Magnetic Resonance Imaging Infarct Research Articles

Biological and Procedural Predictors of Outcome in the Stroke Preclinical Assessment Network (SPAN) Trial.

The SPAN trial (Stroke Preclinical Assessment Network) is the largest preclinical study testing acute stroke interventions in experimental focal cerebral ischemia using endovascular filament middle cerebral artery occlusion (MCAo). Besides testing interventions against controls, the prospective design captured numerous biological and procedural variables, highlighting the enormous heterogeneity introduced by the multicenter structure that might influence stroke outcomes. Here, we leveraged the unprecedented sample size achieved by the SPAN trial and the prospective design to identify the biological and procedural variables that affect experimental stroke outcomes in transient endovascular filament MCAo. The study cohort included all mice enrolled and randomized in the SPAN trial (N=1789). Mice were subjected to 60-minute MCAo and followed for a month. Thirteen biological and procedural independent variables and 4 functional (weight loss and 4-point neuroscore on days 1 and 2, corner test on days 7 and 28, and mortality) and 3 tissue (day 2, magnetic resonance imaging infarct volumes and swelling; day 30, magnetic resonance imaging tissue loss) outcome variables were prospectively captured. Multivariable regression with stepwise elimination was used to identify the predictors and their effect sizes. Older age, active circadian stage at MCAo, and thinner and longer filament silicone tips predicted higher mortality. Older age, larger body weight, longer anesthesia duration, and longer filament tips predicted worse neuroscores, while high-fat diet and blood flow monitoring predicted milder neuroscores. Older age and a high-fat diet predicted worse corner test performance. While shorter filament tips predicted more ipsiversive turning, longer filament tips appeared to predict contraversive turning. Age, sex, and weight interacted when predicting the infarct volume. Older age was associated with smaller infarcts on day 2 magnetic resonance imaging, especially in animals with larger body weights; this association was most conspicuous in females. High-fat diet also predicted smaller infarcts. In contrast, the use of cerebral blood flow monitoring and more severe cerebral blood flow drop during MCAo, longer anesthesia, and longer filament tips all predicted larger infarcts. Bivariate analyses among the dependent variables highlighted a disconnect between tissue and functional outcomes. Our analyses identified variables affecting endovascular filament MCAo outcome, an experimental stroke model used worldwide. Multiple regression refuted some commonly reported predictors and revealed previously unrecognized associations. Given the multicenter prospective design that represents a sampling of real-world conditions, the degree of heterogeneity mimicking clinical trials, the large number of predictors adjusted for in the multivariable model, and the large sample size, we think this is the most definitive analysis of the predictors of preclinical stroke outcome to date. Future multicenter experimental stroke trials should standardize or at least ensure a balanced representation of the biological and procedural variables identified herein as potential confounders.

Cardiovascular disease risk exacerbates brain aging among Hispanic/Latino adults in the SOL-INCA-MRI Study.

Cardiovascular disease (CVD) risk factors are highly prevalent among Hispanic/Latino adults, while the prevalence of MRI infarcts is not well-documented. We, therefore, sought to examine the relationships between CVD risk factors and infarcts with brain structure among Hispanic/Latino individuals. Participants included 1,886 Hispanic/Latino adults (50-85 years) who underwent magnetic resonance imaging (MRI) as part of the Study of Latinos-Investigation of Neurocognitive Aging-MRI (SOL-INCA-MRI) study. CVD risk was measured approximately 10.5 years before MRI using the Framingham cardiovascular risk score, a measure of 10-year CVD risk (low (<10%), medium (10- < 20%), and high (≥20%)). MR infarcts were determined as present or absent. Outcomes included total brain, cerebral and lobar cortical gray matter, hippocampal, lateral ventricle, and total white matter hyperintensity (WMH) volumes. Linear regression models tested associations between CVD risk and infarct with MRI outcomes and for modifications by age and sex. Sixty percent of participants were at medium or high CVD risk. Medium and high CVD risk were associated with lower total brain and frontal gray matter and higher WMH volumes compared to those with low CVD risk. High CVD risk was additionally associated with lower total cortical gray matter and parietal volumes and larger lateral ventricle volumes. Men tended to have greater CVDRF-related differences in total brain volumes than women. The association of CVD risk factors on total brain volumes increased with age, equal to an approximate 7-year increase in total brain aging among the high-CVD-risk group compared to the low-risk group. The presence of infarct(s) was associated with lower total brain volumes, which was equal to an approximate 5-year increase in brain aging compared to individuals without infarcts. Infarcts were also associated with smaller total cortical gray matter, frontal and parietal volumes, and larger lateral ventricle and WMH volumes. The high prevalence of CVD risk among Hispanic/Latino adults may be associated with accelerated brain aging.

