Diffusion-weighted Imaging Lesion Research Articles

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.

Prevalence of small vessel disease and incidental DWI-positive lesions in patients with aneurysmal subarachnoid hemorrhage versus intracerebral hemorrhage.

Aneurysmal subarachnoid hemorrhage (aSAH) and intracerebral hemorrhage (ICH) are main forms of hemorrhagic stroke. Data regarding cerebral small vessel disease (SVD) burden and incidental small lesions on diffusion-weighted imaging (DWI) following aSAH are sparse. We retrospectively analyzed a prospective cohort of aSAH and ICH patients with brain MRI within 30 days after onset from March 2015 to January 2023. White matter hyperintensity (WMH), lacune, perivascular space, cerebral microbleed (CMB), total SVD score, and incidental DWI lesions were assessed and compared between aSAH and ICH. Clinical and radiological characteristics associated with small DWI lesions in aSAH were investigated. We included 180 patients with aSAH (median age [IQR] 53 [47-61] years) and 299 with ICH (63 [53-73] years). DWI lesions were more common in aSAH than ICH (47.8% vs 14.4%, p < 0.001). Higher total SVD score was associated with ICH versus aSAH irrespective of hematoma location, whereas DWI lesions and strictly lobar CMBs were correlated with aSAH. Multivariable analysis showed that shorter time from onset to MRI, anterior circulation aneurysm rupture, CMB ⩾ 5, and total SVD score were associated with DWI lesions in aSAH. Incidental DWI lesions and strictly lobar CMBs were more frequent in aSAH versus ICH whereas ICH had higher SVD burden. Incidental DWI lesions in aSAH were associated with multiple clinical and imaging factors. Longitudinal studies to investigate the dynamic change and prognostic value of the covert hemorrhagic and ischemic lesions in aSAH seem justified.

Abstract WP158: Cortical Superficial Siderosis is Associated With Ischemia After Intracerebral Hemorrhage

Background: Ischemia on diffusion weighted imaging (DWI) after intracerebral hemorrhage (ICH) increases the risk of future ischemic stroke. Radiographic markers of small vessel disease, including cerebral microbleeds (CMB), are associated with DWI lesions. Though cortical superficial siderosis (cSS) is also a hemorrhagic small vessel disease subtype, it is unclear if cSS similarly relates to DWI lesions. We hypothesized that cSS would represent a more severe phenotype of small vessel disease and would associate with DWI lesions after ICH independent to other small vessel disease markers. Methods: Using the Intracerebral Hemorrhage Outcomes Project (ICHOP), we included all cases of spontaneous ICH who underwent DWI and susceptibility imaging/gradient echo. DWI hyperintensities were identified if &gt;10mm from the hematoma with decreased ADC signal. cSS were identified as subarachnoid hemosiderin deposition without acute subarachnoid hemorrhage. The relationship of cSS with DWI lesion presence as the outcome was assessed with logistic regression adjusted for ICH score, blood pressure change within 24 hours, and small vessel disease markers (CMB and white matter hyperintensity). Sensitivity analyses were performed to adjust for demographics and ICH location. A secondary analysis using linear regression assessed the association with the number of DWI lesions adjusted for similar covariates. Results: Of 198 patients analyzed, DWI lesions were observed in 31.3% and cSS in 10.6%. The presence of cSS was associated with DWI lesions (adjusted OR 3.72, CI: 1.29-10.72), independent of other small vessel disease markers. Separate sensitivity analyses adjusting for sex, race, and ICH location did not change the association of cSS with DWI lesions. In secondary analyses, cSS was not associated with greater number of DWI lesions counts (b 0.213, CI -0.53-0.63). Discussion: cSS is associated with the presence of DWI lesions, independent to other small vessel disease markers. cSS may represent a severe phenotype of small vessel disease with a risk of ICH recurrence and ischemia. Further work is required to investigate underlying mechanisms and optimal strategies to mitigate competing risks of future hemorrhage and ischemic events in these patients.

