Neural correlates of mindfulness meditation and hypnosis on magnetic resonance imaging: similarities and differences. A scoping review.

BACKGROUND: Mindfulness meditation (MM) and hypnosis practices are gaining interest in mental health, but their physiological mechanisms remain poorly understood. This study aimed to synthesize the functional, morphometric and metabolic changes associated with each practice using magnetic resonance imaging (MRI), and to identify their similarities and differences. METHODS: MRI studies investigating MM and hypnosis in mental health, specifically stress, anxiety, and depression, were systematically screened following PRISMA guidelines from four research databases (PubMed, Web of Science, Embase, PsycINFO) between 2010 and 2022. RESULTS: In total, 97 references met the inclusion criteria (84 for MM and 13 for hypnosis). This review showed common and divergent points regarding the regions involved and associated brain connectivity during MM practice and hypnosis. The primary commonality between mindfulness and hypnosis was decreased default mode network intrinsic activity and increased central executive network - salience network connectivity. Increased connectivity between the default mode network and the salience network was observed in meditative practice and mindfulness predisposition, but not in hypnosis. CONCLUSIONS: While MRI studies provide a better understanding of the neural basis of hypnosis and meditation, this review underscores the need for more rigorous studies.

ASSESSMENT OF LARGE-SCALE IMAGING PRACTICES IN PATIENTS WITH ACUTE BRAIN HEMORRHAGE IN FRENCH EMERGENCY DEPARTMENTS: Emergency imaging practices in hemorrhagic stroke.

OBJECTIVE: Intracerebral hemorrhage (ICH) is a life-threatening condition, where imaging plays a crucial role but remains poorly standardized. Our main objective was to analyze the imaging protocols used during the acute phase of ICH and ascertain the proportion of patients diagnosed with secondary hemorrhage. PATIENTS AND METHODS: A multicenter retrospective observational study was conducted across over 100 French hospitals affiliated with a national tele-imaging network dedicated to emergency imaging. Among patients managed in the "Stroke Alert" pathway for suspected acute stroke from March 2021 to April 2023, those with ICH diagnosed within 24 hours of symptoms onset were identified. Their imaging reports were reviewed to identify the imaging modality used and protocols performed and investigate whether a secondary cause was identified. RESULTS: Of the 18,356 patients included in the "Stroke Alert" pathway, 662 cerebral hemorrhages were identified (3.6%). Computed tomography (CT) was the most widely used imaging modality in the acute phase (71.8% of examinations). Vascular imaging was performed in 78% of patients with cerebral hemorrhage, most often CT angiography or TOF magnetic resonance angiography. A secondary cause was identified in 8.2% (54/662) of cerebral hemorrhages, including vascular imaging in the vast majority of cases (92.6%). CONCLUSION: Optimization and standardization of imaging protocols in the acute phase of ICH is essential to improve the detection of its secondary causes, particularly vascular, requiring urgent treatment. Vascular imaging improves their early detection.

Perfusion Imaging and Clinical Outcome in Acute Minor Stroke With Large Vessel Occlusion.

BACKGROUND: Whether bridging therapy (intravenous thrombolysis [IVT] followed by mechanical thrombectomy) is superior to IVT alone in minor stroke with large vessel occlusion is unknown. Perfusion imaging may identify subsets of large vessel occlusion-related minor stroke patients with distinct response to bridging therapy. METHODS: We conducted a multicenter international observational study of consecutive IVT-treated patients with minor stroke (National Institutes of Health Stroke Scale score ≤5) who had an anterior circulation large vessel occlusion and perfusion imaging performed before IVT, with a subset undergoing immediate thrombectomy. Propensity score with inverse probability of treatment weighting was used to account for baseline between-groups differences. The primary outcome was 3-month modified Rankin Scale score 0 to 1. We searched for an interaction between treatment group and mismatch volume (critical hypoperfusion-core volume). RESULTS: Overall, 569 patients were included (172 and 397 in the bridging therapy and IVT groups, respectively). After propensity-score weighting, the distribution of baseline variables was similar across the 2 groups. In the entire population, bridging was associated with lower odds of achieving modified Rankin Scale score 0 to 1: odds ratio, 0.73 [95% CI, 0.55-0.96]; P=0.03. However, mismatch volume modified the effect of bridging on clinical outcome (Pinteraction=0.04 for continuous mismatch volume); bridging was associated with worse outcome in patients with, but not in those without, mismatch volume <40 mL (odds ratio, [95% CI] for modified Rankin Scale score 0-1: 0.48 [0.33-0.71] versus 1.14 [0.76-1.71], respectively). Bridging was associated with higher incidence of symptomatic intracranial hemorrhage in the entire population, but this effect was present in the small mismatch subset only (Pinteraction=0.002). CONCLUSIONS: In our population of large vessel occlusion-related minor stroke patients, bridging therapy was associated with lower rates of good outcome as compared with IVT alone. However, mismatch volume was a strong modifier of the effect of bridging therapy over IVT alone, notably with worse outcome with bridging therapy in patients with mismatch volume ≤40 mL. Randomized trials should consider adding perfusion imaging for patient selection.

