Diffusion-weighted Imaging Lesion Research Articles

Abstract TP8: Apparent Diffusion Coefficientvalue Could Be The New Perspective To Ascertain Effectiveness Of Mechanical Thrombectomy In Large Ischemic Regions

Introduction: Recently, we reported that apparent diffusion coefficient (ADC) values are independently associated with diffusion-weighted imaging (DWI) reversal, and DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s are salvageable by mechanical thrombectomy. These areas regain neurological function. This study aimed to determine the effectiveness of mechanical thrombectomy in especially large ischemic regions with mean ADC ≥ 520 х 10 -6 mm 2 /s. Materials and Methods: We conducted a retrospective cohort study including patients with acute ischemic stroke who underwent endovascular mechanical thrombectomy with successful recanalization between April 2017 and March 2021. DWI reversal was assessed through follow-up magnetic resonance imaging 24 h after treatment. Cases with Alberta stroke program early CT score (ASPECTS)-DWI values 3-5 were enrolled in this study. They were classified as DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s and mean ADC < 520 х 10 -6 mm 2 /s. The primary outcome was modified Rankin scale (mRS) score 0-3 (on a scale of 0-6) at 3 months. Results: In total, ASPECTS-DWI values 3-5 were confirmed in 20 patients. Six patients had DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s, and the remaining 14 patients had DWI lesions with mean ADC < 520 х 10 -6 mm 2 /s. DWI reversals were significantly larger in cases with mean ADC ≥ 520 х 10 -6 mm 2 /s than in those with mean ADC < 520 х 10 -6 mm 2 /s (p=.049). The mRS scores at 3 months in cases with mean ADC ≥ 520 х 10 -6 mm 2 /s and ADC < 520 х 10 -6 mm 2 /s were 3 (0.75-3.75) and 5 (4-6), respectively. mRS score was significantly improved in cases with mean ADC ≥ 520 х 10 -6 mm 2 /s than in cases with mean ADC < 520 х 10 -6 mm 2 /s (p=.011). Conclusions: In large ischemic regions (ASPECTS-DWI: 3-5), DWI lesions with mean ADC ≥ 520 х 10 -6 mm 2 /s are associated with preferable outcomes. The ADC value is easily assessed and a useful tool to predict viable lesions. Therefore, the ADC value could be a new perspective to ascertain the effectiveness of mechanical thrombectomy in large ischemic regions. ABBREVIATIONS: ASPECTS = Alberta stroke program early CT score; ADC = apparent diffusion coefficient; DWI = diffusion-weighted imaging; mRS = modified Rankin scale

Diffusion-weighted imaging lesions after endovascular treatment of cerebral aneurysms: A network meta-analysis.

Thromboembolism is one of the common complications in endovascular treatments including coiling alone, stent-assisted coiling (SAC), balloon-assisted coiling (BAC), and flow-diverting (FD) stents. Such treatments are widely used in intracranial aneurysms (IAs), which usually present as positive lesions in diffusion-weighted imaging (DWI). Whether these adjunctive techniques increase postprocedural DWI-positive lesions after endovascular treatment remains unclear. A thorough electronic search for the literature published in English between January 2000 and October 2022 was conducted on PubMed, Medline, and EMBASE. Eighteen studies (3 cohort studies and 15 case-control studies) involving 1,843 patients with unruptured IAs (UIAs) were included. We performed a frequentist framework network meta-analysis (NMA) to compare the rank risks of cerebral thromboembolism of the above four endovascular treatments. The incoherence test was used to analyze the statistical disagreement between direct and indirect evidence. Funnel plots were used to analyze publication bias. The incidences of DWI lesions in patients who received FD stents, SAC, BAC, and coiling alone were 66.1% (109/165), 37.6% (299/795), 31.1% (236/759), and 25.6% (236/921). The incidence of DWI lesions in patients who received FD stents was higher than that in patients who received SAC [OR: 2.40; 95% CI (1.15, 5.00), P < 0.05], BAC [OR: 2.62; 95% CI (1.19, 5.77), P < 0.05], or coiling alone [OR: 2.77; 95% CI (1.26, 6.07), P < 0.05]. The incoherence test showed preferable consistency in this NMA. No obvious publication bias was found in the funnel plot. FD stent placement brings more ischemic lesions identified by DWI than any other procedures for patients with UIA. The characteristics of FD stents may result in a high incidence of DWI lesions.

Cortical Superficial Siderosis and Transient Focal Neurological Episode Preceding Lobar Hemorrhage in Cerebral Amyloid Angiopathy.

Cortical Superficial Siderosis and Transient Focal Neurological Episode Preceding Lobar Hemorrhage in Cerebral Amyloid Angiopathy.

