion this study shows for the first time the repeatability of the SPM-based pseudo-CT approach for brain MR-AC. These results, in addition to the ease of implementation and the quality and robustness previously demonstrated, confer this SPM-based method an ideal candidate for routine brain PET/MRI research and clinical studies.

Large Infarct Volume Post Thrombectomy: Characteristics, Outcomes, and Predictors

BACKGROUND

Despite increasing interest in endovascular therapy (EVT) for large-core strokes, little is known about the predictors of good outcome in these patients. The aim of this study was to analyze patients with large-core strokes post-EVT and to define the predictors of favorable outcome in this population.

METHODS

A retrospective analysis of prospectively collected data on anterior circulation strokes undergoing EVT between January 2015 and February 2018 was performed. Patients with good baseline functional status who underwent EVT for occlusion of an anterior circulation artery and achieved successful recanalization (modified Treatment in Cerebral Ischemia score ≥2b) but had large follow-up infarct volume (FIV ≥70 cm³) were included in the study. Demographic characteristics, clinical and radiologic data, treatment and postprocedural outcomes were extracted and analyzed. The primary outcome was 90-day modified Rankin Scale (mRS) score, stratified by favorable (mRS 0-3) versus unfavorable (mRS 4-6).

RESULTS

Of 355 patients meeting inclusion criteria, 85 (24%) had large FIV on follow-up imaging after EVT and constituted the study cohort. No patients achieved mRS score 0-2 at hospital discharge; 32% had 90-day mRS score 0-3. On multivariate logistic regression analysis, lower FIV (OR, -0.96 [0.95-0.99]; P = 0.007), male sex (OR, -1.29 [1.07-12.3]; P = 0.026), and intravenous tissue plasminogen activator use (OR, 3.6 [2.01-8.9]; P = 0.003) were independent predictors of favorable outcome. Independent predictors of mortality on multivariate analysis were higher FIV (OR, -1.01 [1.007-1.02]; P = 0.001) and female sex (OR, 4.08 [1.25-13.3]; P = 0.02).

CONCLUSIONS

For patients with large-core strokes (≥70 cm³) after EVT, approximately one third have favorable outcome at 90 days. Independent predictors of favorable 90-day outcomes include male sex, intravenous tissue plasminogen activator use, and lower FIV.

Single Word Repetition Predicts Long-Term Outcome of Aphasia Caused by an Ischemic Stroke

PURPOSE

Better understanding of clinical predictors of aphasia outcome is of the utmost importance, in patients' rehabilitation planning, expectation management, and further physiopathology understanding. We aimed to identify clinical predictors of long-term poststroke aphasia's outcome.

METHODS

We conducted a prospective longitudinal observation study of patients with left-Middle Cerebral Artery stroke with aphasia. Patients were evaluated at baseline, day 7 and 6 months with National Institutes of Health Stroke Scale (NIHSS) and Aphasia Rapid Test Other demographic variables and vascular risk factors were collected. A linear regression was performed to identify best predictors of aphasia at 6 months.

FINDINGS

We included 113 patients with a left hemisphere stroke, with 81 reaching the final evaluation. Aphasia Handicap Score at 6 months was predicted by baseline total NIHSS (β = .077, 95%CI = [.026, .127]. P = .004), infarct volume on CT-scan (β = .009, 95%CI = [.003, .015]. P = .003), single word repetition at baseline (β = .188, 95%CI = [.040, .335]. P = .013), and infection during hospitalization (β = .759, 95%CI = [.263, 1.255]. P = .003).

CONCLUSIONS

Aphasia's outcome in patients with stroke is predicted by a single word repetition task at baseline. Infection during hospitalization has a negative impact on aphasia's outcome at 6 months.

miR-183 inhibits microglia activation and expression of inflammatory factors in rats with cerebral ischemia reperfusion via NF-κB signaling pathway

Ischemic stroke represents 87% of all strokes, and is the third leading cause of disability and mortality worldwide. The cause of ischemic stroke is the obstruction of blood flow through the artery that supplies oxygen-rich blood to the brain, with ischemia-reperfusion injury as its major cause. microRNAs (miRNA) are small non-coding RNAs, which serve important roles in the regulation of gene expression at the post-transcription level. The aim of the present study was to investigate the effect of miRNA-183 (miR-183) on microglia activation in rats with cerebral ischemia-reperfusion injury. To this end, a rat cerebral ischemia-reperfusion injury model was established. The results indicated that miR-183 expression was decreased by cerebral ischemia-reperfusion. In addition, treatment using miR-183 agomir significantly reduced the neurological function scores, percentage of cerebral infarction volume, and ionized calcium-binding adapter molecule-1 (IBA-1)-positive cells in the CA1 area of the hippocampus in rats subjected to cerebral ischemia-reperfusion injury, implicating a neuroprotective role for miR-183. MiR-183 agomir treatment also decreased the expression of pro-inflammatory-associated proteins interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α. Finally, the expression of the nuclear factor (NF)-κB p65 and IκBα was decreased and increased by miR-183 agomir treatment, respectively, indicating inhibition of the NF-κB signaling pathway. These observations suggest that miR-183 regulates the activation of microglia in rats with cerebral ischemia-reperfusion injury by inhibiting the NF-κB signaling pathway.

LRG1 Promotes Apoptosis and Autophagy through the TGFβ-smad1/5 Signaling Pathway to Exacerbate Ischemia/Reperfusion Injury

Leucine-rich α2-glycoprotein1 (LRG1), a pleiotropic protein, plays a pathogenic role in multiple human diseases. However, its pathophysiological function in ischemia/reperfusion injury remains unclear. In this study, we discussed the function and mechanism of LRG1 in acute ischemic stroke from both basic and clinical research points of view. Mice underwent transient middle cerebral artery occlusion (tMCAO) surgery 2 weeks after LRG1 was overexpressed by the delivery of adeno-associated virus (AAV). For wild-type mice, both the protein and the transcript of LRG1 in the brain tissue were elevated after tMCAO. Meanwhile, the serum levels of LRG1 were decreased after tMCAO. The neuronal injury was shown aggravated in the AAV-LRG1 group (AAV-LRG1 mice with tMCAO) through infarction volume, neurological score, HE, and Nissl staining. Meanwhile, LRG1 significantly enhanced apoptosis and autophagy during tMCAO, as detected by caspase3, Bax, Bcl-2, LC3II/LC3I, Beclin1, p62, and a TUNEL assay. Furthermore, by overexpression of LRG1, the protein of ALK1 was upregulated and the TGFβ-smad1/5 signaling pathway was activated upon tMCAO. We also showed that patients with acute cerebral infarction had lower serum levels of LRG1 compared to healthy controls. In addition, LRG1 levels were associated with infarction volume, stroke severity, and prognosis in patients with supratentorial infarction. Taken together, the data from this study revealed that LRG1 promoted apoptosis and autophagy through the TGFβ-smad1/5 signaling pathway by up-regulating ALK1, which exacerbates ischemia/reperfusion injury.

