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result(s) for
"McColl, Roderick W."
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Prevalence of pectus excavatum in an adult population-based cohort estimated from radiographic indices of chest wall shape
by
Peshock, Ronald M.
,
Biavati, Mikaela
,
Foglia, Robert
in
Adolescents
,
Adults
,
Biology and Life Sciences
2020
Pectus excavatum is the most common chest wall skeletal deformity. Although commonly evaluated in adolescence, its prevalence in adults is unknown.
Radiographic indices of chest wall shape were analyzed for participants of the first (n = 2687) and second (n = 1780) phases of the population-based Dallas Heart Study and compared to clinical cases of pectus (n = 297). Thoracic computed tomography imaging studies were examined to calculate the Haller index, a measure of thoracic axial shape, and the Correction index, which quantitates the posterior displacement of the sternum relative to the ribs. At the level of the superior xiphoid, 0.5%, 5% and 0.4% of adult Dallas Heart Study subjects have evidence of pectus excavatum using thresholds of Haller index >3.25, Correction index >10%, or both, respectively. Radiographic measures of pectus are more common in females than males and there is a greater prevalence of pectus in women than men. In the general population, the Haller and Correction indices are associated with height and weight, independent of age, gender, and ethnicity. Repeat imaging of a subset of subjects (n = 992) demonstrated decreases in the mean Haller and Correction indices over seven years, suggesting change to a more circular axial thorax, with less sternal depression, over time.
To our knowledge, this is the first study estimating the prevalence of pectus in an unselected adult population. Despite the higher reported prevalence of pectus cases in adolescent boys, this study demonstrates a higher prevalence of radiographic indices of pectus in adult females.
Journal Article
Assessment of diffusion tensor image quality across sites and vendors using the American College of Radiology head phantom
by
Babcock, Evelyn
,
Wang, Zhiyue J.
,
Wisnowski, Jessica
in
Accreditation
,
Contract Services - standards
,
diffusion tensor imaging
2016
The purpose of this study was to explore the feasibility of assessing quality of diffusion tensor imaging (DTI) from multiple sites and vendors using American College of Radiology (ACR) phantom. Participating sites (Siemens (n=2), GE (n=2), and Philips (n=4)) reached consensus on parameters for DTI and used the widely available ACR phantom. Tensor data were processed at one site. B0 and eddy current distortions were assessed using grid line displacement on phantom Slice 5; signal‐to‐noise ratio (SNR) was measured at the center and periphery of the b=0 image; fractional anisotropy (FA) and mean diffusivity (MD) were assessed using phantom Slice 7. Variations of acquisition parameters and deviations from specified sequence parameters were recorded. Nonlinear grid line distortion was higher with linear shimming and could be corrected using the 2nd order shimming. Following image registration, eddy current distortion was consistently smaller than acquisition voxel size. SNR was consistently higher in the image periphery than center by a factor of 1.3–2.0. ROI‐based FA ranged from 0.007 to 0.024. ROI‐based MD ranged from 1.90×10−3 to 2.33×10−3mm2/s(median=2.04×10−3mm2/s). Two sites had image void artifacts. The ACR phantom can be used to compare key quality measures of diffusion images acquired from multiple vendors at multiple sites. PACS number(s): 87.57.‐s, 87.19.lf
Journal Article
Use of Web-Based Calculator for the Implementation of ACR TI-RADS Risk-Stratification System
by
Baker, Chris
,
Quadri Bilal
,
Peshock, Ronald M
in
Calculators
,
Computer programs
,
Electronic health records
2022
In this article, we demonstrate the use of a software-based radiologist reporting tool for the implementation of American College of Radiology Thyroid Imaging, Reporting and Data System thyroid nodule risk-stratification. The technical details are described with emphasis on addressing the information security and patient privacy issues while allowing it to integrate with the electronic health record and radiology reporting dictation software. Its practical implementation is assessed in a quality improvement project in which guideline adherence and recommendation congruence were measured pre and post implementation. The descriptions of our solution and the release of the open-sourced codes may be helpful in future implementation of similar web-based calculators.
Journal Article
The Health & Aging Brain among Latino Elders (HABLE) study methods and participant characteristics
by
Johnson, Leigh A.
,
Braskie, Meredith N.
,
Kothapalli, Deydeep
in
Aging
,
Alzheimer's disease
,
amyloid
2021
Introduction Mexican Americans remain severely underrepresented in Alzheimer's disease (AD) research. The Health & Aging Brain among Latino Elders (HABLE) study was created to fill important gaps in the existing literature. Methods Community‐dwelling Mexican Americans and non‐Hispanic White adults and elders (age 50 and above) were recruited. All participants underwent comprehensive assessments including an interview, functional exam, clinical labs, informant interview, neuropsychological testing, and 3T magnetic resonance imaging (MRI) of the brain. Amyloid and tau positron emission tomography (PET) scans were added at visit 2. Blood samples were stored in the Biorepository. Results Data was examined from n = 1705 participants. Significant group differences were found in medical, demographic, and sociocultural factors. Cerebral amyloid and neurodegeneration imaging markers were significantly different between Mexican Americans and non‐Hispanic Whites. Discussion The current data provide strong support for continued investigations that examine the risk factors for and biomarkers of AD among diverse populations.