Thromboelastography 6s for assessment of platelet function during coil embolization of unruptured intracranial aneurysms

ObjectivesMethods for assessing platelet function in patients with neurovascular disease remain controversial and poorly studied. This study aimed to assess associations between thromboelastography 6s (TEG6s) measurements and postoperative ischemic complications in patients with unruptured intracranial aneurysms (UIAs) treated by coil embolization. MethodsEighty-four patients with UIAs taking a combined aspirin and clopidogrel protocol were retrospectively reviewed from January 2021 to May 2022. Blood samples were obtained for TEG6s to assess platelet function on the day of coil embolization. To identify acute ischemic complications, diffusion-weighted imaging (DWI) was performed within 24 h after coil embolization. Multivariate logistic regression analysis was conducted to identify potential risk factors for postoperative positive DWI (DWI (+)) lesions. ResultsForty-three of the 84 patients (51%) with DWI (+) lesions were identified. Compared with patients without DWI (+) lesions, Adenosine diphosphate (ADP)-induced platelet-fibrin clot strength (MAADP) was significantly higher (53.6 mm [Interquartile range (IQR): 48.3–58.3 mm] vs 46.7 mm [IQR: 36.8–52.2 mm]; p=0.001) and ADP inhibition rate (ADP%) was significantly lower (19% [IQR: 11–31%] vs 31% [IQR: 21–44%]; p=0.001) in DWI (+) patients. Multivariate analysis identified MAADP, ADP%, and procedure time as significant independent predictors of subsequent DWI (+) lesions (odds ratios: 1.07, 0.96, and 1.02, respectively). Based on receiver operating characteristic curve analysis, MAADP >50.9 mm and ADP% <28.8% were associated with postoperative DWI (+) lesions in patients undergoing coil embolization for UIAs. ConclusionsMAADP and ADP% as assessed by TEG6s can offer reliable parameters to predict postoperative ischemic complications after coil embolization of UIAs. Lower MAADP values and higher ADP% may decrease the risk of postoperative ischemic complications.

Sex differences in imaging and clinical characteristics of patients from the WAKE-UP trial.

Sex-based differences in acute ischemic stroke are a well-known phenomenon. We aimed to explore these differences between women and men in the Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke (WAKE-UP) trial. We compared baseline demographic and imaging characteristics (visual fluid-attenuated inversion recovery [FLAIR] positivity, relative FLAIR signal intensity, collateral status) between women and men in all screened patients. In randomized patients (i.e., those with diffusion-weighted imaging (DWI)-FLAIR mismatch), we evaluated a modifying role of sex on the treatment effect of alteplase in multivariable logistic regression, with treatment adjusted for National Institute of Health Stroke Scale (NIHSS) score and age. Dependent variables were modified Rankin Scale (mRS) score of 0-1 at 90 days and distribution of mRS scores at 90 days. Of 1362 screened patients, 529 (38.8%) were women. Women were older than men, had higher baseline NIHSS scores and smoked less frequently. FLAIR positivity of the DWI lesion was equally present in women (174/529, 33.1%) and men (273/833, 33.3%; p=1.00) and other imaging variables also did not differ between the sexes. In a total of 503 randomized patients, of whom 178 were women (35.4%), sex did not modify the treatment effect of alteplase on mRS score 0-1 or on the total distribution of mRS scores. As in many other stroke trials, more men than women were included in the WAKE-UP trial, but the presence of a visual DWI-FLAIR mismatch and the relative FLAIR signal intensity did not differ between the sexes. The treatment effect of alteplase was not modified by sex.

Topographic Mapping of Isolated Thalamic Infarcts Using Vascular and Novel Probabilistic Functional Thalamic Landmarks

PurposeWe aimed to re-evaluate the relationship between thalamic infarct (TI) localization and clinical symptoms using a vascular (VTM) and a novel functional territorial thalamic map (FTM).MethodsMagnetic resonance imaging (MRI) and clinical data of 65 patients with isolated TI were evaluated (female n = 23, male n = 42, right n = 23, left n = 42). A VTM depicted the known seven thalamic vascular territories (VT: inferolateral, anterolateral, inferomedial, posterior, central, anteromedian, posterolateral). An FTM was generated from a probabilistic thalamic nuclei atlas to determine six functionally defined territories (FT: anterior: memory/emotions; ventral: motor/somatosensory/language; medial: behavior/emotions/nociception, oculomotor; intralaminar: arousal/pain; lateral: visuospatial/somatosensory/conceptual and analytic thinking; posterior: audiovisual/somatosensory). Four neuroradiologists independently assigned diffusion-weighted imaging (DWI) lesions to the territories mapped by the VTM and FTM. Findings were correlated with clinical features.ResultsThe most frequent symptom was a hemisensory syndrome (58%), which was not specific for any territory. A co-occurrence of hemisensory syndrome and hemiparesis had positive predictive values (PPV) of 76% and 82% for the involvement of the inferolateral VT and ventral FT, respectively. Thalamic aphasia had a PPV of 63% each for involvement of the anterolateral VT and ventral FT. Neglect was associated with involvement of the inferolateral VT/ventral FT. Interrater reliability for the assignment of DWI lesions to the VTM was fair (κ = 0.36), but good (κ = 0.73) for the FTM.ConclusionThe FTM revealed a greater reproducibility for the topographical assignment of TI than the VTM. Sensorimotor hemiparesis and neglect are predictive for a TI in the inferolateral VT/ventral FT. The hemisensory syndrome alone does not allow any topographical assignment.