Detection of Crossed Cerebellar Diaschisis by Intravoxel Incoherent Motion MR Imaging in Subacute Ischemic Stroke

Intravoxel incoherent motion has received extensive attention in brain studies for its potential as a non-invasive magnetic resonance perfusion method. However, studies on intravoxel incoherent motion imaging and crossed cerebellar diaschisis detection are relatively scarce. The aim of our study was to evaluate the feasibility of using intravoxel incoherent motion imaging in crossed cerebellar diaschisis diagnosis in subacute ischemic stroke patients by comparing results from intravoxel incoherent motion imaging, single-photon emission computed tomography, and arterial spin-labeling perfusion methods. In total, 39 patients with subacute ischemic stroke who underwent intravoxel incoherent motion, arterial spin-labeling, and single-photon emission computed tomography scanning were enrolled. Intravoxel incoherent motion-derived perfusion-related parameters including fast diffusion coefficient, vascular volume fraction, arterial spin-labeling-derived cerebral blood flow as well as single-photon emission computed tomography-derived cerebral blood flow of bilateral cerebellum were measured. A crossed cerebellar diaschisis-positive result was considered present with an asymmetry index ≥10% of single-photon emission computed tomography. In the crossed cerebellar diaschisis-positive group, fast diffusion coefficient, arterial spin-labeling-derived cerebral blood flow, and computed tomography-derived cerebral blood flow of the contralateral cerebellum decreased compared with those of the ipsilesional cerebellum; whereas vascular volume fraction significantly increased. The National Institutes of Health Stroke Scale score and infarct volume in the crossed cerebellar diaschisis-positive group were significantly higher than those in the crossed cerebellar diaschisis-negative group. A positive correlation was detected between the fast diffusion coefficient-based asymmetry index and the single-photon emission computed tomography-based asymmetry index, fast diffusion coefficient-based asymmetry, and arterial spin-labeling based asymmetry index; whereas the vascular volume fraction-based asymmetry index value had a negative correlation with the single-photon emission computed tomography-based asymmetry index and arterial spin-labeling based asymmetry index. Furthermore, the area under the receiver operating characteristic curve value of the arterial spin-labeling-based asymmetry index was 0.923. The fast diffusion coefficient derived from the intravoxel incoherent motion could be valuable for the assessment of crossed cerebellar diaschisis in supratentorial stroke patients.

Maximum lesions area and orthogonal values accessed from DWI images would be alternative imaging markers for predicting the outcome of acute ischemia in the middle cerebral artery territory

BACKGROUND

Evaluating the acute ischemic volume on diffusion-weighted imaging (DWI) in the middle cerebral artery (MCA) territory would predict outcome.

PURPOSE

To investigate the correlations between maximum area with restricted diffusion (MaxA), the orthogonal diameters (OD) as well as lesion volume on DWI, and to explore the role of MaxA and OD on predicting unfavorable outcome after an acute MCA ischemic stroke.

MATERIAL AND METHODS

Sixty consecutive adult patients, including modified Rankin Scale score (mRS) ≤2 (n = 31) and mRS > 2 (n = 29) groups, were retrospectively enrolled. The MaxA and OD of lesions were assessed at the slice containing the largest infarction size on DWI images. We compared the prediction efficiencies of these methods on unfavorable outcomes.

RESULTS

The correlation coefficients between the MaxA and infarction volume and OD and infarction volume were 0.982 ( P < 0.001) and 0.952 ( P < 0.001), respectively. The times required for measuring MaxA (150 s [130-160]) and OD (30 s [20-60]) were much shorter than that for infarction volume measurement (1240 s [180-1480]) ( P = 0.001, P = 0.004). With thresholds of ≥57.3 mL for infarction volume, ≥15.2 cm² for MaxA, and ≥38.1 for the arithmetic product of OD, the AUCs of infarction volume, MaxA, and OD for predicting an unfavorable outcome were 0.818, 0.821, and 0.820, respectively.

CONCLUSION

Since they correlated well with the infarction volume, MaxA and OD assessed on DWI were time-saving and achieved comparable diagnostic efficiencies; thus, they may represent alternative imaging markers for predicting unfavorable outcomes of acute ischemic stroke in MCA territory.

Reliability of ABC/2 Method in Measuring of Infarct Volume in Magnetic Resonance Diffusion-Weighted Image

Aims

Manual planimetry is the current method defining infarct volume on magnetic resonance (MR) diffusion-weighted image. ABC/2 method is an ellipsoid geometric formula with advantage estimation of intraparenchymal hemorrhage volume. Our study aimed to find the reliability and reproducibility of ABC/2 method compared to manual planimetric segmentation method.

Settings and Design

This was a cross-sectional analytical study with retrospective and prospective data collection.

Subjects and Methods

A total of 109 patients with acute ischemic stroke and underwent MR images at Ramathibodi Hospital were retrospectively reviewed. Relationship between manual planimetric segmentation and ABC/2 methods (nonadjusted ABC/2 method and adjusted ABC*/2 method) was determined using Wilcoxon signed-rank test, linear regression analysis, and Bland-Altman plot. Subgroup analysis by location, onset, shape, and size of infarct volume was performed. Interobserver reliability was established using intraclass correlation coefficient and Bland-Altman plot.

Statistical Analysis Used

Wilcoxon signed-rank test, linear regression analysis, and Bland-Altman plot were used for statistical analysis.

Results

Infarct volume measured with nonadjusted ABC/2 method (23.56, 48.81, 4.25, 0.11, 318.94) (mean, standard deviation, median, minimum, maximum) and adjusted ABC*/2 method (13.37, 28.3, 2.08, 0.06, 170.10) was smaller than manual planimetric method (28.50, 58.64, 5.56, 0.27, 335.49) (P < 0.001). Linear regression's slope confirmed underestimation of volume infarct. In round-to-ellipsoid shape and white matter group, the differences found between nonadjusted ABC/2 and manual planimetric methods are not statistically significant.

Conclusions

ABC/2 method is a simple, rapid, and reproducible method with an excellent positive correlation of both adjusted and nonadjusted ABC/2 methods to manual planimetric segmentation method but tendency to underestimated infarct volume. High interobserver reliability and good agreement between two observers have been established. The utilization of nonadjusted ABC/2 method should be used with caution due to its tendency to underestimate the infarct volume.