Imaging of dopamine transporter with [18F]LBT-999: initial evaluation in healthy volunteers.

BACKGROUND: The aim of this study was to evaluate in healthy human brain the distribution, uptake, and kinetics of [18F]LBT-999, a PET ligand targeting the dopamine transporter, to assess its ability to explore dopaminergic innervation, using a shorter protocol, more convenient for patients than currently with [123I]ioflupane. METHODS: After intravenous injection of [18F]LBT-999, 8 healthy subjects (53-80y) underwent a dynamic PET-scan. Venous samples were concomitantly obtained for metabolites analysis. Time activity curves (TACs) were generated for several ROIs (caudate, putamen, occipital cortex, substantia nigra and cerebellum). Cerebellum was used as reference region to calculate binding potentials (BPND). RESULTS: No adverse events or detectable pharmacological effects were reported. [18F]LBT-999 PET revealed a good cerebral distribution, with an intense and symmetric uptake in both putamen and caudate (BPND of 6.75±1.17 and 6.30±1.17, respectively), without other brain abnormal tracer accumulation. Regional TACs showed a plateau from the maximal uptake, 20min pi, to the end of the acquisition for both caudate and putamen, whereas uptake in substantia nigra decreased progressively. A faster clearance and lowest BPND values were observed in both cortex and cerebellum. Ratios to the cerebellum exhibit value of about 3 in substantia nigra, close to 10 for both caudate and putamen, and remained around the value of 1 in cortex. The parent fraction of [18F]LBT-999 in plasma was 80%, 60% and 45% at 15, 30 and 45 min pi, respectively. CONCLUSIONS: These findings support the usefulness of [18F]LBT-999 for a quantitative clinical evaluation of presynaptic dopaminergic innervation.

Transient perivascular inflammation of the carotid artery (TIPIC) syndrome.

Background: The Transient Perivascular Inflammation of the Carotid artery (TIPIC) syndrome is presumably a very rare disease characterized by a local transient inflammation of the tissue around the carotid artery. Its pathophysiology remains unknown. We performed an updated study of TIPIC syndrome cases in the setting of a multinational collaborative study. Methods: This study was conducted as an observational multinational retrospective individual patient level cohort study. Information from all known cases diagnosed with TIPIC syndrome in the literature (2005-2020) was collected after a semi-structured literature search of PubMed and Web of Science. We also collected unpublished information of patients from French, Swiss, and Italian vascular medicine or radiology departments. Results: A total of 72 patients were included and served for data analysis: 42 (58.3%) were women; the mean age was 47.9 (SD=11.4) years. Symptoms were unilateral in 92% of patients and 81.4% required pain killers. At baseline, irrespective of the imaging method used, the median thickness of the carotid lesions was 5 (Q1-Q3: 4-7; range: 2-11) mm and the median length of the lesion was 20 (Q1-Q3: 10-30; range: 3-50) mm. We found a positive linear correlation between thickness and length. At follow-up, the thickness of the carotid lesions decreased to a median of 2 (Q1-Q3: 1-3; range: 0-6) mm; the length decreased to a median 10 (Q1-Q3: 5-15; range: 0-41) mm. A linear correlation between baseline and follow-up values was observed for both thickness and length measurements. Symptoms disappeared after a median of 14 (Q1-Q3: 10-15) days. Thirteen patients experienced a recurrence after a median follow-up of 6 (Q1-Q3: 2-12) months. Conclusions: The present analysis elucidates clinical and sonographic characteristics of TIPIC syndrome, indicating the benign nature of this condition. A future international registry will study the long-term course of the disease.

Quantitative analysis of thrombus migration before mechanical thrombectomy: Determinants and relationship with procedural and clinical outcomes.