Magnetic Resonance Imaging Assists With Determining Etiology After Transient Ischemic Attack or Minor Stroke.

Magnetic resonance imaging infarct topography may assist with determining stroke etiology. The influence of diffusion-weighted imaging (DWI)-positive lesions on etiology determination in patients with transient ischemic attack or minor stroke is not well studied. We prospectively enrolled patients between 2010 and 2017 in 2 studies; participants with a final diagnosis of probable or definite transient ischemic attack or stroke were pooled for analysis. The primary outcome was the adjudicated ischemic etiology. We compared proportion of each etiology (cardioembolic, large-vessel, small-vessel disease, other) in patients who had DWI positivity compared with DWI negativity. We used logistic regression to determine the adjusted odds ratio (OR) for each etiology compared with undetermined by DWI positivity. The final analysis included 1498 patients: 832 (55.5%) were DWI-positive. DWI-positive patients were more likely to be diagnosed with small-vessel disease (19.1% versus 5.3%) and less likely with undetermined etiology (36.9% versus 53.0%; P<0.001). After adjustment, the presence of any DWI lesion was associated with increased odds of assigning any etiology (OR, 1.8 [95% CI, 1.3-2.5]). A single DWI lesion was associated with increased odds of small-vessel disease diagnosis (OR, 9.5 [95% CI, 6.4-14.0]), and multiple DWI lesions with reduced odds of small-vessel disease (OR, 0.2 [95% CI, 0.1-0.4]) but increased odds of all other etiologies compared with undetermined etiology. Any DWI-positive lesion after suspected transient ischemic attack or minor stroke was associated with increased odds of assigning a etiology. Presence and topography of DWI lesions on magnetic resonance imaging may assist with etiology determination and may impact stroke prevention therapies.

Magnetic Resonance Imaging Infarct Volume Correlates with Carotid Intima-Media Thickness and Plaque Echotexture in Ischemic Stroke.

To determine the correlation between cerebral infarct volume, carotid intima-media thickness (CIMT), and plaque echotexture in patients with ischemic stroke. This was a cross-sectional study of 70 patients with ischemic stroke who were imaged using the head coil of a 1.5T Toshiba magnetic resonance machine. The volumes of infarcts were documented and calculated using the manual tracing of the infarct perimeter method. The common carotid CIMT was measured on ultrasound using a linear high-frequency 7.5 MHz transducer. Seventy subjects were evaluated. The mean magnetic resonance imaging cerebral infarct volume was 8.07% volume. Hyperechoic plaques were the most prevalent (36.7%) compared to the hypoechoic (33.3%) and isoechoic (30%) plaques. There was a moderate positive correlation between CIMT and infarct volume (r = 0.70; P = 0.001) in the entire study population. Similarly, positive correlations between CIMT and infarct volume were recorded in both the male (r = 0.73; P = 0.001) and female (r = 0.67; P = 0.001) subjects. Furthermore, subjects who presented in the acute phase (1-3 days) of ictus showed a moderate positive correlation (r = 0.621; P = 0.0001) between CIMT and infarct volume, while there was a strong positive correlation (r = 0.74; P = 0.0001) in subjects that presented in the subacute phase (4-7 days). Common carotid artery CIMT correlated positively with cerebral infarct volume in patients with ischemic stroke. Furthermore, hyperechoic plaques were associated with significantly larger infarct volumes compared to hypoechoic and isoechoic plaques.

Predictive Value of Different Computed Tomography Perfusion Software Regarding 90-Day Outcome of Acute Ischemic Stroke Patients After Endovascular Treatment: A Comparison With Magnetic Resonance Imaging.

This study compared ischemic core and penumbra volumes obtained using different computed tomography perfusion (CTP) software and evaluated the predictive value of CTP and magnetic resonance imaging (MRI) results for 90-day outcomes. In total, 105 acute ischemic stroke patients who underwent endovascular treatment from January 2016 to December 2020 were included. Patients were divided into good and poor outcome groups by a modified Rankin Scale score. Computed tomography perfusion core and penumbra volumes were obtained using OleaSphere and Vitrea software to assess the volumetric relationship with MRI using the Spearman correlation test, intraclass correlation coefficient (ICC), and Bland-Altman plot. Three multivariable models were developed: baseline variables with MRI infarct volume, baseline variables with OleaSphere core volume, and baseline variables with Vitrea core volume. The area under the receiver operating characteristic curve of the 3 models was compared using the DeLong test. Median core volumes were 27.5, 26.9, and 31.1 mL for OleaSphere, Vitrea, and MRI, respectively. There was substantial correlation and excellent agreement between OleaSphere and MRI core volume ( ρ = 0.84, P < 0.001; ICC = 0.84) and Vitrea and MRI core volume ( ρ = 0.80, P < 0.001; ICC = 0.83). The areas under curve for MRI volume, OleaSphere, and Vitrea were 0.86, 0.84, and 0.83, respectively. There were no significant differences ( P = 0.18) between the predictive value of the 3 models. Computed tomography perfusion core volumes showed substantial correlation and excellent agreement with MRI. There was no significant difference in the predictive value of the 3 models, suggesting that core volumes measured using CTP software can predict patient prognosis.

