Structural MRI profiles and tau correlates of atrophy in autopsy-confirmed CTE

Background Chronic traumatic encephalopathy (CTE), a neurodegenerative tauopathy, cannot currently be diagnosed during life. Atrophy patterns on magnetic resonance imaging could be an effective in vivo biomarker of CTE, but have not been characterized. Mechanisms of neurodegeneration in CTE are unknown. Here, we characterized macrostructural magnetic resonance imaging features of brain donors with autopsy-confirmed CTE. The association between hyperphosphorylated tau (p-tau) and atrophy on magnetic resonance imaging was examined. Methods Magnetic resonance imaging scans were obtained by medical record requests for 55 deceased symptomatic men with autopsy-confirmed CTE and 31 men (n = 11 deceased) with normal cognition at the time of the scan, all >60 years Three neuroradiologists visually rated regional atrophy and microvascular disease (0 [none]–4 [severe]), microbleeds, and cavum septum pellucidum presence. Neuropathologists rated tau severity and atrophy at autopsy using semi-quantitative scales. Results Compared to unimpaired males, donors with CTE (45/55=stage III/IV) had greater atrophy of the orbital-frontal (mean diff.=1.29), dorsolateral frontal (mean diff.=1.31), superior frontal (mean diff.=1.05), anterior temporal (mean diff.=1.57), and medial temporal lobes (mean diff.=1.60), and larger lateral (mean diff.=1.72) and third (mean diff.=0.80) ventricles, controlling for age at scan (ps<0.05). There were no effects for posterior atrophy or microvascular disease. Donors with CTE had increased odds of a cavum septum pellucidum (OR = 6.7, p < 0.05). Among donors with CTE, greater tau severity across 14 regions corresponded to greater atrophy on magnetic resonance imaging (beta = 0.68, p < 0.01). Conclusions These findings support frontal-temporal atrophy as a magnetic resonance imaging finding of CTE and show p-tau accumulation is associated with atrophy in CTE.

Subcortical Segmentation of the Fetal Brain in 3D Ultrasound using Deep Learning

The quantification of subcortical volume development from 3D fetal ultrasound can provide important diagnostic information during pregnancy monitoring. However, manual segmentation of subcortical structures in ultra-sound volumes is time-consuming and challenging due to low soft tissue contrast, speckle and shadowing artifacts. For this reason, we developed a convolutional neural network (CNN) for the automated segmentation of the choroid plexus (CP), lateral posterior ventricle horns (LPVH), cavum septum pellucidum et vergae (CSPV), and cerebellum (CB) from 3D ultrasound. As ground-truth labels are scarce and expensive to obtain, we applied few-shot learning, in which only a small number of manual annotations (n = 9) are used to train a CNN. We compared training a CNN with only a few individually annotated volumes versus many weakly labelled volumes obtained from atlas-based segmentations. This showed that segmentation performance close to intra-observer variability can be obtained with only a handful of manual annotations. Finally, the trained models were applied to a large number (n = 278) of ultrasound image volumes of a diverse, healthy population, obtaining novel US-specific growth curves of the respective structures during the second trimester of gestation.

Does the Prevalence of Anatomical Variants of the Brain Ventricles vary according to Socioeconomic Status? A Cross-sectional Imaging Survey in 2 Brazilian Private Hospitals

Background: Anatomical variants of brain ventricles are a known marker for abnormal central nervous system development. They seem to be more prevalent in several neuropsychiatric disorders, e.g. schizophrenia, personality disorders, and psychosis. However, knowledge about the risk factors and their overall prevalence in the general population, especially in developing countries is still limited. Methods: We evaluated the prevalence of prevalence of anatomical ventricular variants [Cavum septum pellucidum (CSP), Cavum vergae (CV), and Cavum velum interpositi (CVI)] in 1467 multislice head CTs from two large private hospitals in the city of Fortaleza, Ceará – Brazil. Results: Hospital one had a higher percentage of patients with low-cost health insurance, strokes, and neurocysticercosis (P<0.05). 15.1% of participants in hospital one versus 7.1% in hospital two had at least one type of cerebral cavum, including vestigial CSP. The rarest types of cava (CV and CVI) were twice more common in hospital one (P<0.05). Logistic regression analysis confirmed that patients from hospital one, older patients, and men were more likely to have any type of cerebral cavum and CSP. Conclusions: Anatomical brain ventricular variants (including vestigial CSP) were present in about 12% of participants of this middle-class Brazilian sample while also being more prevalent in male elderly and participants from lower socioeconomic strata. Further studies are necessary to prospectively investigate the association between socioeconomic variables and how they relate to the prevalence of anatomical brain ventricular variants and other known risk factors for developmental disorders.Trial registration: This study was approved by the Institutional Review Board from both participants institutions- Research Ethics Committee (CEP) - Unichristus (Protocols 099/11 and CAAE: 58763716.3.0000.5049).