BACKGROUND AND PURPOSE: In patients with acute ischemic stroke (AIS) and a large vessel occlusion (LVO), thrombus migration (T-Mig) is a common phenomenon before mechanical thrombectomy (MT), revealed by pre-treatment imaging. Previous works have used qualitative scales to define T-Mig. The aim of this study was to evaluate the determinants and impact of quantitatively assessed T-Mig on procedural characteristics and clinical outcome. METHODS: Consecutive patients with AIS due to LVO treated by MT at a reference academic hospital were analysed. Distance between vessel origin and beginning of the thrombus on MRI (3D-time-of-flight and/or contrast-enhanced magnetic-resonance-angiography) and digital-substracted-angiography (DSA) were measured in millimeters using a curve tool. Thrombus migration was defined quantitatively as ∆TD calculated as the difference between pre-MT-DSA and MRI thrombus location. ∆TD was rated as significant if above 5mm. RESULTS: A total of 267 patients were included (mean age 70±12 years; 46% females) were analyzed. Amongst them, 65 (24.3%) experienced any degree of T-Mig. T-Mig was found to be associated with iv-tPA administration prior to thrombectomy (ß-estimate 2.52; 95% CI [1.25-3.79]; p<0.001), fewer device passes during thrombectomy (1.22±1.31 vs 1.66±0.99; p<0.05), and shorter pre-treatment thrombi (ß-estimate -0.1millimeter; 95% CI [-0.27-0.07]; p<0.05). There was no association between T-Mig and a favourable outcome (defined by a 0-to-2 modified-Rankin-Scale at 3months, adjusted OR: 2.16 [0.93 - 5.02]; p=0.06) CONCLUSION: Thrombus migration happens in almost a fourth of our study sample, and its quantitative extent was associated with iv-tPA administration prior to MT, but not with clinical outcome.

Normal volumetric and T1 relaxation time values at 1.5 T in segmented pediatric brain MRI using a MP2RAGE acquisition.

OBJECTIVES: This study introduced a tailored MP2RAGE-based brain acquisition for a comprehensive assessment of the normal maturing brain. METHODS: Seventy normal patients (35 girls and 35 boys) from 1 to 16 years of age were recruited within a prospective monocentric study conducted from a single University Hospital. Brain MRI examinations were performed at 1.5 T using a 20-channel head coil and an optimized 3D MP2RAGE sequence with a total acquisition time of 6:36 min. Automated 38 region segmentation was performed using the MorphoBox (template registration, bias field correction, brain extraction, and tissue classification) which underwent a major adaptation of three age-group T1-weighted templates. Volumetry and T1 relaxometry reference ranges were established using a logarithmic model and a modified Gompertz growth respectively. RESULTS: Detailed automated brain segmentation and T1 mapping were successful in all patients. Using these data, an age-dependent model of normal brain maturation with respect to changes in volume and T1 relaxometry was established. After an initial rapid increase until 24 months of life, the total intracranial volume was found to converge towards 1400 mL during adolescence. The expected volumes of white matter (WM) and cortical gray matter (GM) showed a similar trend with age. After an initial major decrease, T1 relaxation times were observed to decrease progressively in all brain structures. The T1 drop in the first year of life was more pronounced in WM (from 1000-1100 to 650-700 ms) than in GM structures. CONCLUSION: The 3D MP2RAGE sequence allowed to establish brain volume and T1 relaxation time normative ranges in pediatrics. KEY POINTS: • The 3D MP2RAGE sequence provided a reliable quantitative assessment of brain volumes and T1 relaxation times during childhood. • An age-dependent model of normal brain maturation was established. • The normative ranges enable an objective comparison to a normal cohort, which can be useful to further understand, describe, and identify neurodevelopmental disorders in children.

Challenging diagnosis of chronic cerebral fungal infection: Value of (1→3)-ß-D-glucan and mannan antigen testing in cerebrospinal fluid and of cerebral ventricle puncture.

