Advanced tractography-guided laser ablation of a perirolandic long-term epilepsy-associated tumor: illustrative case.

BACKGROUND: Microsurgical resection of drug-resistant epilepsy-associated perirolandic lesions can lead to postoperative motor impairment. Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (MRgLITT) has emerged as a less invasive alternative, offering reduced surgical risks and improved neurological outcomes. Electrophysiological tools routinely used for motor mapping in resective microsurgery are incompatible with intraoperative MRI. The utilization of advanced neuroimaging adjuncts for eloquent brain mapping during MRgLITT is imperative. The authors present the case of a 17-year-old athlete who underwent MRgLITT for a perirolandic long-term epilepsy-associated tumor (LEAT). They performed probabilistic multi-tissue constrained spherical deconvolution (MT-CSD) tractography to delineate the corticospinal tract (CST) for presurgical planning and intraoperative image guidance. The CST tractography was integrated into neuronavigation and MRgLITT workstation software to guide the ablation while monitoring the CST throughout the procedure. OBSERVATIONS: The integration of CST tractography into neuronavigation workstation planning and laser ablation workstation thermoablation is feasible and practical, facilitating complete ablation of a deep-seated perirolandic LEAT while preserving motor function. LESSONS: Probabilistic MT-CSD tractography enhanced MRgLITT planning as well as intraprocedural CST visualization and preservation, leading to a favorable functional outcome. The limitations of tractography and the predictability of thermal output distribution compared to the gold standard of microsurgical resection merit further discussion. https://thejns.org/doi/10.3171/CASE24139.

Canadian Association of Radiologists Statement on Planetary Health Education in Radiology.

The health of Canadians is already impacted by climate change due to wildfire smoke, heat domes, floods, droughts, and the changing distribution of vector borne disease. The healthcare sector contributes to climate change, accounting for approximately 4.6% of annual greenhouse gas emissions in Canada. Healthcare teams have a responsibility and opportunity to reduce harm by limiting emissions and waste, and engaging the public in understanding the planetary health links between clean air and water, a stable climate, a healthy planet and human health. Transformation of Canadian healthcare to a low carbon, climate resilient system will be enhanced by physician engagement and leadership. Cornerstones to physician participation include knowledge of the anthropogenic etiology of the climate crisis, the human health impacts, and the contribution providing healthcare makes to the climate crisis. Integration of climate change knowledge into the Canadian Radiology educational curricula is essential to position radiologists to lead transformative change in mitigation and adaptation of the healthcare system to the climate crisis. This statement is intended to provide guidelines to optimize education and research for current and future Canadian radiologists, and builds on existing planetary healthcare education publications and the Canadian Association of Radiologists Statement on Environmental Sustainability in Medical Imaging.

Saphenous Vein Graft Pseudoaneurysm Treated With Covered Stenting.

Saphenous vein graft (SVG) pseudoaneurysms are an infrequent, but life-threatening complication of coronary artery bypass grafting (CABG) surgery if left untreated. Here, we discuss the case of a 77-year-old patient, with a prior history of CABG and transcatheter aortic valve implantation (TAVI), who was incidentally found on computed tomography angiography (CTA) to have a pseudoaneurysm of his SVG with an initial chief complaint of dizziness. Despite increasing reports of SVG pseudoaneurysm, there is no consensus on definitive treatment. Due to the high mortality risk of this patient with surgical intervention, a minimally invasive percutaneous coronary intervention was performed. The patient was effectively treated with two overlapping Viabahn-covered stents, which completely excluded the pseudoaneurysm. Follow-up imaging at two months showed two well-positioned overlapping self-expanding stents with total occlusion of the pseudoaneurysm.

MRI signatures of cortical microstructure in human development align with oligodendrocyte cell-type expression.

