Temporal Volume Research Articles

Retinal nerve fiber layer thickness is associated with hippocampus and lingual gyrus volumes in nondemented older adults

ObjectivesAbnormal retina structures, such as thinner retinal nerve fiber layer (RNFL), have been frequently reported in patients with Alzheimer's disease (AD). However, the association between RNFL and brain structures in cognitively normal adults remains unknown. We therefore set out to conduct a cross-sectional investigation to determine whether RNFL thickness is associated with brain structure volumes in nondemented older adults. MethodsWe measured RNFL thickness by optical coherence tomography and brain structure volumes by 3 T magnetic resonance imaging. Cognitive function was assessed using the Chinese version of Repeatable Battery for the Assessment of Neurological Status. Pearson correlation was initially employed to screen for the potential associations among RNFL thickness, brain structure volumes and cognitive function. And then, multivariable linear regression models were conducted to further examine such associations adjusting for possible confounding factors, including age, sex, years of education and the estimated total intracranial volume (eTIV). Results113 participants (≥ 65 years old) were screened and 80 of them (mean age: 68 ± 5.3 years; 48% male) were included in the final analysis. RNFL thickness in temporal quadrant was associated with medial temporal lobes volumes [unadjusted: r = 0.155, P = 0.175; adjusted: β = 0.205 (0.014, 0.383), P = 0.035], and especially associated with the hippocampus volume [unadjusted: r = 0.213, P = 0.062; adjusted: β = 0.251 (0.060, 0.435), P = 0.011] after adjusted for age, sex, years of education and eTIV. Moreover, it showed that RNFL thickness in inferior quadrant [unadjusted: r = 0.221, P = 0.052; adjusted: β = 0.226 (0.010. 0.446), P = 0.041] was significantly associated with occipital lobes volumes after the adjustment of age, sex, years of education and eTIV, and selectively associated with the substructure of lingual gyrus volume [unadjusted: r = 0.223, P = 0.050; adjusted: β = 0.278 (0.058, 0.487), P = 0.014]. In addition, average RNFL thickness was associated with the cognitive domain of visuospatial/constructional [unadjusted: r = 0.114, P = 0.322; adjusted: β = 0.216 (0.006, 0.426), P = 0.044] after the adjustment in these nondemented older adults. ConclusionsQuadrant-specific associations exist between RNFL thickness and brain regions vulnerable to aging or neurodegeneration in older adults with normal cognition. These findings would promote further investigations into using RNFL as a noninvasive and less expensive biomarker of neurocognitive aging and AD-related neurodegeneration.

Predicting high-intensity focused ultrasound thalamotomy lesions using 2D magnetic resonance thermometry and 3D Gaussian modeling.

To develop a method of using two-dimensional (2D) magnetic resonance thermometry, and three-dimensional (3D) Gaussian modeling to predict the volume, shape, and location of 1day postoperative T1w high-intensity focused ultrasound lesions in medication refractory tremor patients; thereby facilitating a better comprehension of thermal damage thresholds, which can be utilized to reduce adverse events, and improve patient outcome. Fifteen patients underwent magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy, which was performed at our center using an InSightec ExAblate 4000 system (Haifa, Israel), and guided by magnetic resonance imaging using a 3T Discovery 750 (General Electric Healthcare, Waukesha, WI, USA). For treatment monitoring, 2D MR thermometry (temperature sensitivity: -0.00909ppm/°C, bandwidth: 279Hz/pixel) was performed in multiple orthogonal planes (sagittal, coronal, and axial) intraoperatively. These images were temporally filtered using a general linear model approach to reduce noise. Temporal volumes of filtered temperature maps with a peak temperature 47°C were aligned and fitted with a 3D Gaussian to create a canonical heating model. We then fitted the filtered 2D temperature maps with a 3D Gaussian, and used the relationships derived from the 3D heating model to estimate the 3D temperature distribution. These temperature distributions were converted into thermal dose distributions and accumulated across time to create an accumulated thermal dose (ATD) profile. Thresholded ATD profiles were then correlated with manually traced T1-weighted 1day postoperative lesion volumes across patients, and linear regression slopes were plotted against varying ATD thresholds. Additionally, the Dice-Sørensen coefficient (DSC) was calculated to quantify the volumetric overlap between predicted, and actual lesions. On average, 18.1 (standard deviation (SD): ±4.6, range: 10-29) sonications were performed with an average peak temperature achieved of 62.4°C (SD: ±2.4, range: 58.2-67.7). An ATD threshold of 35.8 CEM43 was found to give a unity linear regression slope; this corresponded to an average DSC of 0.689 (SD: ±0.090, range: 0.476-0.815). Using multiplanar 2D MR thermometry and 3D Gaussian modeling, we were able to achieve very good (DSC=0.689) predictions of T1w 1day postoperative lesion volume, shape and location at an ATD threshold of approximately 36 CEM43. Furthermore, this method has the potential to be used in clinical evaluations to further elucidate the relationship between thermal damage and clinical outcome. Accurate 3D lesion prediction will facilitate improved clinical decision making in future MRgFUS thalamotomies.