Primary fungal infection of the central nervous system (CNS) is rare but often associated with severe prognosis. Diagnosis is complicated since cerebrospinal fluid (CSF) samples obtained from lumbar puncture usually remain sterile. Testing for fungal antigens in CSF could be a complementary diagnostic tool. We conducted such measurements in CSF from patients with CNS fungal infection and now discuss the usefulness of ventricular puncture. Mannan and (1→3)ß-D-glucan (BDG) testing were retrospectively performed in CSF samples from three patients with proven chronic CNS fungal infection (excluding Cryptococcus), and subsequently compared to 16 controls. Results from lumbar punctures and those from cerebral ventricles were confronted. BDG detection was positive in all the CSF samples (from lumbar and/or ventricular puncture) from the three confirmed cases. In case of Candida infection, mannan antigen measurement was positive in 75% of the CSF samples. In the control group, all antigen detections were negative (n = 15), except for one false positive. Faced with suspected chronic CNS fungal infection, measurement of BDG levels appears to be a complementary diagnostic tool to circumvent the limitations of mycological cultures from lumbar punctures. In the event of negative results, more invasive procedures should be considered, such as ventricular puncture.

Improving diagnosis accuracy of brain volume abnormalities during childhood with an automated MP2RAGE-based MRI brain segmentation.

BACKGROUND AND PURPOSE: It can be challenging to depict brain volume abnormalities in the pediatric population on magnetic resonance imaging (MRI). The aim of the study was to evaluate the inter-radiologist reliability in brain MRI interpretation, including brain volume assessment and the efficiency of an automated brain segmentation. MATERIALS AND METHODS: We performed a single-center prospective study including 44 patients aged six months to five years recruited from the University Hospital, having a 1.5T brain MRI using a MP2RAGE sequence. All MRI were randomly and blindly reviewed by one junior and two senior pediatric radiologists. Inter-observer agreements were assessed using Fleiss' kappa coefficient. Brain volumetry (total intracranial volume (TIV), brain parenchyma, and cerebrospinal fluid volumes) was estimated using the MorphoBox prototype. Clinical head circumference (HC) and z scores were reported. A Pearson correlation coefficient was calculated between brain volumes with HC. RESULTS: Twenty-four brain MRI examinations were normal and twenty were pathological. Brain volume abnormalities were poorly detected by junior and senior radiologists: sensitivities 16.67% [confidence interval 4.7-44.8], 33.33% [13-60] and 30.7% [12-58] and specificities 93.75% [79-98], 84.38% [68-93] and 77% [60-88], respectively. Brain volume apart, interobserver kappa coefficients were 0.93 between junior and seniors as well as between seniors. Brain volumes were significantly correlated with HC (P<0.0001). In patients with normal MRI, brain parenchyma volumes increased regularly with age. Low brain volume was easier to identify with automated quantification. CONCLUSION: Brain volume was poorly appreciated by radiologists. The fully automated brain segmentation used can provide quantitative data to better diagnose, describe, and follow-up brain volume abnormalities.

Impact on child and parent anxiety level of a teddy bear-scale mock magnetic resonance scanner.

BACKGROUND: Pediatric magnetic resonance imaging (MRI) can be stressful. Mock MR scanners have been proven to be effective in avoiding the use of general anesthesia. OBJECTIVES: We prospectively evaluated the impact of a teddy bear-scale model of a mock MR scanner on the anxiety experienced by parents and their children during MRI without general anesthesia . MATERIALS AND METHODS: A 1-year prospective study before and after the installation of a mock scanner in a Pediatric Radiology Department of a university hospital. Anxiety levels were self-estimated by children ages 4 to 16 years and by the parents with a visual analogue scale (from 0, completely relaxed, to 100, extremely stressed) at three moments: in the waiting room, in the preparation room after an explanation by the MRI technologists, and at the issue of the MR acquisition images. Two groups were tested: one with a mock MR scanner, the other without. Analysis of variance (ANOVA) and Fisher exact tests were performed. Motion artifacts were studied. RESULTS: Ninety-one children and their parents were included. The median age was 8 years (standard deviation [SD]=2). In the post mock period, the ambiance of the preparation room was considered by children as significantly more relaxing in 50% vs. 20% (P=0.004) and the anxiety level of children was significantly lower after the explanation, particularly in girls, but unchanged for their parents. The anxiety levels at the end of the examination were significantly lower for parents. The motion artifacts rate was lower (1.7% vs. 4.7%, P=0.04). CONCLUSION: A mock scanner was an efficient tool to improve efficiency of the explanation and to decrease anxiety in children and motion artifacts in pediatric MRI.

Can We Reduce Frame Rate to 15 Images per Second in Pediatric Videofluoroscopic Swallow Studies?