Abstract TP154: Association of Left Ventricular Hypertrophy With Ischemic Lesions After Intracerebral Hemorrhage

Background: Ischemic lesions on diffusion weighted imaging (DWI) occur in one-third of intracerebral hemorrhage (ICH). Due to conflicting prior studies, it is uncertain if the degree of systolic blood pressure reduction increases the risk. Patients with severe, chronic hypertension may be more vulnerable to the development of ischemia after ICH due to altered cerebral autoregulatory limits. Using cardiac remodeling as a biomarker for severe chronic hypertension, we hypothesized that the presence of left ventricular hypertrophy (LVH) is associated with DWI lesions. Methods: Patients with spontaneous ICH enrolled in the Intracerebral Hemorrhage Outcomes Project who underwent DWI imaging and transthoracic echocardiography (TTE) during hospitalization were included. Lesions were identified as hyperintensities &gt;10mm remote from the hematoma with corresponding low ADC signal. LVH presence was identified using clinically obtained TTE reports with imaging evidence of moderate-severe left ventricular wall thickness. The relationship between LVH and DWI ischemic lesions was assessed with logistic regression modeling after adjusting for age, ICH volume, intraventricular hemorrhage, hypertension history, and blood pressure change within 24 hours. A secondary analysis using linear regression assessed the association with the number of DWI lesions adjusting for similar covariates. Results: Of 187 patients analyzed, DWI lesions were observed in 30.5% and LVH was seen in 23.5%. In our logistic regression analyses, we identified that LVH was associated with DWI lesions (adjusted OR 2.77, CI: 1.19-6.40). Separate sensitivity analyses adjusting for sex (OR 2.47, CI 1.05-5.83) and race (OR 2.52, CI 1.08-5.91) did not change these relationships. In secondary analysis, we identified that LVH was associated with increased DWI lesion number (B 1.018, CI 0.40-1.63 ). Discussion: LVH is associated with the presence and burden of DWI lesions. Further work is required to assess aggregate relationships of chronic hypertension/LVH, acute blood pressure change, ischemic lesions, and ICH outcomes to determine whether patients with LVH necessitate different acute blood pressure treatment goals.

Abstract TP126: Diffusion Weighted Image Lesion Dynamics in Acute Ischemic Stroke and Functional Recovery: Application of an Automated Software to 7000 Cases

Introduction: The change in DWI lesion volume in acute ischemic stroke has not been investigated in detail. We aimed to investigate the effect of DWI lesion growth or regression within seven days of onset on functional recovery after ischemic stroke. Methods: From a prospective stroke registry, we retrieved acute ischemic stroke cases who had more than two DWIs during in-hospital care between 2005 and 2022. The DWI lesion volume was automatically measured using JBS-01K (JLK Inc., South Korea), a fully automated and validated deep learning algorithm using 3D U-net. The association between categorized DWI lesion volume change (10, 25, 50, and 75 percentiles corresponding to -45%, 0%, 57%, and 220% of volume change) and functional recovery was assessed using multivariable ordinal logistic regression analysis taking lower modified Rankin scale (mRS) as a dependent variable, adjusting for relevant covariates. Results: A total of 7308 patients with ischemic stroke who underwent follow-up DWIs were included. A male was 62%, mean age of 67.5±13.5, and a median of initial NIHSS 4 [IQR 1-7]. The median of interval between the initial and follow-up DWI was 90 hours [IQR 68.25 - 112.20]. The median of the initial DW lesion volume was 1.00 ml [IQR 0.27-5.98], and the median of the follow-up DW lesion volume was 2.05 ml [IQR 0.27-5.98]. DWI lesion volume was regressed in 1844 cases (25%); 136 cases (13%) of EVT and 1708 cases (27%) of non-EVT cases. Compared with patients with 25-50 percentile strata, the adjusted odds ratios (OR) of having favorable functional recovery for &lt; 10th, 10-25th, 50-75th, and ≥75th percentile were 1.25 [95% CI 1.05 - 1.48], 0.96 [0.83 - 1.11], 0.67 [0.59 - 0.76], and 0.63 [0.55 - 0.72], respectively (Figure). Conclusions: We found that approximately a quarter of patients with ischemic stroke had an interval regression of infarct volume on DWI, which is independently associated with favorable functional recovery.

Magnetic resonance imaging in acute meningoencephalitis of viral and unknown origin: frequent findings and prognostic potential.

