Large Diffusion-weighted Imaging Lesions Research Articles

Outcomes of Mechanical Thrombectomy in Patients with Large Diffusion-Weighted Imaging Lesions.

ObjectiveDespite many advancements in endovascular treatment, the benefits of mechanical thrombectomy (MT) in patients with large infarctions remain uncertain due to hemorrhagic complications. Therefore, we aimed to investigate the efficacy and safety of recanalization via MT within 6 hours after stroke in patients with large cerebral infarction volumes (>70 mL). MethodsWe retrospectively reviewed the medical data of 30 patients with large lesions on initial diffusion-weighted imaging (>70 mL) who underwent MT at our institution within 6 hours after stroke onset. Baseline data, recanalization rate, and 3-month clinical outcomes were analyzed. Successful recanalization was defined as a modified treatment in cerebral ischemia score of 2b or 3. ResultsThe recanalization rate was 63.3%, and symptomatic intracerebral hemorrhage occurred in six patients (20%). The proportion of patients with modified Rankin Scale (mRS) scores of 0–3 was significantly higher in the recanalization group than in the non-recanalization group (47.4% vs. 9.1%, p=0.049). The mortality rate was higher in the non-recanalization group, this difference was not significant (15.8% vs. 36.4%, p=0.372). In the analysis of 3-month clinical outcomes, only successful recanalization was significantly associated with mRS scores of 0–3 (90% vs. 50%, p=0.049). The odds ratio of recanalization for favorable outcomes (mRS 0–3) was 9.00 (95% confidence interval, 0.95–84.90; p=0.055). ConclusionDespite the risk of symptomatic intracerebral hemorrhage, successful recanalization via MT 6 hours after stroke may improve clinical outcomes in patients with large vessel occlusion.

Diffusion-Weighted Imaging Patterns According to the Right-to-Left Shunt Amount in Cryptogenic Stroke

Background: Although patent foramen ovale (PFO) is considered to be the main cause of cryptogenic stroke, it is difficult to define “true” PFO-related stroke. Objective: In this study, we evaluated comprehensive diffusion-weighted imaging (DWI) findings in patients with cryptogenic stroke according to the right-to-left shunt (RLS) amounts on transcranial Doppler (TCD) sonography. Methods: We assessed consecutive patients with cryptogenic stroke between October 2010 and 2018. The RLS amount on TCD was assessed according to the International Consensus Criteria (ICC). Massive RLS was defined as the highest category of ICC (Curtain pattern). We assessed DWI findings, including the location of lesions, involved vascular territory, and DWI lesion patterns. Results: A total of 100 consecutive patients with cryptogenic stroke were assessed, and PFO was found in 59 patients. In multivariable analyses, massive RLS was noted to be positively associated with the presence of cortical lesion (adjusted OR [aOR] 15.75, 95% CI 1.94–127.71, p = 0.010), multiple territory involvement (aOR 5.24, 95% CI 1.57–17.53, p = 0.007), and number of DWI lesions (beta 0.713, 95% CI 0.245 to 1.181, p = 0.003) after adjusting for confounders. Conversely, massive RLS showed inverse correlations with posterior circulation involvement (aOR 0.22, 95% CI 0.06–0.87, p= 0.031) and number of large DWI lesions (beta –0.328, 95% CI –0.629 to –0.026, p = 0.034). Conclusions: We demonstrated that massive RLS on TCD was associated with multiple, small-scattered cortical lesion in patients with cryptogenic stroke. These DWI pattern is highly suggestive of PFO-related stroke.