Structural brain changes in hyperthyroid Graves’ disease: protocol for an ongoing longitudinal, case-controlled study in Göteborg, Sweden—the CogThy project

IntroductionCognitive impairment and reduced well-being are common manifestations of Graves’ disease (GD). These symptoms are not only prevalent during the active phase of the disease but also often prevail for...

Increased Diameters of the Internal Cerebral Veins and the Basal Veins of Rosenthal Are Associated with White Matter Hyperintensity Volume.

White matter hyperintensities on T2-weighted MR imaging are typical in older adults and have been linked to several poor health outcomes, including cognitive impairment and Alzheimer disease. The presence and severity of white matter hyperintensities have traditionally been attributed to occlusive arteriopathy, but recent evidence also implicates deep medullary venule collagenosis and associated vasogenic edema. Historically, postmortem analyses have been the sole way to analyze cerebral veins, but SWI can be now used to examine cortical veins in vivo. The aim of the current study was to determine whether there is an association between the diameters of the large draining cerebral veins/sinuses and white matter hyperintensity volume. T2-weighted FLAIR and SWI were performed in 682 older adults without dementia (mean age, 73.9 ± 5.9 years; 59.1% women). Total and regional white matter hyperintensity volume was derived. We measured the diameters of 5 regions of the cerebral venous draining system: internal cerebral veins, basal veins of Rosenthal, superior sagittal sinus, vein of Galen, and straight sinus terminus. Increased diameter of the internal cerebral veins was associated with greater total white matter hyperintensity volume (β = 0.09, P = .02) and regionally in the parietal (β = 0.10, P = .006), frontal (β = 0.09, P = .02), and temporal (β = 0.09, P = .02) lobes. Increased diameter of the basal veins of Rosenthal was associated with greater total (β = 0.10, P = .01), frontal (β = 0.11, P = .003), and temporal (β = 0.09, P = .02) white matter hyperintensity volume. Our results suggest that the caliber of the internal cerebral veins and of the basal veins of Rosenthal relates to regional white matter disease.

Postoperative brain volumes are associated with one-year neurodevelopmental outcome in children with severe congenital heart disease

Children with congenital heart disease (CHD) remain at risk for neurodevelopmental impairment despite improved perioperative care. Our prospective cohort study aimed to determine the relationship between perioperative brain volumes and neurodevelopmental outcome in neonates with severe CHD. Pre- and postoperative cerebral MRI was acquired in term born neonates with CHD undergoing neonatal cardiopulmonary bypass surgery. Brain volumes were measured using an atlas prior-based automated method. One-year neurodevelopmental outcome was assessed with the Bayley-III. CHD infants (n = 77) had lower pre- and postoperative total and regional brain volumes compared to controls (n = 44, all p < 0.01). CHD infants had poorer cognitive and motor outcome (p ≤ 0.0001) and a trend towards lower language composite score compared to controls (p = 0.06). Larger total and selected regional postoperative brain volumes were found to be associated with better cognitive and language outcomes (all p < 0.04) at one year. This association was independent of length of intensive care unit stay for total, cortical, temporal, frontal and cerebellar volumes. Therefore, reduced cerebral volume in CHD neonates undergoing bypass surgery may serve as a biomarker for impaired outcome.

