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Neurology Jan 2011To estimate longitudinal changes in a quantitative whole-brain and tract-specific MRI study of multiple sclerosis (MS), with the intent of assessing the feasibility of...
OBJECTIVE
To estimate longitudinal changes in a quantitative whole-brain and tract-specific MRI study of multiple sclerosis (MS), with the intent of assessing the feasibility of this approach in clinical trials.
METHODS
A total of 78 individuals with MS underwent a median of 3 scans over 2 years. Diffusion tensor imaging indices, magnetization transfer ratio, and T2 relaxation time were analyzed in supratentorial brain, corpus callosum, optic radiations, and corticospinal tracts by atlas-based tractography. Linear mixed-effect models estimated annualized rates of change for each index, and sample size estimates for potential clinical trials were determined.
RESULTS
There were significant changes over time in fractional anisotropy and perpendicular diffusivity in the supratentorial brain and corpus callosum, mean diffusivity in the supratentorial brain, and magnetization transfer ratio in all areas studied. Changes were most rapid in the corpus callosum, where fractional anisotropy decreased 1.7% per year, perpendicular diffusivity increased 1.2% per year, and magnetization transfer ratio decreased 0.9% per year. The T2 relaxation time changed more rapidly than diffusion tensor imaging indices and magnetization transfer ratio but had higher within-participant variability. Magnetization transfer ratio in the corpus callosum and supratentorial brain declined at an accelerated rate in progressive MS relative to relapsing-remitting MS. Power analysis yielded reasonable sample sizes (on the order of 40 participants per arm or fewer) for 1- or 2-year trials.
CONCLUSIONS
Longitudinal changes in whole-brain and tract-specific diffusion tensor imaging indices and magnetization transfer ratio can be reliably quantified, suggesting that small clinical trials using these outcome measures are feasible.
Topics: Adult; Anisotropy; Brain; Corpus Callosum; Diffusion Magnetic Resonance Imaging; Disease Progression; Feasibility Studies; Female; Follow-Up Studies; Humans; Image Processing, Computer-Assisted; Linear Models; Male; Middle Aged; Multiple Sclerosis; Multiple Sclerosis, Relapsing-Remitting
PubMed: 21220722
DOI: 10.1212/WNL.0b013e318206ca61 -
Stroke Jan 2006Infratentorial abnormalities may cause cognitive deficits, but current research criteria for vascular dementia (VaD) do not consider them. Our purposes were to determine... (Clinical Trial)
Clinical Trial
BACKGROUND AND PURPOSE
Infratentorial abnormalities may cause cognitive deficits, but current research criteria for vascular dementia (VaD) do not consider them. Our purposes were to determine the prevalence of infratentorial abnormalities in VaD, their relation with supratentorial abnormalities, and whether they are relevant to cognition.
METHODS
We examined 182 patients (120 men, mean age=73 years, SD=8) with probable VaD at inclusion into a multicenter clinical trial. MRI scans were evaluated for infratentorial vascular abnormalities, midbrain atrophy, cerebellar atrophy, basilar artery diameter and tortuosity, and supratentorial abnormalities. Cognitive testing included the mini-mental state examination (MMSE) and the vascular dementia assessment scale (VaDAS-cog).
RESULTS
One hundred forty-one (77.5%) patients had infratentorial abnormalities: 119 (65.4%) had focal infratentorial vascular lesions, 65 (35.7%) had diffuse pontine vascular abnormalities hyperintense on T2-weighted images, 20 (11.0%) had midbrain atrophy, and 16 (8.8%) had cerebellar atrophy. Significant correlations were found between number of infratentorial vascular lesions and basilar artery diameter (rs=0.26; P<0.0001), infratentorial and basal ganglia (including thalamus) vascular abnormalities (rs=0.30; P<0.0001), as well as between midbrain atrophy and global supratentorial atrophy (rs=0.27; P<0.0001). Infratentorial vascular abnormalities and cerebellar atrophy were not significantly associated with cognitive impairment. Patients with midbrain atrophy performed worse on cognitive tests than those without midbrain atrophy. After correction for sex, age, education, supratentorial abnormalities, and center, midbrain atrophy remained significantly associated with lower MMSE scores (P<0.05).