Safety, feasibility, and potential efficacy of intraarterial selective cooling infusion for stroke patients treated with mechanical thrombectomy

This is a prospective non-randomized cohort study of 113 consecutive patients to investigate the safety and efficacy of a short-duration intraarterial selective cooling infusion (IA-SCI) targeted into an ischemic territory combined with mechanical thrombectomy (MT) in patients with large vessel occlusion-induced acute ischemic stroke (AIS); 45/113 patients underwent IA-SCI with 350 ml 0.9% saline at 4℃ for 15 min at the discretion of the interventionalist. Key parameters such as vital signs and key laboratory values, symptomatic and any intracranial hemorrhage, coagulation abnormalities, pneumonia, urinary tract infections and mortality were not significantly different between the two groups. Final infarct volume (FIV) was assessed on noncontrast CT performed at three to seven days. After an adjusted regression analysis, the between-group difference in FIV (19.1 ml; 95% confidence interval (CI) 3.2 to 25.2; P = 0.038) significantly favored the IA-SCI group. At 90 days, no differences were found in the proportion of patients who achieved functional independence (mRS 0-2) (51.1% versus. 41.2%, adjusted odd ratio (aOR) 1.9, 95% CI 0.8-2.6, P = 0.192). Combining short-duration IA-SCI with MT was safe. There was a smaller FIV and trend towards clinical benefit that will need to be further evaluated in randomized control trials.

Noninvasive measures of brain edema predict outcome in pediatric cerebral malaria

Background:

Increased brain volume (BV) and subsequent herniation are strongly associated with death in pediatric cerebral malaria (PCM), a leading killer of children in developing countries. Accurate noninvasive measures of BV are needed for optimal clinical trial design. Our objectives were to examine the performance of six different magnetic resonance imaging (MRI) BV quantification measures for predicting mortality in PCM and to review the advantages and disadvantages of each method.

Methods:

Receiver operator characteristics were generated from BV measures of MRIs of children admitted to an ongoing research project with PCM between 2009 and 2014. Fatal cases were matched to the next available survivor. A total of 78 MRIs of children aged 5 months to 13 years (mean 4.0 years), of which 45% were males, were included.

Results:

Areas under the curve (AUC) with 95% confidence interval on measures from the initial MRIs were: Radiologist-derived score = 0.69 (0.58–0.79; P = 0.0037); prepontine cistern anteroposterior (AP) dimension = 0.70 (0.56–0.78; P = 0.0133); SamKam ratio [Rt. parietal lobe height/(prepontine AP dimension + fourth ventricle AP dimension)] = 0.74 (0.63–0.83; P = 0.0002); and global cerebrospinal fluid (CSF) space ascertained by ClearCanvas = 0.67 (0.55–0.77; P = 0.0137). For patients with serial MRIs (n = 37), the day 2 global CSF space AUC was 0.87 (0.71–0.96; P < 0.001) and the recovery factor (CSF volume day 2/CSF volume day 1) was 0.91 (0.76–0.98; P < 0.0001). Poor prognosis is associated with radiologist score of ≥7; prepontine cistern dimension ≤3 mm; cisternal CSF volume ≤7.5 ml; SamKam ratio ≥6.5; and recovery factor ≤0.75.

Conclusion:

All noninvasive measures of BV performed well in predicting death and providing a proxy measure for brain volume. Initial MRI assessment may inform future clinical trials for subject selection, risk adjustment, or stratification. Measures of temporal change may be used to stage PCM.

Safety and efficacy of remote ischemic conditioning in pediatric moyamoya disease patients treated with revascularization therapy

BACKGROUND

Revascularization surgery has been the standard treatment to prevent ischemic stroke in pediatric Moyamoya disease (MMD) patients with ischemic symptoms. However, perioperative complications, such as hyperperfusion syndrome, new infarct on imaging, or ischemic stroke, are inevitable. Remote ischemic conditioning (RIC) is a noninvasive and easy-to-use neuroprotective strategy, and it has potential effects on preventing hyperperfusion syndrome and ischemic infarction.

AIMS

The aim of this study is to investigate the safety and efficacy of RIC in pediatric MMD patients undergoing revascularization surgery.

METHOD

A total of 60 pediatric MMD patients with one or more ischemic symptoms will be recruited and allocated in 1:1 ratio to the RIC group and sham group, respectively. Both RIC and sham RIC will be performed twice daily for 7 consecutive days before revascularization surgery with different cuff pressures during the ischemia period (50 mmHg over-systolic blood pressure and 30 mmHg). Single photon emission computed tomography will be performed within 7 days preoperatively and 3 months postoperatively, respectively, to evaluate the cerebral perfusion status. Other outcomes, including safety, plasma biomarker, functional outcome, and the incidence of infarction and its size, will also be evaluated.

CONCLUSION

This study will provide insights into the preliminary proof of principle, safety, and efficacy of RIC in pediatric MMD patients undergoing revascularization surgery therapy, and this data will provide parameters for future larger scale clinical trials if efficacious.

Fibrinogen consumption is related to intracranial clot burden in acute ischemic stroke: a retrospective hyperdense artery study

Background

Understanding the underlying mechanism of thrombus formation and its components is critical for effective prevention and treatment of ischemic stroke. The generation of thrombotic clots requires conversion of soluble fibrinogen to an insoluble fibrin network. Quantitative features of intracranial clots causing acute ischemic stroke can be studied on non-contrast enhanced CT (NECT). Here, we evaluated on-admission fibrinogen and clot burden in relation to stroke severity, final infarct volume and in-hospital mortality.

Methods

We included 132 consecutive patients with ischemic stroke and presence of hyperdense artery sign admitted within 6 h from symptom onset. Radiological parameters including clot area (corresponding to clot burden) and final infarct volume were manually determined on NECT. National Institute of Health Stroke Scale (NIHSS) was used to quantify disease severity and short-term outcome.

Results

Median patient age was 77, 58 % were women, and 63 % had an occlusion of the proximal middle cerebral artery segment. Thrombolysis was performed in 60 % and thrombectomy in 44 %. We identified several independent associations. Higher fibrinogen levels on admission were associated with smaller clot burden (p = 0.033) and lower NIHSS on admission (p = 0.022). Patients with lower fibrinogen had a higher clot burden (p = 0.028) and greater final infarct volume (p = 0.003). Higher fibrinogen was associated with a lower risk of in-hospital death or NIHSS score >15 if discharged alive (p = 0.028).

Conclusions

Our study suggests that intracranial clot burden in acute ischemic stroke is associated with fibrinogen consumption, and shows a complex relationship with disease severity, infarct size and in-hospital survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1006-6) contains supplementary material, which is available to authorized users.