Abstract WP21: Successful Reperfusion With Thrombectomy in Patients With Large Dwi Lesion is Associated With Reduced Occurrence of Malignant Stroke

Introduction: Malignant middle cerebral artery infarction (MMI) is a severe complication of ischaemic stroke (IS), with a mortality rate up to 80%. Diffusion-weighted imaging (DWI) lesion volume larger than 82 millilitres on cerebral MRI performed within the six first hours is known to be predictive of MMI. These patients, with “malignant profile”, were mostly excluded of endovascular therapy (EVT) randomised trials. The aim of our study was to evaluate whether successful reperfusion after EVT in patients presenting IS with large DWI lesion decreased occurrence of malignant stroke. Methods: We analysed data collected between 2014 and 2018, in a monocentric prospective IS patients registry treated with EVT. Patients were selected if they had a malignant profile and could be eligible to a craniectomy. Thus, selected patients were less than 65-years old, with a severe stroke defined by National Institutes of Health Stroke Scale (NIHSS) score > 15 and with DWI lesion larger than 82ml. We compared patients with successful recanalization (defined by Thrombolysis in Cerebral Ischemia (TICI) 2b or 3) and poor recanalization (TICI 0, 1 or 2A). Primary end point was malignant stroke rate. Secondary end points were craniectomy, haemorrhagic complications, 90-days all-cause mortality rates and 90-days favourable outcome (defined by modified Rankin Scale 0-2). Results: From 2014 to 2018, 66 patients were selected. MMI occurred in 27 patients (42%), and 22 (33%) had effectively craniectomy. Successful recanalization was observed for 46 patients (69.7%). MMI occurrence was significantly lower in the latter patients compared to the poor recanalization group (14/44(31.8%) vs 13/20(65.0%); OR=0.25 (0.08-0.77), p = 0.015). Less craniectomies were performed in the successful recanalization group (12/46 (26.1%) vs 10/20 (50.0%); OR=0.35 (011-1.06), p=0.063).There was no significant difference in symptomatic intracranial haemorrhage rate; in 90-days favourable outcome and all causes mortality rate between the two groups. Conclusion: Successful recanalization performed in IS patients with large DWI lesion decreases the occurrence of malignant strokes and the need for craniectomy procedure. Further data with a larger sample or from randomized studies are needed.

Thrombolysis in Large Diffusion-Weighted Imaging Lesions: Lower Chance but Still a Chance

We sought to investigate whether early thrombolytic treatment can result in favorable functional outcome even in patients with large diffusion-weighted imaging (DWI) lesions. We analyzed 566 patients who received intravenous alteplase within 4.5 hours from onset, initially underwent DWI and magnetic resonance angiography, and had acute infarction confined to anterior circulation. DWI lesion volumes were measured semiautomatically. The association between DWI lesion volume and 3-month outcome in patients who achieved early recanalization was assessed. The DWI lesion volume cutoff, which predicts unfavorable outcome despite recanalization, was determined. In patients with large DWI lesions, the distributions of modified Rankin Scale (mRS) score were compared according to the recanalization status. Four hundred thirty-six patients achieved early recanalization. Among these patients, 283 (65%) patients had a favorable functional outcome (mRS score 0-2). DWI lesion volume (odds ratio [OR], 1.38 per 10 mL; 95% confidence interval [CI], 1.22-1.56) was an independent variable associated with poor outcome, along with hypertension (OR, 1.87; 95% CI, 1.12-3.10), National Institutes of Health Stroke Scale (NIHSS) score (OR, 1.13; 95% CI, 1.08-1.19), and onset-to-needle time (OR, 1.08 per 10 minutes; 95% CI, 1.03-1.13). The DWI lesion of 60 mL or higher highly predicted an unfavorable outcome with a positive predictive value of 95.3%. In patients with a DWI lesion of 60 mL or higher, recanalization had no benefit for an mRS score of 0-2 but was significantly associated with an mRS score of 0-3 (OR, 4.64; 95% CI, 1.08-19.97). Despite early recanalization, the probability of favorable outcome is low in patients with a DWI lesion of 60 mL or higher. Nevertheless, the benefit of recanalization still persists in large DWI lesions.

Is there a benefit of mechanical thrombectomy in patients with large stroke (DWI-ASPECTS ≤ 5)?