Neuroanatomical changes to the cortex during adolescence have been well documented using MRI, revealing ongoing cortical thinning and volume loss with age. However, the underlying cellular mechanisms remain elusive with conventional neuroimaging. Recent advances in MRI hardware and new biophysical models of tissue informed by diffusion MRI data hold promise for identifying the cellular changes driving these morphological observations. This study used ultra-strong gradient MRI to obtain high-resolution, in vivo estimates of cortical neurite and soma microstructure in sample of typically developing children and adolescents. Cortical neurite signal fraction, attributed to neuronal and glial processes, increased with age (mean R2 fneurite=.53, p<3.3e-11, 11.91% increase over age), while apparent soma radius decreased (mean R2 Rsoma=.48, p<4.4e-10, 1% decrease over age) across domain-specific networks. To complement these findings, developmental patterns of cortical gene expression in two independent post-mortem databases were analysed. This revealed increased expression of genes expressed in oligodendrocytes, and excitatory neurons, alongside a relative decrease in expression of genes expressed in astrocyte, microglia and endothelial cell-types. Age-related genes were significantly enriched in cortical oligodendrocytes, oligodendrocyte progenitors and Layer 5-6 neurons (pFDR<.001) and prominently expressed in adolescence and young adulthood. The spatial and temporal alignment of oligodendrocyte cell-type gene expression with neurite and soma microstructural changes suggest that ongoing cortical myelination processes contribute to adolescent cortical development. These findings highlight the role of intra-cortical myelination in cortical maturation during adolescence and into adulthood.

Laser interstitial thermal therapy of a single nodule in a complex epileptic network with multiple periventricular nodular heterotopias.

Surgical management of drug-resistant epilepsy (DRE) in patients with multiple periventricular nodular heterotopias (PVNHs) is challenging. Identifying the location of seizure onset within these complex epileptic networks is difficult, and open resection carries risks of injury to surrounding functional white matter tracts such as optic radiations (ORs). The authors demonstrate tractography-assisted laser ablation of a single nodule in a patient with DRE and multiple PVNHs. Following surgery, visual fields were intact, highlighting the benefits of OR tractographic reconstruction. At 12 months postoperatively, the patient remained seizure free, suggesting the potential efficacy of targeting a single heterotopia within complex networks in well-selected cases. The video can be found here: https://stream.cadmore.media/r10.3171/2024.4.FOCVID2417.

Brain volume and neurodevelopment at 13 years following sepsis in very preterm infants.

BACKGROUND: Associations of neonatal infection with brain growth and later neurodevelopmental outcomes in very preterm (VP) infants are unclear. This study aimed to assess associations of neonatal sepsis in VP infants with (1) brain growth from term-equivalent age to 13 years; and (2) 13-year brain volume and neurodevelopmental outcomes. METHODS: 224 infants born VP ( < 30 weeks' gestation/<1250 g birthweight) were recruited. Longitudinal brain volumes for 68 cortical and 14 subcortical regions were derived from MRI at term-equivalent, 7 and/or 13 years of age for 216 children (79 with neonatal sepsis and 137 without). 177 children (79%) had neurodevelopmental assessments at age 13. Of these, 63 with neonatal sepsis were compared with 114 without. Brain volumetric growth trajectories across time points were compared between sepsis and no-sepsis groups using mixed effects models. Linear regressions compared brain volume and neurodevelopmental outcome measures at 13 years between sepsis and no sepsis groups. RESULTS: Growth trajectories were similar and there was little evidence for differences in brain volumes or neurodevelopmental domains at age 13 years between those with or without sepsis. CONCLUSIONS: Neonatal sepsis in children born VP does not appear to disrupt subsequent brain development, or to have functional consequences in early adolescence. IMPACT STATEMENT: Neonatal sepsis has been associated with poorer short-term neurodevelopmental outcomes and reduced brain volumes in very preterm infants. This manuscript provides new insights into the long-term brain development and neurodevelopmental outcomes of very preterm-born children who did or did not have neonatal sepsis. We found that regional brain volumes up to 13 years, and neurodevelopmental outcomes at age 13, were similar between those with and without neonatal sepsis. The links between neonatal sepsis and long-term neurodevelopment remain unclear.

Transfusion-related cost offsets and time burden in patients with myelofibrosis on momelotinib vs. danazol from MOMENTUM.

Aim: To estimate projected US-based cost and time burden for patients with myelofibrosis and anemia treated with momelotinib compared with danazol. Methods: Cost and time burden were calculated based on the transfusion status of patients in the MOMENTUM trial and estimates extracted from previous studies. Results: Reductions in transfusion associated with momelotinib are projected to result in cost and time savings compared with danazol in transfusion-dependent and transfusion-independent/requiring patients with myelofibrosis, respectively: annual medical costs ($53,143 and $46,455 per person), outpatient transfusion costs ($42,021 and $8,370 per person) and annual time savings (173 and 35 h per person). Conclusion: Fewer transfusions with momelotinib are projected to result in cost and time savings in patients with myelofibrosis and anemia compared with danazol.