Dynamic contrast-enhanced MRI and CT provide comparable measurement of blood-brain barrier permeability in a rodent stroke model

In the current management of acute ischemic stroke (AIS), clinical criteria are used to estimate the risk of hemorrhagic transformation (HT), which is a devastating early complication. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and computed tomography (DCE-CT) may serve as physiologically-based decision making tools to more reliably assess the risk of HT. Before these tools can be properly validated, the comparability of the blood-brain barrier (BBB) permeability measurements they generate should be assessed. Sixteen rats were subjected to a transient middle cerebral artery occlusion before successively undergoing DCE-CT and DCE-MRI at 24-hours. BBB permeability (K(trans)) values were generated from both modalities. A correlation of R=0.677 was found (p<0.01) and the resulting relationship was [DCE-CT=(0.610*DCE-MRI)+4.140]. A variance components analysis found the intra-rat coefficient of variation to be 0.384 and 0.258 for K(trans) values from DCE-MRI and DCE-CT respectively. Permeability measures from DCE-CT were 22% higher than those from DCE-MRI. The results of this study demonstrate for the first time comparability between DCE-CT and DCE-MRI in the assessment of AIS. These results may provide a foundation for future clinical trials making combined use of these modalities.

Endovascular treatment for M2 occlusions in the era of stentrievers: a descriptive multicenter experience

BACKGROUND

Patients with M2 middle cerebral artery (MCA) occlusions are not always considered for endovascular treatment.

OBJECTIVE

To study outcomes in patients with M2 occlusion treated with endovascular procedures in the era of stentrievers.

METHODS

We studied patients prospectively included in the SONIIA registry (years 2011-2012)-a mandatory, externally audited registry that monitors the quality of reperfusion therapies in Catalonia in routine practice. Good recanalization was defined as postprocedure Thrombolysis in Cerebral Infarction (TICI) score 2b-3; dramatic recovery as drop in National Institutes of Health Stroke Scale (NIHSS) score >10 points or NIHSS score <2 at 24-36 h; and good outcome as modified Rankin score (mRS) 0-2 at 3months. A 24 h CT scan determined symptomatic intracranial hemorrhage (SICH) and infarct volume.

RESULTS

Of 571 patients who received endovascular treatment, 65 (11.4%) presented an M2 occlusion on initial angiogram, preprocedure NIHSS 16 (IQR 6). Mean time from symptom onset to groin puncture was 289 ± 195 min. According to interventionalist preferences 86.2% (n=56) were treated with stentrievers (n=7 in combination with intra-arterial tissue plasminogen activator (tPA), 4.6% (n=3) received intra-arterial tPA only, and 9.2% (n=6) diagnostic angiography only. Good recanalization (78.5%) was associated with dramatic improvement (48% vs 14.8%; p=0.02), smaller infarct volumes (8 vs 82 cc; p=0.01) and better outcome (mRS 0-2: 66.3% vs 30%; p=0.03). SICH (9%) was not associated with treatment modality or device used. After adjusting for age and preprocedure NIHSS, good recanalization emerged as an independent predictor of dramatic improvement (OR=5.9 (95% CI 1.2 to 29.2), p=0.03). Independent predictors of good outcome at 3 months were age ( OR=1.067 (95% CI 1.005 to 1132), p=0.03) and baseline NIHSS ( OR=1.162 (95% CI 1.041 to 1.297), p<0.01).

CONCLUSIONS

Endovascular treatment of M2 MCA occlusion with stentrievers seems safe. Induced recanalization may double the chances of achieving a favorable outcome, especially for patients with moderate or severe deficit.

A Precise Method for Linking Neuroanatomy to Function After Stroke: A Pilot Study

PURPOSE

We examined the hypotheses that a comprehensive method for categorizing specific brain regions impaired by stroke is feasible and that this method may be used to explore associations between specific impaired brain regions and functional outcomes.

METHOD

Impaired brain regions were identified with neuroanatomical diagrams. Body function outcomes (motor, somatosensory, and cognition) were measured with the National Institutes of Health Stroke Scale and activity outcomes (functional mobility, self-care, and instrumental activities of daily living) were measured with the Performance Assessment of Self-care Skills. Decision analyses identified brain regions associated with functional outcomes and the influence of ischemia on outcome scores.

RESULTS

Motor control and somatosensation brain regions were linked with motor and somatosensory outcomes; those associated with decision making and motor planning were linked with cognition and functional mobility outcomes. Data were insufficiently powered to examine brain regions associated with self-care and instrumental activities of daily living outcomes.

CONCLUSION

The findings support the feasibility of study methods. Further investigation with larger, well-defined samples is warranted using study methods.

Automated delineation of stroke lesions using brain CT images

Computed tomographic (CT) images are widely used for the identification of abnormal brain tissue following infarct and hemorrhage in stroke. Manual lesion delineation is currently the standard approach, but is both time-consuming and operator-dependent. To address these issues, we present a method that can automatically delineate infarct and hemorrhage in stroke CT images. The key elements of this method are the accurate normalization of CT images from stroke patients into template space and the subsequent voxelwise comparison with a group of control CT images for defining areas with hypo- or hyper-intense signals. Our validation, using simulated and actual lesions, shows that our approach is effective in reconstructing lesions resulting from both infarct and hemorrhage and yields lesion maps spatially consistent with those produced manually by expert operators. A limitation is that, relative to manual delineation, there is reduced sensitivity of the automated method in regions close to the ventricles and the brain contours. However, the automated method presents a number of benefits in terms of offering significant time savings and the elimination of the inter-operator differences inherent to manual tracing approaches. These factors are relevant for the creation of large-scale lesion databases for neuropsychological research. The automated delineation of stroke lesions from CT scans may also enable longitudinal studies to quantify changes in damaged tissue in an objective and reproducible manner.

•

We present an automated method to detect brain lesions in stroke CT images.

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The method accurately warps CT images of patients (and controls) to template space.

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It detects lesion areas as those having abnormal signal compared to control images.

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It yields lesion maps spatially consistent with those produced by expert operators.

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Large-scale lesion databases for neuropsychological research can be created.

Imaging Biomarkers for Intra-arterial Stroke Therapy

Despite high rates of early revascularization with intra-arterial stroke therapy, the clinical efficacy of this approach has not been clearly demonstrated. Neuroimaging biomarkers will be useful in future trials for patient selection and for outcomes evaluation. To identify patients who are likely to benefit from intra-arterial therapy, the combination of vessel imaging, infarct size quantification and degree of neurologic deficit appears critical. Perfusion imaging may be useful in specific circumstances, but requires further validation. For measuring treatment outcomes, surrogate biomarkers that appear suitable are angiographic reperfusion as measured by the modified Thrombolysis in Cerebral Infarction scale and final infarct volume.

Chronic over-expression of TGFβ1 alters hippocampal structure and causes learning deficits

The cytokine transforming growth factor β1 (TGFβ1) is chronically upregulated in several neurodegenerative conditions, including Alzheimer's disease, Parkinson's disease, Creutzfeldt-Jacob disease, amyotrophic lateral sclerosis and multiple sclerosis, and following stroke. Although previous studies have shown that TGFβ1 may be neuroprotective, chronic exposure to elevated levels of this cytokine may contribute to disease pathology on its own. In order to study the effects of chronic exposure to TGFβ1 in isolation, we used transgenic mice that over-express a constitutively active porcine TGFβ1 in astrocytes. We found that TGFβ1 over-expression altered brain structure, with the most pronounced volumetric increases localized to the hippocampus. Within the dentate gyrus (DG) of the hippocampus, increases in granule cell number and astrocyte size were responsible for volumetric expansion, with the increased granule cell number primarily related to a marked reduction in death of new granule cells generated in adulthood. Finally, these cumulative changes in DG microstructure and macrostructure were associated with the age-dependent emergence of spatial learning deficits in TGFβ1 over-expressing mice. Together, our data indicate that chronic upregulation of TGFβ1 negatively impacts hippocampal structure and, even in the absence of disease, impairs hippocampus-dependent learning.