CONCLUSIONS
Infratentorial abnormalities often occur in patients with VaD, but only midbrain atrophy was found to be relevant to cognition.
Topics: Aged; Aged, 80 and over; Atrophy; Brain; Cognition; Dementia, Vascular; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Models, Statistical; Regression Analysis
PubMed: 16339463
DOI: 10.1161/01.STR.0000196984.90718.8a -
Human Brain Mapping Mar 2022For over a century, neuroscientists have been working toward parcellating the human cortex into distinct neurobiological regions. Modern technologies offer many...
For over a century, neuroscientists have been working toward parcellating the human cortex into distinct neurobiological regions. Modern technologies offer many parcellation methods for healthy cortices acquired through magnetic resonance imaging. However, these methods are suboptimal for personalized neurosurgical application given that pathology and resection distort the cerebrum. We sought to overcome this problem by developing a novel connectivity-based parcellation approach that can be applied at the single-subject level. Utilizing normative diffusion data, we first developed a machine-learning (ML) classifier to learn the typical structural connectivity patterns of healthy subjects. Specifically, the Glasser HCP atlas was utilized as a prior to calculate the streamline connectivity between each voxel and each parcel of the atlas. Using the resultant feature vector, we determined the parcel identity of each voxel in neurosurgical patients (n = 40) and thereby iteratively adjusted the prior. This approach enabled us to create patient-specific maps independent of brain shape and pathological distortion. The supervised ML classifier re-parcellated an average of 2.65% of cortical voxels across a healthy dataset (n = 178) and an average of 5.5% in neurosurgical patients. Our patient dataset consisted of subjects with supratentorial infiltrating gliomas operated on by the senior author who then assessed the validity and practical utility of the re-parcellated diffusion data. We demonstrate a rapid and effective ML parcellation approach to parcellation of the human cortex during anatomical distortion. Our approach overcomes limitations of indiscriminately applying atlas-based registration from healthy subjects by employing a voxel-wise connectivity approach based on individual data.
Topics: Cerebral Cortex; Diffusion Tensor Imaging; Glioma; Humans; Image Processing, Computer-Assisted; Machine Learning; Nerve Net
PubMed: 34826179
DOI: 10.1002/hbm.25728 -
NeuroImage Sep 2021Since tau PET tracers were introduced, investigators have quantified them using a wide variety of automated methods. As longitudinal cohort studies acquire second and...
Since tau PET tracers were introduced, investigators have quantified them using a wide variety of automated methods. As longitudinal cohort studies acquire second and third time points of serial within-person tau PET data, determining the best pipeline to measure change has become crucial. We compared a total of 415 different quantification methods (each a combination of multiple options) according to their effects on a) differences in annual SUVR change between clinical groups, and b) longitudinal measurement repeatability as measured by the error term from a linear mixed-effects model. Our comparisons used MRI and Flortaucipir scans of 97 Mayo Clinic study participants who clinically either: a) were cognitively unimpaired, or b) had cognitive impairments that were consistent with Alzheimer's disease pathology. Tested methods included cross-sectional and longitudinal variants of two overarching pipelines (FreeSurfer 6.0, and an in-house pipeline based on SPM12), three choices of target region (entorhinal, inferior temporal, and a temporal lobe meta-ROI), five types of partial volume correction (PVC) (none, two-compartment, three-compartment, geometric transfer matrix (GTM), and a tau-specific GTM variant), seven choices of reference region (cerebellar crus, cerebellar gray matter, whole cerebellum, pons, supratentorial white matter, eroded supratentorial WM, and a composite of eroded supratentorial WM, pons, and whole cerebellum), two choices of region masking (GM or GM and WM), and two choices of statistic (voxel-wise mean vs. median). Our strongest findings were: 1) larger temporal-lobe target regions greatly outperformed entorhinal cortex (median sample size estimates based on a hypothetical clinical trial were 520-526 vs. 1740); 2) longitudinal processing pipelines outperformed cross-sectional pipelines (median sample size estimates were 483 vs. 572); and 3) reference regions including supratentorial WM outperformed traditional cerebellar and pontine options (median sample size estimates were 370 vs. 559). Altogether, our results favored longitudinally SUVR methods and a temporal-lobe meta-ROI that includes adjacent (juxtacortical) WM, a composite reference region (eroded supratentorial WM + pons + whole cerebellum), 2-class voxel-based PVC, and median statistics.
