Globus Pallidus Lesion With Iron Deposition and Dopaminergic Denervation in a Patient With a Pathogenic SLC6A1 Variant: A Case Report.

Objectives: SLC6A1-related disorders encompass heterogeneous neuropsychiatric manifestations through GABAergic dysregulation, without any specific abnormalities on brain MRI, nor evidence of dopaminergic cell loss on I123-FP-ß-CIT SPECT. We report here a case of globus pallidus lesions and dopaminergic denervation in a patient with a pathogenic SLC6A1 variant. Methods: A 26-year-old female patient with intellectual disability, behavioral, and psychiatric disorders treated by neuroleptics for many years developed a parkinsonian syndrome associated with mild hand dystonia and chorea. A 3T brain MRI and I123-FP-ß-CIT SPECT were performed. Results: MRI of the brain found bilateral pallidal lesions consistent with neurodegeneration with iron accumulation. The I123-FP-ß-CIT SPECT showed bilateral striatal presynaptic dopaminergic denervation. Whole-genome sequencing revealed a pathogenic SLC6A1 de novo variant. No additional variant was found in any of the genes responsible for Neurodegeneration with Brain Iron Accumulation (NBIA). Discussion: This is a description of dopaminergic denervation and globus pallidus lesions with iron accumulation related to a SLC6A1 pathogenic variant. These findings expand the phenotype of SLC6A1-related disorder and suggest that it could be considered as a differential diagnosis of NBIA.

Autosomal recessive pathogenic MSTO1 variants in hereditary optic atrophy.

Gerber et al report 2 autosomal recessive pathogenic Misato homolog 1 (MSTO1) variants causing hereditary optic atrophy and raise concerns about a previously identified dominant variant of MSTO1 by Gal et al (2017).

Blood-Brain Barrier Permeability and Kinetics of Inflammatory Markers in Acute Stroke Patients Treated With Thrombectomy.

BACKGROUND AND OBJECTIVES: The aim of this study was to investigate the relationship between baseline blood-brain barrier (BBB) permeability and the kinetics of circulating inflammatory markers in a cohort of acute ischemic stroke (AIS) patients treated with mechanical thrombectomy. METHODS: The CoHort of Patients to Identify Biological and Imaging markerS of CardiovascUlar Outcomes in Stroke includes AIS patients treated with mechanical thrombectomy after admission MRI and undergoing a sequential assessment of circulating inflammatory markers. Baseline dynamic susceptibility perfusion MRI was postprocessed with arrival time correction to provide K2 maps reflecting BBB permeability. After coregistration of apparent diffusion coefficient and K2 maps, the 90th percentile of K2 value was extracted within baseline ischemic core and expressed as a percentage change compared with contralateral normal-appearing white matter. Population was dichotomized according to the median K2 value. Univariable and multiple variable logistic regression analyses were performed to investigate factors associated with increased pretreatment BBB permeability in the whole population and in patients with symptom onset <6 hours. RESULTS: In the whole population (n = 105 patients, median K2 = 1.59), patients with an increased BBB permeability had higher serum levels of matrix metalloproteinase (MMP)-9 at H48 (p = 0.02), a higher C-reactive protein (CRP) serum level at H48 (p = 0.01), poorer collateral status (p = 0.01), and a larger baseline ischemic core (p < 0.001). They were more likely to have hemorrhagic transformation (p = 0.008), larger final lesion volume (p = 0.02), and worst neurologic outcome at 3 months (p = 0.04). The multiple variable logistic regression indicated that an increased BBB permeability was associated only with ischemic core volume (odds ratio [OR] 1.04, 95% CI 1.01-1.06, p < 0.0001). Restricting analysis to patients with symptom onset <6 hours (n = 72, median K2 = 1.27), participants with an increased BBB permeability had higher serum levels of MMP-9 at H0 (p = 0.005), H6 (p = 0.004), H24 (p = 0.02), and H48 (p = 0.01), higher CRP levels at H48 (p = 0.02), and a larger baseline ischemic core (p < 0.0001). The multiple variable logistic analysis showed that increased BBB permeability was independently associated with higher H0 MMP-9 levels (OR 1.33, 95% CI 1.12-1.65, p = 0.01) and a larger ischemic core (OR 1.27, 95% CI 1.08-1.59, p = 0.04). DISCUSSION: In AIS patients, increased BBB permeability is associated with a larger ischemic core. In the subgroup of patients with symptom onset <6 hours, increased BBB permeability is independently associated with higher H0 MMP-9 levels and a larger ischemic core.