Whether to withhold mechanical thrombectomy when the diffusion-weighted imaging (DWI) lesion exceeds a given volume is undetermined. Our aim was to identify markers that will help to select patients with large DWI lesions [DWI-Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) ≤ 5] that may benefit from thrombectomy. From May 2010 to November 2016, 82 acute ischaemic stroke patients with DWI-ASPECTS ≤5 (43 men, 64.6 ± 14.4 years, National Institutes of Health Stroke Scale 18.4 ± 5.4) treated with state-of-the-art mechanical thrombectomy were studied. Thrombectomy alone was performed in 28 (34%) and bridging therapy in 54 (66%) patients. Recanalization was defined as a thrombolysis in cerebral infarction score 2B-3 and significant hemorrhagic transformation as parenchymal haematoma type 2 (European Cooperative Acute Stroke Study 3 classification). Pretreatment variables were compared between patients with a good (modified Rankin Scale 0-2) and a poor (modified Rankin Scale 3-6) neurological outcome at 3 months. Overall, 28 patients (34%) achieved good neurological outcome at 3 months. Recanalizers were significantly more likely to achieve good outcome (61% vs. 7.3%, P < 0.0001), had lower mortality (24% vs. 49%, P = 0.03) and similar rates of parenchymal haematoma type 2 (9.8% vs. 7.3%, P = 1) compared to non-recanalizers. Regression modelling identified DWI-ASPECTS >2 [odds ratio (OR) 6.93; 95% confidence interval (CI) 1.05-45.76, P = 0.04), glycaemia ≤6.8 mmol/l (OR 4.05; 95% CI 1.09-15.0, P = 0.03) and thrombolysis (OR 3.67; 95% CI 1.04-12.9, P = 0.04) as independent predictors of good neurological outcome. In patients with DWI-ASPECTS ≤5, two-thirds of patients experienced good neurological outcome when recanalized by state-of-the-art thrombectomy, whilst only one in 14 non-recanalizers achieved similar outcomes. Pretreatment markers of good neurological outcomes were DWI-ASPECTS >2, intravenous thrombolysis and glycaemia ≤6.8 mmol/l.

Reliability of Two Diameters Method in Determining Acute Infarct Size. Validation as New Imaging Biomarker.

BackgroundIn order to select patients most likely to benefit for thrombolysis and to predict patient outcome in acute ischemic stroke, the volumetric assessment of the infarcted tissue is used. However, infarct volume estimation on Diffusion weighted imaging (DWI) has moderate interrater variability despite the excellent contrast between ischemic lesion and healthy tissue. In this study, we compared volumetric measurements of DWI hyperintensity to a simple maximum orthogonal diameter approach to identify thresholds indicating infarct size >70 ml and >100 ml.MethodsPatients presenting with ischemic stroke with an NIHSS of ≥ 8 were examined with stroke MRI within 24 h after symptom onset. For assessment of the orthogonal DWI lesion diameters (od-values) the image with the largest lesion appearance was chosen. The maximal diameter of the lesion was determined and a second diameter was measured perpendicular. Both diameters were multiplied. Od-values were compared to volumetric measurement and od-value thresholds identifying a lesion size of > 70 ml and > 100 ml were determined. In a selected dataset with an even distribution of lesion sizes we compared the results of the od value thresholds with results of the ABC/2 and estimations of lesion volumes made by two resident physicians.ResultsFor 108 included patients (53 female, mean age 71.36 years) with a median infarct volume of 13.4 ml we found an excellent correlation between volumetric measures and od-values (r2 = 0.951). Infarct volume >100 ml corresponds to an od-value cut off of 42; > 70 ml corresponds to an od-value of 32. In the compiled dataset (n = 50) od-value thresholds identified infarcts > 100 ml / > 70 ml with a sensitivity of 90%/ 93% and with a specificity of 98%/ 89%. The od-value offered a higher accuracy in identifying large infarctions compared to both visual estimations and the ABC/2 method.ConclusionThe simple od-value enables identification of large DWI lesions in acute stroke. The cutoff of 42 is useful to identify large infarctions with volume larger than 100 ml. Further studies can analyze the therapeutic utility of this new method.Trail RegistrationClinicalTrials.org NCT00715533

