Large Diffusion-weighted Imaging 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.

Outcome After Reperfusion Therapies in Patients With Large Baseline Diffusion-Weighted Imaging Stroke Lesions: A THRACE Trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke) Subgroup Analysis.

Stroke patients with large diffusion-weighted imaging (DWI) volumes are often excluded from reperfusion because of reckoned futility. In those with DWIvolume >70 mL, included in the THRACE trial (Mechanical Thrombectomy After Intravenous Alteplase Versus Alteplase Alone After Stroke), we report the associations between baseline parameters and outcome. We examined 304 patients with anterior circulation stroke and pretreatment magnetic resonance imaging. Variables were extracted from the THRACE database, and DWI volumes were measured semiautomatically. Among 53 patients with DWIvolume >70 mL, 12 had favorable outcome (modified Rankin Scale score, ≤2) at 3 months; they had less coronary disease (0/12 versus 12/38; P=0.046) and less history of smoking (1/10 versus 12/31; P=0.013) than patients with modified Rankin Scale score >2. None of the 8 patients >75 years of age reached modified Rankin Scale score ≤2. Favorable outcome occurred in 12 of 37 M1-occluded patients but in 0 of 16 internal carotid-T/L-occluded patients (P=0.010). Favorable outcome was more frequent (6/13) when DWI lesion was limited to the superficial middle cerebral artery territory than when it extended to the deep middle cerebral artery territory (6/40; P=0.050). Stroke patients with DWI lesion >70 mL may benefit from reperfusion therapy, especially those with isolated M1 occlusion or ischemia restricted to the superficial middle cerebral artery territory. The benefit of treatment seems questionable for patients with carotid occlusion or lesion extending to the deep middle cerebral artery territory.

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

Comparison of ¹⁸F-FDG PET/CT and large-scale DWI for evaluation of non-Hodgkin lymphoma bone marrow infiltration

To compare the diagnostic value of ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and large-scale diffusion weighted imaging (DWI) for evaluation of non-Hodgkin lymphoma (NHL) bone marrow (BM) infiltration. A total of 79 patients with pathologically diagnosed NHL underwent ¹⁸F-FDG PET/CT, large scale DWI and BM pathological examination. BM examination as the "gold standard", the performance (the sensitivity, specificity, accuracy, positive and negative predictive value) of ¹⁸F-FDG PET/CT and large scale DWI for evaluation of BM infiltration was compared and the risk of BM infiltration of different subtypes and sources of NHL was analyzed. 25 of 79 cases were diagnosed as BM infiltration by pathological examination with 57 BM sites. Abnormal high BM metabolisms were identified in 22 cases with 56 BM sites by ¹⁸F-FDG PET/CT and 25 cases with 58 BM sites by large-scale DWI. The sensitivity, specificity, accuracy, positive and negative predictive value of ¹⁸F-FDG PET/CT were 80.0%, 96.3%, 91.1%, 90.9%, 91.2%, respectively. And they were 84.0%, 92.6%, 89.9%, 84.0%, and 92.6% by large-scale DWI, respectively. A receiver operating characteristic (ROC) analysis demonstrated that there was no statistical difference in ¹⁸F-FDG PET/CT and large-scale DWI (P>0.05). The area under ROC curve for ¹⁸F-FDG PET/CT and large-scale DWI were 0.911 and 0.883 respectively. The incidences of BM infiltration in aggressive NHL patients by ¹⁸F-FDG PET/CT (21/69, 30.4%) and large-scale DWI (23/69, 33.3%) were higher than those (PET/CT: 10.0%; large-scale DWI: 20.0%; P>0.05) in indolent NHL patients. ¹⁸F-FDG PET/CT and large-scale DWI had important clinical value in diagnosing BM infiltration of NHL. A combination of ¹⁸F-FDG PET/CT, large-scale DWI and pathological examination could improve the positive rate of BM infiltration in NHL.

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.

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.