Abstract 317: Brain MRI And Spectroscopy Biomarkers Predict Outcome After Pediatric Cardiac Arrest In POCCA

Conventional (T2) and diffusion-weighted imaging (DWI) on brain magnetic resonance imaging (MRI) and lactate and N-acetyl-aspartate (NAA) on MR spectroscopy (MRS) can characterize brain hypoxic-ischemic injury. We hypothesized these neuroimaging biomarkers would be associated with 1 year outcome after pediatric cardiac arrest in a multicenter, observational study. Fourteen US centers enrolled children aged &lt; 18 years with pediatric intensive care unit admission post-arrest if pre- arrest Pediatric Cerebral Performance Category score was 1-3. Brain MRI/MRS performed within 2 weeks post-arrest were analyzed independently by 2 pediatric neuroradiologists blinded to outcome. MRI lesions on T2 and DWI were scored by region and severity (0=none, 1=mild, 2=moderate, 3=severe). Total MRI score was a sum of T2 and DWI lesions in gray and white matter (max 34). Lactate and NAA were measured in the basal ganglia, thalamus, and occipital-parietal white/gray matter and quantified by LCModel. Multivariate regression was performed to determine the association with unfavorable outcome (Vineland Adaptive Behavioral Scale &lt; 70 or dead at 1 year). Of 164 children, 66 and 32 had evaluable MRI and MRS data and 23 (35%) and 12 (38%) had unfavorable outcome, respectively. Children with unfavorable outcome had more unwitnessed and out-of-hospital events. DWI lesions in all 4 lobes predicted unfavorable outcome, whereas T2 temporal gray and parietal white matter lesions predicted unfavorable outcome, p&lt;0.05. T2/DWI lesions in the basal ganglia, thalamus, and centrum semi-ovale predicted unfavorable outcome, p&lt;0.05. Cerebellar/ brain stem white matter lesions predicted unfavorable outcome, p&lt;.05. Total MRI scores were markedly higher in the unfavorable group (median [interquartile range]) (22 [7, 32] vs. 1 [0,8], p&lt;0.001). Increased lactate and decreased NAA predicted unfavorable outcome in all 4 regions of interest, p&lt;0.05. In a multivariate logistic regression, MRI total score (odds ratio 1.12 [95% confidence interval 1.05, 1.20]) and witnessed event status (0.07 [0.01, 0.34]) predicted outcome. Brain MRI and MRS biomarkers are useful to identify children with unfavorable outcome within 2 weeks post-cardiac arrest.

Differential Trajectory of Diffusion and Perfusion Magnetic Resonance Imaging of Rat Spinal Cord Injury.

Traumatic spinal cord injury causes rapid neuronal and vascular injury, and predictive biomarkers are needed to facilitate acute patient management. This study examined the progression of magnetic resonance imaging (MRI) biomarkers after spinal cord injury and their ability to predict long-term neurological outcomes in a rodent model, with an emphasis on diffusion-weighted imaging (DWI) markers of axonal injury and perfusion-weighted imaging of spinal cord blood flow (SCBF). Adult Sprague-Dawley rats received a cervical contusion injury of varying severity (injured = 30, sham = 9). MRI at 4 h, 48-h, and 12-weeks post-injury included T1, T2, perfusion, and DWI. Locomotor outcome was assessed up to 12 weeks post-injury. At 4 h, the deficit in SCBF was larger than the DWI lesion, and although SCBF partially recovered by 48 h, the DWI lesion expanded. At 4 h, the volume of the SCBF deficit (R2 = 0.56, padj < 0.01) was significantly correlated with 12-week locomotor outcome, whereas DWI (R2 = 0.30, padj < 0.01) was less predictive of outcome. At 48 h, SCBF (R2 = 0.41, padj < 0.01) became less associated with outcome, and DWI (R2 = 0.38, padj < 0.01) lesion volume became more closely related to outcome. Spinal cord perfusion has unique spatiotemporal dynamics compared with diffusion measures of axonal damage and highlights the importance of acute perfusion abnormalities. Perfusion and diffusion offer complementary and clinically relevant insight into physiological and structural abnormalities following spinal cord injury beyond those afforded by T1 or T2 contrasts.

Diffusion kurtosis imaging in patients with tissue-negative transient ischemic attack.