Is the optimal Tmax threshold identifying perfusion deficit volumes variable across MR perfusion software packages? A pilot study.

PURPOSE: Accurate quantification of ischemic core and ischemic penumbra is mandatory for late-presenting acute ischemic stroke. Substantial differences between MR perfusion software packages have been reported, suggesting that the optimal Time-to-Maximum (Tmax) threshold may be variable. We performed a pilot study to assess the optimal Tmax threshold of two MR perfusion software packages (A: RAPID®; B: OleaSphere®) by comparing perfusion deficit volumes to final infarct volumes as ground truth. METHODS: The HIBISCUS-STROKE cohort includes acute ischemic stroke patients treated by mechanical thrombectomy after MRI triage. Mechanical thrombectomy failure was defined as a modified thrombolysis in cerebral infarction score of 0. Admission MR perfusion were post-processed using two packages with increasing Tmax thresholds (≥ 6 s, ≥ 8 s and ≥ 10 s) and compared to final infarct volume evaluated with day-6 MRI. RESULTS: Eighteen patients were included. Lengthening the threshold from ≥ 6 s to ≥ 10 s led to significantly smaller perfusion deficit volumes for both packages. For package A, Tmax ≥ 6 s and ≥ 8 s moderately overestimated final infarct volume (median absolute difference: - 9.5 mL, interquartile range (IQR) [- 17.5; 0.9] and 0.2 mL, IQR [- 8.1; 4.8], respectively). Bland-Altman analysis indicated that they were closer to final infarct volume and had narrower ranges of agreement compared with Tmax ≥ 10 s. For package B, Tmax ≥ 10 s was closer to final infarct volume (median absolute difference: - 10.1 mL, IQR: [- 17.7; - 2.9]) versus - 21.8 mL (IQR: [- 36.7; - 9.5]) for Tmax ≥ 6 s. Bland-Altman plots confirmed these findings (mean absolute difference: 2.2 mL versus 31.5 mL, respectively). CONCLUSIONS: The optimal Tmax threshold for defining the ischemic penumbra appeared to be most accurate at ≥ 6 s for package A and ≥ 10 s for package B. This implies that the widely recommended Tmax threshold ≥ 6 s may not be optimal for all available MRP software package. Future validation studies are required to define the optimal Tmax threshold to use for each package.

Brush sign and collateral supply as potential markers of large infarct growth after successful thrombectomy.

