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.

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.

Neurocognitive Dysfunction and Smaller Brain Volumes in Adolescents and Adults With a Fontan Circulation.

BACKGROUND: Neurocognitive outcomes beyond childhood in people with a Fontan circulation are not well defined. This study aimed to investigate neurocognitive functioning in adolescents and adults with a Fontan circulation and associations with structural brain injury, brain volumetry, and postnatal clinical factors. METHODS: In a binational study, participants with a Fontan circulation without a preexisting major neurological disability were prospectively recruited from the Australia and New Zealand Fontan Registry. Neurocognitive function was assessed by using Cogstate software in 107 participants with a Fontan circulation and compared with control groups with transposition of the great arteries (n=50) and a normal circulation (n=41). Brain MRI with volumetric analysis was performed in the participants with a Fontan circulation and compared with healthy control data from the ABIDE I and II (Autism Brain Imaging Data Exchange) and PING (Pediatric Imaging, Neurocognition, and Genetics) data repositories. Clinical data were retrospectively collected. RESULTS: Of the participants with a Fontan circulation who had a neurocognitive assessment, 55% were male and the mean age was 22.6 years (SD 7.8). Participants with a Fontan circulation performed worse in several areas of neurocognitive function compared with those with transposition of the great arteries and healthy controls (P<0.05). Clinical factors associated with worse neurocognitive outcomes included more inpatient days during childhood, younger age at Fontan surgery, and longer time since Fontan procedure (P<0.05). Adults with a Fontan circulation had more marked neurocognitive dysfunction than adolescents with a Fontan circulation in 2 domains (psychomotor function, P=0.01 and working memory, P=0.02). Structural brain injury was present in the entire Fontan cohort; the presence of white matter injury was associated with worse paired associate learning (P<0.001), but neither the presence nor severity of infarct, subcortical gray matter injury, and microhemorrhage was associated with neurocognitive outcomes. Compared with healthy controls, people with a Fontan circulation had smaller global brain volumes (P<0.001 in all regions) and smaller regional brain volumes in most cerebral cortical regions (P<0.05). Smaller global brain volumes were associated with worse neurocognitive functioning in several domains (P<0.05). A significant positive association was also identified between global brain volumes and resting oxygen saturations (P≤0.04). CONCLUSIONS: Neurocognitive impairment is common in adolescents and adults with a Fontan circulation and is associated with smaller gray and white matter brain volume. Understanding modifiable factors that contribute to brain injury to optimize neurocognitive function is paramount.

Individual Differences in Intrinsic Brain Networks Predict Symptom Severity in Autism Spectrum Disorders.

The neurobiology of heterogeneous neurodevelopmental disorders such as Autism Spectrum Disorders (ASD) is still unknown. We hypothesized that differences in subject-level properties of intrinsic brain networks were important features that could predict individual variation in ASD symptom severity. We matched cases and controls from a large multicohort ASD dataset (ABIDE-II) on age, sex, IQ, and image acquisition site. Subjects were matched at the individual level (rather than at group level) to improve homogeneity within matched case-control pairs (ASD: n = 100, mean age = 11.43 years, IQ = 110.58; controls: n = 100, mean age = 11.43 years, IQ = 110.70). Using task-free functional magnetic resonance imaging, we extracted intrinsic functional brain networks using projective non-negative matrix factorization. Intrapair differences in strength in subnetworks related to the salience network (SN) and the occipital-temporal face perception network were robustly associated with individual differences in social impairment severity (T = 2.206, P = 0.0301). Findings were further replicated and validated in an independent validation cohort of monozygotic twins (n = 12; 3 pairs concordant and 3 pairs discordant for ASD). Individual differences in the SN and face-perception network are centrally implicated in the neural mechanisms of social deficits related to ASD.

Biallelic Variants in PYROXD2 Cause a Severe Infantile Metabolic Disorder Affecting Mitochondrial Function.

Pyridine Nucleotide-Disulfide Oxidoreductase Domain 2 (PYROXD2; previously called YueF) is a mitochondrial inner membrane/matrix-residing protein and is reported to regulate mitochondrial function. The clinical importance of PYROXD2 has been unclear, and little is known of the protein's precise biological function. In the present paper, we report biallelic variants in PYROXD2 identified by genome sequencing in a patient with suspected mitochondrial disease. The child presented with acute neurological deterioration, unresponsive episodes, and extreme metabolic acidosis, and received rapid genomic testing. He died shortly after. Magnetic resonance imaging (MRI) brain imaging showed changes resembling Leigh syndrome, one of the more common childhood mitochondrial neurological diseases. Functional studies in patient fibroblasts showed a heightened sensitivity to mitochondrial metabolic stress and increased mitochondrial superoxide levels. Quantitative proteomic analysis demonstrated decreased levels of subunits of the mitochondrial respiratory chain complex I, and both the small and large subunits of the mitochondrial ribosome, suggesting a mitoribosomal defect. Our findings support the critical role of PYROXD2 in human cells, and suggest that the biallelic PYROXD2 variants are associated with mitochondrial dysfunction, and can plausibly explain the child's clinical presentation.