Abstract 118: Diffusion Lesion Volume Reduction after Recanalization Therapy for Anterior Circulation Stroke with Major Vessel Occlusion: Analysis from the RESCUE-Japan Registry Study

Objective: Although Diffusion-weighted imaging (DWI) lesions are commonly irreversible, DWI lesion volume reduction (DVR) is occasionally observed. We investigated clinical significance and predictors of DVR in acute stroke patients with major vessel occlusion receiving recanalization therapy (RT). Methods: The Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism (RESCUE)-Japan registry prospectively registered 1,442 stroke patients with major vessel occlusion who were admitted to 84 Japanese stroke centers within 24 hours after onset from July 2010 to June 2011. We retrospectively analyzed all patients with the internal carotid artery or middle cerebral artery (M1 or M2 segments occlusions receiving RT and undergoing MRI both on admission and at 24 hours after onset from the registry. We defined DVR as a 1 or more-point reduction of the DWI-Alberta Stroke Program Early CT Score (ASPECTS), and CT-DWI mismatch (CTDM) as a 2 or more-point lower DWI-ASPECTS than CT-ASPECTS on admission. Reperfusion was defined as TICI grade 2b-3 on catheter angiography or modified Mori grade 3 on MRA immediately after RT. Dramatic recovery (DR) was defined as a 10 or more-point reduction or a total NIHSS score of 0-1 at 24 hours, and favorable outcome (FO) defined as a mRS score 0-2 at 3 months. Results: A total of 390 patients (215 men, 72 years old,) was included. Median baseline NIHSS score was 16 (IQR 10-19) and median baseline DWI-ASPECTS was 8 (6-9). CTDM was seen in 92 patients (28%) on admission. Intravenous thrombolysis and endovascular therapy were performed in 246 patients (63%) and 223 patients (57%), respectively. Reperfusion was obtained in 170 patients (51%). DVR was seen in 51 patients (13%). Eighty-eight patients (23%) obtained DR and 158 patients (41%) achieved FO. On multivariate analyses, DVR was significantly related to DR (OR 3.8, 95%CI 1.5-10) and FO (4.6, 1.8-12). CTDM was an independent predictor of DVR (OR 2.5, 95% CI 1.1-5.8). Conclusions: DVR was significantly related to DR and FO. CTDM is a rough predictor of DVR of which area is considered as a “DWI-bright” ischemic penumbra, and might be a useful marker to identify the adequate candidates for RT in spite of relatively large DWI lesions.

Abstract T P291: Impact of Diastolic Dysfunction for Predicting Mortality in Ischemic Stroke and Transient Ischemic Attack Patients

