The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brain-behavior relationships after stroke.

The goal of the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well-powered meta- and mega-analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and large-scale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided.

Imaging Patterns of Injuries After the 2015 Amtrak Philadelphia Train Derailment.

OBJECTIVE: The purpose of this article is to describe the injury patterns observed in the 2015 Philadelphia Amtrak train derailment. CONCLUSION: Fractures accounted for most observed injuries, but uncommon and potentially serious injuries included posterior sternoclavicular dislocation and mesenteric contusion. Imaging plays a critical role in the triage of patients during mass-casualty events, and familiarity with the injury patterns associated with high-velocity unrestrained blunt force trauma will aid diagnosis in any future similar occurrence.

Location-atypical lesions in non-ketotic hyperglycemic epilepsy: expanding the clinico-radiographic phenotype

Non-ketotic hyperglycemia (NKH) is associated with a spectrum of symptoms and radiographic findings due to poorly-controlled diabetes mellitus. These lesions, which predominantly affect the parieto-occipital cortex, are commonly missed by neurologists and neuroradiologists due to their subtle hypointense appearance on T2-based imaging. We report four atypical cases of this syndrome to highlight its subtle, protean presentation in order to aid timely diagnosis. Based on our institutional case series, we describe four cases of NKH with atypical presentation and lesion burden affecting the anterior cortex. We review the clinical presentations, laboratory abnormalities, neuroimaging, and corresponding electroencephalography. Four patients with atypical NKH were characterized in our series. Presenting symptoms ranged from rhythmic hand-tapping to generalized tonic-clonic status epilepticus. Laboratory values were notable for marked hyperglycemia (range: 447 - 627 mg/dL), mild pseudo-hyponatremia (range: 127 - 136 mmol/L), and elevated hemoglobin A1C levels (range: 10.9 - 16.1%). All patients were found to have the classically described pattern of T2-based hypointensity; three with atypical distributions involving the "anterior" cortex. These lesions corresponded to the electrographic nidus of seizure burden. During follow-up, both seizures and T2-based hypointensity resolved within weeks of serum glucose normalization. Our series of four NKH patients with atypical findings of T2-based signal abnormalities expands the clinico-radiographic phenotype revealing a more protean distribution than previously described. Knowledge of these atypical imaging features will aid both the neurologist and radiologist in timely diagnosis and care of these patients.

Repetitive Strain Injuries of the Upper Extremity: Imaging of Tendon Pathology and Compressive Neuropathies.

Repetitive strain injuries (RSIs) encompass a broad clinicopathologic spectrum which includes discrete patterns of tissue injury involving tendons, bursae and nerves although an element of subjective symptomatology may be contributory. Upper extremity RSIs include De Quervain's tenosynovitis, intersection syndromes, epicondylitis, ulnar, and median neuritis as well as other compressive neuropathies. It is estimated that RSIs cost the US economy over $60 billion annually and while detailed clinical examination remains the diagnostic mainstay, imaging can aid in diagnosis, guide management and reduce costs.

Review of Artificial Intelligence Training Tools and Courses for Radiologists.

Artificial intelligence (AI) systems play an increasingly important role in all parts of the imaging chain, from image creation to image interpretation to report generation. In order to responsibly manage radiology AI systems and make informed purchase decisions about them, radiologists must understand the underlying principles of AI. Our task force was formed by the Radiology Research Alliance (RRA) of the Association of University Radiologists to identify and summarize a curated list of current educational materials available for radiologists.

Smaller spared subcortical nuclei are associated with worse post-stroke sensorimotor outcomes in 28 cohorts worldwide.

Up to two-thirds of stroke survivors experience persistent sensorimotor impairments. Recovery relies on the integrity of spared brain areas to compensate for damaged tissue. Deep grey matter structures play a critical role in the control and regulation of sensorimotor circuits. The goal of this work is to identify associations between volumes of spared subcortical nuclei and sensorimotor behaviour at different timepoints after stroke. We pooled high-resolution T1-weighted MRI brain scans and behavioural data in 828 individuals with unilateral stroke from 28 cohorts worldwide. Cross-sectional analyses using linear mixed-effects models related post-stroke sensorimotor behaviour to non-lesioned subcortical volumes (Bonferroni-corrected, P < 0.004). We tested subacute (≤90 days) and chronic (≥180 days) stroke subgroups separately, with exploratory analyses in early stroke (≤21 days) and across all time. Sub-analyses in chronic stroke were also performed based on class of sensorimotor deficits (impairment, activity limitations) and side of lesioned hemisphere. Worse sensorimotor behaviour was associated with a smaller ipsilesional thalamic volume in both early (n = 179; d = 0.68) and subacute (n = 274, d = 0.46) stroke. In chronic stroke (n = 404), worse sensorimotor behaviour was associated with smaller ipsilesional putamen (d = 0.52) and nucleus accumbens (d = 0.39) volumes, and a larger ipsilesional lateral ventricle (d = -0.42). Worse chronic sensorimotor impairment specifically (measured by the Fugl-Meyer Assessment; n = 256) was associated with smaller ipsilesional putamen (d = 0.72) and larger lateral ventricle (d = -0.41) volumes, while several measures of activity limitations (n = 116) showed no significant relationships. In the full cohort across all time (n = 828), sensorimotor behaviour was associated with the volumes of the ipsilesional nucleus accumbens (d = 0.23), putamen (d = 0.33), thalamus (d = 0.33) and lateral ventricle (d = -0.23). We demonstrate significant relationships between post-stroke sensorimotor behaviour and reduced volumes of deep grey matter structures that were spared by stroke, which differ by time and class of sensorimotor measure. These findings provide additional insight into how different cortico-thalamo-striatal circuits support post-stroke sensorimotor outcomes.

