Natural history of meningiomas: a serial volumetric analysis of 240 tumors.

OBJECTIVE: The management of asymptomatic intracranial meningiomas is controversial. Through the assessment of growth predictors, the authors aimed to create the basis for practicable clinical pathways for the management of these tumors. METHODS: The authors volumetrically analyzed meningiomas radiologically diagnosed at their institution between 2003 and 2015. The primary endpoint was growth of tumor volume. The authors used significant variables from the multivariable regression model to construct a decision tree based on the exhaustive Chi-Square Automatic Interaction Detection (CHAID) algorithm. RESULTS: Of 240 meningiomas, 159 (66.3%) demonstrated growth during a mean observation period of 46.9 months. On multivariable logistic regression analysis, older age (OR 0.979 [95% CI 0.958-1.000], p = 0.048) and presence of calcification (OR 0.442 [95% CI 0.224-0.872], p = 0.019) had a negative predictive value for tumor growth, while T2-signal iso-/hyperintensity (OR 4.415 [95% CI 2.056-9.479], p < 0.001) had a positive predictive value. A decision tree model yielded three growth risk groups based on T2 signal intensity and presence of calcifications. The median tumor volume doubling time (Td) was 185.7 months in the low-risk, 100.1 months in the intermediate-risk, and 51.7 months in the high-risk group (p < 0.001). Whereas 0% of meningiomas in the low- and intermediate-risk groups had a Td of ≤ 12 months, the percentage was 8.9% in the high-risk group (p = 0.021). CONCLUSIONS: Most meningiomas demonstrated growth during follow-up. The absence of calcifications and iso-/hyperintensity on T2-weighted imaging offer a practical way of stratifying meningiomas as low, intermediate, or high risk. Small tumors in the low- or intermediate-risk categories can be monitored with longer follow-up intervals.

Endovascular therapy in patients with large vessel occlusion due to cardioembolism versus large-artery atherosclerosis.

BACKGROUND AND AIMS: To investigate whether stroke aetiology affects outcome in patients with acute ischaemic stroke who undergo endovascular therapy. METHODS: We retrospectively analysed patients from the Bernese Stroke Centre Registry (January 2010-September 2018), with acute large vessel occlusion in the anterior circulation due to cardioembolism or large-artery atherosclerosis, treated with endovascular therapy (±intravenous thrombolysis). RESULTS: The study included 850 patients (median age 77.4 years, 49.3% female, 80.1% with cardioembolism). Compared with those with large-artery atherosclerosis, patients with cardioembolism were older, more often female, and more likely to have a history of hypercholesterolaemia, atrial fibrillation, current smoking (each p < 0.0001) and higher median National Institutes of Health Stroke Scale (NIHSS) scores on admission (p = 0.030). They were more frequently treated with stent retrievers (p = 0.007), but the median number of stent retriever attempts was lower (p = 0.016) and fewer had permanent stent placements (p ⩽ 0.004). Univariable analysis showed that patients with cardioembolism had worse 3-month survival [72.7% versus 84%, odds ratio (OR) = 0.51; p = 0.004] and modified Rankin scale (mRS) score shift (p = 0.043) and higher rates of post-interventional heart failure (33.5% versus 18.5%, OR = 2.22; p < 0.0001), but better modified thrombolysis in cerebral infarction (mTICI) score shift (p = 0.025). Excellent (mRS = 0-1) 3-month outcome, successful reperfusion (mTICI = 2b-3), symptomatic intracranial haemorrhage and Updated Charlson Comorbidity Index were similar between groups. Propensity-matched analysis found no statistically significant difference in outcome between stroke aetiology groups. Stroke aetiology was not an independent predictor of favourable mRS score shift, but lower admission NIHSS score, younger age and independence pre-stroke were (each p < 0.0001). Stroke aetiology was not an independent predictor of heart failure, but older age, admission antithrombotics and dependence pre-stroke were (each ⩽0.027). Stroke aetiology was not an independent predictor of favourable mTICI score shift, but application of stent retriever and no permanent intracranial stent placement were (each ⩽0.044). CONCLUSION: We suggest prospective studies to further elucidate differences in reperfusion and outcome between patients with cardioembolism and large-artery atherosclerosis.

Development of imaging-based risk scores for prediction of intracranial haemorrhage and ischaemic stroke in patients taking antithrombotic therapy after ischaemic stroke or transient ischaemic attack: a pooled analysis of individual patient data from cohort studies.