Approximately 50-60% of patients with a clinical transient ischemic attack (TIA) do not have diffusion-weighted imaging (DWI) evidence of cerebral ischemia. The purpose of this study was to assess the added diagnostic value of diffusion kurtosis imaging (DKI) in the evaluation of patients with TIA who have normal DWI findings. From September 2014 to May 2017, a total of 179 consecutive patients with suspected TIA were eligible for enrollment in our study. The inclusion criteria were a confirmed diagnosis of TIA confirmed by a stroke neurologist, MRI (including DWI and DKI) within 24 h after symptom onset, no stroke history, and no DWI lesion. A follow-up DWI was performed to establish stroke recurrence within a period of 90 days. A total of 98 patients who had no lesions on the baseline DWI were included for data analysis. Of these 98 patients, 31 (31.6%) had positive findings on the initial DKI. In 29 of the 31 (93.5%) patients, the location of the abnormality observed on DKI was consistent with the clinical symptoms. During the 90-day follow-up period, 14 (14.3%) patients developed recurrent stroke. The prevalence of recurrent stroke was higher in the DKI-positive group than in the DKI-negative group (29.0% vs. 7.5%, p = 0.01). A comparison between the patients with and without recurrent stroke showed that an abnormality on the baseline DKI was associated with stroke recurrence. Furthermore, 8 of the 9 stroke patients in the DKI-positive group developed a new ischemic lesion in the artery territory corresponding to the initial DKI abnormality. The new findings suggest the predictive value of DKI on the recurrence of stroke in the patients with TIA who have negative findings on conventional DWI.

Early and Delayed Infarct Growth in Patients Undergoing Mechanical Thrombectomy: A Prospective, Serial MRI Study.

We studied the evolution over time of diffusion weighted imaging (DWI) lesion volume and the factors involved on early and late infarct growth (EIG and LIG) in stroke patients undergoing endovascular treatment (EVT) according to the final revascularization grade. This is a prospective cohort of patients with anterior large artery occlusion undergoing EVT arriving at 1 comprehensive stroke center. Magnetic resonance imaging was performed on arrival (pre-EVT), <2 hours after EVT (post-EVT), and on day 5. DWI lesions and perfusion maps were evaluated. Arterial revascularization was assessed according to the modified Thrombolysis in Cerebral Infarction (mTICI) grades. We recorded National Institutes of Health Stroke Scale at arrival and at day 7. EIG was defined as (DWI volume post-EVT-DWI volume pre-EVT), and LIG was defined as (DWI volume at 5d-DWI volume post-EVT). Factors involved in EIG and LIG were tested via multivariable lineal models. We included 98 patients (mean age 70, median National Institutes of Health Stroke Scale score 17, final mTICI≥2b 86%). Median EIG and LIG were 48 and 63.3 mL in patients with final mTICI<2b, and 3.6 and 3.9 cc in patients with final mTICI≥2b. Both EIG and LIG were associated with higher National Institutes of Health Stroke Scale at day 7 (ρ=0.667; P<0.01 and ρ=0.614; P<0.01, respectively). In patients with final mTICI≥2b, each 10% increase in the volume of DWI pre-EVT and each extra pass leaded to growths of 9% (95% CI, 7%-10%) and 14% (95% CI, 2%-28%) in the DWI volume post-EVT, respectively. Furthermore, each 10% increase in the volume of DWI post-EVT, each extra pass, and each 10 mL increase in TMax6s post-EVT were associated with growths of 8% (95% CI, 6%-9%), 9% (95% CI, 0%-19%), and 12% (95% CI, 5%-20%) in the volume of DWI post-EVT, respectively. Infarct grows during and after EVT, especially in nonrecanalizers but also to a lesser extent in recanalizers. In recanalizers, number of passes and DWI volume influence EIG, while number of passes, DWI, and hypoperfused volume after the procedure determine LIG.

Acute Infarcts on Brain MRI Following Aortic Arch Repair With Circulatory Arrest: Insights From the ACE CardioLink-3 Randomized Trial.