Automated cerebral infarct volume measurement in follow-up noncontrast CT scans of patients with acute ischemic stroke

BACKGROUND AND PURPOSE

Cerebral infarct volume as observed in follow-up CT is an important radiologic outcome measure of the effectiveness of treatment of patients with acute ischemic stroke. However, manual measurement of CIV is time-consuming and operator-dependent. The purpose of this study was to develop and evaluate a robust automated measurement of the CIV.

MATERIALS AND METHODS

The CIV in early follow-up CT images of 34 consecutive patients with acute ischemic stroke was segmented with an automated intensity-based region-growing algorithm, which includes partial volume effect correction near the skull, midline determination, and ventricle and hemorrhage exclusion. Two observers manually delineated the CIV. Interobserver variability of the manual assessments and the accuracy of the automated method were evaluated by using the Pearson correlation, Bland-Altman analysis, and Dice coefficients. The accuracy was defined as the correlation with the manual assessment as a reference standard.

RESULTS

The Pearson correlation for the automated method compared with the reference standard was similar to the manual correlation (R = 0.98). The accuracy of the automated method was excellent with a mean difference of 0.5 mL with limits of agreement of -38.0-39.1 mL, which were more consistent than the interobserver variability of the 2 observers (-40.9-44.1 mL). However, the Dice coefficients were higher for the manual delineation.

CONCLUSIONS

The automated method showed a strong correlation and accuracy with the manual reference measurement. This approach has the potential to become the standard in assessing the infarct volume as a secondary outcome measure for evaluating the effectiveness of treatment.

Size doesn't matter: cortical stroke lesion volume is not associated with upper extremity motor impairment and function in mild, chronic hemiparesis

OBJECTIVES

To determine (1) the relationship between lesion volume and upper extremity (UE) motor impairment using the UE section of the Fugl-Meyer (FM) assessment; and (2) the relationship between lesion volume and UE functional outcomes using the Arm Motor Ability Test (AMAT) Functional Ability (FA) and Time scales.

DESIGN

Secondary retrospective analysis of randomized controlled trial data.

SETTING

Outpatient rehabilitation clinic.

PARTICIPANTS

Subjects with chronic stroke (N=139, 83 men; mean age ± SD of all subjects, 56.7±11.2y; mean time ± SD since stroke onset, 59.6±65.6mo; 90 subjects with right hemiparesis) and stable, active, distal UE movement.

INTERVENTION

Data were collected related to subjects' lesion volume and UE movement before their participation in a multicenter, randomized controlled trial.

MAIN OUTCOME MEASURES

FM and AMAT.

RESULTS

Neither age nor lesion volume was related to FM performance. The P value for the regression coefficient of lesion volume was .045 in the AMAT FA model and .016 in the AMAT Time model. Lesion volume accounted for only an additional 1.7% (AMAT FA) to 3.1% (AMAT Time) of the variability in motor function and was not clinically meaningful.

CONCLUSIONS

Data suggest no relationship between lesion volume and UE impairment, and a small, clinically insignificant relationship between lesion volume and UE motor function. Stroke causes metabolic changes in intact regions and diffuse structural loss in anatomically remote regions from the infarction. These other factors may account for variance in motor outcomes after stroke.

Clinical-radiological severity mismatch phenomenon: patients with severe neurological deficits without matching infarction on computed tomographic scan

OBJECTIVE

The objective was to determine the long-term outcome of patients with severe persistent neurological deficits without a large infarction on computed tomographic (CT) scan.

METHODS

We analyzed the prospectively collected data as part of the randomized, placebo controlled trial in patients with ischemic stroke presenting within 3 hours of symptom onset. Volume of infarction was measured from CT scan acquired at 3 months. Favorable outcome defined by no significant or slight disability on a modified Rankin scale at 12 months. We determined the outcome of patients with National Institutes of Health Stroke Scale score (NIHSS score) ≥ 10 at 24 hours.

RESULTS

Of the 277 patients with NIHSS score ≥ 10 at 24 hours, 88 (32%) met the criteria of clinical-radiological severity mismatch. Compared with patients with NIHSS score ≥ 10 with infarct volume ≥ 20 cc, the patients with NIHSS score ≥ 10 and infarct volume <20 cc were older but there were no differences in the gender, race or vascular risk factors. Patients with clinical-radiological severity mismatch were more likely to have a favorable outcome at 12 months compared with those without mismatch (odd ratio 4.3, 95% confidence interval 1.5-12.6, P = .0063) after adjusting for potential confounders.

CONCLUSIONS

We observed that approximately one-fourth of patients with severe neurological deficits have clinical-radiological severity mismatch. Such patients appear to have a high rate of favorable outcomes at 1 year.

Preferential effect of premorbid statins on atherothrombotic strokes through collateral circulation enhancement

BACKGROUND/AIMS

Endovascular recanalization therapies are an increasingly used strategy for acute cerebral ischemia with heterogeneous clinical outcomes. We aimed to determine the impact of previous medication on ischemic stroke following intra-arterial revascularization therapy.

METHODS

Consecutive patients receiving intra-arterial reperfusion therapy after an acute intracranial occlusion were analyzed. Premorbid use of antiplatelets, statins, oral antidiabetic drugs, antihypertensive drugs and oral anticoagulants were recorded. Collateral pial circulation (CPC) was scored on initial angiogram.

RESULTS

118 patients were included (mean age 70.4 ± 11 years, 45% female). 66 patients (56%) were cardioembolic, 30 (25%) atherothrombotic, and 22 (19%) other/unknown etiologies. No significant impact of medication was detected in all the series or cardioembolic strokes. However, relevant differences were found among atherothrombotic strokes. The previous use of antiplatelets was associated with smaller infarct volume (64 vs. 170 ml; p = 0.043) whereas premorbid statin predicted reduced infarct volume (64 vs. 215 ml; p = 0.019), clinical improvement (79 vs. 29%; p = 0.016) and good CPC (100 vs. 20%; p = 0.04). Statins were the only medication independently predicting reduced infarct volume and clinical improvement and this effect depended on CPC.

CONCLUSION

Previous use of statins may preferentially benefit patients with atherothrombotic strokes by favoring the development of CPC.