BACKGROUND: Balancing the risks of recurrent ischaemic stroke and intracranial haemorrhage is important for patients treated with antithrombotic therapy after ischaemic stroke or transient ischaemic attack. However, existing predictive models offer insufficient performance, particularly for assessing the risk of intracranial haemorrhage. We aimed to develop new risk scores incorporating clinical variables and cerebral microbleeds, an MRI biomarker of intracranial haemorrhage and ischaemic stroke risk. METHODS: We did a pooled analysis of individual-patient data from the Microbleeds International Collaborative Network (MICON), which includes 38 hospital-based prospective cohort studies from 18 countries. All studies recruited participants with previous ischaemic stroke or transient ischaemic attack, acquired baseline MRI allowing quantification of cerebral microbleeds, and followed-up participants for ischaemic stroke and intracranial haemorrhage. Participants not taking antithrombotic drugs were excluded. We developed Cox regression models to predict the 5-year risks of intracranial haemorrhage and ischaemic stroke, selecting candidate predictors on biological relevance and simplifying models using backward elimination. We derived integer risk scores for clinical use. We assessed model performance in internal validation, adjusted for optimism using bootstrapping. The study is registered on PROSPERO, CRD42016036602. FINDINGS: The included studies recruited participants between Aug 28, 2001, and Feb 4, 2018. 15 766 participants had follow-up for intracranial haemorrhage, and 15 784 for ischaemic stroke. Over a median follow-up of 2 years, 184 intracranial haemorrhages and 1048 ischaemic strokes were reported. The risk models we developed included cerebral microbleed burden and simple clinical variables. Optimism-adjusted c indices were 0·73 (95% CI 0·69-0·77) with a calibration slope of 0·94 (0·81-1·06) for the intracranial haemorrhage model and 0·63 (0·62-0·65) with a calibration slope of 0·97 (0·87-1·07) for the ischaemic stroke model. There was good agreement between predicted and observed risk for both models. INTERPRETATION: The MICON risk scores, incorporating clinical variables and cerebral microbleeds, offer predictive value for the long-term risks of intracranial haemorrhage and ischaemic stroke in patients prescribed antithrombotic therapy for secondary stroke prevention; external validation is warranted. FUNDING: British Heart Foundation and Stroke Association.

Imaging Neurovascular Uncoupling in Acute Migraine with Aura with Susceptibility Weighted Imaging.

PURPOSE: Migraine with aura (MwA) in the emergency setting is common and sometimes difficult to distinguish from mimicking conditions. Susceptibility weighted imaging (SWI), a magnet resonance (MR) technique is sensitive to deoxygenated hemoglobin in cerebral veins and depicts these according to their level of oxygenation. Our study aimed at evaluating the frequency of regions of prominent focal veins (PFV) on SWI in the acute phase. METHODS: Between 2011 and 2018 we evaluated symptoms and MR imaging of adult patients with acute MwA attacks (< 5 days after onset of symptoms). Abnormal imaging was visually scored in 12 ROIs on both hemispheres distributed on 3 slices. The score ranged from 0 to 3. RESULTS: In all, 638 patients (436 female) mean age 37.39 years (18-89 ±â€¯14.13) were included. Susceptibility weighted imaging was abnormal in 18.8% of patients. The inferior and posterior medial temporal lobe and the occipital lobe were most often affected. Susceptibility weighted imaging was more likely abnormal when MR was performed within 24 hours with an average around 5 hours after symptom onset. The side of aura symptoms and hemispheric imaging alteration in patients with abnormal SWI was highly significant (p < 0.001). CONCLUSION: In the acute episode of MwA, SWI imaging can show a combination of increased deoxygenation. The results may indicate linking PFV to MwA.

Findings in susceptibility weighted imaging in pediatric patients with migraine with aura.

BACKGROUND: Migraine with aura (MwA) in pediatric patients is clinically frequent. Clinically complex symptoms need to be differentiated to exclude mimicking conditions. PURPOSE: We hypothesize that MwA in children induces abnormalities readily visible in perfusion time to peak (TTP) maps as well as non-enhanced susceptibility weighted magnetic resonance imaging (SWI). MATERIALS AND METHODS: Between 2010 and 2018, we retrospectively evaluated symptoms and imaging of consecutive pediatric patients <18 years with MwA. We visually scored abnormalities on SWI and TTP maps in 12 regions of interest on both hemispheres on three axial slices, as normal, slightly, distinctly or severely abnormal. RESULTS: 99 patients (69.7% female), mean age 14.07 y (±2.8) were included. Focally increased deoxygenation (FID) in SWI was present in 61.6%. FID on SWI was dominant for the left hemisphere (60.7% vs. 31.1%, (p < .001)), and in 8.2% symmetric. Side of aura symptoms and contralateral hemispheric imaging alterations in patients with FID correlated significantly (p = .002.). 61 of 99 patients had perfusion MR and 59% of these patients showed focal increase of TTP. Age correlated significantly with FID in SWI (r = -.248, p = .013) and increase of TTP in perfusion (r = -.252, p = .05). Focal abnormalities correlated significantly between SWI and TTP maps. Brain regions most often abnormal were the temporal superior, occipital and fronto-parietal regions. CONCLUSIONS: This study provides confidence in recognizing FID, and linking FID in SWI to acute MwA in pediatric patients. FID phenomenon had a left hemispheric significant dominance, and can be found bilaterally.