Magnetic resonance imaging (MRI) findings in meningoencephalitis have mainly been described in terms of their diagnostic value rather than their prognostic potential, except for herpes simplex virus (HSV) encephalitis. The aims of our study were to describe frequency and anatomic locations of MRI abnormalities specific to limbic, circadian and motor systems in a cohort of meningoencephalitis patients, as well as to investigate the prognostic value of these MRI findings. A secondary, selective analysis of a retrospective database including all meningitis, meningoencephalitis and encephalitis cases treated between 2016 and 2018 in the University hospital of Bern, Switzerland was performed. Patients with meningitis of any cause, bacterial or autoimmune causes of encephalitis were excluded. MRI scans and clinical data from 129 meningoencephalitis cases found that the most frequent causes were tick-borne encephalitis (TBE, 42%), unknown pathogens (40%), VZV (7%), and HSV1 (5%). At discharge, median modified Rankin Score (mRS) was 3 (interquartile range, IQR, 1), 88% of patients had persisting signs and symptoms. After a median of 17 months, median Glasgow Outcome Score (GOS) was 5 (IQR 1), 39% of patients still had residual signs or symptoms. All patients with HSV, 27% with TBE and 31% of those with meningoencephalitis of unknown etiology had fluid-attenuated inversion recovery (FLAIR) and to a lesser extent diffusion-weighted imaging (DWI) lesions in their initial MRI, with highly overlapping anatomical distribution. In one fifth of TBE patients the limbic system was affected. Worse outcome was associated with presence of DWI and/or FLAIR lesions and lower normalized apparent diffusion coefficient (ADC) signal intensities. Presence of FLAIR lesions, restricted diffusion as well as the extent of ADC hypointensity in initial MRI are parameters which might be of prognostic value regarding the longterm clinical outcome for patients with meningoencephalitis of viral and of unknown origin. Although not described before, affection of limbic structures by TBE is possible as shown by our results: A substantial proportion of our TBE patients had FLAIR signal abnormalities in these regions.

Mechanistic Evaluation of Diffusion Weighted Hyperintense Lesions After Large Spontaneous Intracerebral Hemorrhage: A Subgroup Analysis of MISTIE III.

Ischemic lesions on diffusion weighted imaging (DWI) are common after acute spontaneous intracerebral hemorrhage (ICH) but are poorly understood for large ICH volumes (> 30mL). We hypothesized that large blood pressure drops and effect modification by cerebral small vessel disease markers on magnetic resonance imaging (MRI) are associated with DWI lesions. This was an exploratory analysis of participants in the Minimally Invasive Surgery Plus Alteplase for Intracerebral Hemorrhage Evacuation phase 3 trial with protocolized brain MRI scans within 7days from ICH. Multivariable logistic regression analysis was performed to assess biologically relevant factors associated with DWI lesions, and relationships between DWI lesions and favorable ICH outcomes (modified Rankin Scale 0-3). Of 499 enrolled patients, 300 had MRI at median 7.5days (interquartile range 7-8), and 178 (59%) had DWI lesions. The incidence of DWI lesions was higher in patients with systolic blood pressure (SBP) reduction ≥ 80mm Hg in first 24h (76%). In adjusted models, factors associated with DWI lesions were as follows: admission intraventricular hematoma volume (p = 0.03), decrease in SBP ≥ 80mm Hg from admission to day 1 (p = 0.03), and moderate-to-severe white matter disease (p = 0.01). Patients with DWI lesions had higher odds of severe disability at 1month (p = 0.04), 6months (p = 0.036), and 12months (p < 0.01). No evidence of effect modification by cerebral small vessel disease on blood pressure was found. In patients with large hypertensive ICH, white matter disease, intraventricular hemorrhage volume, and large reductions in SBP over the first 24h were independently associated with DWI lesions. Further investigation of potential hemodynamic mechanisms of ischemic injury after large ICH is warranted.

Effect of Cerebral Small Vessel Disease Burden on Infarct Growth Rate and Stroke Outcomes in Large Vessel Occlusion Stroke Receiving Endovascular Treatment.

This study aimed to investigate the association between cerebral small vessel disease (CSVD) burden and infarct growth rate (IGR) in patients with large vessel occlusion (LVO) stroke who underwent endovascular treatment (EVT). A retrospective analysis was conducted on a cohort of 495 patients with anterior circulation stroke who received EVT. CSVD burden was assessed using a CSVD score based on neuroimaging features. IGR was calculated from diffusion-weighted imaging (DWI) lesion volumes divided by the time from stroke onset to imaging. Clinical outcomes included stroke progression and functional outcomes at 3 months. Multivariate analyses were performed to assess the relationship between CSVD burden, IGR, and clinical outcomes. The fast IGR group had a higher proportion of high CSVD scores than the slow IGR group (24.4% vs. 0.8%, p < 0.001). High CSVD burden was significantly associated with a faster IGR (odds ratio [95% confidence interval], 26.26 [6.26-110.14], p < 0.001) after adjusting for confounding factors. High CSVD burden also independently predicted stroke progression and poor functional outcomes. This study highlights a significant relationship between CSVD burden and IGR in LVO stroke patients undergoing EVT. High CSVD burden was associated with faster infarct growth and worse clinical outcomes.