Automated Perfusion-Diffusion Magnetic Resonance Imaging in Childhood Arterial Ischemic Stroke.

Background and Purpose: Recent studies using automated perfusion imaging software have identified adults most likely to benefit from reperfusion therapies in extended time windows. The time course of penumbral tissue is poorly characterized in childhood arterial ischemic stroke (AIS). We explore the feasibility of using automated perfusion-diffusion imaging software to characterize penumbra in childhood AIS. Methods: An observational cohort study of children with acute unilateral AIS presenting to our institution. Diffusion-weighted imaging and dynamic susceptibility contrast perfusion magnetic resonance imaging performed within 72 hours of symptom onset were necessary for inclusion. Perfusion-diffusion mismatch was estimated using RAPID software. Ischemic core was defined as apparent diffusion coefficient <620×10−6 mm2/s and hypoperfusion as Tmax >6 seconds. Favorable mismatch profile was defined as core volume <70 mL, mismatch volume ≥15 mL, and a mismatch ratio ≥1.8. Results: Twenty-nine children (median 8 years old, interquartile range, 4.4­14.6) were included (26 unilateral middle cerebral artery and 3 unilateral cerebellar infarcts). Median Pediatric National Institutes of Health Stroke Scale was 4 (interquartile range, 3­11). Most cases had cryptogenic (n=11) or focal cerebral arteriopathy (n=9) causes. Median time-to-imaging =13.7 hours (interquartile range, 7.5­25.3). RAPID detected an ischemic core in 19 (66%) patients. In the remaining cases, the mean apparent diffusion coefficient values were mostly higher than the threshold as the majority of these presentations were delayed (median >21 hours) and infarct volumes were small (<3.5 mL). Overall, 3 children, imaged at 3.75, 11, and 23.5 hours had favorable mismatch profiles. Conclusions: This study demonstrates it is feasible to rapidly assess perfusion-diffusion mismatch in childhood AIS using automated software. Favorable mismatch profiles, using adult-based parameters, persisted beyond the standard 4.5 hours window for thrombolysis, suggesting potential therapeutic benefit of RAPID use. Further work is required to determine the utility of perfusion-based imaging to guide clinical decision making, whether adult thresholds require modification in childhood AIS, and to investigate the effect of time-delay and cause on mismatch characteristics.

White matter tracts related to memory and emotion in very preterm children.

BACKGROUND: Very preterm (VP) children are at risk of memory and emotional impairments; however, the neural correlates remain incompletely defined. This study investigated the effect of VP birth on white matter tracts traditionally related to episodic memory and emotion. METHODS: The cingulum, fornix, uncinate fasciculus, medial forebrain bundle and anterior thalamic radiation were reconstructed using tractography in 144 VP children and 33 full-term controls at age 7 years. RESULTS: Compared with controls, VP children had higher axial, radial, and mean diffusivities and neurite orientation dispersion, and lower volume and neurite density in the fornix, along with higher neurite orientation dispersion in the medial forebrain bundle. Support vector classification models based on tract measures significantly classified VP children and controls. Higher fractional anisotropy and lower diffusivities in the cingulum, uncinate fasciculus, medial forebrain bundle and anterior thalamic radiation were associated with better episodic memory, independent of key perinatal risk factors. Support vector regression models using tract measures did not predict episodic memory and emotional outcomes. CONCLUSIONS: Altered tract structure is related to adverse episodic memory outcomes in VP children, but further research is required to determine the ability of tract structure to predict outcomes of individual children. IMPACT: We studied white matter fibre tracts thought to be involved in episodic memory and emotion in VP and full-term children using diffusion magnetic resonance imaging and machine learning. VP children have altered fornix and medial forebrain bundle structure compared with full-term children. Altered tract structure can be detected using machine learning, which accurately classified VP and full-term children using tract data. Altered cingulum, uncinate fasciculus, medial forebrain bundle and anterior thalamic radiation structure was associated with poorer episodic memory skills using linear regression. The ability of tract structure to predict episodic memory and emotional outcomes of individual children based on support vector regression was limited.