Quantification of cerebral veins in patients with acute migraine with aura: A fully automated quantification algorithm using susceptibility-weighted imaging.

INTRODUCTION: Susceptibility weighted imaging (SWI) is a very sensitive technique that often depicts prominent focal veins (PFV) in patients with acute migraine with aura (MwA). Interpretation of visual venous asymmetry (VVA) between brain hemispheres on SWI may help support the clinical diagnosis of MwA. Our goal was to develop an automated algorithm for segmentation and quantification of cerebral veins using SWI. MATERIALS AND METHODS: Expert readers visually evaluated SWI of patients with acute MwA for VVA. Subsequently a fully automated algorithm based on 3D normalization and 2D imaging processing using SPM and MATLAB image processing software including top-hat transform was used to quantify cerebral veins and to calculate volumetric differences between hemispheres. RESULTS: Fifty patients with MwA were examined with SWI. VVA was present in 20 of 50 patients (40%). In 95% of patients with VVA, the fully automated calculation agreed with the side that visually harboured more PFV. Our algorithm showed a sensitivity of 95%, specificity of 90% and accuracy of 92% for detecting VVA. Patients with VVA had significantly larger vein volume on the hemisphere with more PFV compared to patients without (15.90 ± 5.38 ml vs 11.93 ± 5.31 ml; p = 0.013). The mean difference in venous volume between hemispheres in patients with VVA was larger compared to patients without VVA (16.34 ± 7.76% vs 4.31 ± 3.26% p < 1E-10). The average time between aura onset and SWI correlated negatively with venous volume of the dominant brain hemisphere (r = -0.348; p = 0.038). CONCLUSION: A fully automated algorithm can accurately identify and quantify cerebral venous distribution on SWI. Absolute quantification may be useful for the future assessment of patients with suspected diseases, which may be associated with a unilateral abnormal degree of venous oxygenation.

Prediction of cerebral venous thrombosis with a new clinical score and D-dimer levels.

OBJECTIVE: To investigate prediction of cerebral venous thrombosis (CVT) by clinical variables and D-dimer levels. METHODS: This prospective multicenter study included consecutive patients with clinically possible CVT. On admission, patients underwent clinical examination, blood sampling for D-dimers measuring (ELISA test), and magnetic resonance/CT venography. Predictive value of clinical variables and D-dimers for CVT was calculated. A clinical score to stratify patients into groups with low, moderate, or high CVT risk was established with multivariate logistic regression. RESULTS: CVT was confirmed in 26.2% (94 of 359) of patients by neuroimaging. The optimal estimate of clinical probability was based on 6 variables: seizure(s) at presentation (4 points), known thrombophilia (4 points), oral contraception (2 points), duration of symptoms >6 days (2 points), worst headache ever (1 point), and focal neurologic deficit at presentation (1 point) (area under the curve [AUC] 0.889). We defined 0 to 2 points as low CVT probability (negative predictive value [NPV] 94.1%). Of the 186 (51.8%) patients who had a low probability score, 11 (5.9%) had CVT. The frequency of CVT was 28.3% (34 of 120) in patients with a moderate (3-5 points) and 92.5% (49 of 53) in patients with a high (6-12 points) probability score. All low CVT probability patients with CVT had D-dimers >500 µg/L. Predictive value of D-dimers for CVT for >675 µg/L (best cutoff) vs >500 µg/L was as follows: sensitivity 77.7%, specificity, 77%, NPV 90.7%, and accuracy 77.2% vs sensitivity 89.4%, specificity 66.4%, NPV 94.6%, and accuracy 72.4%, respectively. Adding the clinical score to D-dimers >500 µg/L resulted in the best CVT prediction score explored (at the cutoff ≥6 points: sensitivity 83%/specificity 86.8%/NPV 93.5%/accuracy 84.4%/AUC 0.937). CONCLUSION: The proposed new clinical score in combination with D-dimers may be helpful for predicting CVT as a pretest score; none of the patients with CVT showed low clinical probability for CVT and D-dimers <500 µg/L. CLINICALTRIALSGOV IDENTIFIER: NCT00924859.

The index vein pointing to the origin of the migraine aura symptom: A case series.