Aortic arch atheroma and stroke recurrence in mild stroke patients: ADS post-hoc analysis

BackgroundAortic arch atheroma is one of the embolic sources in patients with ischemic stroke. Although transesophageal echocardiogram (TEE) is the golden standard to evaluate the aortic arch atheroma, it is invasive and may be limited to patients with suspected embolism. Present post-hoc analysis evaluated the acute dual study data on mild stroke patients who had aortic arch atheroma proven by TEE and evaluate whether combined cilostazol and aspirin therapy might reduce the rate of stroke recurrence comparing aspirin therapy. MethodsAortic arch atheroma was defined as aortic arch plaque with a maximal intima-medial thickness of ≥4.0 mm. Stroke recurrence included new diffusion-weighted image (DWI) lesions within 14 days. ResultAmong 316 (227 [72%] men; median, 66 [interquartile, 60–76] years old) patients, TEE found that 93 patients (29%) had the aortic arch atheroma, and 223 (71%) did not had it. The aortic arch atheroma group was older (P = 0.001) and accompanied with diabetes mellitus (P = 0.003), dyslipidemia (P = 0.046), smoking (P = 0.034), and had previous ischemic stroke history (P = 0.042) and multiple infarcts (P = 0.024) on admission. During hospitalization, new DWI lesion was frequently observed in the aortic arch atheroma group compared to the group without it (14.1% vs. 6.8%, P = 0.049). The rates of new DWI lesion were not different between dual antiplatelet therapy group and aspirin group (14.9% vs. 13.3%, P = 1.000). ConclusionAortic arch atheroma was the representative of systematic arteriosclerosis associated with new DWI lesion in short-term. Combined antiplatelet therapy using cilostazol did not prevent new DWI appearance comparing aspirin therapy in this cohort.

Perfusion deficits in thrombolysis-treated acute ischemic stroke patients with negative or positive diffusion-weighted imaging

ObjectiveMagnetic resonance imaging (MRI) and CT perfusion may provide diagnostic information for intravenous tissue-type plasminogen activator (IV t-PA) administration in acute ischemic stroke (AIS) patients. We aimed to compare the clinical features and perfusion deficits of diffusion weighted imaging (DWI)-negative and DWI-positive AIS patients.MethodsThis retrospective and observational study included thrombolysis-treated AIS patients undergoing multimodel CT imaging before treatment and DWI after treatment between 2021 and 2022. Two experienced neuroradiologists blindly and independently examined the images to identify perfusion deficits in AIS patients. The patients were divided into DWI-positive and DWI-negative groups based on visible hyperintense lesions on DWI. A modified Rankin scale (mRS) score of ≤ 2 indicated good functional outcomes at discharge. Sensitivity analysis was conducted to determine whether CT perfusion was an independent predictor of positive DWI imaging on follow-up.ResultsThis study included 151 patients, of whom 35 (23.2%) patients were DWI-negative on follow-up. These DWI-negative patients were less likely to have a medical history of atrial fibrillation; they had lower triglyceride levels, a shorter admission time, lower National Institutes of Health Stroke Scale (NIHSS) scores after IV t-PA and lower mRS scores at discharge, and had better functional outcomes. A total of 37.1% of DWI-positive and 25.7% of DWI-negative patients had vascular stenosis (P = 0.215). A total of 47.4% of DWI-positive and 37.1% of DWI-negative patients had CT perfusion deficits (P = 0.284). A total of 73.5% of patients with normal CT perfusion had positive DWI, while 19.1% of patients with perfusion deficits had negative DWI. The sensitivity and specificity of NCCT were 14.8% and 97.1% (Kappa = 0.061, P = 0.074), CTP was 47.4% and 62.9% for predicting DWI lesion (Kappa = 0.069, P = 0.284).ConclusionsAbout 23.2% of AIS patients who received intravenous thrombolysis treatment did not have a relevant DWI-MRI lesion on follow-up. Over one-third of patients in the DWI-MRI negative group showed CT perfusion deficits, with a sensitivity of 47.4% for predicting DWI lesions in non-mechanical thrombectomy patients.

[The value of a nomogram for predicting the outcome of intracerebral hemorrhage based on clinical characteristics and diffusion-weighted imaging of hyperintense lesions].