Background: The aim of this study is to identify whether diastolic dysfunction predicts 90-day mortality and develop and validate a risk score model using information available at hospital presentation in ischemic stroke or transient ischemic attack (TIA) patients Methods: Consecutive ischemic stroke or TIA patients within 48 hours of onset were enrolled. Diastolic filling pressure was estimated as the ratio of early transmitral flow velocity (E) to mitral annular velocity (e’) on transthoracic echocardiography performed within 24 hours of presentation. Plasma brain natriuretic peptide (BNP) and D-dimer were measured on admission. We calculated initial diffusion weighted imaging (DWI) lesion volume. Stroke severity was assessed by the National Institute of Health Stroke Scale (NIHSS) score. Mortality was evaluated at 90-day follow-up. Univariate and multivariate analyses were conducted to identify predictors of 90-day mortality. Results: A total of 265 patients with ischemic stroke or TIA were enrolled. Of these, nineteen (7%) patients deceased at 90-day follow-up. At univariate analysis, higher age (p=0.002), atrial fibrillation (p&lt;0.001), use of antiplatelet agent (p=0.005) and anticoagulant agent (p=0.017), cardioembolic infarction (p&lt;0.001), higher NIHSS score (p&lt;0.001), larger DWI lesion volume (p=0.002), internal carotid artery occlusion (p&lt;0.001), higher E/e’ (p&lt;0.001), PT-INR level (p=0.004), BNP level (p&lt;0.001) and D-dimer level (p&lt;0.001) and lower albumin level (p=0.002) were associated with death. Multivariable predictors of 90-day mortality included higher E/e’ (Odds ratio [OR]=1.176; 95% confidence interval [CI], 1.051 to 1.317), NIHSS score (OR=1.180; 95% CI, 1.067- 1.306) and D-dimer level (OR=1.137; 95% CI, 1.009 to 1.281). The END score (1 point each for E/e’ of &gt;= 18.5, NIHSS score of &gt;= 17 and D-dimer level of &gt;= 2.0) stratified patients with a predicted probability of death rate from 0% to 77.8%. The c statistic was 0.947. Conclusions: Diastolic dysfunction could be one of the most important predictors of 90-day mortality of acute ischemic stroke and TIA. The END score may assist clinicians in estimating stroke mortality at hospital presentation.

Neuropsychological Effects of MRI-Detected Brain Lesions After Left Atrial Catheter Ablation for Atrial Fibrillation

Background— MRI-detected brain lesions are common after left atrial catheter ablation for symptomatic atrial fibrillation. The clinical relevance of these acute ischemic lesions is not fully understood, but ablation-related cerebral injury could contribute to cognitive dysfunction. Methods and Results— In the prospective Mesh Ablator versus Cryoballoon Pulmonary Vein Ablation of Symptomatic Paroxysmal Atrial Fibrillation (MACPAF) study, serial 3-T brain MRIs and neuropsychological assessment were performed to analyze the rate of ablation-related brain lesions and their effect on cognitive function. Thirty-seven patients with paroxysmal atrial fibrillation (median age, 63.0 [interquartile range, 57–68] years; 41% female; median CHA 2 DS 2 VASc score 2 [interquartile range, 1–3]) underwent 41 ablation procedures according to study criteria. None of these patients had overt neurological deficits after ablation. High-resolution diffusion-weighted imaging, performed within 48 hours after ablation, showed that new brain lesions (range, 1–17) were present in 16 (43.2%) patients after 18 (43.9%) left atrial catheter ablation procedures. Follow-up MRI at 6 months (median, 6.5; interquartile range, 6–7) revealed that 7 (12.5%) of the 56 total acute brain lesions after ablation formed a persistent glial scar in 5 (31.3%) patients. Large diffusion-weighted imaging lesions and a corresponding fluid-attenuated inversion recovery lesion 48 hours after ablation predicted lesion persistence on 6-month follow-up. Neither persistent brain lesions nor the ablation procedure itself had a significant effect on attention or executive functions, short-term memory, or verbal and nonverbal learning after 6 months. Conclusions— Ablation-related acute ischemic brain lesions persist to some extent but do not cause cognitive impairment 6 months after the ablation procedure. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01061931.

Combining Magnetic Resonance Imaging within Six-Hours of Symptom Onset with Clinical Follow-Up at 24 h Improves Prediction of ‘malignant’ Middle Cerebral Artery Infarction