Competency-Based Medical Education in Radiology: A Survey of Medical Student Perceptions.

PURPOSE: Implementing competency-based medical education in diagnostic radiology residencies will change the paradigm of learning and assessment for residents. The objective of this study is to evaluate medical student perceptions of competency-based medical education in diagnostic radiology programs and how this may affect their decision to pursue a career in diagnostic radiology. METHODS: First-, second-, and third-year medical students at a Canadian university were invited to complete a 14-question survey containing a mix of multiple choice, yes/no, Likert scale, and open-ended questions. This aimed to collect information on students' understanding and perceptions of competency-based medical education and how the transition to competency-based medical education would factor into their decision to enter a career in diagnostic radiology. RESULTS: The survey was distributed to 300 medical students and received 63 responses (21%). Thirty-seven percent of students had an interest in pursuing diagnostic radiology that ranged from interested to committed and 46% reported an understanding of competency-based medical education and its learning approach. The implementation of competency-based medical education in diagnostic radiology programs was reported to be a positive factor by 70% of students and almost all reported that breaking down residency into measurable milestones and required case exposure was beneficial. CONCLUSIONS: This study demonstrates that medical students perceive competency-based medical education to be a beneficial change to diagnostic radiology residency programs. The changes accompanying the transition to competency-based medical education were favored by students and factored into their residency decision-making.

Long-term development of white matter fibre density and morphology up to 13 years after preterm birth: A fixel-based analysis.

BACKGROUND: It is well documented that infants born very preterm (VP) are at risk of brain injury and altered brain development in the neonatal period, however there is a lack of long-term, longitudinal studies on the effects of VP birth on white matter development over childhood. Most previous studies were based on voxel-averaged, non-fibre-specific diffusion magnetic resonance imaging (MRI) measures, such as fractional anisotropy. In contrast, the novel diffusion MRI analysis framework, fixel-based analysis (FBA), enables whole-brain analysis of microstructural and macrostructural properties of individual fibre populations at a sub-voxel level. We applied FBA to investigate the long-term implications of VP birth and associated perinatal risk factors on fibre development in childhood and adolescence. METHODS: Diffusion images were acquired for a cohort of VP (born <30 weeks' gestation) and full-term (FT, ≥37 weeks' gestation) children at two timepoints: mean (SD) 7.6 (0.2) years (n â€‹= â€‹138 VP and 32 FT children) and 13.3 (0.4) years (n â€‹= â€‹130 VP and 45 FT children). 103 VP and 21 FT children had images at both ages for longitudinal analysis. At every fixel (individual fibre population within an image voxel) across the white matter, we compared FBA metrics (fibre density (FD), cross-section (FC) and a combination of these properties (FDC)) between VP and FT groups cross-sectionally at each timepoint, and longitudinally between timepoints. We also examined associations between known perinatal risk factors and FBA metrics in the VP group. RESULTS: Compared with FT children, VP children had lower FD, FC and FDC throughout the white matter, particularly in the corpus callosum, tapetum, inferior fronto-occipital fasciculus, fornix and cingulum at ages 7 and 13 years, as well as the corticospinal tract and anterior limb of the internal capsule at age 13 years. VP children also had slower FDC development in the corpus callosum and corticospinal tract between ages 7 and 13 years compared with FT children. Within VP children, earlier gestational age at birth, lower birth weight z-score, and neonatal brain abnormalities were associated with lower FD, FC and FDC throughout the white matter at both ages. CONCLUSIONS: VP birth and concomitant perinatal risk factors are associated with fibre tract-specific alterations to axonal development in childhood and adolescence.

White matter extension of the Melbourne Children's Regional Infant Brain atlas: M-CRIB-WM.

Brain atlases providing standardised identification of neonatal brain regions are key in investigating neurological disorders of early childhood. Our previously developed Melbourne Children's Regional Infant Brain (M-CRIB) and M-CRIB 2.0 neonatal brain atlases provide standardised parcellation of 100 brain regions including cortical, subcortical, and cerebellar regions. The aim of this study was to extend M-CRIB atlas coverage to include 54 white matter (WM) regions. Participants were 10 healthy term-born neonates that were used to create the initial M-CRIB atlas. WM regions were manually segmented based on T2 images and co-registered diffusion tensor imaging-based, direction-encoded colour maps. Our labelled regions imitate the Johns Hopkins University neonatal atlas, with minor anatomical modifications. All segmentations were reviewed and approved by a paediatric radiologist and a neurosurgery research fellow for anatomical accuracy. The resulting neonatal WM atlas comprises 54 WM regions: 24 paired regions, and six unpaired regions comprising five corpus callosum subdivisions, and one pontine crossing tract. Detailed protocols for manual WM parcellations are provided, and the M-CRIB-WM atlas is presented together with the existing M-CRIB cortical, subcortical, and cerebellar parcellations in 10 individual neonatal MRI data sets. The novel M-CRIB-WM atlas, along with the M-CRIB cortical and subcortical atlases, provide neonatal whole brain MRI coverage in the first multi-subject manually parcellated neonatal atlas compatible with atlases commonly used at older time points. The M-CRIB-WM atlas is publicly available, providing a valuable tool that will help facilitate neuroimaging research into neonatal brain development in both healthy and diseased states.