Arterial blood gas analysis of samples directly obtained beyond cerebral arterial occlusion during endovascular procedures predicts clinical outcome

Real-time intra-procedure information about ischemic brain damage degree may help physicians in taking decisions about pursuing or not recanalization efforts.

METHODS

We studied gasometric parameters of blood samples drawn through microcatheter in 16 stroke patients who received endovascular reperfusion procedures. After crossing the clot with microcatheter, blood sample was obtained from the middle cerebral artery (MCA) segment distal to occlusion (PostOcc); another sample was obtained from carotid artery (PreOcc). An arterial blood gas (ABG) study was immediately performed. We defined clinical improvement as National Institutes of Health Stroke Scale (NIHSS) decrease of ≥4.

RESULTS

The ABG analysis showed differences between PreOcc and PostOcc blood samples in mean oxygen partial pressure (Pre-PaO2: 78.9 ± 16 .3 vs. 73.9 ± 14 .9 mmHg; P < .001). Patients who presented clinical improvement had higher Post-PaO2 (81 ± 11 .4 vs. 64.8 ± 14 .4 mmHg; P = .025). A receiver-operator characteristic (ROC) curve determined Post-PaO2 > 70 mmHg that better predicted further clinical improvement. Patients with Post-PaO2 > 70 mmHg had higher chances of clinical improvement (81.8% vs. 0%; P = .002) and lower disability (median mRS:3 vs. 6; P= .024). In the logistic regression the only independent predictor of clinical improvement was Post-PaO2 > 70 (OR: 5.21 95% CI: 1.38-67.24; P = .013).

CONCLUSION

Direct local blood sampling from ischemic brain is feasible during endovascular procedures in acute stroke patients. A gradient in oxygenation parameters was demonstrated between pre- and post-occlusion blood samples. ABG information may be used to predict clinical outcome and help in decision making in the angio-suite.

Interobserver variability in the interpretation of computed tomography following aneurysmal subarachnoid hemorrhage

Object

Numerous abnormal findings may be evident on CT scans after aneurysmal subarachnoid hemorrhage (SAH). Here, the authors assess the interobserver variability in the radiological interpretation of the initial CT scan following SAH.

Methods

Two experienced reviewers, a neurosurgeon and a neuroradiologist, independently prospectively reviewed the initial CT scans of 413 patients enrolled in the CONSCIOUS-1 trial. Measured variables included SAH, intraventricular hemorrhage, intracerebral hemorrhage, subdural hematoma, chronic infarction, midline shift, and hydrocephalus. To assess interobserver variability, weighted kappa values and intraclass correlation coefficients (ICCs) were calculated and Bland-Altman analysis was performed.

Results

Moderate to substantial agreement was found for most of the CT scanning findings. There was fair to moderate interobserver agreement between reviewers when determining the extent of SAH based on a descriptive categorical classification (kappa 0.41; 95% CI 0.33–0.49), and better agreement when a semiquantitative scale was used (ICC 0.56; 95% CI 0.49–0.62). There was poor agreement between reviewers for the presence of hydrocephalus (kappa 0.34; 95% CI 0.20–0.48), but substantial to near perfect agreement on ventriculocranial ratio measurements (ICC 0.77; 95% CI 0.72–0.81).

Conclusions

The authors' findings suggest that there is considerable interobserver variability in the interpretation of CT scans after SAH. Quantitative measures may reduce interobserver variability in comparison with qualitative or categorical scales. Variability in interpretation of CT scans has implications for patient care and conduct of clinical trials. It may be beneficial to develop standardized assessments to ensure consistent evaluation of measured variables.

Hemorrhagic transformation in acute cerebellar infarction

BACKGROUND

Hemorrhagic transformation (HT) is a well-known consequence of acute ischemic stroke, but little is known about HT in cerebellar infarction.

METHODS

Patients with acute cerebellar infarction within 48 h of onset were retrospectively recruited. MRI, including diffusion-weighted imaging (DWI) and T(2)*-gradient echo imaging (T(2)*), was performed twice (upon admission and 2 weeks after stroke onset). Infarct diameter and volume were measured by manual tracing on initial DWI. HT was evaluated with follow-up T(2)*, and all patients were divided into two groups according to the presence of HT (HT group and non-HT group). The frequency of HT and the factors associated with HT were investigated.

RESULTS

Ninety-six patients (64 males, median age 74 years, IQR 65-81 years, and National Institute of Health Stroke Scale score 5, IQR 1-14) were enrolled. Forty-two patients (43%) showed HT on follow-up T(2)* (HT group). Infarct diameter and volume were larger in the HT group than in the non-HT group (3.2 vs. 1.6 cm, respectively, p < 0.001, for infarct diameter and 8.0 vs. 1.7 cm(3), respectively, p < 0.001 for infarct volume). Multivariate logistic regression analysis revealed that both infarct diameter >2.7 cm (OR 7.58, 95% CI 2.82-20.4, p < 0.001) and volume >4.5 cm(3) (OR 11.5, 95% CI 3.80-34.8, p < 0.001) were independent factors associated with HT.

CONCLUSIONS

Half of the patients with acute cerebellar infarcts had HT on follow-up T(2)*. Initial infarct diameter and volume on DWI were independent factors associated with HT.

Improvement in aphasia scores after stroke is well predicted by initial severity

BACKGROUND AND PURPOSE

Most improvement from poststroke aphasia occurs within the first 3 months, but there remains unexplained variability in recovery. Recently, we reported a strong correlation between initial impairment and change scores in motor recovery at 90 days. We wanted to determine whether aphasia recovery (defined as a change from baseline to 90 days) shows a comparably strong correlation and whether the relation was similar to that in motor recovery.

METHODS

Twenty-one stroke patients had aphasia scores on the Western Aphasia Battery (WAB) obtained on stroke admission (WAB(initial)) and at 90 days (WAB(3 mo)). The relation between actual change (Delta) scores (defined as WAB(3 mo)- WAB(initial)) and WAB(initial) was calculated in multiple-regression analysis.

RESULTS

Regression analysis demonstrated that WAB(initial) was highly correlated with DeltaWAB (R(2)=0.81, P<0.001) and that, in addition, the relation between WAB(initial) and DeltaWAB was proportional, such that patients recovered 0.73 of maximal potential recovery (WAB(maximum)-WAB(initial)).

CONCLUSIONS

We show that, like motor recovery, there is a highly predictable relation between aphasia recovery and initial impairment, which is also proportional in nature. The comparability of recovery from motor and language impairment suggests that common mechanisms may govern reduction of poststroke neurologic impairment across different functional domains and that they could be the focus of therapeutic intervention.