Objective: To investigate the value of a nomogram predicting the outcome of intracerebral hemorrhage (ICH) based on clinical characteristics and diffusion-weighted imaging (DWI) of hyperintense lesions. Methods: A case-control study. Consecutive patients, aged 30-88(59±13) years old, with ICH were recruited at the Stroke Center of Zhengzhou People's Hospital from January 2018 to August 2021. Patients were divided into a group with DWI lesions and a group without DWI lesions depending on whether there were DWI hyperintense lesions distant from the hematoma. Prognosis was evaluated at 90 days via the modified Rankin Scale (mRS). Univariate and multivariable logistic regression models were used to identify independent predictors of a poor ICH outcome (mRS score≥4), and a nomogram model was developed. The performance of the nomogram was validated via the area under the receiver operating characteristic curve (AUC) and a calibration chart. Results: Of the 303 patients included in the study, 24.8% presented with DWI lesions; 17.5% with asymptomatic DWI lesions and 7.3% with symptomatic DWI lesions. Poor outcomes were significantly more frequent in the group with DWI lesions than in the group without DWI lesions (χ2=21.32, P<0.001). In multivariable regression analysis, age [odds ratio (OR)=1.032, 95% confidence interval (CI) 1.002-1.063, P=0.035], hematoma volume (OR=1.050, 95%CI 1.011-1.090, P=0.012), hematoma location (OR=3.839, 95%CI 1.248-11.805, P=0.019), DWI lesions (OR=3.955, 95%CI 1.906-8.206, P<0.001), and baseline NIHSS scores (OR=1.102, 95%CI 1.038-1.170, P=0.001) were independent predictors of a poor outcome. In subgroup analysis patients with asymptomatic DWI lesions had a 3-fold greater risk of a poor outcome compared to those without DWI lesions (OR=3.135, 95%CI 1.382-7.112, P=0.006), and patients with symptomatic DWI lesions had a 7-fold greater risk of a poor outcome compared to those without DWI lesions (OR=7.126, 95%CI 2.279-22.277, P=0.001). A nomogram model was established based on the independent predictors for a poor outcome. The AUC of the nomogram was 0.846 (95%CI 0.795-0.898), and a calibration chart indicated good consistency between values predicted by the nomogram and actual observed values. Conclusions: DWI lesions are an independent risk factor for a poor outcome in patients with ICH-particularly symptomatic DWI lesions. A nomogram model based on clinical characteristics and DWI lesions exhibited good efficacy when predicting the outcome of ICH.

Safety Aspects and Procedural Characteristics of Ambulatory Diagnostic Cerebral Catheter Angiography.

Diagnostic cerebral catheter angiography is used to assess avariety of neurovascular pathologies especially in patients before and after endovascular neurointerventional treatment. In many centers diagnostic cerebral angiographies are performed with the patient staying for one night in the hospital because there are not yet sufficient data on the safety of ambulatory cerebral angiography. At the same time hospitals face agrowing demand to perform ambulatory medical procedures. A total of 426 ambulatory diagnostic cerebral angiographies were retrospectively analyzed. Technical details of the angiographies were analyzed to identify procedural risk factors. Out of 426 patients 14 (3.3%) had some form of complication, 3 developed minor transient neurological symptoms, 1 patient developed Quincke's edema probably as an adverse reaction to contrast agent, 1 patient had an asymptomatic carotid dissection and 1 had afall of unknown etiology. Of the 14complications 8 were puncture site complications with 1 re-bleeding, 1 dissection, and 6 minor complications, 421 punctures were femoral, 3 radial and 2 brachial. Out of 333 patients with magnetic resonance imaging (MRI) after angiography 21 showed focal diffusion-weighted imaging (DWI) lesions but none of these lesions were symptomatic. The rate of DWI lesions was significantly higher in selectively angiography territories than in other territories. The use of aSimmons 2catheter significantly increased the rate of DWI lesions (p = 0.047), whereas 3D rotational angiography did not (p = 0.55). The rate of DWI lesions per selectively accessed vessel was 4.6% with ahigher rate in the anterior than in the posterior circulation. Diagnostic cerebral catheter angiography can be safely performed in an ambulatory setting.

Preoperative cerebral angiography nearly doubles the rate of diffusion-weighted imaging lesion detection following minimally invasive surgery for intracerebral hemorrhage

BackgroundDiffusion-weighted imaging (DWI) lesions have been linked to poor outcomes after intracerebral hemorrhage (ICH). We aimed to assess the impact of cerebral digital subtraction angiography (DSA) on the presence of...