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 2261: Presence of Large Deep White Matter Lesion May Predict Futile Recanalization in Endovascular Therapy for Acute Ischemic Stroke

Background: A subset of stroke patients treated with endovascular recanalization therapy suffers poor outcome despite good arterial recanalization. The aim of this study is to identify whether large ischemic lesion in deep white matter (DWM) on diffusion weighted imaging (DWI) prior to therapy predicts futile recanalization. Method: Consecutive acute stroke patients with anterior circulation ischemia whose artery had been recanalized at Thrombolysis in Myocardial Infarct (TIMI) flow grade 2 or 3 following endovascular therapy were included. All patients underwent CT and MRI before endovascular therapy. We defined large DWI - DWM lesion if DWI showed the hyperintense lesion in the DWM which mostly extended between anterior and posterior horn of the lateral ventricle. We identified Alberta Stroke Program Early CT Scores (ASPECTS) of CT and DWI, and volumes measured on initial DWI and mean transit time of perfusion weighted images. We assessed the prevalence of TIMI grade 3 recanalization and parenchymal hemorrhage type 2, and final ischemic lesion volume after endovascular therapy. Stroke severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) score. Futile recanalization was defined as a 30-day modified Rankin Scale score 3 to 6 despite recanalization at TIMI grade 2 or 3. Univariate and multivariate regression analyses were performed to identify predictors of futile recanalization. Results: Partial or complete recanalization (TIMI grade 2 or 3) was observed in 35 of 46 patients (76 %). Of the 35 patients, futile recanalization was observed in 20 patients (57 %). Patients with futile recanalization had older age (median, 74 versus 58 years old, p = 0.053), higher initial NIHSS score (median, 17 versus 9, p = 0.042), pre-treatment large DWI - DWM lesion (45 versus 9 %, p = 0.022), and larger final ischemic lesion volume (median, 37 versus 9 ml, p = 0.003). ASPECTS of CT (median, 9 versus 9, p = 0.527) and DWI (median, 8 versus 8, p = 0.943) and initial ischemic lesion volumes on DWI (median, 21 versus 14 ml, p = 0.230) and on mean transit time (median, 189 versus 192 ml, p = 0.976) did not demonstrate statistically significance between patients with and without futile recanalization. There were also no significant differences between the outcome groups in times from stroke onset to imaging or endovascular therapy. Logistic regression analysis demonstrated that large DWI - DWM lesion was an independent predictor of futile recanalization (OR 10.40, 95 % CI 1.03 to 105.21, p = 0.047). Conclusion: Patients who have large pre-treatment DWI - DWM lesion may be poor candidates for endovascular therapy.

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.

Postthrombolysis Blood Pressure Elevation Is Associated With Hemorrhagic Transformation

Reliable predictors of hemorrhagic transformation (HT) after stroke thrombolysis have not been identified. We analyzed hemorrhage in a randomized trial of tissue plasminogen activator (t-PA) vs placebo in ischemic stroke patients. We hypothesized that acute diffusion-weighted imaging (DWI) lesion volumes would be larger and blood pressures would be higher in patients with HT. HT was assessed 2 to 5 days after treatment in 97 patients. Hemorrhage was assessed by using susceptibility-weighted imaging sequences and was classified as petechial hemorrhagic infarction (HI) or parenchymal hematoma (PH). PH was more frequent in t-PA- (11/49) than in placebo- (4/48) treated patients (P=0.049). Patients with PH had larger DWI lesion volumes (63.1+/-56.1 mL) than did those without HT (27.6+/-39.0 mL, P=0.033). There were no differences in baseline systolic blood pressure (SBP) between patients with and without hemorrhage. Weighted average SBP 24 hours after treatment was higher in patients with PH (159.4+/-18.8 mL, P<0.011) relative to those without HT (143.1+/-20.0 mL). Multinomial logistic regression indicated that PH was predicted by DWI lesion volume (odds ratio=1.16 per 10 mL; 95% CI, 1.03 to 1.30), atrial fibrillation (odds ratio=9.33; 95% CI, 2.30 to 37.94), and 24-hour weighted average SBP (odds ratio=1.59 per 10 mm Hg; 95% CI, 1.14 to 2.23). Pretreatment DWI lesion volume and postthrombolysis BP are both predictive of HT. Consideration should be given to excluding patients with very large baseline DWI volumes from t-PA therapy and to more stringent BP control after stroke thrombolysis.