Videofluoroscopic Swallow studies (VFSS) are useful radiological examinations to explore swallowing disorders but which require ionizing radiation. The aim of our study was to evaluate the comparability of pediatric VFSS at 15 frames per second (fps) with 30 fps. Fifty-five loops including 190 swallowings of VFSS at 30 fps performed on 32 consecutive pediatric patients in a University Hospital Center were retrospectively modified by a software to delete one image out of two to obtain secondary loops with a frame rate of 15 fps. An otorhinolaryngologist-phonatrician and a radiologist reviewed all swallowings blindly and randomly using the penetration and aspiration scale (PAS). In case of discordance, they concluded a consensual interpretation. Fifteen girls and seventeen boys were included. The median age was 4 years and 8 months (range = 4 months-16 yr.). 144 swallowings were normal. Swallowing disorder was confirmed in 46 swallowings, (23 supraglottic penetrations and 23 aspirations). Considering each swallowing at 15 fps, sensitivity and specificity were, respectively, 93% (CI 0.82-0.98) and 98% (CI 0.94-0.99). The Cohen'Kappa coefficient between each interpretation at 15 and 30 fps was "almost perfect" (κ = 0.95; CI 0.88-0.99). Considering each loop, conclusion was identical. Reducing frame rate at 15 fps during pediatric VFSS seemed to be acceptable with comparable diagnostic performances without clinical impact compared to 30 fps, while being an efficient way to reduce the ionizing radiation exposition in children. We would suggest reconsidering the possibility of using VFSS with a 15 fps in a pediatric population.

Posterior fossa tumors in children: Radiological tips & tricks in the age of genomic tumor classification and advance MR technology.

Imaging plays a major role in the comprehensive assessment of posterior fossa tumor in children (PFTC). The objective is to propose a global method relying on the combined analysis of radiological, clinical and epidemiological criteria, (taking into account the child's age and the topography of the lesion) in order to improve our histological approach in imaging, helping the management and approach for surgeons in providing information to the patients' parents. Infratentorial tumors are the most frequent in children, representing mainly medulloblastoma, pilocytic astrocytoma and brainstem glioma. Pre-surgical identification of the tumor type and its aggressiveness could be improved by the combined analysis of key imaging features with epidemiologic data.

Better Collaterals Are Independently Associated With Post-Thrombolysis Recanalization Before Thrombectomy.

Background and Purpose- In acute stroke patients with large vessel occlusion, the goal of intravenous thrombolysis (IVT) is to achieve early recanalization (ER). Apart from occlusion site and thrombus length, predictors of early post-IVT recanalization are poorly known. Better collaterals might also facilitate ER, for instance, by improving delivery of the thrombolytic agent to both ends of the thrombus. In this proof-of-concept study, we tested the hypothesis that good collaterals independently predict post-IVT recanalization before thrombectomy. Methods- Patients from the registries of 6 French stroke centers with the following criteria were included: (1) acute stroke with large vessel occlusion treated with IVT and referred for thrombectomy between May 2015 and March 2017; (2) pre-IVT brain magnetic resonance imaging, including diffusion-weighted imaging, T2*, MR angiography, and dynamic susceptibility contrast perfusion-weighted imaging; and (3) ER evaluated ≤3 hours from IVT start on either first angiographic run or noninvasive imaging. A collateral flow map derived from perfusion-weighted imaging source data was automatically generated, replicating a previously validated method. Thrombus length was measured on T2*-based susceptibility vessel sign. Results- Of 224 eligible patients, 37 (16%) experienced ER. ER occurred in 10 of 83 (12%), 17 of 116 (15%), and 10 of 25 (40%) patients with poor/moderate, good, and excellent collaterals, respectively. In multivariable analysis, better collaterals were independently associated with ER ( P=0.029), together with shorter thrombus ( P<0.001) and more distal occlusion site ( P=0.010). Conclusions- In our sample of patients with stroke imaged with perfusion-weighted imaging before IVT and intended for thrombectomy, better collaterals were independently associated with post-IVT recanalization, supporting our hypothesis. These findings strengthen the idea that advanced imaging may play a key role for personalized medicine in identifying patients with large vessel occlusion most likely to benefit from IVT in the thrombectomy era.

Thrombus Length Predicts Lack of Post-Thrombolysis Early Recanalization in Minor Stroke With Large Vessel Occlusion.