A large diffusion-weighted imaging lesion ≤six-hours of symptom onset was found to predict the development of 'malignant' middle cerebral artery infarction with high specificity, positive predictive value, and negative predictive value, but sensitivity was low. We tested the hypothesis that sensitivity can be improved by adding information from clinical follow-up examination after 24 h. We analyzed data from a prospective, multicenter, observational cohort study of patients with acute ischemic stroke and middle cerebral artery occlusion studied by stroke magnetic resonance imaging ≤six-hours of symptom onset. We used the National Institutes of Health Stroke Scale to assess severity of symptoms after 24 h. We used the Classification and Regression Trees analysis to define the optimal thresholds of diffusion-weighted imaging lesion volume and the National Institutes of Health Stroke Scale after 24 h in patients developing 'malignant' middle cerebral artery infarction. We calculated sensitivity, specificity, positive predictive value, and negative predictive value for two simple predictive models based on acute diffusion-weighted imaging lesion volume alone and acute diffusion-weighted imaging lesion volume together with the National Institutes of Health Stroke Scale after 24 h. Of 135 patients, 27 (20%) developed a 'malignant' middle cerebral artery infarction. The Classification and Regression Trees analysis identified acute diffusion-weighted imaging lesion ≥78 ml and the National Institutes of Health Stroke Scale score after 24 h ≥22 as optimal cut-offs. Inclusion of the National Institutes of Health Stroke Scale score after 24 h in a simple two-step decision tree increased sensitivity from 0·59 to 0·79, while specificity, positive predictive value, and negative predictive value remained largely unchanged. Clinical follow-up examination after 24 h helps identify patients at risk of 'malignant' middle cerebral artery infarction that are missed by predictive algorithms based on early diffusion-weighted imaging lesion volume alone.

Impact of Diffusion-Weighted Imaging Lesion Volume on the Success of Endovascular Reperfusion Therapy

Diffusion-weighted imaging (DWI) lesion volume is associated with poor outcome after thrombolysis, and it is unclear whether endovascular therapies are beneficial for large DWI lesion. Our aim was to assess the impact of pretreatment DWI lesion volume on outcomes after endovascular therapy, with a special emphasis on patients with complete recanalization. We analyzed data collected between April 2007 and November 2011 in a prospective clinical registry. All acute ischemic stroke patients with complete occlusion of internal carotid artery or middle cerebral artery treated by endovascular therapy were included. DWI lesion volumes were measured by the RAPID software. Favorable outcome was defined by modified Rankin Scale of 0 to 2 at 90 days. A total of 139 acute ischemic stroke patients were included. Median DWI lesion volume was 14 cc (interquartile range, 5-43) after a median onset time to imaging of 110 minutes (interquartile range, 77-178). Higher volume was associated with less favorable outcome (adjusted odds ratio, 0.55; 95% confidence interval, 0.31-0.96). A complete recanalization was achieved in 65 (47%) patients after a median onset time of 238 minutes (interquartile range, 206-285). After adjustment for volume, complete recanalization was associated with more favorable outcome (adjusted odds ratio, 6.32; 95% confidence interval, 2.90-13.78). After stratification of volume by tertiles, complete recanalization was similarly associated with favorable outcome in the upper 2 tertiles (P<0.005). Our results emphasize the importance of initial DWI volume and recanalization on clinical outcome after endovascular treatment. Large DWI lesions may still benefit from recanalization in selected patients.