Normal Appearance of Large Field Diffusion Weighted Imaging on 3.0T MRI

To evaluate the normal appearance of large field diffusion weighted imaging (DWI) on 3.0T magnetic resonance imaging (MRI). Twenty healthy volunteers and thirty patients with benign prostate hyperplasia were included in this study. All patients were examined with large field DWI on 3.0T MRI. Normal tissue appearance was analyzed and apparent diffusion coefficient (ADC) of normal tissue with high signal intensity was measured. The ADC values of bilateral symmetrical tissue were also compared. The ADC values of intervertebral disks of healthy people younger than 50 years and exceeding 50 years were compared. Salivary gland, spleen, kidney, gallbladder, bladder, prostate, seminal vesicle, testis, intervertebral disk, liquid in articular cavity and lymph node showed high signal intensity on large field DWI, while lung, liver and bone showed hypo-signal intensity. The mean ADC values of partial hyperintensity tissue were as followed: parotid gland (1.088 +/- 0.114) x 10(-3) mm2/S, submaxillary gland (1.309 +/- 0.189) x 10(-3) mm2/s, kidney (1.909 +/- 0.143) x 10(-3) mm2/s, seminal vesicle (1.669 +/- 0.168) x 10(-3) mm2/s, testis (1.028 +/- 0.075) x 10(-3) mm2/s, spleen (0.963 +/- 0.108) x 10(-3) mm2/s, bladder (2.898 +/- 0.267) x 10(-3) mm2/s, prostate (1.448 +/- 0.132) x 10(-3) mm2/s, intervertebral disks (1.360 +/- 0.140) x 10(-3) mm2/s. No statistical significance was found between the ADC values of bilateral symmetrical tissues. The difference of ADC values of intervertebral disks of healthy people younger than 50 years [(1.372 +/- 0.142) x 10(-3) mm2/s] and exceeding 50 years [(1.344 +/- 0.134) x 10(-3) mm2/s] showed statistical significance (P = 0.040). Understanding the high signal intensity of normal tissue on large field DWI may help to differentiate the normal tissues and abnormal ones.

Age-Related Changes of Bone Marrow of Normal Adult Man on Diffusion Weighted Imaging

To investigate the signal intensity and apparent diffusion coefficient (ADC) of bone marrow of normal adult man on diffusion weighted imaging (DWI). Fifteen healthy volunteers and thirty-eight patients with benign prostatic hyperplasia or normal prostate were enrolled in this study, with age range 28-82 years old (mean 55.26 +/- 18.05 years). All people were examined with large field DWI on a 3.0T magnetic resonance scanner, which ranges from the top of head to the lower limb. The signal-to-noise ratio (SNR) on the DWI and ADC of lumber vertebra at renal hilum level, left ilium and superior segment of left femur were measured. The measured SNR and ADC value of the above sites were compared by one way analysis of variance and their correlations with age were investigated by Pearson's correlation analysis. The SNR of lumber vertebra, left ilium and left femur showed no significant difference (F= 0.271, P = 0.763). The SNR of lumber vertebra (r = 0.309, P = 0.024) and left ilium (r = 0.359, P = 0.008) showed positive correlation with age, while the SNR of left femur showed no correlation with age (r = -0.163, P = 0.283). The ADC of lumber vertebra [(0.617 +/- 0.177) x 10(-3) mm2/s] was significantly higher than that of left ilium [(0.404 +/- 0.112) x 10(-3) mm2/s, P < 0.001] and left femur [(0.362 +/- 0.092) x 10(-3) mm2/s, P < 0.001], while the ADC of left ilium and left femur had no significant difference. The ADC of lumber vertebra, left ilium and left femur showed no correlation with age. Understanding of age-related changes of normal adult bone marrow on DWI is very important to differentiate the normal bone marrow and abnormal lesions.