Background and Purpose- Whether bridging therapy, that is, intravenous thrombolysis [IVT] followed by mechanical thrombectomy, is beneficial as compared with IVT alone in minor stroke (National Institutes of Health Stroke Scale ≤5) with large vessel occlusion is unknown and should be tested in randomized trials. To help select the most appropriate candidates for such trials, we aimed to identify strong predictors of lack of post-IVT early recanalization (ER)-a surrogate marker of poor outcome. Methods- From a large multicenter French registry of patients with large vessel occlusion referred for thrombectomy immediately after IVT start between 2015 and 2017, we extracted 97 minor strokes with ER evaluated on first angiographic run or noninvasive imaging ≤3 hours from IVT start. Thrombus length was measured using the susceptibility vessel sign on T2* imaging. Results- Median National Institutes of Health Stroke Scale was 3 (interquartile range, 2-4), and occlusion sites were proximal (intracranial carotid or M1) and distal (M2) in 50% and 50% of patients, respectively. On pre-IVT MRI, median length of susceptibility vessel sign (visible in 90%) was 9.2 mm (interquartile range, 7.4-13.3). ER was present in 34% of patients, and susceptibility vessel sign length was the only clinical or radiological variable associated with no-ER after stepwise variable selection into a multivariable model (odds ratio, 1.53 per 1-mm increase; 95% CI, 1.21-1.92; P<0.001). The C statistic of susceptibility vessel sign length for no-ER prediction was 0.82 (95% CI, 0.73-0.92), and the optimal cutoff (Youden) was 9 mm. Sensitivity and specificity of this cutoff for no-ER were 67.8% (95% CI, 55.9-79.7) and 84.6% (95% CI, 70.7-98.5), respectively. Conclusions- ER was frequent in this cohort of IVT-treated minor stroke patients with large vessel occlusion considered for thrombectomy, and thrombus length was a powerful independent predictor of no-ER. These findings may help design randomized trials aiming to test bridging therapy versus IVT alone in this population.

Imaging spectrum of Bing-Neel syndrome: how can a radiologist recognise this rare neurological complication of Waldenström's macroglobulinemia?

OBJECTIVES: Bing-Neel syndrome (BNS) is a rare neurological complication of Waldenström's macroglobulinemia. The aim of this study is to describe the spectrum of radiological manifestations of this syndrome and their prevalence in order to facilitate its early diagnosis. METHODS: Twenty-four patients with BNS were diagnosed between 1994 and 2016 in eight centres in France. We retrospectively examined the medical records of these patients as well as the corresponding literature, focusing on imaging studies. Recorded data were statistically analysed and radiological findings described. RESULTS: The mean age of our patients was 62.4 years (35-80 years). The vast majority of patients were men, with a male to female ratio of 9:1. Findings included parenchymal or meningeal involvement or both. The most common finding was leptomeningeal infiltration, either intracranial or spinal, with a prevalence reaching 70.8%. Dural involvement was present in 37.5% of patients. In 41.7% (10/24) of patients, there was parenchymal involvement with a higher prevalence of brain comparing to medullar involvement (33.3% and 23.1% respectively). High T2 signal of the parenchyma was identified in 41.7% of patients and high signal in diffusion was evident in 25% of them. Intraorbital or periorbital involvement was also detected in four cases. A proposition regarding the appropriate imaging protocol completed our study. CONCLUSION: BNS's diagnosis remains challenging. Central nervous system MRI findings in the setting of known or suspected Waldenström's macroglobulinemia appear to be highly suggestive of BNS and appropriate imaging protocols should be implemented for their depiction. KEY POINTS: • Diagnosis of Bing-Neel syndrome (BNS) remains challenging and recent expert recommendations include MRI in the diagnostic criteria for the syndrome. • The most common radiological manifestations of BNS are leptomeningeal/dural infiltration or parenchymal involvement of brain or spinal cord, but many atypical forms may exist with various presentations. • Appropriate imaging protocol for BNS should include enhanced MRI studies of both brain and spine.

Post-Thrombolysis Recanalization in Stroke Referrals for Thrombectomy: Incidence, Predictors, and Prediction Scores.