OBJECTIVE: This case series describes and discusses the potential clinical utility of a prominent vein (index vein) found on susceptibility-weighted MRI during migraine aura that drains the cortical area responsible for patients' symptoms. METHODS: Six patients with acute migraine aura had a prominent draining sulcal vein on emergency MRI done initially for suspected stroke. The location of the prominent vein was correlated to patients' symptoms, and the diameter was compared to the corresponding contralateral vein. RESULTS: In our patients with typical migraine aura, an accentuated sulcal vein pointed towards the cortical area correlating with the clinical presentation. Such an index vein outstands the ipsilateral area of hypoperfusion and exceeds the corresponding contralateral vessel in diameter by a factor 2.0 ± 1.6 (mean ± SD). CONCLUSION: This case series provides a definition of an index vein in MRI pointing to the area where the patients' symptoms originate. Although confirmation in a larger systematic study is necessary, the presence of such an index vein might support that, in patients with an acute neurologic deficit, migraine aura is the underlying etiology.

MRI characteristics in acute ischemic stroke patients with preceding direct oral anticoagulant therapy as compared to vitamin K antagonists.

BACKGROUND: Despite the utility of neuroimaging in the diagnostic and therapeutic management of patients with acute ischemic stroke (AIS), imaging characteristics in patients with preceding direct oral anticoagulants (DOAC) compared to vitamin K antagonists (VKA) have hardly been described. We aimed to determine presence of large vessel occlusion (LVO), thrombus length, infarction diameter, and occurrence of hemorrhagic transformation in AIS patients with preceding DOAC as compared to VKA therapy. METHODS: Using a prospectively collected cohort of AIS patients, we performed univariate and multivariable regression analyses regarding imaging outcomes. Additionally, we provide a sensitivity analysis for the subgroup of patients with confirmed therapeutic anticoagulation. RESULTS: We included AIS in patients with preceding DOAC (N = 75) and VKA (N = 61) therapy, median age 79 (IQR 70-83), 39% female. Presence of any LVO between DOAC and VKA patients (29.3% versus 37.7%, P = 0.361), and target LVO for endovascular therapy (26.7% versus 27.9%, P = 1.0) was equal with a similar occlusion pattern. DOAC as compared to VKA were associated with a similar rate of target LVO for EVT (aOR 0.835, 95% CI 0.368-1.898). The presence of multiple lesions and characteristics of the thrombus were similar in DOAC and VKA patients. Acute ischemic lesion diameter in real world patients was equal in patients taking DOAC as compared to VKA. Lesion diameter in VKA patients (median 13 mm, IQR 6-26 versus median 20 mm, IQR 7-36, P = 0.001), but not DOAC patients was smaller in the setting of confirmed therapeutic VKA. The frequency of radiological hemorrhagic transformation and symptomatic intracranial hemorrhage in OAC patients was low. Sensitivity analysis considering only patients with confirmed therapeutic anticoagulation did not change any of the results. CONCLUSION: Preceding DOAC treatment showed equal rates of LVO and infarct size as compared to VKA in AIS patients. This study adds to the knowledge of imaging findings in AIS patients with preceding anticoagulation.

Symptomatic and asymptomatic intracranial atherosclerotic stenosis: 3 years' prospective study.

BACKGROUND: Intracranial stenoses can cause TIA/ischaemic stroke. The purpose of this study was to assess vascular risk factors, clinical and imaging findings and outcome in Caucasians with intracranial stenosis under best prevention management. METHODS: In this prospective observational study (from 05/2012, to last follow-up 06/2017) we compared vascular risk factors, imaging findings and long-term outcome in Swiss patients with symptomatic versus asymptomatic intracranial atherosclerotic stenoses on best prevention management. RESULTS: 62 patients were included [35.5% women, median age 68.3 years], 33 (53.2%) with symptomatic intracranial stenoses. Vascular risk factors (p = 0.635) and frequency of anterior circulation stenoses (66.7% vs. 55.2%; p = 0.354) did not differ between symptomatic and asymptomatic patients, but CT/MR-perfusion deficits in the territory of the stenosis (81.8% vs. 51.7%; p = 0.011) were more common in symptomatic patients. Outcome in symptomatic and asymptomatic patients at last follow-up was similar (mRS 0-1:66.7% vs. 75%;adjp = 0.937, mRS adjp-shift = 0.354, survival:100% vs. 96.4%;adjp = 0.979). However, during 59,417 patient follow-up days, symptomatic patients experienced more cerebrovascular events (ischaemic stroke or TIA) [37.5% vs. 7.1%;adjHR 7.58;adjp = 0.012], mainly in the territory of the stenosis [31.3% vs. 3.6%;adjHR 12.69;adjp = 0.019], more vascular events (i.e. ischaemic stroke/TIA/TNA and acute coronary/peripheral vascular events) [62.5% vs. 14.3%;adjHR 6.37;adjp = 0.001]) and more multiple vascular events (p-trend = 0.006; ≥ 2:37.5% vs. 10.7%;adj OR 5.37;adjp = 0.022) than asymptomatic patients. CONCLUSIONS: Despite best prevention management, one in three patients with a symptomatic intracranial stenosis suffered a cerebrovascular event, three in five a vascular event and two in five ≥ 2 vascular events. There is an unmet need for more rigorous and effective preventive strategies in patients with symptomatic intracranial stenoses.