Estimated cost & time savings in patients with the blood cancer myelofibrosisMyelofibrosis is a rare blood cancer often associated with bone marrow damage, too few of some types of blood cells and symptoms including tiredness, night sweating, itching and feelings of fullness and pain because of increased spleen size. Patients with anemia (too few red blood cells) may require regular blood transfusions and this is one sign that myelofibrosis is getting worse. MOMENTUM was a Phase III clinical trial showing that the drug momelotinib was safe and effective in patients with myelofibrosis who were previously treated with a type of drug called a JAK inhibitor. In particular, the trial showed that momelotinib reduced the need for transfusions compared with danazol, another drug typically used to treat patients with anemia. Based on this transfusion information from MOMENTUM and other publicly available information about estimated medical costs and patients' time spent in receiving transfusions, the analysis described here shows that a reduction in the number of transfusions with momelotinib compared with danazol is estimated to lead to cost savings as well as reduced patient time spent in transfusion-related travel, preparing and waiting for transfusions and receiving and recovering from transfusions.

Sounding out the dynamics: a concise review of high-speed photoacoustic microscopy.

Significance: Photoacoustic microscopy (PAM) offers advantages in high-resolution and high-contrast imaging of biomedical chromophores. The speed of imaging is critical for leveraging these benefits in both preclinical and clinical settings. Ongoing technological innovations have substantially boosted PAM's imaging speed, enabling real-time monitoring of dynamic biological processes. Aim: This concise review synthesizes historical context and current advancements in high-speed PAM, with an emphasis on developments enabled by ultrafast lasers, scanning mechanisms, and advanced imaging processing methods. Approach: We examine cutting-edge innovations across multiple facets of PAM, including light sources, scanning and detection systems, and computational techniques and explore their representative applications in biomedical research. Results: This work delineates the challenges that persist in achieving optimal high-speed PAM performance and forecasts its prospective impact on biomedical imaging. Conclusions: Recognizing the current limitations, breaking through the drawbacks, and adopting the optimal combination of each technology will lead to the realization of ultimate high-speed PAM for both fundamental research and clinical translation.

Childhood development of brain white matter myelin: a longitudinal T1w/T2w-ratio study.

Myelination of human brain white matter (WM) continues into adulthood following birth, facilitating connection within and between brain networks. In vivo MRI studies using diffusion weighted imaging (DWI) suggest microstructural properties of brain WM increase over childhood and adolescence. Although DWI metrics, such as fractional anisotropy (FA), could reflect axonal myelination, they are not specific to myelin and could also represent other elements of WM microstructure, for example, fibre architecture, axon diameter and cell swelling. Little work exists specifically examining myelin development. The T1w/T2w ratio approach offers an alternative non-invasive method of estimating brain myelin. The approach uses MRI scans that are routinely part of clinical imaging and only require short acquisition times. Using T1w/T2w ratio maps from three waves of the Neuroimaging of the Children's Attention Project (NICAP) [N = 95 (208 scans); 44% female; ages 9.5-14.20 years] we aimed to investigate the developmental trajectories of brain white matter myelin in children as they enter adolescence. We also aimed to investigate whether longitudinal changes in myelination of brain WM differs between biological sex. Longitudinal regression modelling suggested non-linear increases in WM myelin brain wide. A positive parabolic, or U-shaped developmental trajectory was seen across 69 of 71 WM tracts modelled. At a corrected level, no significant effect for sex was found. These findings build on previous brain development research by suggesting that increases in brain WM microstructure from childhood to adolescence could be attributed to increases in myelin.

The relationship between cognition and white matter tract damage after mild traumatic brain injury in a premorbidly healthy, hospitalised adult cohort during the post-acute period.