to investigate the frequency and distribution of new ischemic brain lesions detected by diffusion-weighted imaging on brain magnetic resonance imaging after aortic arch surgery. This preplanned secondary analysis of the randomized, controlled ACE (Aortic Surgery Cerebral Protection Evaluation) CardioLink-3 trial compared the safety and efficacy of innominate versus axillary artery cannulation during elective proximal aortic arch surgery. Participants underwent pre and postoperative magnetic resonance imaging. New ischemic lesions were defined as lesions visible on postoperative, but not preoperative diffusion weighted imaging. Of the 111 trial participants, 102 had complete magnetic resonance imaging data. A total of 391 new ischemic lesions were observed on diffusion-weighted imaging in 71 (70%) patients. The average number of lesions in patients with ischemic lesion were 5.5±4.9 with comparable numbers in the right (2.9±2.0) and left (3.0±2.3) hemispheres (P=0.49). Half the new lesions were in the middle cerebral artery territory; 63% of the cohort had ischemic lesions in the anterior circulation, 49% in the posterior circulation, 42% in both, and 20% in watershed areas. A probability mask of all diffusion-weighted imaging lesions revealed that the cerebellum was commonly involved. More severe white matter hyperintensity on preoperative magnetic resonance imaging (odds ratio, 1.80 [95% CI, 1.10-2.95]; P=0.02) and lower nadir nasopharyngeal temperature during surgery (odds ratio per 1°C decrease, 1.15 [95% CI, 1.00-1.32]; P=0.05) were associated with the presentation of new ischemic lesion; older age (risk ratio per 1-year increase, 1.02 [95% CI, 1.00-1.04]; P=0.03) and lower nadir temperature (risk ratio per 1°C decrease, 1.06 [95% CI, 1.00-1.14]; P=0.06) were associated with greater number of lesions. In patients who underwent elective proximal aortic arch surgery, new ischemic brain lesions were common, and predominantly involved the middle cerebral artery territory or cerebellum. Underlying small vessel disease, lower temperature nadir during surgery, and advanced age were risk factors for perioperative ischemic lesions. URL: https://www. gov; Unique identifier: NCT02554032.

Editors' Note: Accuracy of CT Perfusion-Based Core Estimation of Follow-up Infarction: Effects of Time Since Last Known Well.

In a prospective multicenter study of 101 patients, Dr. Sarraj and colleagues assessed the accuracy of baseline CT perfusion (CTP) estimates of ischemic core, relative to follow-up diffusion-weighted imaging (DWI) lesion infarct volumes, in patients with ischemic stroke who achieved complete reperfusion with endovascular thrombectomy. The authors found that significant overestimation of the volume of irreversibly injured ischemic core—by 10 mL or more—was rare and was only observed in patients who presented within 90 minutes of last known well and achieved reperfusion within 120 minutes of CTP acquisition. Such overestimation also primarily occurred in the white matter. The overestimation of ischemia was eliminated by using a more conservative threshold for relative cerebral flood flow (rCBF) of <20% as opposed to the more typically used threshold of <30% in patients presenting within 90 minutes. In response, Drs. Garcia-Camba and Jacobi note that the prevalence and temporal distribution of patients with a large ischemic core (≥50 mL) was not reported; this could affect the overestimation rate in the study and potentially limit the generalizability of its findings. Replying to this, the authors note that their cohort was derived from consecutively enrolled patients at 9 high-volume thrombectomy centers and did not exclude patients from treatment based on ischemic core estimates. They note that their cohort reflects contemporary clinical practice, reporting the number of patients with different ischemic core volume thresholds, and note that overestimation rates did not vary with core size. They point to ongoing trials of thrombectomy in patients with large estimated core volumes and to the SELECT2 study, which includes CTP and noncontrast CT imaging, and will help establish if there is a ceiling to thrombectomy benefit in patients with large vessel occlusion based on noncontrast CT or CTP findings. This exchange highlights our evolving understanding of the concept and measurement of ischemic core and its changing importance in patient selection decisions for thrombectomy. In a prospective multicenter study of 101 patients, Dr. Sarraj and colleagues assessed the accuracy of baseline CT perfusion (CTP) estimates of ischemic core, relative to follow-up diffusion-weighted imaging (DWI) lesion infarct volumes, in patients with ischemic stroke who achieved complete reperfusion with endovascular thrombectomy. The authors found that significant overestimation of the volume of irreversibly injured ischemic core—by 10 mL or more—was rare and was only observed in patients who presented within 90 minutes of last known well and achieved reperfusion within 120 minutes of CTP acquisition. Such overestimation also primarily occurred in the white matter. The overestimation of ischemia was eliminated by using a more conservative threshold for relative cerebral flood flow (rCBF) of <20% as opposed to the more typically used threshold of <30% in patients presenting within 90 minutes. In response, Drs. Garcia-Camba and Jacobi note that the prevalence and temporal distribution of patients with a large ischemic core (≥50 mL) was not reported; this could affect the overestimation rate in the study and potentially limit the generalizability of its findings. Replying to this, the authors note that their cohort was derived from consecutively enrolled patients at 9 high-volume thrombectomy centers and did not exclude patients from treatment based on ischemic core estimates. They note that their cohort reflects contemporary clinical practice, reporting the number of patients with different ischemic core volume thresholds, and note that overestimation rates did not vary with core size. They point to ongoing trials of thrombectomy in patients with large estimated core volumes and to the SELECT2 study, which includes CTP and noncontrast CT imaging, and will help establish if there is a ceiling to thrombectomy benefit in patients with large vessel occlusion based on noncontrast CT or CTP findings. This exchange highlights our evolving understanding of the concept and measurement of ischemic core and its changing importance in patient selection decisions for thrombectomy.