Patent Foramen Ovale Closure Decreases the Incidence but Not the Size of New Brain Infarction on Magnetic Resonance Imaging: An Analysis of the REDUCE Trial.

Randomized patent foramen ovale closure trials have used open-label end point ascertainment which increases the risk of bias and undermines confidence in the conclusions. The Gore REDUCE trial prospectively performed baseline and follow-up magnetic resonance imaging (MRIs) for all subjects providing an objective measure of the effectiveness of closure. We performed blinded evaluations of the presence, location, and volume of new infarct on diffusion-weighted imaging of recurrent clinical stroke or new infarct (>3 mm) on T2/fluid attenuated inversion recovery from baseline to follow-up MRI at 2 years, comparing closure to medical therapy alone. We also examined the effect of shunt size and the development of atrial fibrillation on infarct burden at follow-up. At follow-up, new clinical stroke or silent MRI infarct occurred in 18/383 (4.7%) patients who underwent closure and 19/177 (10.7%) medication-only patients (relative risk, 0.44 [95% CI, 0.24–0.81], P=0.02). Clinical strokes were less common in closure patients compared with medically treated patients, 5 (1.3%) versus 12 (6.8%), P=0.001, while silent MRI infarcts were similar, 13 (3.4%) versus 7 (4.0%), P=0.81. There were no differences in number, volumes, and distribution of new infarct comparing closure patients to those treated with medication alone. There were also no differences of number, volumes, and distribution comparing silent infarcts to clinical strokes. Infarct burden was also similar for patients who developed atrial fibrillation and for those with large shunts. The REDUCE trial demonstrates that patent foramen ovale closure prevents recurrent brain infarction based on the objective outcome of new infarcts on MRI. Only clinical strokes were reduced by closure while silent infarctions were similar between study arms, and there were no differences in infarct volume or location comparing silent infarcts to clinical strokes. URL: https://www.clinicaltrials.gov; Unique identifier: NCT00738894.

Associations between cerebral magnetic resonance imaging infarct volume and acute ischemic stroke etiology.

BackgroundIdentifying ischemic stroke etiology is necessary for proper treatment and secondary prevention. We sought to define associations between infarct volume and stroke subtypes.Materials and methodsInclusion criteria necessitated a Johns Hopkins Hospital inpatient admission (2017–2019) for ischemic stroke with confirmatory brain magnetic resonance imaging. Infarct volume was calculated using MRIcron© by a masked reviewer. Ischemic strokes were adjudicated using TOAST classification. Multivariable/multinomial logistic regression determined associations between infarct volume and stroke subtypes with interaction terms for infarct number and location. Stepwise adjustment accounted for potential confounders.ResultsPatients (N = 150) were on average 61 years old, male (58%), and black (57%). Each 5mL increase in infarct volume was associated with cardioembolic (OR 1.07, 95%CI 1.01–1.14) and large-artery occlusions (OR 1.10, 95%CI 1.02–1.18), but lower odds of lacunar stroke (OR 0.18, 95%CI 0.06–0.55). There was no difference in risk of cardioembolic (base) and large-artery atherosclerotic strokes with increasing infarct volume (RRR 1.01, 95%CI 0.94–1.09), but risk of lacunar stroke was decreased (RRR 0.17, 95%CI 0.06–0.53). Infarct number (single vs multiple) modified the association between volume and subtype for large-artery occlusions (p-interaction 0.09).ConclusionsIn this study, larger volume infarcts were significantly associated with both cardioembolic and large-artery atherosclerotic strokes (no difference in the degree of association) and decreased odds of lacunar stroke. A single, large-volume stroke was associated with large-artery atherosclerosis, while multiple infarcts were associated with cardioembolism. Given the differential associations between volume, number of lesions, and stroke etiology, defining stroke subtypes in light of infarct volume might aid in clinical practice.