Introduction: Recent developments in neuroimaging techniques enable increasingly sensitive consideration of the cognitive impact of damage to white matter tract (WMT) microstructural organisation after mild traumatic brain injury (mTBI). Objective: This study investigated the relationship between WMT microstructural properties and cognitive performance. Participants setting and design: Using an observational design, a group of 26 premorbidly healthy adults with mTBI and a group of 20 premorbidly healthy trauma control (TC) participants who were well-matched on age, sex, premorbid functioning and a range of physical, psychological and trauma-related variables, were recruited following hospital admission for traumatic injury. Main measures: All participants underwent comprehensive unblinded neuropsychological examination and structural neuroimaging as outpatients 6-10 weeks after injury. Neuropsychological examination included measures of speed of processing, attention, memory, executive function, affective state, pain, fatigue and self-reported outcome. The WMT microstructural properties were estimated using both diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) modelling techniques. Tract properties were compared between the corpus callosum, inferior longitudinal fasciculus, uncinate fasciculus, anterior corona radiata and three segmented sections of the superior longitudinal fasciculus. Results: For the TC group, in all investigated tracts, with the exception of the uncinate fasciculus, two DTI metrics (fractional anisotropy and apparent diffusion coefficient) and one NODDI metric (intra-cellular volume fraction) revealed expected predictive linear relationships between extent of WMT microstructural organisation and processing speed, memory and executive function. The mTBI group showed a strikingly different pattern relative to the TC group, with no relationships evident between WMT microstructural organisation and cognition on most tracts. Conclusion: These findings indicate that the predictive relationship that normally exists in adults between WMT microstructural organisation and cognition, is significantly disrupted 6-10 weeks after mTBI and suggests that WMT microstructural organisation and cognitive function have disparate recovery trajectories.

Association of Acute Infarct Topography With Development of Cerebral Palsy and Neurologic Impairment in Neonates With Stroke.

BACKGROUND AND OBJECTIVES: Research investigating neonatal arterial ischemic stroke (NAIS) outcomes have shown that combined cortical and basal ganglia infarction or involvement of the corticospinal tract predict cerebral palsy (CP). The research question was whether voxel-based lesion-symptom mapping (VLSM) on acute MRI can identify brain regions associated with CP and neurodevelopmental impairments in NAIS. METHODS: Newborns were recruited from prospective Australian and Swiss pediatric stroke registries. CP diagnosis was based on clinical examination. Language and cognitive-behavioral impairments were assessed using the Pediatric Stroke Outcome Measure, dichotomized to good (0-0.5) or poor (≥1), at ≥18 months of age. Infarcts were manually segmented using diffusion-weighted imaging, registered to a neonatal-specific brain template. VLSM was conducted using MATLAB SPM12 toolbox. A general linear model was used to correlate lesion masks with motor, language, and cognitive-behavioral outcomes. Voxel-wise t-statistics were calculated, correcting for multiple comparisons using family-wise error (FWE) rate. RESULTS: Eighty-five newborns met the inclusion criteria. Infarct lateralization was left hemisphere (62%), right (8%), and bilateral (30%). At a median age of 2.1 years (interquartile range 1.9-2.6), 33% developed CP and 42% had neurologic impairments. Fifty-four grey and white matter regions correlated with CP (t > 4.33; FWE < 0.05), including primary motor pathway regions, such as the precentral gyrus, and cerebral peduncle, and regions functionally connected to the primary motor pathway, such as the pallidum, and corpus callosum motor segment. No significant correlations were found for language or cognitive-behavioral outcomes. DISCUSSION: CP after NAIS correlates with infarct regions directly involved in motor control and in functionally connected regions. Areas associated with language or cognitive-behavioral impairment are less clear.

Health care resource utilization and costs among patients with multiple myeloma with exposure to double-class or triple-class multiple myeloma treatments: A retrospective US claims database analysis.