Distribution Pattern Analysis of Cortical Brain Infarcts on Diffusion-Weighted Magnetic Resonance Imaging: A Hypothesis-Generating Approach to the Burden of Silent Embolic Stroke.

Background In patients with covert cerebrovascular disease or proximal source of embolism, embolic silent brain infarction may precede major stroke events. Therefore, characterization of particularly cortical silent brain infarction is essential for identifying affected patients and commencing adequate secondary prevention. This study aimed to investigate differences in the distribution pattern of cortical ischemic stroke lesions to assess potential predilection sites of cortical silent brain infarction. Methods and Results We prospectively included all consecutive patients with stroke presenting from January 1 to December 31, 2018. Diffusion-weighted imaging lesions were used to generate voxel-based lesion maps and assigned to atlas-based cortical regions of interest in middle cerebral artery territories. Each region-of-interest lesion frequency was related to the respective region-of-interest volume to identify frequently affected and underrepresented cerebral cortex areas. Diffusion-weighted imaging data for voxel-based lesion maps were available in 334 out of 633 patients. Primary analysis revealed that small- (<0.24 cc) and medium-sized (0.24-2640 cc) lesions distributed predominantly along regions associated with sensorimotor or language function. Detailed analysis within middle cerebral artery territories showed an approximated frequency of missed cortical stroke lesions of up to 67% in the right and 69% in the left hemisphere. In particular, the frontal, temporal, and occipital cortices were underrepresented. Larger lesion size and areas associated with higher cortical function led to hospital admission. Conclusions Cortical brain infarcts in hospitalized patients are not dispersed equally but are predominantly located in brain structures associated with motor control and sensory and language function. Matching underrepresented cerebral cortex regions to symptoms not yet associated with stroke warrants further exploration.

Remote diffusion-weighted imaging lesions and blood pressure variability in primary intracerebral hemorrhage.

ObjectiveThe aim of this study was to examine the association between remote diffusion-weighted imaging lesions (R-DWILs) and blood pressure variability (BPV) in patients with primary intracerebral hemorrhage (ICH).MethodsWe conducted a retrospective review of a consecutive cohort of 375 patients with primary ICH within 24 h onset. R-DWILs were defined as hyperintensity lesions in DWI remote from the hematoma. Blood pressure recordings were extracted up to 24 h post-admission. BPV was measured using SD, coefficient of variation (CV), and successive variation (SV).ResultsRemote DWI lesions were detected in 65 (17.3%) primary ICH patients. In multivariable logistic regression analysis, parameters of BPV were independently associated with R-DWILs, and the results remained consistent after being adjusted with mean SBP. SD, CV, and SV values in the highest quintile, showed 3- to 8-fold increased risk of R-DWILs, compared with the lowest quintile. ΔSBP demonstrated a significant difference in 2 different predictive models. Max SBP only dictated a significant difference in model 1. Mean SBP, admission SBP, and min SBP, failed to present an association with R-DWILs in model 1 or model 2.ConclusionOur results provided additional evidence that BPV is associated with the development of R-DWILs in primary ICH.

Deep profiling of multiple ischemic lesions in a large, multi-center cohort: Frequency, spatial distribution, and associations to clinical characteristics.

Background purposeA substantial number of patients with acute ischemic stroke (AIS) experience multiple acute lesions (MAL). We here aimed to scrutinize MAL in a large radiologically deep-phenotyped cohort.Materials and methodsAnalyses relied upon imaging and clinical data from the international MRI-GENIE study. Imaging data comprised both Fluid-attenuated inversion recovery (FLAIR) for white matter hyperintensity (WMH) burden estimation and diffusion-weighted imaging (DWI) sequences for the assessment of acute stroke lesions. The initial step featured the systematic evaluation of occurrences of MAL within one and several vascular supply territories. Associations between MAL and important imaging and clinical characteristics were subsequently determined. The interaction effect between single and multiple lesion status and lesion volume was estimated by means of Bayesian hierarchical regression modeling for both stroke severity and functional outcome.ResultsWe analyzed 2,466 patients (age = 63.4 ± 14.8, 39% women), 49.7% of which presented with a single lesion. Another 37.4% experienced MAL in a single vascular territory, while 12.9% featured lesions in multiple vascular territories. Within most territories, MAL occurred as frequently as single lesions (ratio ∼1:1). Only the brainstem region comprised fewer patients with MAL (ratio 1:4). Patients with MAL presented with a significantly higher lesion volume and acute NIHSS (7.7 vs. 1.7 ml and 4 vs. 3, pFDR < 0.001). In contrast, patients with a single lesion were characterized by a significantly higher WMH burden (6.1 vs. 5.3 ml, pFDR = 0.048). Functional outcome did not differ significantly between patients with single versus multiple lesions. Bayesian analyses suggested that the association between lesion volume and stroke severity between single and multiple lesions was the same in case of anterior circulation stroke. In case of posterior circulation stroke, lesion volume was linked to a higher NIHSS only among those with MAL.ConclusionMultiple lesions, especially those within one vascular territory, occurred more frequently than previously reported. Overall, multiple lesions were distinctly linked to a higher acute stroke severity, a higher total DWI lesion volume and a lower WMH lesion volume. In posterior circulation stroke, lesion volume was linked to a higher stroke severity in multiple lesions only.