Cranial Ultrasound in Preterm Neonates of Gestational Age 28 to 34 Weeks: A Single Centre Experience From Western India

Context: Intraventricular hemorrhage and periventricular leukomalacia, the common brain injuries in premature infants, are major causes for early death in the neonatal period and later motor and cognitive disabilities. This study was undertaken to find out the incidence of normal cranial ultrasound (CUS), normal variants, and abnormal CUS findings. Evidence Acquisition: This prospective, observational study was conducted at Neonatal ICU, Department of Paediatrics, Civil Hospital, Ahmedabad, over a period of 2 years from September 1, 2014, to August 31, 2016. Detailed history, examination, and risk factor assessment was done for all 180 subjects. The neonates were subjected to cranial ultrasound during admission and on follow-up. Results: Upon sonographic evaluation, 125 (69.44%) neonates had normal ultrasound, 34 (18.90%) had normal variants, and 21 (11.66%) had abnormal cranial ultrasound findings. The predominant normal variants observed were cavum septum pellucidum (18; 10%) and choroid plexus cyst (11; 6.1%). The most common abnormality detected was intraventricular hemorrhage (15; 8.3%) and was found to have a clinically significant correlation with surfactant use and with mechanical ventilation ( P value < .05). Follow-up scans could be performed on 70 subjects out of which 2 had normal variants and 3 had abnormal CUS findings. Conclusion: Establishing institutional CUS scanning protocols will go a long way in decreasing morbidity and mortality in preterm neonates.

Neuroradiologic Evaluation of MRI in High-Contact Sports

Background and Purpose: Athletes participating in high-contact sports experience repeated head trauma. Anatomical findings, such as a cavum septum pellucidum, prominent CSF spaces, and hippocampal volume reductions, have been observed in cases of mild traumatic brain injury. The extent to which these neuroanatomical findings are associated with high-contact sports is unknown. The purpose of this study was to determine whether there are subtle neuroanatomic differences between athletes participating in high-contact sports compared to low-contact athletic controls.Materials and Methods: We performed longitudinal structural brain MRI scans in 63 football (high-contact) and 34 volleyball (low-contact control) male collegiate athletes with up to 4 years of follow-up, evaluating a total of 315 MRI scans. Board-certified neuroradiologists performed semi-quantitative visual analysis of neuroanatomic findings, including: cavum septum pellucidum type and size, extent of perivascular spaces, prominence of CSF spaces, white matter hyperintensities, arterial spin labeling perfusion asymmetries, fractional anisotropy holes, and hippocampal size.Results: At baseline, cavum septum pellucidum length was greater in football compared to volleyball controls (p = 0.02). All other comparisons were statistically equivalent after multiple comparison correction. Within football at baseline, the following trends that did not survive multiple comparison correction were observed: more years of prior football exposure exhibited a trend toward more perivascular spaces (p = 0.03 uncorrected), and lower baseline Standardized Concussion Assessment Tool scores toward more perivascular spaces (p = 0.02 uncorrected) and a smaller right hippocampal size (p = 0.02 uncorrected).Conclusion: Head impacts in high-contact sport (football) athletes may be associated with increased cavum septum pellucidum length compared to low-contact sport (volleyball) athletic controls. Other investigated neuroradiology metrics were generally equivalent between sports.

Identifying degenerative effects of repetitive head trauma with neuroimaging: a clinically-oriented review

Background and Scope of Review Varying severities and frequencies of head trauma may result in dynamic acute and chronic pathophysiologic responses in the brain. Heightened attention to long-term effects of head trauma, particularly repetitive head trauma, has sparked recent efforts to identify neuroimaging biomarkers of underlying disease processes. Imaging modalities like structural magnetic resonance imaging (MRI) and positron emission tomography (PET) are the most clinically applicable given their use in neurodegenerative disease diagnosis and differentiation. In recent years, researchers have targeted repetitive head trauma cohorts in hopes of identifying in vivo biomarkers for underlying biologic changes that might ultimately improve diagnosis of chronic traumatic encephalopathy (CTE) in living persons. These populations most often include collision sport athletes (e.g., American football, boxing) and military veterans with repetitive low-level blast exposure. We provide a clinically-oriented review of neuroimaging data from repetitive head trauma cohorts based on structural MRI, FDG-PET, Aβ-PET, and tau-PET. We supplement the review with two patient reports of neuropathology-confirmed, clinically impaired adults with prior repetitive head trauma who underwent structural MRI, FDG-PET, Aβ-PET, and tau-PET in addition to comprehensive clinical examinations before death. Review Conclusions Group-level comparisons to controls without known head trauma have revealed inconsistent regional volume differences, with possible propensity for medial temporal, limbic, and subcortical (thalamus, corpus callosum) structures. Greater frequency and severity (i.e., length) of cavum septum pellucidum (CSP) is observed in repetitive head trauma cohorts compared to unexposed controls. It remains unclear whether CSP predicts a particular neurodegenerative process, but CSP presence should increase suspicion that clinical impairment is at least partly attributable to the individual’s head trauma exposure (regardless of underlying disease). PET imaging similarly has not revealed a prototypical metabolic or molecular pattern associated with repetitive head trauma or predictive of CTE based on the most widely studied radiotracers. Given the range of clinical syndromes and neurodegenerative pathologies observed in a subset of adults with prior repetitive head trauma, structural MRI and PET imaging may still be useful for differential diagnosis (e.g., assessing suspected Alzheimer’s disease).

Excision of Colloid Cyst through Interhemispheric, Transcallosal, Transcavum, Interfornicial Approach

Colloid cysts (CC) occur predominantly in the midline with majority involving roof of the third ventricle. In cases of cavum septum pellucidum (CSP), the surgeon can lose orientation when normal intraventricular structures are not encountered during surgery. We report a patient with CSP, who underwent right frontal parasagittal craniotomy, interhemispheric, transcallosal approach to reach the lesion. Lesion may not be seen in its usual location of foramen of Monroe, and entering the cavum may be confusing because no intraventricular landmarks will be seen. Excision of the cyst through the cavum usually requires interfornicial approach, and this structure must be separated gently to avoid injury.