Background and Purpose­Whether all acute stroke patients with large vessel occlusion need to undergo intravenous thrombolysis before mechanical thrombectomy (MT) is debated as (1) the incidence of post-thrombolysis early recanalization (ER) is still unclear; (2) thrombolysis may be harmful in patients unlikely to recanalize; and, conversely, (3) transfer for MT may be unnecessary in patients highly likely to recanalize. Here, we determined the incidence and predictors of post-thrombolysis ER in patients referred for MT and derive ER prediction scores for trial design. Methods­Registries from 4 MT-capable centers gathering patients referred for MT and thrombolyzed either on site (mothership) or in a non MT-capable center (drip-and-ship) after magnetic resonance­ or computed tomography­based imaging between 2015 and 2017. ER was identified on either first angiographic run or noninvasive imaging. In the magnetic resonance imaging subsample, thrombus length was determined on T2*-based susceptibility vessel sign. Independent predictors of no- ER were identified using multivariable logistic regression models, and scores were developed according to the magnitude of regression coefficients. Similar registries from 4 additional MT-capable centers were used as validation cohort. Results­In the derivation cohort (N=633), ER incidence was ≈20%. In patients with susceptibility vessel sign (n=498), no-ER was independently predicted by long thrombus, proximal occlusion, and mothership paradigm. A 6-point score derived from these variables showed strong discriminative power for no-ER (C statistic, 0.854) and was replicated in the validation cohort (n=353; C statistic, 0.888). A second score derived from the whole sample (including negative T2* or computed tomography­based imaging) also showed good discriminative power and was similarly validated. Highest grades on both scores predicted no-ER with >90% specificity, whereas low grades did not reliably predict ER. Conclusions­The substantial ER rate underlines the benefits derived from thrombolysis in bridging populations. Both prediction scores afforded high specificity for no-ER, but not for ER, which has implications for trial design.

Brain tissue pulsatility mediates cognitive and electrophysiological changes in normal aging: Evidence from ultrasound tissue pulsatility imaging (TPI).

Aging is characterized by a cognitive decline of fluid abilities and is also associated with electrophysiological changes. The vascular hypothesis proposes that brain is sensitive to vascular dysfunction which may accelerate age-related brain modifications and thus explain age-related neurocognitive decline. To test this hypothesis, cognitive performance was measured in 39 healthy participants from 20 to 80 years, using tests assessing inhibition, fluid intelligence, attention and crystallized abilities. Brain functioning associated with attentional abilities was assessed by measuring the P3b ERP component elicited through an auditory oddball paradigm. To assess vascular health, we used an innovative measure of the pulsatility of deep brain tissue, due to variations in cerebral blood flow over the cardiac cycle. Results showed (1) a classical effect of age on fluid neurocognitive measures (inhibition, fluid intelligence, magnitude and latency of the P3b) but not on crystallized measures, (2) that brain pulsatility decreases with advancing age, (3) that brain pulsatility is positively correlated with fluid neurocognitive measures and (4) that brain pulsatility strongly mediated the age-related variance in cognitive performance and the magnitude of the P3b component. The mediating role of the brain pulsatility in age-related effect on neurocognitive measures supports the vascular hypothesis of cognitive aging.

Susceptibility-Diffusion Mismatch in Hyperacute Stroke: Correlation with Perfusion-Diffusion Mismatch and Clinical Outcome.

BACKGROUND: A prominent vein (PV) on susceptibility-weighted imaging (SWI) was recently proposed to be a marker of the penumbra. We aimed to compare the utility of SWI and perfusion-weighted imaging (PWI) sequences for the evaluation of the penumbra in hyperacute middle cerebral artery (MCA) stroke, and to determine whether SWI-DWI mismatch is a neuroimaging marker of clinical outcome. METHODS: A total of 149 consecutive patients with MCA stroke were prospectively enrolled. Magnetic resonance imaging (MRI) was performed within 6 hours of the onset of stroke. The ASPECTS values on diffusion-weighted imaging (DWI), PWI (delayed mean transit time), and SWI (visualization of PVs) were calculated by 2 independent raters. Correlation between PWI-ASPECTS and SWI-ASPECTS was calculated with the Pearson coefficient. Reliability of the PV rating system was calculated by an intraclass correlation coefficient (ICC). Favorable outcome was defined as a modified Rankin Scale score of 0-2 at 3 months for the 88 patients who received thrombolytic therapy. RESULTS: The ASPECTS-SWI and ASPECTS-PWI scores showed a good correlation (Pearson coefficient of .69, P <.001). The reproducibility between the findings of the junior and the senior radiologists was excellent with an ICC of .89 (confidence interval of 95% (IC95): .85-.92, P <.001). However, neither SWI-DWI mismatch nor PWI-SWI mismatch was associated with clinical outcome. CONCLUSION: SWI and PWI were complementary but not commutable for the assessment of the penumbra. Susceptibility-diffusion mismatch was not found in this study to have predictive value for stroke outcome.