BACKGROUND: Despite recent advancements in the therapeutic landscape, multiple myeloma (MM) remains incurable. There are multiple treatment options available with a novel mechanism of action, but there is limited evidence describing the economic burden among patients with MM exposed to different drug classes and combinations and across different health care settings. OBJECTIVE: To describe all-cause and MM-related health care resource utilization (HCRU) and costs among patients with MM exposed to different drug classes and combinations (ie, double-class and triple-class-exposed) and characterize the economic burden in different health care settings among these patients with MM. METHODS: We conducted a retrospective cohort study using the IBM MarketScan databases. The study included adult patients (aged ≥18 years) diagnosed with MM between December 1, 2015, and December 31, 2019. The study sample comprised double-class-exposed (DCE) and triple-class-exposed (TCE) cohorts, categorized based on their earliest exposure to different combinations of immunomodulatory drugs, proteasome inhibitors, or targeted monoclonal antibody. Patients with at least 1 subsequent line of therapy following the categorization were included, and the start date of the first subsequent line of therapy was the index date. The primary outcomes were all-cause and MM-related HCRU and costs during the follow-up period. Costs were stratified across 8 care settings defined by place of service. The Kaplan-Meier sample average technique was used to estimate the cumulative mean outcomes, accounting for differential follow-up periods. The outcomes were reported as per patient per month (PPPM). 18 years) diagnosed with MM between December 1, 2015, and December 31, 2019. The study sample comprised double-class-exposed (DCE) and triple-class-exposed (TCE) cohorts, categorized based on their earliest exposure to different combinations of immunomodulatory drugs, proteasome inhibitors, or targeted monoclonal antibody. Patients with at least 1 subsequent line of therapy following the categorization were included, and the start date of the first subsequent line of therapy was the index date. The primary outcomes were all-cause and MM-related HCRU and costs during the follow-up period. Costs were stratified across 8 care settings defined by place of service. The Kaplan-Meier sample average technique was used to estimate the cumulative mean outcomes, accounting for differential follow-up periods. The outcomes were reported as per patient per month (PPPM). RESULTS: The study included 1,521 patients with MM, of whom 1,016 (66.8%) were DCE and 505 (33.2%) were TCE. The mean total all-cause health care costs were $20,338 PPPM, and approximately 85% of the total all-cause costs were MM-related. The mean all-cause and MM-related total costs were driven by overall drug costs primarily attributed to MM treatment and administration costs. The TCE cohort was associated with more HCRU and incurred higher costs than the DCE cohort across all categories. The hospital-based ambulatory setting had the highest all-cause and MM-related costs during the follow-up period: $7,302 (95% CI = $6,801-$7,784) PPPM and $6,695 (95% CI = $6,239-$7,136) PPPM, respectively. CONCLUSIONS: The study findings suggest that the economic burden following exposure to multiple drug classes and combinations is substantial, especially among the TCE cohort and in the ambulatory setting. These findings highlight the need for more effective treatments that can mitigate the economic burden of patients with MM. Future research on the HCRU and costs related to recently approved MM treatments with novel mechanisms is warranted. DISCLOSURES: At the time of this study, Dr Yang was a postdoctoral fellow and the fellowship was supported by GSK. Dr Boytsov is a full-time employee of GSK. Dr Carlson discloses consulting fees from Pfizer, AbbVie, and Genentech. Dr Barthold reports no disclosures.

Cerebral microhaemorrhage count is related to processing speed, but not level of symptom reporting, independently of age, psychological status and premorbid functioning, after first-ever mild traumatic brain injury.

Cerebral microhaemorrhage is a commonly identified neuropathological consequence of mild traumatic brain injury (mTBI) and can be identified in vivo using susceptibility weighted imaging (SWI). This study aimed to determine whether SWI-detected microhaemorrhages are more common in individuals after a single, first-ever, mTBI event relative to trauma controls (TC) and to investigate whether a linear relationship exists between microhaemorrhage numbers and cognition or symptom reporting in the post-acute period after injury, independently of age, psychological status and premorbid level of functioning. Microhaemorrhagic lesions were identified by expert clinical examination of SWI for 78 premorbidly healthy adult participants who were admitted to hospital after a traumatic injury and had suffered a first-ever mTBI (n = 47) or no head strike (n = 31). Participants underwent objective cognitive examination of processing speed, attention, memory, and executive function as well as self-reported post-concussion symptomatology. Bootstrapping analyses were used as data were not normally distributed. Analyses revealed that the mTBI group had significantly more microhaemorrhages than the TC group (Cohen's d = 0.559). These lesions were only evident in 28% of individuals. The mTBI participants demonstrated a significant linear association between number of microhaemorrhages and processing speed, independently of age, psychological status, or premorbid level of functioning. This study shows that a single mTBI causes cerebral microhaemorrhages to occur in a minority of premorbidly healthy individuals. Greater microhaemorrhage count is independently associated with slower processing speed, but not symptom reporting, during the post-acute injury period.

Intracoronary Imaging and Physiology to Guide PCI: Are We Ready for a Class I Guideline Recommendation?

PURPOSE OF REVIEW: Over the last decade, there has been a plethora of evidence to support the utilization of intravascular coronary imaging and physiological assessment to guide percutaneous coronary interventions (PCI). While there is a class I recommendation for the use of coronary physiology to guide PCI, the use of intravascular coronary imaging remains a class IIa recommendation. Herein, we aimed to review the recent scientific evidence from major trials highlighting the consideration for a future class I guideline recommendation for the use of intracoronary imaging. RECENT FINDINGS: The benefits of intravascular ultrasound (IVUS) and optical coherence tomography (OCT) to guide and optimize PCI have been demonstrated in several large trials. These trials have demonstrated that IVUS reduces major adverse cardiovascular events. Similarly, intracoronary physiology has been demonstrated to be an important tool to guide revascularization decision-making and been associated with a lower incidence of death, non-fatal myocardial infarction, and repeat revascularization compared with angiography alone. With existing clinical outcomes data on the benefit of intracoronary physiology and imaging-guided PCI as well as forthcoming data from ongoing trials regarding the use of these modalities, the interventional cardiology community is bound to transition from routine PCI to precision-, image-, and physiology-guided PCI.