Peer Review and Transparency in Evidence-Source Selection in Value and Health Technology Assessment.

OBJECTIVES: Value and health technology assessment (V/HTA) is often used in clinical, access, and reimbursement decisions. V/HTA data-source selection may not be transparent, which is a necessary element for stakeholder understanding and trust and for fostering accountability among decision makers. Peer review is considered one mechanism for judging data trustworthiness. Our objective was (1) to use publicly available documentation of V/HTA methods to identify requirements for inclusion of peer-reviewed evidence sources, (2) to compare and contrast US and non-US approaches, and (3) to assess evidence sources used in published V/HTA reports. METHODS: Publicly available methods documentation from 11 V/HTA organizations in North America and Europe were manually searched and abstracted for descriptions of requirements and recommendations regarding search strategy and evidence-source selection. The bibliographies of a subset of V/HTA reports published in 2018 were manually abstracted for evidence-source types used in each. RESULTS: Heterogeneity in evidence-source retrieval and selection was observed across all V/HTA organizations, with more pronounced differences between US and non-US organizations. Not all documentation of organizations' methods address the evidence-source selection processes (7 of 11), and few explicitly reference peer-reviewed sources (3 of 11). Documentation of the evidence-source selection strategy was inconsistent across reports (6 of 13), and the level of detail provided varied across organizations. Some information on evidence-source selection was often included in confidential documentation and was not publicly available. CONCLUSIONS: Disparities exist among V/HTA organizations in requirements and guidance regarding evidence-source selection. Standardization of evidence-source selection strategies and documentation could help improve V/HTA transparency and has implications for decision making based on report findings.

Evolution of Veterans Affairs Transcatheter Aortic Valve Replacement Program: The First 100 Patients.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is a widely established alternative to surgery in intermediate- and high-risk patients. TAVR program development within the Veterans Affairs (VA) system has been previously described. However, national TAVR registries do not capture VA outcomes data, and few data have been reported regarding TAVR outcomes at lower-volume federal institutions. The study aim was to demonstrate the evolution of a successful VA TAVR program. METHODS: A retrospective analysis was performed of the first 100 TAVR patients at San Francisco VA Medical Center. Mortality and major complications were evaluated. RESULTS: Between 25th November 2013 and 31st August 2016, a total of 100 TAVR procedures was performed at the authors' institution. The mean patient age was 79.7 ± 8.7 years. Patients underwent TAVR via percutaneous-transfemoral (n = 90), surgical cutdown-transfemoral (n = 8), or transapical (n = 2) approaches. The valve systems employed were Edwards SAPIEN (n = 16), SAPIEN XT (n = 31), SAPIEN 3 (n = 23), and Medtronic CoreValve (n = 16) and CoreValve Evolut R (n = 14). The overall device success was 96%. TAVR-in-TAVR was required in the remaining 4% of patients, and was successful. All-cause procedural mortality was 1%. Complications included tamponade (1%), stroke (2%), temporary hemodialysis (1%), vascular injuries requiring intervention (4%), and permanent pacemaker implantation (14%). There were no conversions to surgical aortic valve replacement. Twenty-two (22%) patients had mild, two (2%) had moderate, and none (0%) had severe paravalvular leakage. The post-procedure aortic valve gradient by echocardiography was 8.6 ± 4.5 mmHg. Follow up was 100% complete and survival was 99%, 93%, and 89% at one, six, and 12 months, respectively. CONCLUSIONS: Successful outcomes were demonstrated for a VA TAVR program that compared favorably with benchmarks established by the National Transcatheter Valve Therapies Registry. These results provide a necessary transparency of TAVR outcomes at a federal institution.

Structural connectivity relates to perinatal factors and functional impairment at 7years in children born very preterm.