Volumetric effects of motor cortex injury on recovery of dexterous movements

Due to the heterogeneous nature of most brain injuries, the contributions of gray and white matter involvement to motor deficits and recovery potential remain obscure. We tested the hypothesis that duration of hand motor impairment and recovery of skilled arm and hand motor function depends on the volume of gray and white matter damage of the frontal lobe. Lesions of the primary motor cortex (M1), M1 + lateral premotor cortex (LPMC), M1 + LPMC + supplementary motor cortex (M2) or multifocal lesions affecting motor areas and medial prefrontal cortex were evaluated in rhesus monkeys. Fine hand motor function was quantitatively assessed pre-lesion and for 3-12 months post-lesion using two motor tests. White and gray matter lesion volumes were determined using histological and quantitative methods. Regression analyses showed that duration of fine hand motor impairment was strongly correlated (R(2)>0.8) with the volume of gray and white matter lesions, with white matter lesion volume being the primary predictor of impairment duration. Level of recovery of fine hand motor skill was also well correlated (R(2)>0.5) with gray and white matter lesion volume. In some monkeys post-lesion skill exceeded pre-lesion skill in one or both motor tasks demonstrating that continued post-injury task practice can improve motor performance after localized loss of frontal motor cortex. These findings will assist in interpreting acute motor deficits, predicting the time course and expected level of functional recovery, and designing therapeutic strategies in patients with localized frontal lobe injury or neurosurgical resection.

Higher mean platelet volume determined shortly after the symptom onset in acute ischemic stroke patients is associated with a larger infarct volume on CT brain scans and with worse clinical outcome

OBJECTIVE

Mean platelet volume (MPV) determined shortly after the onset of acute ischemic stroke represents the pre-stroke values. Data on its relationship to stroke severity/outcome have been conflicting. We related MPV to infarct volume on CT brain scans and risk of death/dependence 7 days and 3 months post-stroke.

METHODS

MPV (within 30h since stroke onset), infarct volume (13-83h since stroke onset) and clinical outcomes were evaluated in 81 consecutive patients (32 men, age 52-91 years, 10 small artery occlusion, 10 large artery atherosclerosis, 29 cardioembolic, 32 multiple probable/possible etiology).

RESULTS

Higher MPV was independently associated with larger ln-infarct volume [estimate 0.259, 95% confidence interval (CI) 0.004-0.513, P=0.046], greater risk of death/dependence 7 days post-stroke [relative risk (RR)=1.077, 95% CI 1.005-1.115, P=0.036], and greater risk of death/dependence 3 months post-stroke (RR=1.077, 95% CI 1.001-1.158, P=0.048). Considered covariates: stroke etiology, CT scan timing, platelet count and other hematological parameters, demographic variables, history of cerebrovascular, cardiac or cardiovascular diseases, diabetes, serum chemistry, previous antiplatelet and statin use and treatments delivered after the index event.

CONCLUSIONS

Data support the view about MPV as a determinant of severity/outcome of the acute ischemic stroke.

Reproducibility over a 1-month period of 1H-MR spectroscopic imaging NAA/Cr ratios in clinically stable multiple sclerosis patients

N-acetylaspartate/creatine (NAA/Cr) ratios, assessed with proton magnetic resonance spectroscopy, are increasingly used as a surrogate marker for axonal dysfunction and degeneration in multiple sclerosis (MS). The purpose of this study was to test short-time reproducibility of NAA/Cr ratios in patients with clinically stable MS. In 35 MS patients we analysed NAA/Cr ratios obtained with ¹H-MR spectroscopic imaging at the centrum semiovale either with lateral ventricles partially included (group 1; n=15) or more cranially with no ventricles included (group 2; n=20). To test short-term reproducibility of the NAA/Cr measurements, patients were scanned twice 4 weeks apart. We determined mean NAA/Cr and Cho/Cr ratios of 12 grey matter and 24 white matter voxels. Mean NAA/Cr ratios of both the white and grey matter did not change after 4 weeks. Overall 4-week reproducibility of the NAA/Cr ratio, expressed as coefficient of variation, was 4.8% for grey matter and 3.5% for white matter. Reproducibility of cranial scanning of the ventricles was slightly better than with cerebrospinal fluid included. Our study shows good short-term reproducibility of NAA/Cr ratio measurements in the centrum semiovale, which supports the reliability of this technique for longitudinal studies.

Inter-individual variability in the capacity for motor recovery after ischemic stroke

BACKGROUND

Motor recovery after stroke is predicted only moderately by clinical variables, implying that there is still a substantial amount of unexplained, biologically meaningful variability in recovery. Regression diagnostics can indicate whether this is associated simply with Gaussian error or instead with multiple subpopulations that vary in their relationships to the clinical variables.

OBJECTIVE

To perform regression diagnostics on a linear model for recovery versus clinical predictors.

METHODS

Forty-one patients with ischemic stroke were studied. Impairment was assessed using the upper extremity Fugl-Meyer Motor Score. Motor recovery was defined as the change in the upper extremity Fugl-Meyer Motor Score from 24 to 72 hours after stroke to 3 or 6 months later. The clinical predictors in the model were age, gender, infarct location (subcortical vs cortical), diffusion weighted imaging infarct volume, time to reassessment, and acute upper extremity Fugl-Meyer Motor Score. Regression diagnostics included a Kolmogorov-Smirnov test for Gaussian errors and a test for outliers using Studentized deleted residuals.

RESULTS

In the random sample, clinical variables explained only 47% of the variance in recovery. Among the patients with the most severe initial impairment, there was a set of regression outliers who recovered very poorly. With the outliers removed, explained variance in recovery increased to 89%, and recovery was well approximated by a proportional relationship with initial impairment (recovery congruent with 0.70 x initial impairment).

CONCLUSIONS

Clinical variables only moderately predict motor recovery. Regression diagnostics demonstrated the existence of a subpopulation of outliers with severe initial impairment who show little recovery. When these outliers were removed, clinical variables were good predictors of recovery among the remaining patients, showing a tight proportional relationship to initial impairment.

Measurement of reaching kinematics and prehensile dexterity in nonhuman primates

A modified "Klüver" or dexterity board was developed to assess fine control of hand and digit movements by nonhuman primates during the acquisition of small food pellets from wells of different diameter. The primary advantages of the new device over those used previously include standardized positioning of target food pellets and controlled testing of each hand without the need for restraints, thereby allowing the monkey to move freely about the cage. Three-dimensional video analysis of hand motion was used to provide measures of reaching accuracy and grip aperture, as well as temporal measures of reach duration and food-pellet manipulation. We also present a validated performance score based on these measures, which serves as an indicator of successful food-pellet retrieval. Tests in three monkeys show that the performance score is an effective measure with which to study fine motor control associated with learning and handedness. We also show that the device and performance scores are effective for differentiating the effects of localized injury to motor areas of the cerebral cortex.

Cognitive Disorders in Acute Stroke: Prevalence and Clinical Determinants

BACKGROUND

Although cognitive impairment early after stroke is a powerful predictor of long-term functional dependence and dementia, little is known about the characteristics and determinants of cognitive dysfunction in acute stroke.