OBJECTIVES: To investigate the relationships between brush sign and cerebral collateral status on infarct growth after successful thrombectomy. METHODS: HIBISCUS-STROKE cohort includes acute ischemic stroke patients treated with thrombectomy after MRI triage and undergoing a day-6 MRI including FLAIR images to quantify final infarct volume (FIV). Successful reperfusion was defined as a modified thrombolysis in cerebral infarction score ≥ 2B. Infarct growth was calculated by subtracting FIV from baseline ischemic core after co-registration and considered large (LIG) when > 11.6 mL. Brush sign was assessed on T2*-weighted-imaging and collaterals were assessed using the hypoperfusion intensity ratio, which is the volume of Time-To-Tmax (Tmax) ≥ 10 s divided by the volume of Tmax ≥ 6 s. Good collaterals were defined by a hypoperfusion intensity ratio < 0.4. RESULTS: One hundred and twenty-nine patients were included, of whom 45 (34.9%) had a brush sign and 63 (48.8%) good collaterals. Brush sign was associated with greater infarct growth (p = 0.01) and larger FIV (p = 0.02). Good collaterals were associated with a smaller baseline ischemic core (p < 0.001), larger penumbra (p = 0.04), and smaller FIV (p < 0.001). Collateral status was not significantly associated with brush sign (p = 0.20) or with infarct growth (p = 0.67). Twenty-eight (22.5%) patients experienced LIG. Univariate regressions indicated that brush sign (odds ratio (OR) = 4.8; 95% confidence interval (CI): [1.9;13.3]; p = 0.004) and hemorrhagic transformation (OR = 1.7; 95%CI: [1.2;2.6]; p = 0.04) were predictive of LIG. In multivariate regression, only the brush sign remained predictive of LIG (OR = 5.2; 95%CI: [1.8-16.6], p = 0.006). CONCLUSIONS: Brush sign is a predictor of LIG after successful thrombectomy and cerebral collateral status is not. KEY POINTS: • Few predictors of ischemic growth are known in ischemic stroke patients achieving successful mechanical thrombectomy. • Our results suggest that the brush sign-a surrogate marker of severe hypoperfusion-is independently associated with large ischemic growth (> 11.6 mL) after successful thrombectomy whereas cerebral collateral status does not.

Assessment of three MR perfusion software packages in predicting final infarct volume after mechanical thrombectomy.

AIMS: To evaluate the performance of three MR perfusion software packages (A: RAPID; B: OleaSphere; and C: Philips) in predicting final infarct volume (FIV). METHODS: This cohort study included patients treated with mechanical thrombectomy following an admission MRI and undergoing a follow-up MRI. Admission MRIs were post-processed by three packages to quantify ischemic core and perfusion deficit volume (PDV). Automatic package outputs (uncorrected volumes) were collected and corrected by an expert. Successful revascularization was defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score ≥2B. Uncorrected and corrected volumes were compared between each package and with FIV according to mTICI score. RESULTS: Ninety-four patients were included, of whom 67 (71.28%) had a mTICI score ≥2B. In patients with successful revascularization, ischemic core volumes did not differ significantly from FIV regardless of the package used for uncorrected and corrected volumes (p>0.15). Conversely, assessment of PDV showed significant differences for uncorrected volumes. In patients with unsuccessful revascularization, the uncorrected PDV of packages A (median absolute difference -40.9 mL) and B (median absolute difference -67.0 mL) overestimated FIV to a lesser degree than package C (median absolute difference -118.7 mL; p=0.03 and p=0.12, respectively). After correction, PDV did not differ significantly from FIV for all three packages (p≥0.99). CONCLUSIONS: Automated MRI perfusion software packages estimate FIV with high variability in measurement despite using the same dataset. This highlights the need for routine expert evaluation and correction of automated package output data for appropriate patient management.

Gyriform infiltration as imaging biomarker for molecular glioblastomas.