Penumbra Consumption Rates Based on Time-to-Maximum Delay and Reperfusion Status: A Post Hoc Analysis of the DEFUSE 3 Trial

In patients with acute large vessel occlusion, the natural history of penumbral tissue based on perfusion time-to-maximum (Tmax) delay is not well established in relation to late-window endovascular thrombectomy. In this study, we sought to evaluate penumbra consumption rates for Tmax delays in patients with large vessel occlusion evaluated between 6 and 16 hours from last known normal. This is a post hoc analysis of the DEFUSE 3 trial (The Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke), which included patients with an acute ischemic stroke due to anterior circulation occlusion within 6 to 16 hours of last known normal. The primary outcome is percentage penumbra consumption, defined as (24-hour magnetic resonance imaging infarct volume-baseline core infarct volume)/(Tmax 6 or 10 s volume-baseline core volume). We stratified the cohort into 4 categories based on treatment modality and Thrombolysis in Cerebral Infarction (TICI score; untreated, TICI 0-2a, TICI 2b, and TICI3) and calculated penumbral consumption rates in each category. We included 141 patients, among whom 68 were untreated. In the untreated versus TICI 3 patients, a median (interquartile range) of 53.7% (21.2%-87.7%) versus 5.3% (1.1%-14.6%) of penumbral tissue was consumed based on Tmax >6 s (P<0.001). In the same comparison for Tmax>10 s, we saw a difference of 165.4% (interquartile range, 56.1%-479.8%) versus 25.7% (interquartile range, 3.2%-72.1%; P<0.001). Significant differences were not demonstrated between untreated and TICI 0-2a patients for penumbral consumption based on Tmax >6 s (P=0.52) or Tmax >10 s (P=0.92). Among extended window endovascular thrombectomy patients, Tmax >10-s mismatch volume may comprise large volumes of salvageable tissue, whereas nearly half the Tmax >6-s mismatch volume may remain viable in untreated patients at 24 hours.

Intracoronary injection of haematopoietic precursor cells regenerates the borders, but not the core, of old myocardial scars.

AimsCell therapy regenerative potential is hindered by cell access to the infarct zone. We studied function recovery at the scar zone and its impact in global left ventricular function after intracoronary injection of haematopoietic precursor cells.Methods and resultsHaematopoietic precursor cells were obtained by blood apheresis in patients with an old myocardial infarction, and the presence of CD34+ and CD133+ cells was quantified. Left ventricular function, volumes, and infarct zone segmental motion were measured by magnetic resonance imaging (MRI) and echo left ventricular segmental strain (LVSS). The aphaeresis product was administered to 20 patients in the coronary artery responsible for the myocardial infarction. High cell yield in blood aphaeresis product allowed us to inject a high number of cells in most patients. Three patients were excluded because of insufficient CD133+ cell number, and one more patient was excluded because of artefacts in MRI images. The remaining 16 patients were compared with 16 controls. After 1 year, infarct zone reduction was related to the number of CD133+ (R = 0.53; P %3C 0.05) and CD34+ (R = 0.63; P %3C 0.01) cells injected. The number of CD133+ cells injected was also related to an improvement in LVSS (R = 0.62; P %3C 0.01). In turn, scar zone reduction was related to an improvement in LVSS (R = 0.64; P %3C 0.01). End‐diastolic volume showed a reduction at follow‐up in the treated group when compared with control patients. MRI infarct area segments systolic thickness increase improved after treatment in treated patients [expressed as median (interquartile range)] [0.42 (−0.38 to 1.14) vs. 1.06 (−0.10 to 2.12) mm; P %3C 0.01], but not in controls [2.02 (0.75 to 3.4) vs. 1.91 (0.77–3.17) mm; P = not significant (n.s.)]. In cell therapy patients, the borders of the infarct zone, but not the core, showed a significant recovery [proximal rim: 0.48 (−0.18 to 1.33) vs. 1.07 (0.22–2.40) mm; P %3C 0.05, distal rim: 0.75 (0.26–1.40) vs. 1.76 (0.65–2.86) mm; P %3C 0.05, and core: 0.36 (−0.33 to 1.20) vs. 0.60 (−0.18 to 1.62) mm; P = n.s.]. That improvement was not observed in the control group [proximal rim: 1.20 (0.33–2.53) vs. 0.82 (−0.13 to 1.65) mm; P = n.s., distal rim: 1.24 (0.80–1.72) vs. 0.96 (0.19–1.81) mm; P = n.s., and core: 0.30 (−0.42 to 1.64) vs. 0.07 (−0.60 to 1.20) mm; P = n.s.]. Only small size infarcts showed a complete recovery in the cell therapy patients [systolic thickness increase post‐treatment increment in infarcts ≤6 segments vs. >6 segments affected: 0.28 (−0.19 to 0.71) vs. −1.21 (−2.60 to −0.53) mm; P %3C 0.01].ConclusionsIntracoronary injection of peripheral blood‐derived haematopoietic precursor cells produces a complete recovery of the borders and partial regeneration of the infarct core, which is directly related to the number of CD133+ and CD34+ cells injected. Cell therapy infarct zone regeneration prevents ventricular remodelling by preserving segmental contractility and halting left ventricular dilatation.