The collateral map: prediction of lesion growth and penumbra after acute anterior circulation ischemic stroke

ObjectivesThis study evaluated the collateral map’s ability to predict lesion growth and penumbra after acute anterior circulation ischemic strokes.MethodsThis was a retrospective analysis of selected data from a prospectively collected database. The lesion growth ratio was the ratio of the follow-up lesion volume to the baseline lesion volume on diffusion-weighted imaging (DWI). The time-to-maximum (Tmax)/DWI ratio was the ratio of the baseline Tmax  > 6 s volume to the baseline lesion volume. The collateral ratio was the ratio of the hypoperfused lesion volume of the phase_FU (phase with the hypoperfused lesions most approximate to the follow-up DWI lesion) to the hypoperfused lesion volume of the phase_baseline of the collateral map. Multiple logistic regression analyses were conducted to identify independent predictors of lesion growth. The concordance correlation coefficients of Tmax/DWI ratio and collateral ratio for lesion growth ratio were analyzed.ResultsFifty-two patients, including twenty-six males (mean age, 74 years), were included. Intermediate (OR, 1234.5; p < 0.001) and poor collateral perfusion grades (OR, 664.7; p = 0.006) were independently associated with lesion growth. Phase_FUs were immediately preceded phases of the phase_baselines in intermediate or poor collateral perfusion grades. The concordance correlation coefficients of the Tmax/DWI ratio and collateral ratio for the lesion growth ratio were 0.28 (95% CI, 0.17–0.38) and 0.88 (95% CI, 0.82–0.92), respectively.ConclusionPrecise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments. Further studies are needed to generalize the findings of this study.Clinical relevance statementPrecise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments.Key Points• Cell viability in cerebral ischemia due to proximal arterial steno-occlusion mainly depends on the collateral circulation.• The collateral map shows salvageable brain extent, which can survive by recanalization treatments after acute anterior circulation ischemic stroke.• Precise estimation of salvageable brain makes it possible to make patient-specific treatment decision.

Automated acute ischemic stroke lesion delineation based on apparent diffusion coefficient thresholds.

Automated lesion segmentation is increasingly used in acute ischemic stroke magnetic resonance imaging (MRI). We explored in detail the performance of apparent diffusion coefficient (ADC) thresholding for delineating baseline diffusion-weighted imaging (DWI) lesions. Retrospective, exploratory analysis of the prospective observational single-center 1000Plus study from September 2008 to June 2013 (clinicaltrials.org; NCT00715533). We built a fully automated lesion segmentation algorithm using a fixed ADC threshold (≤620 × 10-6 mm2/s) to delineate the baseline DWI lesion and analyzed its performance compared to manual assessments. Diagnostic capabilities of best possible ADC thresholds were investigated using receiver operating characteristic curves. Influential patient factors on ADC thresholding techniques' performance were studied by conducting multiple linear regression. 108 acute ischemic stroke patients were selected for analysis. The median Dice coefficient for the algorithm was 0.43 (IQR 0.20-0.64). Mean ADC values in the DWI lesion (β = -0.68, p < 0.001) and DWI lesion volumes (β = 0.29, p < 0.001) predicted performance. Optimal individual ADC thresholds differed between subjects with a median of ≤691 × 10-6 mm2/s (IQR ≤660-750 × 10-6 mm2/s). Mean ADC values in the DWI lesion (β = -0.96, p < 0.001) and mean ADC values in the brain parenchyma (β = 0.24, p < 0.001) were associated with the performance of individual thresholds. The performance of ADC thresholds for delineating acute stroke lesions varies substantially between patients. It is influenced by factors such as lesion size as well as lesion and parenchymal ADC values. Considering the inherent noisiness of ADC maps, ADC threshold-based automated delineation of very small lesions is not reliable.

