Publications by authors named "Sair H"

Neurological recovery in individuals with spinal cord injury (SCI) is multifaceted, involving mechanisms such as remyelination and perilesional spinal neuroplasticity, with cortical reorganization being one contributing factor. Cortical reorganization, in particular, can be evaluated through network (graph) analysis of interregional functional connectivity. This study aimed to investigate cortical reorganization patterns in persons with chronic SCI using a multilayer community detection approach on resting-state functional MRI data.

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  • Resting-state functional MRI (rs-fMRI) is gaining traction in clinical settings for brain mapping, but faces challenges with standardization, reliability, and interpretation of results across different medical centers.
  • Key issues include variability in cognitive network representation and the effects of neurovascular uncoupling, which affect the accuracy of language lateralization and overall connectivity detection.
  • Despite these challenges, rs-fMRI is viewed as a valuable complement to task-based fMRI (tb-fMRI) in clinical presurgical contexts and is expected to grow in use as solutions to its limitations are developed.
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  • Oligodendroglioma is a brain tumor characterized by specific genetic mutations and treatments typically involve surgery followed by either observational care or a combination of radiation and chemotherapy.
  • This study analyzed data from 277 patients with IDH-mutant, 1p/19q codeleted oligodendrogliomas to examine the impact of different adjuvant treatment regimens on progression-free survival (PFS).
  • Results indicated that patients with grade 3 tumors showed significantly longer PFS when treated with radiation and PCV chemotherapy compared to those receiving radiation with TMZ or no adjuvant therapy, emphasizing the need for more research in this area.
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Background: Early detection of acute brain injury (ABI) at the bedside is critical in improving survival for patients with extracorporeal membrane oxygenation (ECMO) support. We aimed to examine the safety of ultra-low-field (ULF; 0.064-T) portable magnetic resonance imaging (pMRI) in patients undergoing ECMO and to investigate the ABI frequency and types with ULF-pMRI.

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Background: While the diagnosis of frontotemporal dementia (FTD) is based mostly on clinical features, [F]-FDG-PET has been investigated as a potential imaging standard in ambiguous cases, with arterial spin-labeling (ASL) MRI gaining recent interest.

Purpose: The purpose of this study is to conduct a systematic review and meta-analysis on the diagnostic performance of ASL MRI in patients with FTD and compare it with that of [F]-FDG-PET.

Data Sources: A systematic search of PubMed, Scopus, and Embase was conducted until March 13, 2024.

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Background: White matter signal abnormalities have been associated with traumatic brain injury (TBI) and repetitive head impacts (RHI) in contact sports (e.g. American football, rugby).

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  • Oligodendrogliomas, known for specific genetic mutations (IDH1/2) and chromosome deletions (1p/19q), were analyzed in a study to understand the clinical significance of additional genomic alterations like CIC, FUBP1, and TERTp using clinically standardized NGS panels.
  • The analysis included 277 patients diagnosed between 2005 and 2021, revealing that among the 95 patients with NGS reports, CIC, FUBP1, and TERTp were the most commonly altered genes.
  • While these genetic alterations were frequent, the study found that most did not significantly impact progression-free or overall survival, except for a noted reduction in progression-free survival associated with CIC alterations in specific
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Background And Purpose: The human brain displays structural and functional disparities between its hemispheres, with such asymmetry extending to the frontal aslant tract. This plays a role in a variety of cognitive functions, including speech production, language processing, and executive functions. However, the factors influencing the laterality of the frontal aslant tract remain incompletely understood.

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Autism is traditionally diagnosed behaviorally but has a strong genetic basis. A genetics-first approach could transform understanding and treatment of autism. However, isolating the gene-brain-behavior relationship from confounding sources of variability is a challenge.

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Functional magnetic resonance imaging (fMRI) has the potential to provide noninvasive functional mapping of the brain with high spatial and temporal resolution. However, fMRI independent components (ICs) must be manually inspected, selected, and interpreted, requiring time and expertise. We propose a novel approach for automated labeling of fMRI ICs by establishing their characteristic spatio-functional relationship.

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  • Over 1.2 million pulmonary artery catheters (PACs) are used annually in cardiac patients in the U.S., but these devices can't be used during traditional MRI scans, prompting research into their safety in this imaging technique.
  • Two experiments tested the safety of PACs in MRI settings, ensuring that the electromagnetic field exposure stayed within the FDA's safety limits while assessing potential adverse effects.
  • The study showed that low-field MRI was safe and effective for patients with PACs, allowing for quality imaging to detect acute brain injuries that might be missed with standard CT scans.
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Early, accurate diagnosis of neurodegenerative dementia subtypes such as Alzheimer's disease (AD) and frontotemporal dementia (FTD) is crucial for the effectiveness of their treatments. However, distinguishing these conditions becomes challenging when symptoms overlap or the conditions present atypically. Resting-state fMRI (rs-fMRI) studies have demonstrated condition-specific alterations in AD, FTD, and mild cognitive impairment (MCI) compared to healthy controls (HC).