Infarct Volume Before Hemicraniectomy in Large Middle Cerebral Artery Infarcts Poorly Predicts Catastrophic Outcome.

Infarct volumes predict malignant infarcts in patients undergoing decompressive hemicraniectomy (DH) for large middle cerebral artery territory infarcts. The aim of the study was to determine the optimal magnetic resonance imaging infarct volume threshold that predicts a catastrophic outcome at 1 year (modified Rankin Scale score of 5 or death). We included consecutive patients who underwent DH for large middle cerebral artery infarcts. We analyzed infarct volumes before DH with semi-automated methods on b1000 diffusion-weighted imaging sequences and apparent diffusion coefficient maps. We studied infarct volume thresholds for prediction of catastrophic outcomes, and analyzed sensitivity, specificity, and the area under the curve, a value ≥0.70 indicating an acceptable prediction. Of 173 patients (109 men, 63%; median age 53 years), 42 (24.3%) had catastrophic outcomes. Magnetic resonance imaging b1000 diffusion-weighted imaging and apparent diffusion coefficient infarct volumes were associated to the occurrence of 1-year catastrophic outcome (adjusted odds ratio, 9.17 [95% CI, 2.00-42.04] and odds ratio, 4.18 [95% CI, 1.33-13.19], respectively, per 1 log increase). The optimal volume cutoff of were 211 mL on b1000 diffusion-weighted imaging and 181 mL on apparent diffusion coefficient maps. The 2 methods showed similar sensitivities and specificities and overlapping area under the curve of 0.64 (95% CI, 0.54-0.74). In patients with large middle cerebral artery infarcts, optimal magnetic resonance imaging infarct volume thresholds showed poor accuracy and low specificity to predict 1-year catastrophic outcome, with different b1000 diffusion-weighted imaging and apparent diffusion coefficient thresholds. In the setting of DH, optimal infarct volumes alone should not be used to deny DH, irrespectively of the method used.

Effect of computed tomography perfusion post-processing algorithms on optimal threshold selection for final infarct volume prediction.

In acute ischemic stroke (AIS) patients, eligibility for endovascular intervention is commonly determined through computed tomography perfusion (CTP) analysis by quantifying ischemic tissue using perfusion parameter thresholds. However, thresholds are not uniform across all analysis methods due to dependencies on patient demographics and computational algorithms. This study aimed to investigate optimal perfusion thresholds for quantifying infarct and penumbra volumes using two post-processing CTP algorithms: Vitrea Bayesian and singular value decomposition plus (SVD+). We utilized 107 AIS patients (67 non-intervention patients and 40 successful reperfusion of thrombolysis in cerebral infarction (2b/3) patients). Infarct volumes were predicted for both post-processing algorithms through contralateral hemisphere comparisons using absolute time-to-peak (TTP) and relative regional cerebral blood volume (rCBV) thresholds ranging from +2.8 seconds to +9.3 seconds and -0.23 to -0.56 respectively. Optimal thresholds were determined by minimizing differences between predicted CTP and 24-hour fluid-attenuation inversion recovery magnetic resonance imaging infarct. Optimal thresholds were tested on 60 validation patients (30 intervention and 30 non-intervention) and compared using RAPID CTP software. Among the 67 non-intervention and 40 intervention patients, the following optimal thresholds were determined: intervention Bayesian: TTP = +4.8 seconds, rCBV = -0.29; intervention SVD+: TTP = +5.8 seconds, rCBV = -0.29; non-intervention Bayesian: TTP = +5.3 seconds, rCBV = -0.32; non-intervention SVD+: TTP = +6.3 seconds, rCBV = -0.26. When comparing SVD+ and Bayesian post-processing algorithms, optimal thresholds for TTP were significantly different for intervention and non-intervention patients. rCBV optimal thresholds were equal for intervention patients and significantly different for non-intervention patients. Comparison with commercially utilized software indicated similar performance.