BACKGROUND: Molecular glioblastomas (i.e. without the histological but with the molecular characteristics of IDH-wild-type glioblastoma) frequently lack contrast enhancement, which can wrongly lead to suspect a lower-grade glioma. Herein, we aimed to assess the diagnostic value of gyriform infiltration as an imaging marker for molecular glioblastomas. METHODS: Two independent investigators reviewed the MRI scans from patients with newly diagnosed gliomas for the presence of a gyriform infiltration defined as an elective cortical hypersignal on MRI FLAIR sequence. Diagnostic test performance of this sign for the diagnosis of molecular glioblastoma were calculated. RESULTS: A total of 426 patients were included, corresponding to 31 molecular glioblastoma, 294 IDH-wild-type glioblastoma, 50 IDH-mutant astrocytoma, and 51 IDH-mutant 1p19q-codeleted oligodendroglioma. A gyriform infiltration was observed in 16/31 (52%) molecular glioblastoma, 40/294 (14%) IDH-wild-type glioblastoma, and none of the IDH-mutant glioma. All the 56 gyriform-infiltration-positive tumors were IDH-wild-type and all but two had a TERT promoter mutation. The inter-rater agreement was good (κ = 0.69, p < 0.001). The sensitivity, specificity, positive predictive value and negative predictive value of the presence of a gyriform infiltration for the diagnosis of molecular glioblastoma were 52%, 90%, 29%, 96%, respectively. The median overall survival was better for gyriform-infiltration-negative patients compared to gyriform-infiltration-positive patients in the whole series and in patients with non-enhancing lesions (n = 95) (25.6 vs 16.9 months, p = 0.005 and 20.2 months vs not reached, p < 0.001). CONCLUSION: Gyriform infiltration is a specific imaging marker of molecular glioblastomas that can help distinguishing these tumors from IDH-mutant lower-grade gliomas.

Glial Fibrillary Acidic Protein Autoimmunity: A French Cohort Study.

BACKGROUND AND OBJECTIVES: To report the clinical, biological, and imaging features and clinical course of a French cohort of patients with glial fibrillary acidic protein (GFAP) autoantibodies. METHODS: We retrospectively included all patients who tested positive for GFAP antibodies in the CSF by immunohistochemistry and confirmed by cell-based assay using cells expressing human GFAPα since 2017 from 2 French referral centers. RESULTS: We identified 46 patients with GFAP antibodies. Median age at onset was 43 years, and 65% were men. Infectious prodromal symptoms were found in 82%. Other autoimmune diseases were found in 22% of patients, and coexisting neural autoantibodies in 11%. Tumors were present in 24%, and T-cell dysfunction in 23%. The most frequent presentation was subacute meningoencephalitis (85%), with cerebellar dysfunction in 57% of cases. Other clinical presentations included myelitis (30%) and visual (35%) and peripheral nervous system involvement (24%). MRI showed perivascular radial enhancement in 32%, periventricular T2 hyperintensity in 41%, brainstem involvement in 31%, leptomeningeal enhancement in 26%, and reversible splenial lesions in 4 cases. A total of 33 of 40 patients had a monophasic course, associated with a good outcome at last follow-up (Rankin Score ≤2: 89%), despite a severe clinical presentation. Adult and pediatric features are similar. Thirty-two patients were treated with immunotherapy. A total of 11/22 patients showed negative conversion of GFAP antibodies. DISCUSSION: GFAP autoimmunity is mainly associated with acute/subacute meningoencephalomyelitis with prodromal symptoms, for which tumors and T-cell dysfunction are frequent triggers. The majority of patients followed a monophasic course with a good outcome.

Multiple sclerosis lesions segmentation from multiple experts: The MICCAI 2016 challenge dataset.

MRI plays a crucial role in multiple sclerosis diagnostic and patient follow-up. In particular, the delineation of T2-FLAIR hyperintense lesions is crucial although mostly performed manually - a tedious task. Many methods have thus been proposed to automate this task. However, sufficiently large datasets with a thorough expert manual segmentation are still lacking to evaluate these methods. We present a unique dataset for MS lesions segmentation evaluation. It consists of 53 patients acquired on 4 different scanners with a harmonized protocol. Hyperintense lesions on FLAIR were manually delineated on each patient by 7 experts with control on T2 sequence, and gathered in a consensus segmentation for evaluation. We provide raw and preprocessed data and a split of the dataset into training and testing data, the latter including data from a scanner not present in the training dataset. We strongly believe that this dataset will become a reference in MS lesions segmentation evaluation, allowing to evaluate many aspects: evaluation of performance on unseen scanner, comparison to individual experts performance, comparison to other challengers who already used this dataset, etc.

Intracranial non-myxoid angiomatoid fibrous histiocytoma with EWSR1-CREB1 transcript fusion treated with doxorubicin: A case report.