Abstract 53: The Malignant MRI profile: Implications for Endovascular Therapy

Background: The Malignant MRI profile identifies stroke patients with poor outcomes and an increased incidence of parenchymal hematoma following iv thrombolysis; outcomes following endovascular reperfusion therapy have not been described. Methods: The NIH funded DEFUSE 2 trial enrolled consecutive acute stroke patients in whom endovascular therapy was anticipated. An MRI scan was obtained immediately prior to intra-arterial reperfusion therapy, then repeated following the procedure and on day 5. Perfusion-weighted (PWI) and diffusion-weighted imaging (DWI) maps were created and lesion volumes estimated with an automated software program (RAPID). In the DEFUSE 2, the Malignant profile was pre-specified as a DWI lesion ≥70mL and/or a PWI lesion based on Tmax&gt;10sec threshold (Tmax&gt;10s) ≥100mL. A receiver operating characteristic (ROC) curve analysis was performed to identify Tmax&gt;10s and DWI volumes that predicted poor outcome (defined as a mRS 5-6 at 30 days) with a high specificity. Patients with an M1 or ICA occlusion who did not undergo endovascular therapy based on local site criteria were also included in the ROC analysis. Results: We report a preliminary analysis of the DEFUSE 2 database (full data will be presented at the meeting). One hundred and one patients were triaged to the cath lab for endovascular therapy. Of the 83 patients who had adequate data available for this analysis, 9 (11%) met the predefined criteria for the Malignant profile. 56% of the Malignant patients had poor outcome compared with 30% of the non-Malignant cases (p=0.14). Malignant patients had an increased risk of parenchymal hematoma (PH1 or PH2): 44% vs. 14% (p=0.04). Only 1 of the Malignant patients achieved a mRS of 0-2 at 30 days. Early reperfusion was obtained in 6 of the 9 Malignant patients but was not associated with an increase in favorable clinical outcome or a decrease in the risk of poor outcome. Fifteen patients with an M1 or ICA occlusion did not undergo endovascular therapy based on local site criteria. Ten of these patients had the Malignant profile and 8 of these 10 had a poor outcome. ROC curve analysis identified a DWI lesion of 112 mL and a Tmax&gt;10s lesion of 116 mL as optimal thresholds to predict poor outcome; both achieved a specificity of 98% and sensitivities of 27% and 24% respectively. 81% (13/16) of the Malignant patients identified by the DWI and/or Tmax&gt;10s optimal thresholds had poor outcome. Conclusion: Patients with large baseline DWI and/or large severe PWI lesions are likely to have poor outcomes with or without endovascular reperfusion therapy. Automated imaging software can identify these patients rapidly.

Diffusion-weighted imaging and magnetic resonance spectroscopy of sporadic Creutzfeldt–Jakob disease: correlation with clinical course

Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal disease with variable clinical courses. The presence or absence of basal ganglia (BG) involvement has been reported to be associated with clinical course. We investigated the association of clinical course of sCJD with diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) as well as BG involvement at early stage. DWI and single voxel proton MRS were performed in 14 patients with sCJD during the initial diagnostic workup. Apparent diffusion coefficient (ADC) and metabolites were measured in medial occipitoparietal cortices where large hyperintense DWI lesions were found in all patients. The presence or absence of BG involvement, ADC, N-acetylaspartate (NAA)/creatine (Cr) ratios, and choline (Cho)/Cr ratios were correlated with disease duration (i.e., the time from the symptom onset to death). The disease duration ranged from 2 to 31 months (median, 16). Hyperintense DWI lesions were observed bilaterally in both cortices and basal ganglia in eight patients and in cortices alone in six patients. Patients with BG involvement had shorter disease duration (median, 6.8 versus 20.5; p = 0.039) than those without and lower NAA/Cr ratios (median, 1.41 versus 2.03; p = 0.001). ADC and Cho/Cr ratios were not significantly different between the patients with BG involvement and those without. By multiple regression analysis, NAA/Cr ratios had the greatest correlation with the disease duration (p = 0.029). The disease duration of sCJD was variable. NAA/Cr ratios of the affected brain at the early stage of sCJD can be used as a useful parameter in predicting the clinical course.

Differential Pathophysiological Mechanisms of Stroke Evolution between New Lesions and Lesion Growth: Perfusion-Weighted Imaging Study