Exercise as therapy for neurodevelopmental and cognitive dysfunction in people with a Fontan circulation: A narrative review.

People with a Fontan circulation are at risk of neurodevelopmental delay and disability, and cognitive dysfunction, that has significant implications for academic and occupational attainment, psychosocial functioning, and overall quality of life. Interventions for improving these outcomes are lacking. This review article discusses current intervention practices and explores the evidence supporting exercise as a potential intervention for improving cognitive functioning in people living with a Fontan circulation. Proposed pathophysiological mechanisms underpinning these associations are discussed in the context of Fontan physiology and avenues for future research are recommended.

Long-lasting effects of very preterm birth on brain structure in adulthood: A systematic review and meta-analysis.

Early life experiences, such as very preterm (VP) birth, can affect brain and cognitive development. Several prior studies investigated brain structure in adults born VP; synthesising these studies may help to provide a clearer understanding of long-term effects of VP birth on the brain. We systematically searched Medline and Embase for articles that investigated brain structure using MRI in adulthood in individuals born VP (<32 weeks' gestation) or with very low birth weight (VLBW; <1500 g), and controls born at term or with normal birth weight. In total, 77 studies met the review inclusion criteria, of which 28 studies were eligible for meta-analyses, including data from up to 797 VP/VLBW participants and 518 controls, aged 18-33 years. VP/VLBW adults exhibited volumetric, morphologic and microstructural alterations in subcortical and temporal cortical regions compared with controls, with pooled standardised mean differences up to - 1.0 (95% confidence interval: -1.2, -0.8). This study suggests there is a persisting neurological impact of VP birth, which may provide developmental neurobiological insights for adult cognition in high-risk populations.

Intrinsic and secondary epileptogenicity in focal cortical dysplasia type II.

OBJECTIVE: Favorable seizure outcome is reported following resection of bottom-of-sulcus dysplasia (BOSD). We assessed the distribution of epileptogenicity and dysplasia in and around BOSD to better understand this clinical outcome and the optimal surgical approach. METHODS: We studied 27 children and adolescents with magnetic resonance imaging (MRI)-positive BOSD who underwent epilepsy surgery; 85% became seizure-free postresection (median = 5.0 years follow-up). All patients had resection of the dysplastic sulcus, and 11 had additional resection of the gyral crown (GC) or adjacent gyri (AG). Markers of epileptogenicity were relative cortical hypometabolism on preoperative 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET), and spiking, ripples, fast ripples, spike-high-frequency oscillation cross-rate, and phase amplitude coupling (PAC) on preresection and postresection electrocorticography (ECoG), all analyzed at the bottom-of-sulcus (BOS), top-of-sulcus (TOS), GC, and AG. Markers of dysplasia were increased cortical thickness on preoperative MRI, and dysmorphic neuron density and variant allele frequency of somatic MTOR mutations in resected tissue, analyzed at similar locations. RESULTS: Relative cortical metabolism was significantly reduced and ECoG markers were significantly increased at the BOS compared to other regions. Apart from spiking and PAC, which were greater at the TOS compared to the GC, there were no significant differences in PET and other ECoG markers between the TOS, GC, and AG, suggesting a cutoff of epileptogenicity at the TOS rather than a tapering gradient on the cortical surface. MRI and tissue markers of dysplasia were all maximal in the BOS, reduced in the TOS, and mostly absent in the GC. Spiking and PAC reduced significantly over the GC after resection of the dysplastic sulcus. SIGNIFICANCE: These findings support the concept that dysplasia and intrinsic epileptogenicity are mostly limited to the dysplastic sulcus in BOSD and support resection or ablation confined to the MRI-visible lesion as a first-line surgical approach. 18 F-FDG PET and ECoG abnormalities in surrounding cortex seem to be secondary phenomena.

Karawun: a software package for assisting evaluation of advances in multimodal imaging for neurosurgical planning and intraoperative neuronavigation.