P3‐036: LONG‐TERM RESULTS OF CEREBRAL NEUROGENESIS STIMULATION WITH TRANSCATHETER INTRACEREBRAL LOW‐LEVEL LASER (LIGHT) THERAPY FOR ALZHEIMER'S DISEASE

The research is devoted to long-term results of cerebral neurogenesis after trans-catheteric intracerebral Low-level Laser Therapy (LLLT) in Alzheimer's disease (AD) patients. 220 patients with AD were examined. The examination included CDR definition, Tomography Dementia Rating scale (TDR), MMSE, cerebral CT, MRI, SG, rheoencephalography (REG), cerebral MUGA. We selected 93 patients aged 34–80 (average age 67.5), 32 (34.40%) male, 61 (65.59%) female. - Test Group, 48 (51.61%) patients: preclinical stage (TDR-0 dementia level) - 4 patients, early stage (TDR-1) - 16, middle stage (TDR-2) - 21, severe stage (TDR-3) - 7 patients. They all underwent transcatheter intracerebral LLLT (helium-neon laser). - Control Group, 45 (48.39%) patients: preclinical stage (TDR-0 dementia level) - 6 patients, early stage (TDR-1) - 13, middle stage (TDR-2) - 15, severe stage (TDR-3) - 11 patients. These patients received conservative treatment (Memantine or Rivastigmine). All 48 (100%) Test Group patients demonstrated improved microcirculation along with improved metabolism in neurons, neurogenesis and cerebral regenerative processes with 10–20% increase in cerebral temporal regions volume. The process was accompanied by decrease in dementia level and cognitive functions restoration, which made it possible to transfer the treated patients to a lighter stage TDR group. The resulting positive effect in TDR-0 and TDR-1 patients was observed for 10 years; in TDR-2 patients - 4–5 years; in TDR-3 patients - 2−2.5 years. Control Group treatment resulted in a lack of neurogenesis, as well as in further increase in cerebral involutive changes and decrease in the volume of temporal lobes. In patients with early stages of AD (TDR-0, TDR-1), temporary stabilization of the condition was noted for 0.5 - 2 years followed by growing dementia and cognitive impairment. In patients with more severe stages of AD (TDR-2, TDR-3), further dementia and cognitive impairment growth was noted.

Neuropsychological Decline Improves Prediction of Dementia Beyond Alzheimer's Disease Biomarker and Mild Cognitive Impairment Diagnoses.

Background:A clinical diagnosis of cognitive impairment is traditionally based on a single cognitive exam, but serial cognitive testing can be sensitive to subtle cognitive changes in asymptomatic individuals and inform cognitive trajectory.Objective:We evaluated the prognostic utility of identifying longitudinal neuropsychological decline along with single cognitive exam and Alzheimer’s disease (AD) cerebrospinal fluid (CSF) biomarkers in predicting dementia. We also examined brain volumetric differences based on decline trajectories.Method:Regression models quantified 12-month neuropsychological decline relative to normative expectations among non-demented older adults (N = 1,074). Progression to dementia over follow-up (18-120 months) was diagnosed using independent modes of assessment.Results:In Cox regression models controlling for age, sex, education, apolipoprotein E4, and baseline cognitive diagnosis, neuropsychological decline predicted increased dementia risk, χ2 = 69.861, p < 0.001, odds ratio = 2.841, even after correction for CSF biomarkers (amyloid-β, phosphorylated tau, total tau), χ2 = 26.365, p < 0.001, odds ratio = 2.283. Voxel-based morphometry analysis indicated smaller hippocampal and medial temporal volume in participants with neuropsychological decline.Conclusions:Longitudinal diagnosis of neuropsychological decline improved prognostic accuracy beyond single cognitive exam diagnoses and AD CSF biomarkers, even in asymptomatic older adults. Older adults with a trajectory of neuropsychological decline exhibit smaller medial temporal and hippocampal brain volume. Longitudinal diagnostic approaches may benefit selection and randomization procedures for AD clinical trials in asymptomatic individuals.

Relations between cognitive and motor deficits and regional brain volumes in individuals with alcoholism