Outcome of patients with large vessel occlusion in the anterior circulation and low NIHSS score.

BACKGROUND: Optimal management of patients with large vessel occlusion (LVO) and low NIHSS score is unknown, which was the aim to investigate in this study. METHODS: This is a retrospective analysis of a prospective single tertiary care centre 14-year cohort of patients with LVO in the anterior circulation and NIHSS score ≤ 5 on admission. Outcome was analysed according to primary intended therapy. RESULTS: Among 185 patients (median age 67.4 years), 52.4% received primary conservative therapy (including 26.8% secondary reperfusion in case of secondary neurological deterioration), 12.4% IV thrombolysis (IVT) only and 35.1% primary endovascular therapy (EVT). 95 (51.4%) patients experienced neurological deterioration until 3 months. Primary-IVT-only and primary-EVT compared to conservative-therapy patients had better 3 months' outcome (54.5% vs. 30.8%: adjustedOR 6.02; adjustedp = 0.004 for mRS 0-1 and 54.7% vs. 30.8%: adjustedOR 5.09; adjustedp = 0.002, respectively). Also mRS shift analysis favored primary-IVT-only and primary-EVT patients (adjustedOR 6.25; adjustedp = 0.001 and adjustedOR 3.14; adjustedp = 0.003). Outcome in primary-IVT-only vs. primary-EVT patients did not differ significantly. Patients who received secondary EVT because of neurological deterioration after primary-conservative-therapy had worse 3 months' outcome than primary-EVT patients (20.8% vs. 30.8%: adjustedOR 0.24; adjustedp = 0.047 for mRS 0-1 and adjustedOR 0.31; adjustedp = 0.019 in mRS shift analysis). Survival and symptomatic intracranial haemorrhage did not differ amongst groups. CONCLUSIONS: Our data indicate that primary IVT and/or EVT may be better than primary conservative therapy in patients with LVO in the anterior circulation and low NIHSS score. Furthermore, primary EVT was better than secondary EVT in case of neurological deterioration. There is an unmet need for RCTs to find the optimal therapy for this patient group.

Plaque vulnerability in patients with high- and moderate-grade carotid stenosis - comparison of plaque features on MRI with histopathological findings.

  BACKGROUND: Plaque vulnerability plays an important role in determining the risk of subsequent cerebrovascular events in patients with carotid stenosis. Plaque morphology magnetic resonance imaging (MRI) can be used to assess plaque vulnerability. We therefore set out to examine the diagnostic accuracy of plaque morphology MRI compared with histopathological findings as gold standard in moderate- to high-grade carotid stenosis at our centre. METHODS: A total of 36 patients with moderate- to high-grade carotid stenosis underwent plaque morphology MRI with a multisequence protocol (time of flight sequence, dark blood T1- [native and post-gadolinium] and T2-weighted sequence with fat suppression). The status of the fibrous cap, calcification, lipid-rich necrotic core (LRNC) and intraplaque haemorrhage (IPH) were assessed by means of qualitative MR analysis of plaque characteristics and compared with the histopathological findings. Detection statistics (sensitivity, specificity), chi-squared test, Cohen’s kappa (κ), percentage of agreement and phi coefficient (φ) were determined. RESULTS: Carotid stenosis was symptomatic (transient ischaemic attack, amaurosis fugax or ischaemic stroke in the territory of the stenosed carotid artery) in 25 patients (69.5%). Twenty-eight patients (77.8%) had a high-grade and eight patients (12.2%) a moderate-grade stenosis. Significant congruence between MRI and histology was found for plaque calcification (89% histology, 75% MRI, κ = 0.364, p = 0.013), for LRNC (89% histology, 53% MRI, κ = 0.245, p = 0.025) and IPH (75% histology, 53% MRI, κ = 0.314, p = 0.035). In a subgroup of patients with symptomatic stenosis, the agreement for LRNC and IPH was slightly better (LRNC κ = 0.390, p = 0.014; IPH κ = 0.386, p = 0.045). Status of the fibrous cap, essentially ulceration, did not show any significant agreement (κ = 0.032, p = 0.842). There was significant correlation between LRNC on MRI and symptomatic carotid stenosis (φ = 0.339, p = 0.042). CONCLUSION: Plaque morphology MRI is capable of identifying the main components of atherosclerotic plaques with moderate to good accuracy as compared with histopathological findings as gold standard. LRNC seems to be a useful marker of plaque vulnerability and warrants its use in clinical decision making.  .