Topics: Aged; Aged, 80 and over; Brain; Carbolines; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Positron-Emission Tomography; tau Proteins
PubMed: 34118395
DOI: 10.1016/j.neuroimage.2021.118259 -
Scientific Reports Sep 2023Children cooled for HIE and who did not develop cerebral palsy (CP) still underperform at early school age in motor and cognitive domains and have altered...
Children cooled for HIE and who did not develop cerebral palsy (CP) still underperform at early school age in motor and cognitive domains and have altered supra-tentorial brain volumes and white matter connectivity. We obtained T1-weighted and diffusion-weighted MRI, motor (MABC-2) and cognitive (WISC-IV) scores from children aged 6-8 years who were cooled for HIE secondary to perinatal asphyxia without CP (cases), and controls matched for age, sex, and socioeconomic status. In 35 case children, we measured cerebellar growth from infancy (age 4-15 days after birth) to childhood. In childhood, cerebellar volumes were measured in 26 cases and 23 controls. Diffusion properties (mean diffusivity, MD and fractional anisotropy, FA) were calculated in 24 cases and 19 controls, in 9 cerebellar regions. Cases with FSIQ ≤ 85 had reduced growth of cerebellar width compared to those with FSIQ > 85 (p = 0.0005). Regional cerebellar volumes were smaller in cases compared to controls (p < 0.05); these differences were not significant when normalised to total brain volume. There were no case-control differences in MD or FA. Interposed nucleus volume was more strongly associated with IQ in cases than in controls (p = 0.0196). Other associations with developmental outcome did not differ between cases and controls.
Topics: Infant, Newborn; Female; Pregnancy; Child; Humans; Cerebral Palsy; Brain Diseases; Infant, Newborn, Diseases; Brain; Cerebellum
PubMed: 37684324
DOI: 10.1038/s41598-023-41838-3 -
Developmental Medicine and Child... Jan 2002The purpose of the present study was to describe in greater anatomical detail the changes in brain structure that occur during maturation between childhood and...
The purpose of the present study was to describe in greater anatomical detail the changes in brain structure that occur during maturation between childhood and adolescence. High-resolution MRI, tissue classification, and anatomical segmentation of cortical and subcortical regions were used in a sample of 35 normally developing children and adolescents between 7 and 16 years of age (mean age 11 years; 20 males, 15 females). Each cortical and subcortical measure was examined for age and sex effects on raw volumes and on the measures as proportions of total supratentorial cranial volume. Results indicate age-related increases in total supratentorial cranial volume and raw and proportional increases in total cerebral white matter. Gray-matter volume reductions were only observed once variance in total brain size was proportionally controlled. The change in total cerebral white-matter proportion was significantly greater than the change in total cerebral gray-matter proportion over this age range, suggesting that the relative gray-matter reduction is probably due to significant increases in white matter. Total raw cerebral CSF volume increases were also observed. Within the cerebrum, regional patterns varied depending on the tissue (or CSF) assessed. Only frontal and parietal cortices showed changes in gray matter, white matter, and CSF measures. Once the approximately 7% larger brain volume in males was controlled, only mesial temporal cortex, caudate, thalamus, and basomesial diencephalic structures showed sex effects with the females having greater relative volumes in these regions than the males. Overall, these results are consistent with earlier reports and describe in greater detail the regional pattern of age-related differences in gray and white matter in normally developing children and adolescents.