Journal Article
Magnetic resonance imaging of cerebellar–prefrontal and cerebellar–parietal functional connectivity
2005
Recent studies of the cerebellum indicated its involvement in a diverse array of functions, and analyses of non-human primate neuroanatomy have revealed connections between cerebellum and cerebral cortex that might support cerebellar contributions to a wider range of functions than traditionally thought. These include cortico-ponto-cerebellar projections originating throughout cerebral cortex, in addition to projections from the dentate nucleus of the cerebellum to prefrontal and posterior parietal cortices via the thalamus. Such projections likely serve as important substrates for cerebellar involvement in human cognition, assuming their analogues are prominent in the human brain. These connections can be examined from a functional perspective through the use of functional connectivity MRI (FCMRI), a technique that allows the in vivo examination of coherence in MR signal among functionally related brain regions. Using this approach, low-frequency fluctuations in MR signal in the dentate nucleus correlated with signal fluctuations in cerebellar, thalamic, limbic, striatal, and cerebrocortical regions including parietal and frontal sites, with prominent coherence in dorsolateral prefrontal cortex. These findings indicate that FCMRI is a useful tool for examining functional relationships between the cerebellum and other brain regions, and they support the findings from non-human primate studies showing anatomic projections from cerebellum to regions of cerebral cortex with known involvement in higher cognitive functions. To our knowledge, this represents the first demonstration of functional coherence between the dentate nucleus and parietal and prefrontal cortices in the human brain, suggesting the presence of cerebellar–parietal and cerebellar–prefrontal functional connectivity.
Journal Article
Association of Depressive Symptoms with Hippocampal Volume in 1936 Adults
by
Peshock, Ronald
,
Rush, A John
,
Brown, E Sherwood
in
Adult
,
Adult and adolescent clinical studies
,
Atrophy
2014
Hippocampal atrophy is reported in major depressive disorder (MDD). However, sample sizes were generally modest, and participant characteristics, including age, differed between studies. This study used a community sample to examine relationships between current depressive symptom severity and hippocampal volume across the adult lifespan. A total of 1936 adults with magnetic resonance images of the brain and Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR) scores were included. Brain volumes were quantified using the FSL program. Multiple linear regressions were performed using left, right, and total hippocampal volume as criterion variables, and predictor variables of QIDS-SR total, total brain volume, age, gender, education, psychotropic medications, alcohol use, and race/ethnicity. Post hoc analyses were conducted in participants with QIDS-SR scores 11 (moderate or greater depressive symptom severity) and <11, and older and younger adults. In the primary analysis (sample as a whole) QIDS-SR was inversely associated with total hippocampal volume (b=-0.044, p=0.032, (CI-0.019 to -0.001)) but not with left or right hippocampal volume evaluated individually. In participants with QIDS-SR scores of <11, hippocampal volumes were not associated with QIDS-SR scores. In those with QIDS-SR scores 11 total, right, and left hippocampal volumes were modestly, but significantly, associated with QIDS-SR scores. The association between QIDS-SR scores and the hippocampal volume was much stronger in older persons. Findings suggest smaller hippocampal volumes among those with greater reported depressive symptom severity-an association that is strongest in people with at least moderate depressive symptom levels.