ANAID-ICH nomogram for predicting unfavorable outcome after intracerebral hemorrhage.

Diffusion-weighted imaging lesions (DWILs) are associated with unfavorable outcome in intracerebral hemorrhage (ICH). We proposed a novel predictive nomogram incorporating DWILs. A total of 738 patients with primary ICH in a tertiary hospital were prospectively enrolled as a training cohort. DWILs were defined as remote focal hyperintensities on DWI corresponding to low intensities on apparent diffusion coefficient images and remote from the focal hematoma. The outcome of interest was modified Rankin Scale scores of 4-6 at 90 days after onset. Multivariate logistic regression was used to construct a nomogram. Model performance was tested in the training cohort and externally validated with respect to discrimination, calibration, and clinical usefulness in another institute. Additionally, the nomogram was compared with the ICH score in terms of predictive ability. Overall, 153 (20.73%) and 23 (15.54%) patients developed an unfavorable outcome in the training and validation cohorts, respectively. The multivariate analysis revealed that age, National Institutes of Health Stroke Scale (NIHSS) score, anemia, infratentorial location, presence of DWILs, and prior ICH were associated with unfavorable outcome. Our ANAID-ICH nomogram was constructed according to the aforementioned variables; the area under the receiver operating characteristic curve was 0.842 and 0.831 in the training and validation sets, respectively. With regard to the 90-day outcome, the nomogram showed a significantly higher predictive value than the ICH score in both cohorts. The ANAID-ICH nomogram comprising age, NIHSS score, anemia, infratentorial location, presence of DWILs, and prior ICH may facilitate the identification of patients at higher risk for an unfavorable outcome.

Fluid-attenuated inversion recovery vascular hyperintensity-diffusion-weighted imaging mismatch and functional outcome after endovascular reperfusion therapy for acute ischemic stroke.

Fluid-attenuated inversion recovery vascular hyperintensity (FVH) outside of the diffusion-weighted imaging (DWI) lesion, termed FVH-DWI mismatch, may represent penumbral tissue with good collateral status. Consecutive patients who underwent endovascular reperfusion therapy (EVT) for acute internal carotid artery (ICA) or middle cerebral artery (MCA)-M1 occlusion were enrolled. FVH-DWI mismatch score was defined as the number of cortical Alberta Stroke Program Early CT Score areas (I and M1 to M6) that involved FVH but no DWI lesion (0 to 7 points). The outcome measure was set as good functional outcome, defined as a modified Rankin Scale score of 0 to 2, at 90 days after onset. Of 196 consecutive patients who underwent EVT for acute ICA or MCA-M1 occlusion, 32 without brain MRI before EVT were excluded, and the remaining 164 were analyzed. The median FVH-DWI mismatch score was 2 (interquartile range, 0 to 4). At 90 days after EVT, 2 patients were lost-to follow-up, and 73 had good functional outcome. The frequency of good functional outcome at 90 days after EVT increased significantly with increasing FVH-DWI mismatch score (P for trend <0.001). FVH-DWI mismatch score was independently associated with good functional outcome at 90 days after onset (adjusted odds ratio per 1 point,1.46; 95% confidence interval, 1.15-1.89). Patients with large FVH-DWI mismatch had good functional outcome after EVT for acute ICA or MCA-M1 occlusion.

Transient global amnesia with unexpected clinical and radiological findings: A case series and systematic review

BackgroundTransient global amnesia (TGA) represents a benign neurological syndrome of unknown pathophysiology, often accompanied by vanishing hippocampal punctate diffusion-weighted imaging lesions (HPDL). The literature suggests that TGA may present with unusual features. This study analyses atypical clinical and radiological manifestations of patients with TGA and/or HPDL. MethodsWe retrospectively reviewed patients with atypical clinical or radiological presentations of TGA and/or HPDL in three neurology centers. We also performed a systematic review of literature using predefined search terms. Results were classified as: A) Atypical clinical manifestations of TGA (such as amnesia with additional manifestations, or only non-amnesic manifestations); B) Atypical radiological manifestations of clinically typical TGA. ResultsWe identified 83 patients: 18 in our centres (median age 63.5 years, 39% female) and 65 in the literature. In group A, 43 patients presented atypical clinical manifestations such as TGA with added transitory cognitive or sensory-motor deficits, seizures, headaches, but also non-amnesic presentations associated with HPDL and incidental HPDL without symptoms. In group B, 40 patients with typical clinical TGA showed extra-hippocampal punctate diffusion lesions (E-HPDL) which disappeared on follow-up imaging. Using clinical and radiological manifestations, we classified these patients into different categories describing a “TGA-PDL spectrum”. ConclusionsTGA may have atypical clinical manifestations despite typical neuroimaging and patients with typical TGA may show vanishing extra-hippocampal punctate diffusion lesions. TGA, related clinical manifestations, and vanishing punctate diffusion lesions should be considered part of a larger “TGA-PDL spectrum”, allowing for better diagnosis of typical and atypical cases and stimulating further studies.