Background: Stroke evolution frequently occurs during the first week after stroke. However, the association between the type of stroke evolution and baseline perfusion severity has not been investigated. Methods: We analyzed clinical and serial MRI data on patients with acute middle cerebral artery infarcts. Multimodal MRIs were acquired before treatment and on day 7. Time to peak (T_max) perfusion lesion maps were then generated, and changes in the day 7 diffusion-weighted imaging (DWI) were classified; new lesions were defined as new DWI lesions not contiguous with initial abnormalities, and infarct growth as enlargement of DWI lesions. Results: Among 74 patients (mean age 64.2 years), 51 received recanalization therapy. The day 7 DWI revealed the presence of new lesions in 39 cases (52.7%) and infarct growth (mean ± SD 20.0 ± 4.3 ml) in 52. No correlation was observed between new lesion and infarct growth (r = 0.029, p = 0.805). Most new lesions were multiple and small, located in cortical/superficial areas and within the mild perfusion delay (2 ≤ T_max < 4 s) regions, whereas infarct growth generally occurred within the severer perfusion delay regions. Multiple regression analysis revealed that large mild perfusion delay was independently associated with new lesions, whereas large initial DWI lesions and a severer perfusion delay (4 ≤ T_max < 8 s) were associated with infarct growth. In terms of treatment, endovascular therapy was associated with new lesions, whereas the degree of angiographic recanalization was inversely associated with infarct growth. Conclusions: The types of stroke evolution differed depending on the baseline hypoperfusion severity, and the mode and effect of recanalization therapy. A poor correlation was observed between new lesions and infarct growth.

Risk for symptomatic intracerebral hemorrhage after thrombolysis assessed by diffusion‐weighted magnetic resonance imaging

The risk for symptomatic intracerebral hemorrhage (sICH) associated with thrombolytic treatment has not been evaluated in large studies using diffusion-weighted imaging (DWI). Here, we investigated the relation between pretreatment DWI lesion size and the risk for sICH after thrombolysis. In this retrospective multicenter study, prospectively collected data from 645 patients with anterior circulation stroke treated with intravenous or intraarterial thrombolysis within 6 hours (<3 hours: n = 320) after symptom onset were pooled. Patients were categorized according to the pretreatment DWI lesion size into three prespecified groups: small (< or =10 ml; n = 218), moderate (10-100 ml; n = 371), and large (>100 ml; n = 56) DWI lesions. In total, 44 (6.8%) patients experienced development of sICH. The sICH rate was significantly different between subgroups: 2.8, 7.8, and 16.1% in patients with small, moderate, and large DWI lesions, respectively (p < 0.05). This translates to a 5.8 (2.8)-fold greater sICH risk for patients with large DWI lesions as compared with patients with small (or moderate) DWI lesions. The results were similar in the large subgroup (n = 536) of patients treated with intravenous tissue plasminogen activator. DWI lesion size remained an independent risk factor when including National Institutes of Health Stroke Scale, age, time to thrombolysis, and leukoariosis in a logistic regression analysis. This multicenter study provides estimates of sICH risk in potential candidates for thrombolysis. The sICH risk increases gradually with increasing DWI lesion size, indicating that the potential benefit of therapy needs to be balanced carefully against the risk for sICH, especially in patients with large DWI lesions.

Clinical review: Imaging in ischaemic stroke – implications for acute management

Imaging has become a cornerstone of stroke management, translating pathophysiological knowledge to everyday decision-making. Plain computed tomography is widely available and remains the standard for initial assessment: the technique rules out haemorrhage, visualizes the occluding thrombus and identifies early tissue hypodensity and swelling, which have different implications for thrombolysis. Based on evidence from positron emission tomography (PET), however, multimodal imaging is increasingly advocated. Computed tomography perfusion and angiography provide information on the occlusion site, on recanalization and on the extent of salvageable tissue. Magnetic resonance-based diffusion-weighted imaging (DWI) has exquisite sensitivity for acute ischaemia, however, and there is increasingly robust evidence that DWI combined with perfusion-weighted magnetic resonance imaging (PWI) and angiography improves functional outcome by selecting appropriate patients for thrombolysis (small DWI lesion but large PWI defect) and by ruling out those who would receive no benefit or might be harmed (very large DWI lesion, no PWI defect), especially beyond the 3-hour time window. Combined DWI–PWI also helps predict malignant oedema formation and therefore helps guide selection for early brain decompression. Finally, DWI–PWI is increasingly used for patient selection in therapeutic trials. Although further methodological developments are awaited, implementing the individual pathophysiologic diagnosis based on multimodal imaging is already refining indications for thrombolysis and offers new opportunities for management of acute stroke patients.