Brush Sign Is Associated With Increased Severity in Cerebral Venous Thrombosis.

Background and Purpose- The brush sign (BS) is an abnormally accentuated signal drop of the subependymal and deep medullary veins in paramagnetic-sensitive magnetic resonance sequences, previously described in acute ischemic stroke. We aimed to describe the BS in patients with thrombosis of the cerebral veins and sinuses and explore its association with clinical severity, thrombosis extent, parenchymal brain lesion, and clinical prognosis. Methods- We assessed consecutive adult patients admitted to 2 university hospitals with diagnosis of acute thrombosis of the cerebral veins and sinuses and imaging assessment with magnetic resonance imaging, including paramagnetic-sensitive sequences. Demographics, imaging findings, clinical presentation, and functional outcome at 3 months were analyzed according to the presence of BS. Results- In 118 patients included, BS was observed in gradient-echo T2*weighted (T2*WI) in 16% and susceptibility-weighted imaging in 13% of cases. All patients with BS had thrombosis of the superior sagittal sinus, straight sinus, or deep venous system. BS was associated with ipsilateral parenchymal lesion (odds ratio, 6.4; 95% CI, 1.9-21.1; P=0.002) and higher thrombus load (median [interquartile range] 5 [4-6] versus 2 [2-4]); P<0.0001). BS was also associated with focal neurological deficits (OR 4.2; 95%CI, 1.4-12.7, P=0.01). The functional outcome at 3 months was not significantly different in patients with BS. Conclusions- BS in T2*WI and susceptibility-weighted imaging was observed in approximately one in 7 patients with acute thrombosis of the cerebral veins and sinuses. BS was significantly associated with ipsilateral parenchymal brain lesion, extent of thrombosis, and manifestation with focal neurological deficits. This suggests that BS can represent a marker of severity in thrombosis of the cerebral veins and sinuses.

Segmentation of Peripheral Nerves From Magnetic Resonance Neurography: A Fully-Automatic, Deep Learning-Based Approach.

Diagnosis of peripheral neuropathies relies on neurological examinations, electrodiagnostic studies, and since recently magnetic resonance neurography (MRN). The aim of this study was to develop and evaluate a fully-automatic segmentation method of peripheral nerves of the thigh. T2-weighted sequences without fat suppression acquired on a 3 T MR scanner were retrospectively analyzed in 10 healthy volunteers and 42 patients suffering from clinically and electrophysiologically diagnosed sciatic neuropathy. A fully-convolutional neural network was developed to segment the MRN images into peripheral nerve and background tissues. The performance of the method was compared to manual inter-rater segmentation variability. The proposed method yielded Dice coefficients of 0.859 ± 0.061 and 0.719 ± 0.128, Hausdorff distances of 13.9 ± 26.6 and 12.4 ± 12.1 mm, and volumetric similarities of 0.930 ± 0.054 and 0.897 ± 0.109, for the healthy volunteer and patient cohorts, respectively. The complete segmentation process requires less than one second, which is a significant decrease to manual segmentation with an average duration of 19 ± 8 min. Considering cross-sectional area or signal intensity of the segmented nerves, focal and extended lesions might be detected. Such analyses could be used as biomarker for lesion burden, or serve as volume of interest for further quantitative MRN techniques. We demonstrated that fully-automatic segmentation of healthy and neuropathic sciatic nerves can be performed from standard MRN images with good accuracy and in a clinically feasible time.

Predictors of Unexpected Early Reocclusion After Successful Mechanical Thrombectomy in Acute Ischemic Stroke Patients.