METHODS

We administered a neuropsychological examination covering 7 cognitive domains to 190 patients within 3 weeks after a first stroke. We also assembled lesion characteristics, clinical factors at admission, demographic characteristics and vascular risk factors. Multivariate logistic regression adjusted for age, gender and education was performed to examine determinants of acute cognitive impairment.

RESULTS

Overall, 74% of patients with a cortical stroke, 46% with a subcortical stroke and 43% with an infratentorial stroke demonstrated acute cognitive impairment. Disorders in executive functioning (39%) and visual perception/construction (38%) were the most common. The prevalence and severity of deficits in executive functioning, language, verbal memory and abstract reasoning was more pronounced following left compared to right cortical stroke (all p < 0.05). Intracerebral haemorrhage (OR = 5.6; 95% CI = 1.2-25.4) and cortical involvement of the stroke (OR = 3.6; 95%, CI = 1.3-9.9) were independent determinants of acute cognitive impairment, whereas premorbid moderate alcohol consumption exerted a protective effect (OR = 0.4; 95% CI = 0.1-1.1).

CONCLUSIONS

Cognitive impairment is common in the first weeks after stroke, with executive and perceptual disorders being the most frequent. Intracerebral haemorrhage, cortical involvement of the lesion and premorbid moderate alcohol consumption are independently associated with acute cognitive impairment.

Predictive value of ischemic lesion volume assessed with magnetic resonance imaging for neurological deficits and functional outcome poststroke: A critical review of the literature

OBJECTIVE

Ischemic lesion volume is assumed to be an important predictor of poststroke neurological deficits and functional outcome. This critical review examines the methodological quality of MRI studies and the predictive value of hemispheric infarct volume for neurological deficits (at body function level) and functional outcome (at activities level).

METHODS

Using Medline, PiCarta, and Embase to identify studies, 13 of the 747 identified studies met the authors' inclusion criteria. Subsequently, studies were tested for adherence to the key methodological criteria for internal, statistical, and external validity. Each criterion was weighted binary, and studies with 6 points or more were judged to be valid for assessing the predictive value of MRI for outcome.

RESULTS

The 13 included studies had several methodological weaknesses with respect to internal validity, and none of them took lesion location into account. Only a few used outcome measures according to the International Classification of Functioning, Disability and Health and followed patients beyond 6 months. Correlation coefficients between MRI lesion volume and outcomes were higher for outcomes defined at body function level (National Institutes of Health Stroke Scale; median 0.67; range: 0.57-0.91) than for those defined at the level of activities (Barthel Index; median -0.49; range: -0.33 to -0.74).

CONCLUSIONS

Methodological shortcomings of most studies confound the prognostic value of MRI in predicting stroke outcome, and few studies have focused on functional outcome. Future studies should investigate the added value of MRI volume over clinical neurological variables in predicting functional outcome beyond 6 months poststroke.

Comparison of Three Methods for the Estimation of Total Intracranial Volume

There is a well-known close relationship between the total intracranial volume (TIV) and the brain size. Several studies in different countries have estimated the cranial capacity, which indirectly reflects the brain volume. However, we have not seen a study evaluating the results of the methodologies for the assessment of TIV. This study was carried out on 30 normal subjects whose ages ranged between 19 and 77 years old (males, 18; females, 12). Three different methods were used to assess the TIV. The mean (+/-SD) estimated TIV using linear dimensions method in males and females were 1416.8 +/- 64 cm and 1291.9 +/- 152 cm, respectively. The mean estimated TIV using point counting method in males and females was 1474 +/- 93 cm and 1252 +/- 72 cm, respectively. By using the planimetric method of the mean and SD of TIV, male and females were 1492.1 +/- 74 cm and 1319.6 +/- 100 cm, respectively. There were no statistical difference between TIV measurements obtained using the optimized stereologic technique and planimetry (P > 0.05). TIV between males and females was statistically significant (P < 0.001). This study showed that there are minor differences among the given 3 distinct methods. With the disadvantage of requiring more time to apply, the planimetry and point counting methods provide more assumption-free results than the anthropometric approach. However, the anthropometric method can be applied to assess TIV without needing sophisticated tools.

Prognostic significance of plasma resistin levels in patients with atherothrombotic ischemic stroke

BACKGROUND

Resistin (RSN) is an adipocytokine involved in insulin resistance, obesity and atherosclerosis. This study aimed to investigate the association between plasma RSN and outcome after ischemic stroke.

METHODS

RSN measured within 24 h after the event was related to functional outcome and 5-year survival in 211 subjects with first-ever atherothrombotic ischemic stroke. Prognosis was assessed by the Kaplan Meier and the Cox techniques.

RESULTS

The probabilities of death were 80.4%, 46.2% and 15.7% (p<0.001) for patients stratified according to tertiles of RSN (>30 ng/mL, 20-30 ng/mL and<20 ng/mL, respectively). The proportion of dependency (modified Rankin Scale score>or=3) was greater in 5-year survivors with RSN in the upper tertile (6/11 [54.5%]) compared to the middle (20/56 [35.7%]) and the lowest tertile (8/43 [18.6%]; p<0.01). C-reactive protein levels (hazard ratio [HR] 3.96 [95% CI 2.06, 8.91]; p<0.001), coronary heart disease (2.69 [1.62, 6.23]; p<0.001), RSN levels (2.12 [1.31, 5.08] p<0.001), National Institute of Health Stroke Scale score (2.02 [1.23, 4.49]; p<0.01) and age (1.84 [1.19, 3.93]; p<0.01) were independent predictors of death.

CONCLUSIONS

High plasma RSN appears to be associated with increased risk of 5-year mortality or disability after atherothrombotic ischemic stroke, independently of other adverse predictors.

Hemicraniectomy after middle cerebral artery infarction with life-threatening Edema trial (HAMLET). Protocol for a randomised controlled trial of decompressive surgery in space-occupying hemispheric infarction

Background

Patients with a hemispheric infarct and massive space-occupying brain oedema have a poor prognosis. Despite maximal conservative treatment, the case fatality rate may be as high as 80%, and most survivors are left severely disabled. Non-randomised studies suggest that decompressive surgery reduces mortality substantially and improves functional outcome of survivors. This study is designed to compare the efficacy of decompressive surgery to improve functional outcome with that of conservative treatment in patients with space-occupying supratentorial infarction

Methods

The study design is that of a multi-centre, randomised clinical trial, which will include 112 patients aged between 18 and 60 years with a large hemispheric infarct with space-occupying oedema that leads to a decrease in consciousness. Patients will be randomised to receive either decompressive surgery in combination with medical treatment or best medical treatment alone. Randomisation will be stratified for the intended mode of conservative treatment (intensive care or stroke unit care). The primary outcome measure will be functional outcome, as determined by the score on the modified Rankin Scale, at one year.