Journal Article
The associations between type 2 diabetes and plasma biomarkers of Alzheimer’s disease in the Health and Aging Brain Study: Health Disparities (HABS-HD)
2024
Alzheimer’s disease (AD) affects Latinos disproportionately. One of the reasons underlying this disparity may be type 2 diabetes (T2D) that is a risk factor for AD. The purpose of this study was to examine the associations of T2D and AD blood biomarkers and the differences in these associations between Mexican Americans and non-Hispanic Whites. This study was a secondary analysis of baseline data from the observational Health and Aging Brain Study: Health Disparities (HABS-HD) that investigated factors underlying health disparities in AD in Mexican Americans in comparison to non-Hispanic Whites. HABS-HD participants were excluded if they had missing data or were large outliers (z-scores >|4|) on a given AD biomarker. Fasting blood glucose and glycosylated hemoglobin (HbA1c) levels were measured from clinical labs. T2D was diagnosed by licensed clinicians. Plasma amyloid-beta 42 and 40 (Aβ 42/42 ) ratio, total tau (t-tau), and neurofilament light (NfL) were measured via ultra-sensitive Simoa assays. The sample sizes were 1,552 for Aβ 42/40 ratio, 1,570 for t-tau, and 1,553 for NfL. Mexican Americans were younger (66.6±8.7 vs. 69.5±8.6) and had more female (64.9% female vs. 55.1%) and fewer years of schooling (9.5±4.6 vs. 15.6±2.5) than non-Hispanic Whites. Mexican Americans differed significantly from non-Hispanic Whites in blood glucose (113.5±36.6 vs. 99.2±17.0) and HbA1c (6.33±1.4 vs. 5.51±0.6) levels, T2D diagnosis (35.3% vs. 11.1%), as well as blood Aβ 42/40 ratio (.051±.012 vs. .047±.011), t-tau (2.56±.95 vs. 2.33±.90), and NfL levels (16.3±9.5 vs. 20.3±10.3). Blood glucose, blood HbA1c, and T2D diagnosis were not related to Aβ 42/40 ratio and t-tau but explained 3.7% of the variation in NfL ( p < .001). Blood glucose and T2D diagnosis were not, while HbA1c was positively ( b = 2.31, p < .001, β = 0.26), associated with NfL among Mexican Americans. In contrast, blood glucose, HbA1c, and T2D diagnosis were negatively ( b = -0.09, p < .01, β = -0.26), not ( b = 0.34, p = .71, β = 0.04), and positively ( b = 3.32, p < .01, β = 0.33) associated with NfL, respectively in non-Hispanic Whites. To conclude, blood glucose and HbA1c levels and T2D diagnosis are associated with plasma NfL levels, but not plasma Aβ and t-tau levels. These associations differ in an ethnicity-specific manner and need to be further studied as a potential mechanism underlying AD disparities.
Journal Article
The relationships between ethnoracial identity, Aβ positivity, APOEε4, and medial temporal lobe tau PET
2026
INTRODUCTION Clarifying relationships between amyloid, tau, and cognition is crucial to understanding dementia risk, but has been mainly performed in non‐Hispanic White (NHW) participants. It is unknown whether findings are generalizable to other ethnoracial groups. METHODS We evaluated relationships between amyloid‐β (Aβ) positivity, apolipoprotein E allele (APOE) ε4, tau‐positron emission tomography (PET) 18F‐PI‐2620, and cognitive performance in 1181 cognitively unimpaired (451 NHW, 353 Hispanic, and 377 Black) and 383 mild cognitively impaired (85 NHW, 129 Hispanic, and 169 Black) participants from the Health and Aging Brain Study‐Health Disparities. RESULTS Black (β = 0.28, p < 0.001) and Hispanic (β = 0.34, p < 0.001) participants had higher medial temporal lobe (MTL) tau than NHW participants; however, findings were attenuated when accounting for choroid plexus off‐target binding. Hispanic participants showed higher tau in lateral temporal regions compared to NHW and Black participants; however, reducing meningeal off‐target binding through erosion demonstrated similar lateral temporal tau across groups. DISCUSSION Factors other than amyloid and tau may impact cognition in Black participants. PI2620 off‐target ethnoracial differences should be investigated. Highlights Hispanic and Black participants showed higher medial temporal lobe (MTL) tau levels than non‐Hispanic White (NHW) participants. The relationship between amyloid‐β (Aβ), MTL tau, and cognition differed in the Black cohort. Choroid plexus off‐target binding partially contributed to MTL tau signal. Lateral temporal tau was the same across groups upon removing meningeal binding.
Journal Article
Measurement of Peripheral Vision Reaction Time Identifies White Matter Disruption in Patients with Mild Traumatic Brain Injury
by
Womack, Kyle B.
,
Turtzo, L. Christine
,
Lytton, William W.
in
Adolescent
,
Adult
,
Brain Concussion - complications
2017
This study examined whether peripheral vision reaction time (PVRT) in patients with mild traumatic brain injury (mTBI) correlated with white matter abnormalities in centroaxial structures and impairments in neuropsychological testing. Within 24 h after mTBI, crossed reaction times (CRT), uncrossed reaction times (URT), and crossed–uncrossed difference (CUD) were measured in 23 patients using a laptop computer that displayed visual stimuli predominantly to either the left or the right visual field of the retina. The CUD is a surrogate marker of the interhemispheric transfer time (ITT). Within 7 days after the injury, patients received a diffusion tensor-MRI (DTI) scan and a battery of neuropsychological tests. Nine uninjured control subjects received similar testing. Patients 18–50 years of age were included if they had a post-resuscitation Glasgow Coma Scale >13 and an injury mechanism compatible with mTBI. Healthy controls were either age- and gender-matched family members of the TBI patients or healthy volunteers. CUD deficits >2 standard deviations (SD) were seen in 40.9% of patients. The CUD of injured patients correlated with mean diffusivity (MD) (p < 0.001, ρ = −0.811) in the posterior corpus callosum. Patients could be stratified on the basis of CUD on the Stroop 1, Controlled Oral Word Association Test (COWAT), and the obsessive-compulsive component of the Basic Symptom Inventory tests. These studies suggest that the PVRT indirectly measures white matter integrity in the posterior corpus callosum, a brain region frequently damaged by mTBI.
Journal Article