Background and Purpose- Sustained successful reperfusion is an important prognostic factor for good clinical outcome in acute ischemic stroke. We aimed to identify the prevalence, clinical impact, and predictors of early reocclusion after initially successful thrombectomies within a prospective cohort. Methods- A total of 711 stroke patients with successful reperfusion (modified Thrombolysis in Cerebral Infarction, 2b/3) followed with magnetic resonance or computed tomographic angiography at 24 to 48 hours were included. Multivariable logistic regression analysis was used to evaluate associated factors and clinical impact. Results are displayed as adjusted odds ratio (aOR) and 95% CI. Improvement in accuracy of additional imaging findings on angiography control runs after the intervention was evaluated by area under the curve. Results- Early reocclusion was observed in 16 of 711 successfully reperfused patients (2.3%; 95% CI, 1.1-3.3; median delay: 20 hours). Suggestive predictors were higher platelets on admission (aOR, 1.01; 95% CI, 1.01-1.02), prestroke functional dependence (aOR, 7.12; 95% CI, 1.49-34.03), and stroke of undetermined or other specified pathogenesis in the TOAST classification (aOR, 7.19; 95% CI, 1.10-47.05 and aOR, 36.50; 95% CI, 4.47-298.11, respectively). When implementing residual embolic fragments or stenosis at the thrombectomy site into the logistic regression model, discrimination between patients with and without reocclusion improved significantly (area under the curve, 0.955 versus 0.854; P=0.023). Early reocclusion was an independent predictor of unfavorable outcome at 90 days (aOR for modified Rankin Scale ≤2, 0.13; 95% CI, 0.03-0.57). Conclusions- Early reocclusion within 48 hours after successful mechanical thrombectomy is rare but associated with poor outcome. Patients with high platelets on admission and residual embolic fragments or stenosis at the thrombectomy site are at high risk for reocclusion, which may be prevented or corrected after carefully re-evaluating the last angiographic run.

Association of anemia and hemoglobin decrease during acute stroke treatment with infarct growth and clinical outcome.

BACKGROUND AND PURPOSE: Anemia is associated with worse outcome in stroke, but the impact of anemia with intravenous thrombolysis or endovascular therapy has hardly been delineated. The aim of this study was to analyze the role of anemia on infarct evolution and outcome after acute stroke treatment. METHODS: 1158 patients from Bern and 321 from Los Angeles were included. Baseline data and 3 months outcome assessed with the modified Rankin Scale were recorded prospectively. Baseline DWI lesion volumes were measured in 345 patients and both baseline and final infarct volumes in 180 patients using CT or MRI. Multivariable and linear regression analysis were used to determine predictors of outcome and infarct growth. RESULTS: 712 patients underwent endovascular treatment and 446 intravenous thrombolysis. Lower hemoglobin at baseline, at 24h, and nadir until day 5 predicted poor outcome (OR 1.150-1.279) and higher mortality (OR 1.131-1.237) independently of treatment. Decrease of hemoglobin after hospital arrival, mainly induced by hemodilution, predicted poor outcome and had a linear association with final infarct volumes and the amount and velocity of infarct growth. Infarcts of patients with newly observed anemia were twice as large as infarcts with normal hemoglobin levels. CONCLUSION: Anemia at hospital admission and any hemoglobin decrease during acute stroke treatment affect outcome negatively, probably by enlarging and accelerating infarct growth. Our results indicate that hemodilution has an adverse effect on penumbral evolution. Whether hemoglobin decrease in acute stroke could be avoided and whether this would improve outcome would need to be studied prospectively.

Rates and Quality of Preinterventional Reperfusion in Patients With Direct Access to Endovascular Treatment.

Background and Purpose- Preinterventional reperfusion before endovascular treatment (ET) is a benefit of bridging with intravenous tPA (tissue-type plasminogen activator). However, detailed data on reperfusion quality and rates of obviating ET in a cohort of patients with immediate access to ET is lacking. Purpose of this analysis was to evaluate prevalence and quality of preinterventional reperfusion in mothership patients. Methods- All mothership patients (n=627) from a prospective registry subjected to angiography with an intention to perform ET were reviewed. Preinterventional change of occlusion site (COS) was categorized into COS with Thrombolysis in Cerebral Infarction (TICI) 0/1, COS with TICI ≥2a, COS with TICI ≥2b, and COS with perfusion worsening. Predictors and clinical relevance were evaluated using multivariable logistic regression and results are displayed as adjusted odds ratios (aOR) and corresponding 95% confidence intervals (95% CI). Results- Prevalence of COS in all patients was 10.7% (95% CI, 8.3%-13.1%), subdividing into 2.7% COS with TICI 0/1, 6.2% COS with ≥TICI 2a (including 2.9% with TICI ≥2b), and 1.8% COS with perfusion worsening. Factors related to COS with ≥TICI 2a were intravenous tPA (aOR, 11.98; 95% CI, 4.5-31.6), cardiogenic thrombus origin (aOR, 2.3; 95% CI, 1.1-4.6), and thrombus length (aOR per 1 mm increase 0.926; 95% CI, 0.87-0.99). Additional ET was performed despite COS with ≥TICI 2a in 51.3%. COS with ≥TICI 2a showed a tendency for favorable outcomes (modified Rankin Scale, ≤2; aOR, 2.65; 95% CI, 0.98-7.17). Rates of COS with ≥TICI 2a were particularly low in internal carotid artery and proximal M1 occlusions (2.2%; 95% CI, 0.9%-5%), where intravenous tPA was associated with perfusion worsening (aOR, 4.33; 95% CI, 1.12-16.80). Conclusions- Prevalence of preinterventional reperfusion is non-negligible in patients with direct access to ET and is clearly favored by intravenous tPA treatment. However, it is often incomplete and often requires additional ET. Preinterventional reperfusion of internal carotid artery and proximal M1 occlusions is rare and usually of low quality, where intravenous tPA may also promote perfusion worsening.