Infarct size assessment through necrosis biomarker release estimation by kinetic modelling: Toward a new gold standard?

Infarct size, a key prognostic factor in ST-segment elevation myocardial infarction (STEMI), is best assessed by late gadolinium enhancement in cardiac magnetic resonance imaging (MRI). MRI availability being limited, necrosis biomarkers (peak concentration and/or area under the concentration versus time curve (AUC)) are used as surrogate markers of infarct size. These methods, excluding biomarkers kinetic data, may provide inaccurate results. We recently developed and published about compartmental kinetic models allowing estimation of the total amount of necrosis biomarker released in STEMI, A 0 , with reduced blood sampling. We sought to evaluate the correlation between A 0 of necrosis biomarkers and MRI measurements of infarct size in STEMI patients. We retrospectively included all STEMI patients with timely reperfusion and a cardiac MRI in the early recovery period in Tours University Hospital (France) from February 2015 to September 2017. Kinetics of Creatine kinase (CK), troponin I (cTnI) and/or T (cTnT), were described using our models and we compared the maximum concentration (Cmax), estimated AUC and A 0 to MRI measurements of infarct size. Forty-one patients were included; all had CK assays, 16 had cTnI assays and 25 hs-cTnT assays. Our population had similar characteristics to the STEMI population reported in the latest FAST-MI registry. The models described satisfactorily biomarker kinetic data. Infarct size was correlated with all CK and hs-cTnT parameters, particularly cTnT A 0 (R 2 = 67,1%) and CK Cmax (R 2 = 64,8%). The correlation was lower with cTnI parameters ( Fig. 1 ). Our models described accurately necrosis biomarkers kinetics following STEMI. The total amount of hs-cTnT released and estimated CK peak concentration were best correlated to MRI infarct size and may be used as easy and accurate estimators of infarct size. This method may be a major advance for future clinical trials on cardioprotection.

Boosted Tree Model Reforms Multimodal Magnetic Resonance Imaging Infarct Prediction in Acute Stroke.

Stroke imaging is pivotal for diagnosis and stratification of patients with acute ischemic stroke to treatment. The potential of combining multimodal information into reliable estimates of outcome learning calls for robust machine learning techniques with high flexibility and accuracy. We applied the novel extreme gradient boosting algorithm for multimodal magnetic resonance imaging-based infarct prediction. In a retrospective analysis of 195 patients with acute ischemic stroke, fluid-attenuated inversion recovery, diffusion-weighted imaging, and 10 perfusion parameters were derived from acute magnetic resonance imaging scans. They were integrated to predict final infarct as seen on follow-up T2-fluid-attenuated inversion recovery using the extreme gradient boosting and compared with a standard generalized linear model approach using cross-validation. Submodels for recanalization and persistent occlusion were calculated and were used to identify the important imaging markers. Performance in infarct prediction was analyzed with receiver operating characteristics. Resulting areas under the curve and accuracy rates were compared using Wilcoxon signed-rank test. The extreme gradient boosting model demonstrated significantly higher performance in infarct prediction compared with generalized linear model in both cross-validation approaches: 5-folds (P<10e-16) and leave-one-out (P<0.015). The imaging parameters time-to-peak, mean transit time, time-to-maximum, and diffusion-weighted imaging were indicated as most valuable for infarct prediction by the systematic algorithm rating. Notably, the performance improvement was higher with 5-folds cross-validation approach than leave-one-out. We demonstrate extreme gradient boosting as a state-of-the-art method for clinically applicable multimodal magnetic resonance imaging infarct prediction in acute ischemic stroke. Our findings emphasize the role of perfusion parameters as important biomarkers for infarct prediction. The effect of cross-validation techniques on performance indicates that the intrapatient variability is expressed in nonlinear dynamics of the imaging modalities.

Left Ventricular Speckle Tracking Global Longitudinal Strain Predicts Magnetic Resonance Imaging Infarct Scar Volume and Ventricular Remodelling in St-Elevation Myocardial Infarction Patients Revascularised with Percutaneous Coronary Interventions

Aim: Echocardiographic strain measurements can detect subclinical left ventricular (LV) dysfunction. We sought to determine the relationship between LV global longitudinal strain (GLS), scar volume, and LV remodelling following ST-elevation myocardial infarction (STEMI).

White Matter Hyperintensity-Adjusted Critical Infarct Thresholds to Predict a Favorable 90-Day Outcome.