The 2015 Amtrak Philadelphia Train Derailment: After-Action Review of the Emergency Radiology Response at Temple University Health System.

PURPOSE: The aim of this article is to assess a large tertiary care medical center's emergency radiology response after the 2015 Amtrak Philadelphia train derailment. METHODS AND MATERIALS: A total of 55 patients with 308 total CTs and radiographs ordered within 12 hours of arrival to Temple University Health System (combining Temple University Hospital and Episcopal Hospital) emergency departments on May 12 to 13, 2015, were included in this study. A retrospective PACS and electronic medical record chart review of emergency department imaging turnaround times (TAT) during this event was completed and compared with emergency department radiology operations for the same 12-hour period throughout the preceding year. Wilcoxon's rank-sum test analysis was performed. RESULTS: A total of 308 CTs and radiographs were performed, and 91 radiologically evident injuries were observed in a total of 30 patients, with fractures (n = 51) as the most common type of injury. There were no significant differences in time from patient arrival to beginning of radiological examination (26 min; interquartile range [IQR], 11-58 min) compared with annual median (28 min; IQR, 10-131 min; P = .232). Examination completion TATs were significantly increased (35 min; IQR, 17-112 min) compared with annual median (10 min; IQR, 5-15 min; P < .001), and time required from viewing of the examination by the radiologist to the examination being marked as read was significantly decreased (17 min; IQR, 6-45 min) compared with annual median (248 min; IQR, 126-441 min; P < .001). CONCLUSIONS: The analysis highlights areas of efficiency in our response but also indicates areas for process improvement in future potential mass casualty events.

Lysosomal iron modulates NMDA receptor-mediated excitation via small GTPase, Dexras1.

BACKGROUND: Activation of NMDA receptors can induce iron movement into neurons by the small GTPase Dexras1 via the divalent metal transporter 1 (DMT1). This pathway under pathological conditions such as NMDA excitotoxicity contributes to metal-catalyzed reactive oxygen species (ROS) generation and neuronal cell death, and yet its physiological role is not well understood. RESULTS: We found that genetic and pharmacological ablation of this neuronal iron pathway in the mice increased glutamatergic transmission. Voltage sensitive dye imaging of hippocampal slices and whole-cell patch clamping of synaptic currents, indicated that the increase in excitability was due to synaptic modification of NMDA receptor activity via modulation of the PKC/Src/NR2A pathway. Moreover, we identified that lysosomal iron serves as a main source for intracellular iron signaling modulating glutamatergic excitability. CONCLUSIONS: Our data indicates that intracellular iron is dynamically regulated in the neurons and robustly modulate synaptic excitability under physiological condition. Since NMDA receptors play a central role in synaptic neurophysiology, plasticity, neuronal homeostasis, neurodevelopment as well as in the neurobiology of many diseases, endogenous iron is therefore likely to have functional relevance to each of these areas.

Modulation of age at onset in Huntington's disease and spinocerebellar ataxia type 2 patients originated from eastern India.

To identify the genetic modifier(s) that might alter the age at onset in Huntington's disease (HD) we have analyzed variations in GluR6 kainate receptor (GluR6), CA150 gene, Delta2642 and polymorphic CCG repeat variation in huntingtin (htt) gene in 77 HD patients and normal individuals. In addition, variation in the RAI1 gene was analyzed in 30 spinocerebellar ataxia (SCA2) patients and normal individuals to show the possible influence on the age at onset. Multiple regression analysis indicated that variation in GluR6 and CCG repeat genotype might explain 6.2% and 3.1%, respectively, of the variability in the age at onset in HD. Similar analysis with SCA2 patients indicated that RAI1 might explain about 13% of the variability in the age at onset. Specific alleles in GluR6 and CA150 locus were only observed in HD patients.