Multivessel Occlusion in Patients Subjected to Thrombectomy: Prevalence, Associated Factors, and Clinical Implications.

BACKGROUND AND PURPOSE: Patients with embolic large-vessel occlusion may present with additional coincidental acute occlusions within or distant from the involved territory, referred to as multivessel occlusion (MVO). Purpose of this study was to assess prevalence of MVO, associated factors, and clinical relevance in patients undergoing endovascular stroke treatment. METHODS: Image data of consecutive endovascular candidates (n=720) with direct access to angiography were extracted from a prospective registry. Prevalence of MVO was assessed with multimodal magnetic resonance imaging/computed tomography and confirmed by intra-arterial angiography. Explorative analysis of associated factors and clinical relevance was evaluated using multivariable logistic regression including variables with P<0.15 in univariate comparison. Good functional outcome was defined as modified Rankin Scale score ≤2 at day 90. RESULTS: MVO was present in 10.7% of patients (95% confidence interval [CI], 6.4%-13.0%). Two, 3, and 4 concomitant occlusions were found in 80.5%, 16.9%, and 2.6% of MVO cases, respectively. Detection rate on initial radiological report was 54.5%. Downstream MVO was present in around one third of MVO (n=27/77, 35.1%), whereas all other MVO (n=50/77, 64.9%) occurred in different territories. Independent factors related to MVO were statin treatment (adjusted odds ratio [aOR], 0.477; 95% CI, 0.276-0.827), higher systolic blood pressure (aOR per mm Hg increase, 1.014; 95% CI, 1.005-1.023), and primary occlusion site M2 (aOR, 1.870; 95% CI, 1.103-3.170). MVO was related to lower rates of successful reperfusion (aOR, 0.549; 95% CI, 0.316-0.953) and lower rates of good functional outcome (aOR, 0.437; 95% CI, 0.207-0.923). CONCLUSIONS: Every tenth patient subjected to angiography for endovascular stroke treatment experienced MVO in our series, and only half were prospectively identified on preinterventional diagnostic imaging. Patients with MVO had higher baseline systolic blood pressure and were less often medicated with statins, an observation that warrants external validation and evaluation regarding causality. Occurrence of MVO has implication for treatment decisions, negatively affects endovascular treatment success, and is predictive of worse clinical outcome.

Impact of smoking on stroke outcome after endovascular treatment.

BACKGROUND: Recent studies suggest a paradoxical association between smoking status and clinical outcome after intravenous thrombolysis (IVT). Little is known about relationship between smoking and stroke outcome after endovascular treatment (EVT). METHODS: We analyzed data of all stroke patients treated with EVT at the tertiary stroke centre of Berne between January 2005 and December 2015. Using uni- and multivariate modeling, we assessed whether smoking was independently associated with excellent clinical outcome (modified Rankin Scale (mRS) 0-1) and mortality at 3 months. In addition, we also measured the occurrence of symptomatic intracranial hemorrhage (sICH) and recanalization. RESULTS: Of 935 patients, 204 (21.8%) were smokers. They were younger (60.5 vs. 70.1 years of age, p<0.001), more often male (60.8% vs. 52.5%, p = 0.036), had less often from hypertension (56.4% vs. 69.6%, p<0.001) and were less often treated with antithrombotics (35.3% vs. 47.7%, p = 0.004) as compared to nonsmokers. In univariate analyses, smokers had higher rates of excellent clinical outcome (39.1% vs. 23.1%, p<0.001) and arterial recanalization (85.6% vs. 79.4%, p = 0.048), whereas mortality was lower (15.6% vs. 25%, p = 0.006) and frequency of sICH similar (4.4% vs. 4.1%, p = 0.86). After correcting for confounders, smoking still independently predicted excellent clinical outcome (OR 1.758, 95% CI 1.206-2.562; p<0.001). CONCLUSION: Smoking in stroke patients may be a predictor of excellent clinical outcome after EVT. However, these data must not be misinterpreted as beneficial effect of smoking due to the observational study design. In view of deleterious effects of cigarette smoking on cardiovascular health, cessation of smoking should still be strongly recommended for stroke prevention.