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor that has only been reported in the central nervous system in case reports. After surgery, patients exhibit tumor recurrence. Pathological diagnosis of AHF remains difficult, especially in sites other than skin. AFH can harbor characteristic translocations implying that the Ewing sarcoma breakpoint region 1 gene (EWSR1) fuses with the transcription factor cyclic AMP response element binding (CREB) family genes. Doxorubicin is a chemotherapy that has previously been used successfully in two metastatic soft tissue AFH cases but never in intracranial AFH. The present report describes a case of an adult with a progressive classical intracranial non-myxoid AFH with ESWR1-CREB1 transcript fusion 4 years after surgery. The patient was treated with doxorubicin as a single agent chemotherapy. This treatment resulted in a prolonged stable disease 15 months after treatment discontinuation. This is the first reported case of a treatment with doxorubicin in an adult with progressive intracranial AFH with ESWR1-CREB1 transcript fusion which was sustained after treatment discontinuation.

Large vessel cardioembolic stroke and embolic stroke of undetermined source share a common profile of matrix metalloproteinase-9 level and susceptibility vessel sign length.

BACKGROUND: Embolic stroke of undetermined source (ESUS) accounts for up to 25% of ischemic strokes. Identification of biomarkers that could improve the prediction of stroke subtype and subsequently of stroke prevention still remains a major issue. METHODS: The HIBISCUS-STROKE cohort includes ischemic stroke patients with large vessel occlusion treated with mechanical thrombectomy following admission magnetic resonance imaging. Presence and length of susceptibility vessel sign (SVS) were assessed by gradient-recalled echo T2*-weighted imaging. Matrix metalloproteinase-9 (MMP-9) was measured on sera collected at admission. A multiple logistic regression model was performed to detect independent markers distinguishing cardioembolic (CE) from large-artery atherosclerosis (LAA) subtype. RESULTS: A total of 147 patients were included, of them the etiology was distributed as follows: 86 (58.5%) CE, 26 (17.7%) LAA, and 35 (23.8%) ESUS. The optimal cutoff for differentiating CE from LAA subtype was 14.5 mm for SVS length (sensitivity, 79.7%; specificity, 72.7%) and 1110 ng/ml for admission MMP-9 level (sensitivity, 85.3%; specificity, 52.2%). Multivariate analysis revealed that current smoking (odds ratio [OR] 0.07, 95% confidence interval [CI] 0.01-0.93), tandem occlusion (OR 0.01, 95% CI 0.01-0.21), SVS length (OR 0.78, 95% CI 0.63-0.97), and admission MMP-9 level (OR 0.99, 95% CI 0.99-1.00) were inversely associated with CE subtype. SVS length and MMP-9 level did not differ between ESUS and CE subtypes. CONCLUSION: SVS length and admission MMP-9 level may improve the prediction of CE subtype whose profile is close to ESUS, thus suggesting a common cardiac embolic source.

Aquaporin 4 distribution in the brain and its relevance for the radiological appearance of neuromyelitis optica spectrum disease.

BACKGROUND AND PURPOSE: To determine the precise incidence of lesions at sites of high Aquaporin-4 expression (hAQP4) and their possible association with known neuromyelitis optica spectrum disease (NMOSD) lesions patterns. MATERIALS AND METHODS: A retrospective analysis of brain and, when available, spinal cord MRI scans of 54 NMOSD patients recruited among the French NMOSD cohort was performed. Brain lesions were annotated as MS-like, non-specific, or evocative of NMOSD. The topography of hAQP4 was reassessed by human brain atlas. The incidence of lesions in hAQP4 and their association with lesions evocative of NMOSD was estimated. RESULTS: Among those included (41/54 female, mean age: 45 years) 47/54 (87%) presented brain lesions. Twenty-six/47 (55%) had lesions in hAQP4. Thirty-two/54 patients (60%) had lesions considered evocative of NMOSD. The majority of them also presented lesions in hAQP4 (65%, 21/32). Patients with lesions in hAQP4 and lesions evocative of NMOSD demonstrated more extensive myelitis compared to the other patients (7 [6-10] versus 4 [3-5] vertebral segments, P=0.009). CONCLUSION: The coexistence of lesions evocative of NMOSD and in hAQP4 is associated with significantly more extensive myelitis, and might have pathophysiological and clinical significance.