There is increasing interest in defining stroke lesion volume thresholds to predict poststroke outcome. However, there is a paucity of data on factors that impact the association between critical infarct thresholds volume and outcome. We sought to determine whether lesion thresholds best predicting outcome depend on the degree of preexisting white matter hyperintensity (WMH) lesion burden. Magnetic resonance imaging infarct volumes were quantified in 414 consecutive patients with anterior circulation ischemic strokes evaluated between January 2014 and December 2014. The WMH lesion volume was graded according to the Fazekas scale and dichotomized to absent to mild versus moderate to severe. Receiver operator characteristics curves were calculated to determine the infarct volume threshold best predicting the 90-day outcome. Multivariable logistic regression was used to determine whether the critical lesion thresholds independently predicted a favorable 90-day outcome after adjusting for pertinent confounders. The infarct volumes thresholds predicting the 90-day outcome for the entire cohort (standard thresholds) were ≤29.5 mL (modified Rankin scale [mRS] 0-1), ≤29.9 mL (mRS 0-2), and ≤34.1 mL (mRS 0-3). For patients with absent-to-mild WMH lesion burden, WMH-adjusted critical infarct thresholds were significantly greater than the standard infarct thresholds. In the fully adjusted multivariable regression models, the WMH-adjusted infarct thresholds correctly predicted the outcome to a similar degree as the standard thresholds. In this proof-of-concept study, the WMH lesion burden impacted the critical outcome-predicting infarct thresholds. If confirmed, using a WMH-adjusted infarct threshold could allow defining patients that have a favorable outcome despite having relatively large infarct volumes.

MRI Detection of Cerebral Infarction in Subarachnoid Hemorrhage.

To investigate magnetic resonance imaging (MRI) detection of cerebral infarction (CI) in patients presenting with subarachnoid hemorrhage (SAH). CI is a well-known complication of SAH that is typically detected on computed tomography (CT). MRI has improved sensitivity for acute CI over CT, particularly with multiple, small, or asymptomatic lesions. With IRB approval, 400 consecutive SAH patients admitted to our institution from August 2006 to March 2011 were retrospectively reviewed. Traumatic SAH and secondary SAH were excluded. Data were collected on demographics, cause of SAH, Hunt Hess and World Federation of Neurosurgical Societies grades, and neuroimaging results. MRIs were categorized by CI pattern as single cortical (SC), single deep (SD), multiple cortical (MC), multiple deep (MD), and multiple cortical and deep (MCD). Among 123 (30.8%) SAH patients who underwent MRIs during their hospitalization, 64 (52%) demonstrated acute CI. The mean time from hospital admission to MRI was 5.7days (range 0-29days). Among the 64 patients with MRI infarcts, MRI CI pattern was as follows: MC in 20 (31%), MCD in 18 (28%), SC in 16 (25%), SD in 3 (5%), MD in 2 (3%), and 5 (8%) did not have images available for review. Most infarcts detected on MRI (39/64 or 61%) were not visible on CT. The use of MRI increases the detection of CI in SAH. Unlike CT studies, MRI-detected CI in SAH tends to involve multiple vascular territories. Studies that rely on CT may underestimate the burden of CI after SAH.

The single nucleotide polymorphism rs2208454 confers an increased risk for ischemic stroke: a case-control study.

A recent genome-wide association study identified a strong association of covert magnetic resonance imaging infarcts with the single nucleotide polymorphism (SNP) rs2208454. The aim of this study was to determine whether the rs2208454 polymorphism is associated with an increased risk for ischemic stroke (IS). Ischemic stroke patients (n = 712) and control subjects (n = 774) from a southern Chinese Han population were included. The snapshot technique was used for genotype analysis. Compared with the GT+GG or GG genotype, the frequency of the TT genotype was significantly higher in IS than in controls. After adjusting for age, gender, family history of IS, hypertension history, and history of diabetes mellitus, a significant correlation between the TT genotype and IS persisted (TT vs. GT+GG: adjusted OR = 1.79, 95% CI: 1.16-2.77; TT vs. GG: adjusted OR = 1.88, 95% CI: 1.20-2.94). In subgroup analyses, SNP rs2208454 was significantly associated with large artery atherosclerosis (LAA) (TT vs. GG: adjusted OR = 2.16, 95% CI: 1.19-3.93), but failed to show significant association with small-artery occlusion or cardioembolism IS subtypes. Single nucleotide polymorphism rs2208454 confers an increased risk for IS in a southern Chinese Han population. When the IS subtype was examined, the effect of the SNP was restricted to LAA.