Topics: Adolescent; Age Factors; Brain; Cerebral Cortex; Child; Child Development; Female; Humans; Magnetic Resonance Imaging; Male
PubMed: 11811649
DOI: 10.1017/s0012162201001591 -
Journal of Neurology, Neurosurgery, and... Aug 1973The morphological characteristics of brain death were examined in baboons and cats after artificial cerebral ischaemia. All animals showed autolytic changes in the...
The morphological characteristics of brain death were examined in baboons and cats after artificial cerebral ischaemia. All animals showed autolytic changes in the brain, ischaemic neuronal changes, midbrain haemorrhages, focal necrosis of the brain-stem, demarcation at C 1/C 2 cord segment, and displacement of cerebellar tissue. Ultrastructural examination revealed extreme brain oedema, autolytic changes, and complete obstruction of capillaries by astrocytic and endothelial swelling and intravascular blebs. These data indicate that brain death develops in several stages. If the process starts in the supratentorial space it first leads to a breakdown of the cerebral circulation and to transtentorial herniation. As a result, midbrain haemorrhages develop and the infratentorial pressure begins to rise. The second stage is terminated by demarcation of the brain. The circulatory arrest is initially caused by venous compression but becomes irreversible when vascular obstruction develops.
Topics: Animals; Autolysis; Brain; Brain Death; Brain Stem; Cats; Cerebellum; Cerebral Cortex; Cerebral Hemorrhage; Cerebral Ventricles; Cerebrovascular Circulation; Disease Models, Animal; Haplorhini; Ischemic Attack, Transient; Necrosis; Nerve Degeneration; Papio; Pons; Spinal Cord; Time Factors
PubMed: 4199913
DOI: 10.1136/jnnp.36.4.497 -
Transient immediate postoperative homotopic functional disconnectivity in low-grade glioma patients.NeuroImage. Clinical 2018The aim of this longitudinal study is to evaluate large-scale perioperative resting state networks reorganization in patients with diffuse low-grade gliomas following...
BACKGROUND AND PURPOSE
The aim of this longitudinal study is to evaluate large-scale perioperative resting state networks reorganization in patients with diffuse low-grade gliomas following awake surgery.
MATERIALS AND METHODS
Eighty-two patients with diffuse low-grade gliomas were prospectively enrolled and underwent awake surgical resection. Resting-state functional images were acquired at three time points: preoperative (MRI-1), immediate postoperative (MRI-2) and three months after surgery (MRI-3). We simultaneously performed perfusion-weighted imaging.
RESULTS
Comparing functional connectivity between MRI-1 and MRI-2, we observed a statistically significant functional homotopy decrease in cortical and subcortical supratentorial structures (P < 0.05). A functional homotopy increase was observed between MRI-2 and MRI-3 in parietal lobes, cingulum and putamen (P < 0.05). No significant functional connectivity modification was noticed between MRI-1 and MRI-3. Regional cerebral blood flow appeared transiently reduced on MRI-2 (P < 0.05). No correlation between neurological deficit and interhemispheric connectivity results was found.
CONCLUSION/INTERPRETATION
We found a supratentorial widely distributed functional homotopy disruption between preoperative and immediate postoperative time points with a complete restitution three months after surgery with simultaneous variation of regional cerebral blood flow.
Topics: Adult; Brain; Brain Mapping; Brain Neoplasms; Female; Glioma; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Nerve Net; Neurosurgical Procedures; Postoperative Period
PubMed: 29876257
DOI: 10.1016/j.nicl.2018.02.023 -
Diagnostic and Interventional Radiology... 2017We aimed to evaluate the magnetic resonance imaging (MRI) and clinical features of maple syrup urine disease (MSUD).
PURPOSE
We aimed to evaluate the magnetic resonance imaging (MRI) and clinical features of maple syrup urine disease (MSUD).
METHODS
This retrospective study consisted of 10 MSUD patients confirmed by genetic testing. All patients underwent brain MRI. Phenotype, genotype, and areas of brain injury on MRI were retrospectively reviewed.