Avoiding New Biopsies by Identification of IDH1 and TERT Promoter Mutation in Nondiagnostic Biopsies From Glioma Patients.

BACKGROUND: Biopsies in patients with a suspected glioma are occasionally nondiagnostic. OBJECTIVE: To explore the utility of molecular testing in this setting by determining whether IDH1 and TERT promoter (pTERT) mutations could be detected in nondiagnostic biopsies from glioma patients. METHODS: Using SNaPshot polymerase chain reaction, we retrospectively assessed IDH1 and pTERT mutation status in nondiagnostic biopsies from 28 glioma patients. RESULTS: The nondiagnostic biopsy (needle biopsy n = 25, open or endoscopic biopsy n = 3) consisted of slight glial cell hypercellularity, hemorrhage, and/or necrosis. After another biopsy (n = 23) or a subsequent surgical resection (n = 5) the diagnosis was an IDH1-wildtype (WT) pTERT-mutant glioma (glioblastoma n = 16, astrocytoma n = 4), an IDH1-mutant pTERT-mutant oligodendroglioma (n = 1), an IDH1-mutant pTERT-WT astrocytoma (n = 1), and an IDH1-WT pTERT-WT glioblastoma (n = 6). An IDH1 mutation was identified in the nondiagnostic biopsies of the 2 IDH-mutant gliomas, and a pTERT mutation in the nondiagnostic biopsies of 16 out of the 21 of pTERT mutant-gliomas (76%). Overall, an IDH1 and/or a pTERT mutation were detected in 17 out of 28 (61%) of nondiagnostic biopsies. Retrospective analysis of the nondiagnostic biopsies based on these results and on imaging characteristics suggested that a new biopsy could have been avoided in 6 patients in whom a diagnosis of "molecular glioblastoma" could have been done with a high level of confidence. CONCLUSION: In the present series, IDH1 and pTERT mutations could be detected in a high proportion of nondiagnostic biopsies from glioma patients. Molecular testing may facilitate the interpretation of nondiagnostic biopsies in patients with a suspected glioma.

Impact of Collateral Status on Neuroprotective Effect of Cyclosporine A in Acute Ischemic Stroke.

BACKGROUND: Neuroprotection for acute ischemic stroke remains an elusive goal. Intracranial collaterals may favor neuroprotective drugs delivery at the acute stage of ischemic stroke. A recent phase 2 study showed that cyclosporine A (CsA) reduced ischemic damage in patients with a proximal occlusion who experienced effective recanalization. Collateral flow may improve this benefit. MATERIALS & METHODS: Collateral supply was assessed using dynamic susceptibility contrast MRI in 47 patients among the 110 patients from the original study and were graded in two groups: good collaterals and poor collaterals. Patients with good collaterals had significantly smaller initial infarct in both CsA group (p = 0.003) and controls (p = 0.016). Similarly, the final lesion volume was significantly lower in patients with good collaterals in both groups. RESULTS: In patients with either good or poor collaterals CsA showed no additional benefit on ischemic lesion progression and final infarct size at day 30. CONCLUSION: We failed to demonstrate any significant additional benefit of CsA in patients with good collateral circulation.

MRI Assessment of Oxygen Metabolism and Hemodynamic Status in Symptomatic Intracranial Atherosclerotic Stenosis: A Pilot Study.