Relationship between ST-segment resolution and anterior infarct size after primary percutaneous coronary intervention: analysis from the INFUSE-AMI trial

ST-segment resolution (STR) after reperfusion therapy has been shown to correlate with prognosis in patients with ST-segment elevation myocardial infarction (STEMI). We investigated whether acute ECG measurements also correlate with ultimate infarct size. The INFUSE-AMI trial randomized 452 patients with anterior STEMI to intracoronary bolus abciximab vs. no abciximab, and to thrombus aspiration vs. no aspiration. Infarct size as percentage of total LV mass was calculated by cardiac magnetic resonance imaging (MRI) 30 days post intervention. Five ECG methods were analysed for their ability to predict MRI infarct mass: (1) summed STR across all infarct-related ECG leads (ΣSTR); (2) STR in the single lead with maximum baseline ST-segment elevation (maxSTR); (3) summed residual ST-segment elevation across all infarct-related leads at 60 min post intervention (ΣST residual); (4) maximum residual ST-segment elevation in the worst single lead at 60 min post intervention (maxST residual); (5) number of new significant Q-waves (Qwave) at 60 min. All ECG methods strongly correlated with 30-day MRI infarct mass (all p<0.003). Simpler ECG measurements such as maxSTresidual and Qwave were as predictive as more complex measurements. A subset analysis of 158 patients who had microvascular obstruction (MVO) determined by MRI 5 days post intervention also showed strong correlations of MVO with the ECG measures. ST-segment and Q-wave changes after primary PCI in anterior STEMI strongly correlated with 30-day infarct size by MRI. In particular, maxST residual and Qwave at 60 min are simple ECG parameters that offer rapid analysis for prognostication.

Infarct size and mortality in patients with proximal versus mid left anterior descending artery occlusion: The Intracoronary Abciximab and Aspiration Thrombectomy in Patients With Large Anterior Myocardial Infarction (INFUSE-AMI) trial

This study aimed to compare infarct size and clinical outcomes in patients with proximal versus mid left anterior descending (mLAD) infarction. The extent of myocardium at risk is an important prognostic determinate in patients with ST-segment elevation myocardial infarction. The INFUSE-AMI trial randomized patients with anterior ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention with bivalirudin anticoagulation to intracoronary (IC) bolus abciximab versus no abciximab and to thrombus aspiration versus no aspiration. The primary end point was magnetic resonance imaging infarct size (% of left ventricular mass) at 30 days. Lesion location was independently assessed and was defined as proximal (pLAD) if present before or at first significant septal perforator branch, or mLAD if beyond. Among 452 patients, 292 (64.7%) had pLAD and 159 (35.3%) had mLAD occlusions. Patients with pLAD infarcts were significantly more likely to have Killip class >1 heart failure and ejection fraction <40% and to present earlier to the hospital. Proximal LAD infarcts had significantly lower rates of final Thrombolysis In Myocardial Infarction flow 3 and procedural success but similar rates of myocardial blush grade 2/3 and ST-segment resolution compared with mLAD infarcts. Infarct size at 30 days was significantly greater in the pLAD group (19.3% [9.2-25.9] vs 14.3% [6.2-18.9], P < .0001). Mortality at 30 days was also higher in the pLAD group (4.2% vs 0.6%, P = .04). The effect of IC abciximab on reducing infarct size was comparable in both groups. ST-segment elevation myocardial infarction caused by pLAD compared with mLAD occlusion results in larger infarcts and greater mortality even with contemporary reperfusion therapy.

Discontinuing prophylactic transfusions increases the risk of silent brain infarction in children with sickle cell disease: data from STOP II

AbstractIn the STOP II trial, discontinuation of prophylactic transfusions in high risk children with sickle cell disease (SCD) resulted in a high rate of reversion to abnormal blood-flow velocities on transcranial Doppler (TCD) ultrasonography and strokes. We analyzed data from STOP II to determine the effect of discontinuing transfusions on the development or progression of silent brain infarcts on magnetic resonance imaging (MRI). At study entry, 21 of 79 (27%) patients had evidence of silent infarcts. There were no statistically significant differences in baseline characteristics between patients with normal brain MRI or silent infarcts at study entry. At study end, 3 of 37 (8.1%) patients in the continued-transfusion group developed new brain MRI lesions compared with 11 of 40 (27.5%) in the transfusion-halted group (P = .03). The total number of lesions remained essentially unchanged decreasing from 25 to 24 in the continued-transfusion group while increasing from 27 to 45 in transfusion-halted patients. Thus, discontinuation of transfusions in children with SCD and abnormal TCD who revert to low-risk increases the risk of silent brain infarction. Together with data from STOP, these findings demonstrate that transfusions prevent the development of silent infarcts in patients with SCD and abnormal TCD but normal MRA.