RESULTS
Six patients (60%) had the classic form of MSUD with BCKDHB mutation, three patients (30%) had the intermittent form (two with BCKDHA mutations and one with DBT mutation), and one patient (10%) had the thiamine-responsive form with DBT mutation. On diffusion-weighted imaging, nine cases presented restricted diffusion in myelinated areas, and one intermittent case with DBT mutation was normal. The classic form of MSUD involved the basal ganglia in six cases; the cerebellum, mesencephalon, pons, and supratentorial area in five cases; and the thalamus in four cases, respectively. The intermittent form involved the cerebellum, pons, and supratentorial area in two cases. The thiamine-responsive form involved the basal ganglia and supratentorial area.
CONCLUSION
Our preliminary results indicate that patients with MSUD presented more commonly in classic form with BCKDHB mutation and displayed extensive brain injury on MRI.
Topics: Brain; Child; Child, Preschool; Female; Humans; Infant; Infant, Newborn; Magnetic Resonance Imaging; Male; Maple Syrup Urine Disease; Retrospective Studies
PubMed: 28830848
DOI: 10.5152/dir.2017.16466 -
JAMA Neurology Apr 2018Preventing delayed neurological sequelae is a major goal of treating acute carbon monoxide poisoning, but to our knowledge there are no reliable tools for assessing the... (Observational Study)
Observational Study
IMPORTANCE
Preventing delayed neurological sequelae is a major goal of treating acute carbon monoxide poisoning, but to our knowledge there are no reliable tools for assessing the probability of these sequelae.
OBJECTIVES
To determine whether acute brain lesions on diffusion-weighted imaging are related to subsequent development of delayed neurological sequelae after acute carbon monoxide poisoning.
DESIGN, SETTING, AND PARTICIPANTS
This registry-based observational study was conducted at a university hospital in Seoul, Korea, between April 1, 2011, and December 31, 2015. Of 700 patients (aged ≥18 years) with acute carbon monoxide poisoning, 433 patients (61.9%) who underwent diffusion-weighted imaging at an emergency department were considered for the study. Patients who developed cardiac arrest before diffusion-weighted imaging (n = 3), had persistent neurological symptoms at discharge (n = 8), committed suicide soon after discharge (n = 1), and were lost to follow-up (n = 34) were excluded.
EXPOSURE
The presence of unambiguous, high-signal-intensity, acute brain lesions on diffusion-weighted imaging (b = 1000 s/mm2).
MAIN OUTCOMES AND MEASURES
Development of delayed neurological sequelae defined as any neurological symptoms or signs that newly developed within 6 weeks of discharge.
RESULTS
Of the 387 included patients (143 women [37.0%]; median age, 42.0 years [interquartile range, 32.0-56.0 years]), acute brain lesions on diffusion-weighted imaging were observed in 104 patients (26.9%). Among these, 77 patients (19.9%) had globus pallidus lesions, 13 (3.4%) had diffuse lesions, and 57 (14.7%) had focal lesions (37 patients [9.6%] had >1 pattern concurrently). Lesions were supratentorial and infratentorial in 101 and 23 patients, respectively. Delayed neurological sequelae occurred in 101 patients (26.1%). Multivariable logistic regression analysis indicated that the presence of acute brain lesions was independently associated with development of delayed neurological sequelae (adjusted odds ratio, 13.93; 95% CI, 7.16-27.11; P < .001). The sensitivity and specificity of acute brain lesions to assess the probability of delayed neurological sequelae were 75.2% (95% CI, 66.8%-83.7%) and 90.2% (95% CI, 86.8%-93.7%), respectively. In addition, the positive and negative predictive values were 73.1% (95% CI, 64.6%-81.6%) and 91.2% (95% CI, 87.9%-94.5%), respectively.
CONCLUSIONS AND RELEVANCE
The presence of acute brain lesions was significantly associated with the development of delayed neurological sequelae. Diffusion-weighted imaging during the acute phase of carbon monoxide poisoning may therefore help identify patients at risk of developing these debilitating sequelae.
Topics: Adult; Brain; Carbon Monoxide Poisoning; Diffusion Magnetic Resonance Imaging; Disease Management; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Nervous System Diseases; Neurologic Examination; Registries
PubMed: 29379952
DOI: 10.1001/jamaneurol.2017.4618