BACKGROUND AND PURPOSE: Hemodynamic and metabolic impairment in intracranial atherosclerotic stenosis (ICAS) may promote stroke vulnerability particularly in borderzone areas. Perfusion and oxygen mapping magnetic resonance imaging (MRI) may provide useful information in this setting. METHODS: In this pilot study, patients with symptomatic atherosclerotic anterior circulation stenosis ≥60%, without other sources of ischemic stroke, were included. High-resolution vessel wall MRI quantified the stenosis degree, and hemodynamic and metabolic impairment was assessed at baseline using dynamic susceptibility contrast perfusion and multiparametric quantitative blood-oxygen-level-dependent (mqBOLD) oxygenation MRI. All parameters were assessed within both hemispheres and in borderzone areas. RESULTS: Forty-three subjects with intracranial artery narrowing were screened from November 2014 to January 2016. Eleven patients met the study criteria (mean ± standard deviation age = 64.4 ± 10.6 years, the mean degree of stenosis was 76.9 ± 23.4%). No interhemispheric differences were observed across oxygen (cerebral metabolic rate of oxygen and tissular saturation of oxygen) or perfusion (mean transit time, time to maximum, Tmax , normalized cerebral blood volume [nCBV], and normalized cerebral blood flow) parameters. A positive correlation was observed between the stenosis degree and ipsilateral nCBV (R = .77, P = .008). In addition, a significant increase in CBV was observed in anterior cortical borderzones ipsilateral to stenosis (nCBV = 7.20 ± 1.81 vs. 5.45 ± 1.40 mL/100 g, P = .02). CONCLUSION: Symptomatic ICAS had no global impact on perfusion and oxygen mapping MRI at resting state. A significant increase in nCBV was found within anterior borderzone areas.

Conventional MRI radiomics in patients with suspected early- or pseudo-progression.

BACKGROUND: After radiochemotherapy, 30% of patients with early worsening MRI experience pseudoprogression (Psp) which is not distinguishable from early progression (EP). We aimed to assess the diagnostic value of radiomics in patients with suspected EP or Psp. METHODS: Radiomics features (RF) of 76 patients (53 EP and 23 Psp) retrospectively identified were extracted from conventional MRI based on four volumes-of-interest. Subjects were randomly assigned into training and validation groups. Classification model (EP versus Psp) consisted of a random forest algorithm after univariate filtering. Overall (OS) and progression-free survivals (PFS) were predicted using a semi-supervised principal component analysis, and forecasts were evaluated using C-index and integrated Brier scores (IBS). RESULTS: Using 11 RFs, radiomics classified patients with 75.0% and 76.0% accuracy, 81.6% and 94.1% sensitivity, 50.0% and 37.5% specificity, respectively, in training and validation phases. Addition of MGMT promoter status improved accuracy to 83% and 79.2%, and specificity to 63.6% and 75%. OS model included 14 RFs and stratified low- and high-risk patients both in the training (hazard ratio [HR], 3.63; P = .002) and the validation (HR, 3.76; P = .001) phases. Similarly, PFS model stratified patients during training (HR, 2.58; P = .005) and validation (HR, 3.58; P = .004) phases using 5 RF. OS and PFS forecasts had C-index of 0.65 and 0.69, and IBS of 0.122 and 0.147, respectively. CONCLUSIONS: Conventional MRI radiomics has promising diagnostic value, especially when combined with MGMT promoter status, but with moderate specificity. In addition, our results suggest a potential for predicting OS and PFS.

Collateral circulation assessment within the 4.5 h time window in patients with and without DWI/FLAIR MRI mismatch.