Estimating Perfusion Deficits in Acute Stroke Patients Without Perfusion Imaging.

Perfusion weighted imaging (PWI) is critical for determining whether stroke patients presenting in an extended time window are candidates for mechanical thrombectomy. However, PWI is not always available. Fluid-attenuated inversion recovery hyperintense vessels (FHVs) are seen in patients with a PWI lesion. We investigated whether a scale measuring the extent FHV could serve as a surrogate for PWI to determine eligibility for thrombectomy. The National Institutes of Health (NIH) FHV score was developed to quantify the burden of FHV and applied to magnetic resonance imaging scans of stroke patients with fluid-attenuated inversion recovery and perfusion imaging. The NIH-FHV was combined with the diffusion weighted image volume to estimate the diffusion-perfusion mismatch ratio. Linear regression was used to compare PWI volumes and mismatch ratios with estimates from the NIH-FHV score. Receiver operating characteristic analysis was used to test the ability of the NIH-FHV score to identify a significant mismatch. There were 101 patients included in the analysis, of whom 78% had a perfusion deficit detected on PWI with a mean lesion volume of 47 (±59) mL. The NIH-FHV score was strongly associated with the PWI lesion volume (P<0.001; R2=0.32; β-coefficient, 0.57). When combined with diffusion weighted image lesion volume, receiver operating characteristic analysis testing the ability to detect a mismatch ratio ≥1.8 using the NIH-FHV score resulted in an area under the curve of 0.94. The NIH-FHV score provides an estimate of the PWI lesion volume and, when combined with diffusion weighted imaging, may be helpful when trying to determine whether there is a clinically relevant diffusion-perfusion mismatch in situations where perfusion imaging is not available. Further studies are needed to validate this approach.

Association of Stroke Lesion Pattern and White Matter Hyperintensity Burden With Stroke Severity and Outcome.

To examine whether high white matter hyperintensity (WMH) burden is associated with greater stroke severity and worse functional outcomes in lesion pattern-specific ways. MR neuroimaging and NIH Stroke Scale data at index stroke and the modified Rankin Scale (mRS) score at 3-6 months after stroke were obtained from the MRI-Genetics Interface Exploration study of patients with acute ischemic stroke (AIS). Individual WMH volume was automatically derived from fluid-attenuated inversion recovery images. Stroke lesions were automatically segmented from diffusion-weighted imaging (DWI) images, parcellated into atlas-defined brain regions and further condensed to 10 lesion patterns via machine learning-based dimensionality reduction. Stroke lesion effects on AIS severity and unfavorable outcomes (mRS score >2) were modeled within purpose-built Bayesian linear and logistic regression frameworks. Interaction effects between stroke lesions and a high vs low WMH burden were integrated via hierarchical model structures. Models were adjusted for age, age2, sex, total DWI lesion and WMH volumes, and comorbidities. Data were split into derivation and validation cohorts. A total of 928 patients with AIS contributed to acute stroke severity analyses (age: 64.8 [14.5] years, 40% women) and 698 patients to long-term functional outcome analyses (age: 65.9 [14.7] years, 41% women). Stroke severity was mainly explained by lesions focused on bilateral subcortical and left hemispherically pronounced cortical regions across patients with both a high and low WMH burden. Lesions centered on left-hemispheric insular, opercular, and inferior frontal regions and lesions affecting right-hemispheric temporoparietal regions had more pronounced effects on stroke severity in case of high compared with low WMH burden. Unfavorable outcomes were predominantly explained by lesions in bilateral subcortical regions. In difference to the lesion location-specific WMH effects on stroke severity, higher WMH burden increased the odds of unfavorable outcomes independent of lesion location. Higher WMH burden may be associated with an increased stroke severity in case of stroke lesions involving left-hemispheric insular, opercular, and inferior frontal regions (potentially linked to language functions) and right-hemispheric temporoparietal regions (potentially linked to attention). Our findings suggest that patients with specific constellations of WMH burden and lesion locations may have greater benefits from acute recanalization treatments. Future clinical studies are warranted to systematically assess this assumption and guide more tailored treatment decisions.