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Background And Purpose: Artificial intelligence models in radiology are frequently developed and validated using data sets from a single institution and are rarely tested on independent, external data sets, raising questions about their generalizability and applicability in clinical practice. The American Society of Functional Neuroradiology (ASFNR) organized a multicenter artificial intelligence competition to evaluate the proficiency of developed models in identifying various pathologies on NCCT, assessing age-based normality and estimating medical urgency.

Materials And Methods: In total, 1201 anonymized, full-head NCCT clinical scans from 5 institutions were pooled to form the data set.

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Early detection of acute brain injury (ABI) is critical to intensive care unit (ICU) patient management and intervention to decrease major complications. Head CT (HCT) is the standard of care for the assessment of ABI in ICU patients; however, it has limited sensitivity compared to MRI. We retrospectively compared the ability of ultra-low-field portable MR (ULF-pMR) and head HCT, acquired within 24 h of each other, to detect ABI in ICU patients supported on extracorporeal membrane oxygenation (ECMO).

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Deep learning models have demonstrated great potential in medical imaging but are limited by the expensive, large volume of annotations required. To address this, we compared different active learning strategies by training models on subsets of the most informative images using real-world clinical datasets for brain tumor segmentation and proposing a framework that minimizes the data needed while maintaining performance. Then, 638 multi-institutional brain tumor magnetic resonance imaging scans were used to train three-dimensional U-net models and compare active learning strategies.

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Article Synopsis
  • The study aimed to assess the safety and effectiveness of ultra-low-field portable MRI (ULF-pMRI) for detecting acute brain injuries (ABI) in patients on extracorporeal membrane oxygenation (ECMO) support.* -
  • Conducted at two academic centers, the study involved 50 patients, with successful imaging and a low incidence of adverse events; ABI was found in 44% of patients, mostly ischemic strokes.* -
  • ULF-pMRI proved to be a safe and potentially more sensitive method for detecting ischemic brain injuries compared to traditional head CT scans, indicating its usefulness in clinical settings and further research.*
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Purpose: In this study we gathered and analyzed the available evidence regarding 17 different imaging modalities and performed network meta-analysis to find the most effective modality for the differentiation between brain tumor recurrence and post-treatment radiation effects.

Methods: We conducted a comprehensive systematic search on PubMed and Embase. The quality of eligible studies was assessed using the Assessment of Multiple Systematic Reviews-2 (AMSTAR-2) instrument.

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Resting-state (rs) fMRI has been shown to be useful for preoperative mapping of functional areas in patients with brain tumors and epilepsy. However, its lack of standardization limits its widespread use and hinders multicenter collaboration. The American Society of Functional Neuroradiology, American Society of Pediatric Neuroradiology, and the American Society of Neuroradiology Functional and Diffusion MR Imaging Study Group recommend specific rs-fMRI acquisition approaches and preprocessing steps that will further support rs-fMRI for future clinical use.

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Background: Cerebral cavernous malformation with symptomatic hemorrhage (SH) are targets for novel therapies. A multisite trial-readiness project (https://www.clinicaltrials.

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Background: Quantitative susceptibility mapping (QSM) and dynamic contrast-enhanced quantitative perfusion (DCEQP) magnetic resonance imaging sequences assessing iron deposition and vascular permeability were previously correlated with new hemorrhage in cerebral cavernous malformations. We assessed their prospective changes in a multisite trial-readiness project.

Methods: Patients with cavernous malformation and symptomatic hemorrhage (SH) in the prior year, without prior or planned lesion resection or irradiation were enrolled.

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Purpose: We aimed to develop and validate a deep learning (DL) model to automatically segment posterior fossa ependymoma (PF-EPN) and predict its molecular subtypes [Group A (PFA) and Group B (PFB)] from preoperative MR images.

Experimental Design: We retrospectively identified 227 PF-EPNs (development and internal test sets) with available preoperative T2-weighted (T2w) MR images and molecular status to develop and test a 3D nnU-Net (referred to as T2-nnU-Net) for tumor segmentation and molecular subtype prediction. The network was externally tested using an external independent set [n = 40; subset-1 (n = 31) and subset-2 (n =9)] and prospectively enrolled cases [prospective validation set (n = 27)].

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Background: Accumulating evidence suggests that post-traumatic stress disorder (PTSD) may increase the risk of various types of dementia. Despite the large number of studies linking these critical conditions, the underlying mechanisms remain unclear. The past decade has witnessed an exponential increase in interest on brain imaging research to assess the neuroanatomical underpinnings of PTSD.

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Deep convolutional neural networks (DCNNs) have shown promise in brain tumor segmentation from multi-modal MRI sequences, accommodating heterogeneity in tumor shape and appearance. The fusion of multiple MRI sequences allows networks to explore complementary tumor information for segmentation. However, developing a network that maintains clinical relevance in situations where certain MRI sequence(s) might be unavailable or unusual poses a significant challenge.

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