OBJECTIVES: The aim of the present study was to assess the association between collateral status and DWI-FLAIR mismatch in patients with acute ischemic stroke within the 4.5 h time-window. METHODS: We analysed DWI, FLAIR, and PWI data in patients within 4.5 h after symptom onset from the I-KNOW European database. Collateral flow maps were graded by analyzing contrast 'staining' extent over the early, mid and late perfusion phases. ADC values, DWI lesion volume, and normalised perfusion parameters (CBV,Tmax) within DWI lesions were determined. Visibility of parenchymal hyperintensivty on FLAIR was evaluated ("FLAIR positive"), and DWI-FLAIR mismatch was assessed. Spontaneously reperfused regions were defined as voxels with Tmax <6 s within the DWI lesion. Final infarct size was assessed on day-30 FLAIR images. RESULTS: Of the 168 patients included in I-KNOW database, 87 were eligible for this study. DWI-FLAIR mismatch was present in 69 patients. There was no difference between poor and good collaterals status according to age, sex, baseline NIHSS score, time to MRI and DWI lesion volume. Collateral status was significantly better in the FLAIR positive group (p = .001). Patients with poor collaterals had significantly increased Tmax (p = .005). Baseline DWI lesion volume and final lesion volume were significantly smaller in patients with good collateral status (p < .001 and 0.01, respectively). CONCLUSIONS: We found that patients with early FLAIR lesion visibility have a better collateral status. This finding has implications for the management of stroke patients with unknown time-of-onset, and more widely should be considered in the current context of extending the therapeutic window.

Objective Evaluation of Multiple Sclerosis Lesion Segmentation using a Data Management and Processing Infrastructure.

We present a study of multiple sclerosis segmentation algorithms conducted at the international MICCAI 2016 challenge. This challenge was operated using a new open-science computing infrastructure. This allowed for the automatic and independent evaluation of a large range of algorithms in a fair and completely automatic manner. This computing infrastructure was used to evaluate thirteen methods of MS lesions segmentation, exploring a broad range of state-of-theart algorithms, against a high-quality database of 53 MS cases coming from four centers following a common definition of the acquisition protocol. Each case was annotated manually by an unprecedented number of seven different experts. Results of the challenge highlighted that automatic algorithms, including the recent machine learning methods (random forests, deep learning, …), are still trailing human expertise on both detection and delineation criteria. In addition, we demonstrate that computing a statistically robust consensus of the algorithms performs closer to human expertise on one score (segmentation) although still trailing on detection scores.

Impact of the Thrombectomy Trials on the Management and Outcome of Large Vessel Stroke: Data From the Lyon Stroke Center.

Introduction: Randomized trials (RT) have recently validated the superiority of thrombectomy over standard medical care, including intravenous thrombolysis (IVT). However, data on their impact on routine clinical care remains scarce. Methods: Using a prospective observational registry, we assessed: (1) the clinical and radiological characteristics of all consecutive patients treated with thrombectomy; (2) the outcome of all patients with M1 occlusion (treated with thrombectomy or IVT alone). Two periods were compared: before (2013-2014) and after (2015-2016) the publication of RT. Results: Endovascular procedures significantly increased between the two periods (N = 82 vs. 314, p < 0.0001). In 2015-2016, patients were older (median [IQR]: 69 [57-80]; vs. 66 [53-74]; p = 0.008), had shorter door-to-clot times (69 [47-95]; vs. 110 [83-155]; p < 0.0001) resulting in a trend toward shorter delay from symptom onset to reperfusion (232 [185-300]; vs. 250 [200-339]; p = 0.1), with higher rates of reperfusion (71 vs. 48%; p = 0.0001). Conversely, no significant differences in baseline NIHSS scores, ASPECTS, delay to IVT or intracranial hemorrhage were found. In 2015-2016, patients with M1 occlusion were treated with thrombectomy more often than in 2013-2014 (87 vs. 32%, respectively; p < 0.0001), with a significant improvement in clinical outcome (shift analysis, lower modified Rankin scale scores: OR = 1.68; 95% CI: 1.10-2.57; p = 0.017). Conclusion: Following the publication of RT, thrombectomy was rapidly implemented with significant improvements in intrahospital delay and reperfusion rates. Treatment with thrombectomy increased with better clinical outcomes in patients with M1 occlusion.