Assessment of Brain Magnetic Resonance and Spectroscopy Imaging Findings and Outcomes After Pediatric Cardiac Arrest

Morbidity and mortality after pediatric cardiac arrest are chiefly due to hypoxic-ischemic brain injury. Brain features seen on magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) after arrest may identify injury and aid in outcome assessments. To analyze the association of brain lesions seen on T2-weighted MRI and diffusion-weighted imaging and N-acetylaspartate (NAA) and lactate concentrations seen on MRS with 1-year outcomes after pediatric cardiac arrest. This multicenter cohort study took place in pediatric intensive care units at 14 US hospitals between May 16, 2017, and August 19, 2020. Children aged 48 hours to 17 years who were resuscitated from in-hospital or out-of-hospital cardiac arrest and who had a clinical brain MRI or MRS performed within 14 days postarrest were included in the study. Data were analyzed from January 2022 to February 2023. Brain MRI or MRS. The primary outcome was an unfavorable outcome (either death or survival with a Vineland Adaptive Behavior Scales, Third Edition, score of <70) at 1 year after cardiac arrest. MRI brain lesions were scored according to region and severity (0 = none, 1 = mild, 2 = moderate, 3 = severe) by 2 blinded pediatric neuroradiologists. MRI Injury Score was a sum of T2-weighted and diffusion-weighted imaging lesions in gray and white matter (maximum score, 34). MRS lactate and NAA concentrations in the basal ganglia, thalamus, and occipital-parietal white and gray matter were quantified. Logistic regression was performed to determine the association of MRI and MRS features with patient outcomes. A total of 98 children, including 66 children who underwent brain MRI (median [IQR] age, 1.0 [0.0-3.0] years; 28 girls [42.4%]; 46 White children [69.7%]) and 32 children who underwent brain MRS (median [IQR] age, 1.0 [0.0-9.5] years; 13 girls [40.6%]; 21 White children [65.6%]) were included in the study. In the MRI group, 23 children (34.8%) had an unfavorable outcome, and in the MRS group, 12 children (37.5%) had an unfavorable outcome. MRI Injury Scores were higher among children with an unfavorable outcome (median [IQR] score, 22 [7-32]) than children with a favorable outcome (median [IQR] score, 1 [0-8]). Increased lactate and decreased NAA in all 4 regions of interest were associated with an unfavorable outcome. In a multivariable logistic regression adjusted for clinical characteristics, increased MRI Injury Score (odds ratio, 1.12; 95% CI, 1.04-1.20) was associated with an unfavorable outcome. In this cohort study of children with cardiac arrest, brain features seen on MRI and MRS performed within 2 weeks after arrest were associated with 1-year outcomes, suggesting the utility of these imaging modalities to identify injury and assess outcomes.

Novel deep-learning-based diffusion weighted imaging sequence in 1.5 T breast MRI

PurposeThis study aimed to assess the technical feasibility, the impact on image quality, and the acquisition time (TA) of a new deep-learning-based reconstruction algorithm in diffusion weighted imaging (DWI) of breast magnetic resonance imaging (MRI). MethodsRetrospective analysis of 55 female patients who underwent breast DWI at 1.5 T. Raw data were reconstructed using a deep-learning (DL) reconstruction algorithm on a subset of the acquired averages, therefore a reduction of TA. Clinically used standard DWI sequence (DWIStd) and the DL-reconstructed images (DWIDL) were compared. Two radiologists rated the image quality of b800 and ADC images, using a Likert-scale from 1 to 5 with 5 being considered perfect image quality. Signal intensities were measured by placing a region of interest (ROI) at the same position in both sequences. ResultsTA was reduced by 40 % in DWIDL, compared to DWIStd, DWIDL improved noise and sharpness while maintaining contrast, the level of artifacts, and diagnostic confidence. There were no differences regarding the signal intensity values of the apparent diffusion coefficient (ADC), (p = 0.955), b50-values (p = 0.070) and b800-values (p = 0.415) comparing standard and DL-imaging. Lesion assessment showed no differences regarding the number of lesions in ADC and DWI (both p = 1.000) and regarding the lesion diameter in DWI (p = 0.961;0.972) and ADC (p = 0.961;0.972). ConclusionsThe novel deep-learning-based reconstruction algorithm significantly reduces TA in breast DWI, while improving sharpness, reducing noise, and maintaining a comparable level of image quality, artifacts, contrast, and diagnostic confidence. DWIDL does not influence the quantifiable parameters.

Hyperglycemia, Ischemic Lesions, and Functional Outcomes After Intracerebral Hemorrhage.