OBJECTIVE: To use structural connectivity to (1) compare brain networks between typically and atypically developing (very preterm) children, (2) explore associations between potential perinatal developmental disturbances and brain networks, and (3) describe associations between brain networks and functional impairments in very preterm children. METHODS: 26 full-term and 107 very preterm 7-year-old children (born <30weeks' gestational age and/or <1250g) underwent T1- and diffusion-weighted imaging. Global white matter fibre networks were produced using 80 cortical and subcortical nodes, and edges were created using constrained spherical deconvolution-based tractography. Global graph theory metrics were analysed, and regional networks were identified using network-based statistics. Cognitive and motor function were assessed at 7years of age. RESULTS: Compared with full-term children, very preterm children had reduced density, lower global efficiency and higher local efficiency. Those with lower gestational age at birth, infection or higher neonatal brain abnormality score had reduced connectivity. Reduced connectivity within a widespread network was predictive of impaired IQ, while reduced connectivity within the right parietal and temporal lobes was associated with motor impairment in very preterm children. CONCLUSIONS: This study utilised an innovative structural connectivity pipeline to reveal that children born very preterm have less connected and less complex brain networks compared with typically developing term-born children. Adverse perinatal factors led to disturbances in white matter connectivity, which in turn are associated with impaired functional outcomes, highlighting novel structure-function relationships.

Automated alignment of perioperative MRI scans: A technical note and application in pediatric epilepsy surgery.

Conventional image registration utilizing brain voxel information may be erroneous in a neurosurgical setting due to pathology and surgery-related anatomical distortions. We report a novel application of an automated image registration procedure based on skull segmentation for magnetic resonance imaging (MRI) scans acquired before, during and after surgery (i.e., perioperative). The procedure was implemented to assist analysis of intraoperative brain shift in 11 pediatric epilepsy surgery cases, each of whom had up to five consecutive perioperative MRI scans. The procedure consisted of the following steps: (1) Skull segmentation using tissue classification tools. (2) Estimation of rigid body transformation between image pairs using registration driven by the skull segmentation. (3) Composition of transformations to provide transformations between each scan and a common space. The procedure was validated using locations of three types of reference structural landmarks: the skull pin sites, the eye positions, and the scalp skin surface, detected using the peak intensity gradient. The mean target registration error (TRE) scores by skull pin sites and scalp skin rendering were around 1 mm and <1 mm, respectively. Validation by eye position demonstrated >1 mm TRE scores, suggesting it is not a reliable reference landmark in surgical scenarios. Comparable registration accuracy was achieved between opened and closed skull scan pairs and closed and closed skull scan pairs. Our procedure offers a reliable registration framework for processing intrasubject time series perioperative MRI data, with potential of improving intraoperative MRI-based image guidance in neurosurgical practice. Hum Brain Mapp 37:3530-3543, 2016. © 2016 Wiley Periodicals, Inc.

The late presenting STEMI: How ECG scores can be used to estimate event time.

INTRODUCTION: Patients presenting with ST elevation myocardial infarction (STEMI) derive significant benefit from timely percutaneous coronary intervention (PCI). Electrocardiogram (ECG) scoring systems can complement history to estimate the infarction age and inform clinical decision-making. CASE: A 76year old man presented with eight days of dyspnea on exertion and chest pain. Triage ECG showed ST elevation and Q waves in the anterior leads. The patient was taken for coronary angiography and found to have a 100% occlusion of the left anterior descending artery. DISCUSSION: Determining timing of acute coronary syndromes is challenging. ECG indices aid clinical history by quantifying infarction acuity.

Engineering functional two- and three-dimensional liver systems in vivo using hepatic tissue sheets.

Hepatic tissue engineering using primary hepatocytes has been considered a valuable new therapeutic modality for several classes of liver diseases. Recent progress in the development of clinically feasible liver tissue engineering approaches, however, has been hampered mainly by insufficient cell-to-cell contact of the engrafted hepatocytes. We developed a method to engineer a uniformly continuous sheet of hepatic tissue using isolated primary hepatocytes cultured on temperature-responsive surfaces. Sheets of hepatic tissue transplanted into the subcutaneous space resulted in efficient engraftment to the surrounding cells, with the formation of two-dimensional hepatic tissues that stably persisted for longer than 200 d. The engineered hepatic tissues also showed several characteristics of liver-specific functionality. Additionally, when the hepatic tissue sheets were layered in vivo, three-dimensional miniature liver systems having persistent survivability could be also engineered. This technology for liver tissue engineering is simple, minimally invasive and free of potentially immunogenic biodegradable scaffolds.

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.

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.

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.

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.