PURPOSE: The neuroimaging research community-which includes a broad range of scientific, medical, statistical, and engineering disciplines-has developed many tools to advance our knowledge of brain structure, function, development, aging, and disease. Past research efforts have clearly shaped clinical practice. However, translation of new methodologies into clinical practice is challenging. Anything that can reduce these barriers has the potential to improve the rate at which research outcomes can contribute to clinical practice. In this article, we introduce Karawun, a file format conversion tool, that has become a key part of our work in translating advances in diffusion imaging acquisition and analysis into neurosurgical practice at our institution. METHODS: Karawun links analysis workflows created using open-source neuroimaging software, to Brainlab (Brainlab AG, Munich, Germany), a commercially available surgical planning and navigation suite. Karawun achieves this using DICOM standards supporting representation of 3D structures, including tractography streamlines, and thus offers far more than traditional screenshot or color overlay approaches. RESULTS: We show that neurosurgical planning data, created from multimodal imaging data using analysis methods implemented in open-source research software, can be imported into Brainlab. The datasets can be manipulated as if they were created by Brainlab, including 3D visualizations of white matter tracts and other objects. CONCLUSION: Clinicians can explore and interact with the results of research neuroimaging pipelines using familiar tools within their standard clinical workflow, understand the impact of the new methods on their practice and provide feedback to methods developers. This capability has been important to the translation of advanced analysis techniques into practice at our institution.

A diffusion MRI study of brain white matter microstructure in adolescents and adults with a Fontan circulation: Investigating associations with resting and peak exercise oxygen saturations and cognition.

INTRODUCTION: Adolescents and adults with a Fontan circulation are at risk of cognitive dysfunction; Attention and processing speed are notable areas of concern. Underlying mechanisms and brain alterations associated with worse long-term cognitive outcomes are not well determined. This study investigated brain white matter microstructure in adolescents and adults with a Fontan circulation and associations with resting and peak exercise oxygen saturations (SaO2), predicted maximal oxygen uptake during exercise (% pred VO2), and attention and processing speed. METHODS: Ninety-two participants with a Fontan circulation (aged 13-49 years, ≥5 years post-Fontan completion) had diffusion MRI. Averaged tract-wise diffusion tensor imaging (DTI) metrics were generated for 34 white matter tracts of interest. Resting and peak exercise SaO2 and % pred VO2 were measured during cardiopulmonary exercise testing (CPET; N = 81). Attention and processing speed were assessed using Cogstate (N = 67 and 70, respectively). Linear regression analyses adjusted for age, sex, and intracranial volume were performed to investigate associations between i) tract-specific DTI metrics and CPET variables, and ii) tract-specific DTI metrics and attention and processing speed z-scores. RESULTS: Forty-nine participants were male (53%), mean age was 23.1 years (standard deviation (SD) = 7.8 years). Mean resting and peak exercise SaO2 were 93.1% (SD = 3.6) and 90.1% (SD = 4.7), respectively. Mean attention and processing speed z-scores were -0.63 (SD = 1.07) and -0.72 (SD = 1.44), respectively. Resting SaO2 were positively associated with mean fractional anisotropy (FA) of the left corticospinal tract (CST) and right superior longitudinal fasciculus I (SLF-I) and negatively associated with mean diffusivity (MD) and radial diffusivity (RD) of the right SLF-I (p ≤ 0.01). Peak exercise SaO2 were positively associated with mean FA of the left CST and were negatively associated with mean RD of the left CST, MD of the left frontopontine tract, MD, RD and axial diffusivity (AD) of the right SLF-I, RD of the left SLF-II, MD, RD and AD of the right SLF-II, and MD and RD of the right SLF-III (p ≤ 0.01). Percent predicted VO2 was positively associated with FA of the left uncinate fasciculus (p < 0.01). Negative associations were identified between mean FA of the right arcuate fasciculus, right SLF-II and right SLF-III and processing speed (p ≤ 0.01). No significant associations were identified between DTI-based metrics and attention. CONCLUSION: Chronic hypoxemia may have long-term detrimental impact on white matter microstructure in people living with a Fontan circulation. Paradoxical associations between processing speed and tract-specific DTI metrics could be suggestive of compensatory white matter remodeling. Longitudinal investigations focused on the mechanisms and trajectory of altered white matter microstructure and associated cognitive dysfunction in people with a Fontan circulation are required to better understand causal associations.