Background Ischemic lesions observed on diffusion-weighted imaging (DWI) magnetic resonance imaging are associated with poor outcomes after intracerebral hemorrhage (ICH). We evaluated the association between hyperglycemia, ischemic lesions, and functional outcomes after ICH. Methods and Results This was a retrospective observational analysis of 1167 patients who received magnetic resonance imaging in the ERICH (Ethnic and Racial Variations in Intracerebral Hemorrhage) study. A machine learning strategy using the elastic net regularization and selection procedure was used to perform automated variable selection to identify final multivariable logistic regression models. Sensitivity analyses with alternative model development strategies were performed, and predictive performance was compared. After covariate adjustment, white matter hyperintensity score, leukocyte count on admission, and non-Hispanic Black race (compared with non-Hispanic White race) were associated with the presence of DWI lesions. History of ICH and ischemic stroke, presence of DWI lesions, deep ICH location (versus lobar), ICH volume, age, lower Glasgow Coma Score on admission, and medical history of diabetes were associated with poor 6-month modified Rankin Scale outcome (4-6) after covariate adjustment. Inclusion of interactions between race and ethnicity and variables included in the final multivariable model for functional outcome improved model performance; a significant interaction between race and ethnicity and medical history of diabetes and serum blood glucose on admission was observed. Conclusions No measure of hyperglycemia or diabetes was associated with presence of DWI lesions. However, both medical history of diabetes and presence of DWI lesions were independently associated with poor functional outcomes after ICH.

Predicting DWI-FLAIR mismatch on NCCT: the role of artificial intelligence in hyperacute decision making.

The presence of diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) mismatch was used to determine eligibility for intravenous thrombolysis in clinical trials. However, due to the restricted availability of MRI and the ambiguity of image assessment, it is not widely implemented in clinical practice. A total of 222 acute ischemic stroke patients underwent non-contrast computed tomography (NCCT), DWI, and FLAIR within 1 h of one another. Human experts manually segmented ischemic lesions on DWI and FLAIR images and independently graded the presence of DWI-FLAIR mismatch. Deep learning (DL) models based on the nnU-net architecture were developed to predict ischemic lesions visible on DWI and FLAIR images using NCCT images. Inexperienced neurologists evaluated the DWI-FLAIR mismatch on NCCT images without and with the model's results. The mean age of included subjects was 71.8 ± 12.8  years, 123 (55%) were male, and the baseline NIHSS score was a median of 11 [IQR, 6-18]. All images were taken in the following order: NCCT - DWI - FLAIR, starting after a median of 139 [81-326] min after the time of the last known well. Intravenous thrombolysis was administered in 120 patients (54%) after NCCT. The DL model's prediction on NCCT images revealed a Dice coefficient and volume correlation of 39.1% and 0.76 for DWI lesions and 18.9% and 0.61 for FLAIR lesions. In the subgroup with 15  mL or greater lesion volume, the evaluation of DWI-FLAIR mismatch from NCCT by inexperienced neurologists improved in accuracy (from 0.537 to 0.610) and AUC-ROC (from 0.493 to 0.613). The DWI-FLAIR mismatch may be reckoned using NCCT images through advanced artificial intelligence techniques.

Pathological Changes of Small Vessel Disease in Intracerebral Hemorrhage: a Systematic Review and Meta-analysis.

In intracerebral hemorrhage (ICH) with pathology-proven etiology, we performed a systematic review and meta-analysis to elucidate the association between cerebral amyloid angiopathy (CAA) and arteriolosclerosis, and directly compared MRI and pathological changes of markers of cerebral small vessel disease (CSVD). Studies enrolling primary ICH who had received an etiological diagnosis through biopsy or autopsy were searched using Ovid MEDLINE, PubMed, and Web of Science from inception to June 8, 2022. We extracted pathological changes of CSVD for each patient whenever available. Patients were grouped into CAA + arteriolosclerosis, strict CAA, and strict arteriolosclerosis subgroups. Of 4155 studies identified, 28 studies with 456 ICH patients were included. The frequency of lobar ICH (p<0.001) and total microbleed number (p=0.015) differed among patients with CAA + arteriolosclerosis, strict CAA, and strict arteriolosclerosis. Concerning pathology, severe CAA was associated with arteriolosclerosis (OR 6.067, 95% CI 1.107-33.238, p=0.038), although this association was not statistically significant after adjusting for age and sex. Additionally, the total microbleed number (median 15 vs. 0, p=0.006) was higher in ICH patients with CAA evidence than those without CAA. The pathology of CSVD imaging markers was mostly investigated in CAA-ICH. There was inconsistency concerning CAA severity surrounding microbleeds. Small diffusion-weighted imaging lesions could be matched to acute microinfarct histopathologically. Studies that directly correlated MRI and pathology of lacunes, enlarged perivascular spaces, and atrophy were scarce. Arteriolosclerosis might be associated with severe CAA. The pathological changes of CSVD markers by ICH etiology are needed to be investigated further.