Despite the common co-occurrence of cognitive impairment and brain structural deficits in alcoholism, demonstration of relations between regional gray matter volumes and cognitive and motor processes have been relatively elusive. In pursuit of identifying brain structural substrates of impairment in alcoholism, we assessed executive functions (EF), episodic memory (MEM), and static postural balance (BAL) and measured regional brain gray matter volumes of cortical, subcortical, and cerebellar structures commonly affected in individuals with alcohol dependence (ALC) compared with healthy controls (CTRL). ALC scored lower than CTRL on all composite scores (EF, MEM, and BAL) and had smaller frontal, cingulate, insular, parietal, and hippocampal volumes. Within the ALC group, poorer EF scores correlated with smaller frontal and temporal volumes; MEM scores correlated with frontal volume; and BAL scores correlated with frontal, caudate, and pontine volumes. Exploratory analyses investigating relations between subregional frontal volumes and composite scores in ALC yielded different patterns of associations, suggesting that different neural substrates underlie these functional deficits. Of note, orbitofrontal volume was a significant predictor of memory scores, accounting for almost 15% of the variance; however, this relation was evident only in ALC with a history of a non-alcohol substance diagnosis and not in ALC without a non-alcohol substance diagnosis. The brain-behavior relations observed provide evidence that the cognitive and motor deficits in alcoholism are likely a result of different neural systems and support the hypothesis that a number of identifiable neural systems rather than a common or diffuse neural pathway underlies cognitive and motor deficits observed in chronic alcoholism.

Water flow, oil biodegradation, and hydrodynamic traps in the Llanos Basin, Colombia

In this study, we provide new data to understand the groundwater flow patterns in the Llanos Basin and their impact on oil biodegradation and the geothermal regimes as well as how the structural styles and anthropogenic activities impact these patterns. Previous studies suggest an active flow of groundwater and variable salinities whose spatial pattern is apparently unrelated to topographically driven groundwater flow. These observations have led to different hypotheses regarding the influence of groundwater flow on Llanos Basin geothermal gradients and oil biodegradation. In this contribution, we present data regarding the hydraulic heads, salinities, geothermal gradients, and structural styles of the Llanos Basin to propose hypotheses explaining these observations. Structural cross sections and subsurface stratigraphic correlations allow us to suggest that the pattern of flow is best explained by a correlation between groundwater flow and structural styles. A basement map of the Llanos Basin confirms that the most important factor controlling geothermal gradients is the type of basement, whereas the factor of groundwater flow appears to be of secondary importance. The evolution of the basin and the frequent absence of correlation between fresh water and the more biodegraded oils support the interpretation that biodegradation is controlled by an older flow of water that started as early as the Oligocene. Finally, mass balances suggest that the temporal scales and volumes of groundwater flow are much larger than the scales observed during the development of the oil fields.

Automated quantitative tumour response assessment of MRI in neuro-oncology with artificial neural networks: a multicentre, retrospective study.

The Response Assessment in Neuro-Oncology (RANO) criteria and requirements for a uniform protocol have been introduced to standardise assessment of MRI scans in both clinical trials and clinical practice. However, these criteria mainly rely on manual two-dimensional measurements of contrast-enhancing (CE) target lesions and thus restrict both reliability and accurate assessment of tumour burden and treatment response. We aimed to develop a framework relying on artificial neural networks (ANNs) for fully automated quantitative analysis of MRI in neuro-oncology to overcome the inherent limitations of manual assessment of tumour burden. In this retrospective study, we compiled a single-institution dataset of MRI data from patients with brain tumours being treated at Heidelberg University Hospital (Heidelberg, Germany; Heidelberg training dataset) to develop and train an ANN for automated identification and volumetric segmentation of CE tumours and non-enhancing T2-signal abnormalities (NEs) on MRI. Independent testing and large-scale application of the ANN for tumour segmentation was done in a single-institution longitudinal testing dataset from the Heidelberg University Hospital and in a multi-institutional longitudinal testing dataset from the prospective randomised phase 2 and 3 European Organisation for Research and Treatment of Cancer (EORTC)-26101 trial (NCT01290939), acquired at 38 institutions across Europe. In both longitudinal datasets, spatial and temporal tumour volume dynamics were automatically quantified to calculate time to progression, which was compared with time to progression determined by RANO, both in terms of reliability and as a surrogate endpoint for predicting overall survival. We integrated this approach for fully automated quantitative analysis of MRI in neuro-oncology within an application-ready software infrastructure and applied it in a simulated clinical environment of patients with brain tumours from the Heidelberg University Hospital (Heidelberg simulation dataset). For training of the ANN, MRI data were collected from 455 patients with brain tumours (one MRI per patient) being treated at Heidelberg hospital between July 29, 2009, and March 17, 2017 (Heidelberg training dataset). For independent testing of the ANN, an independent longitudinal dataset of 40 patients, with data from 239 MRI scans, was collected at Heidelberg University Hospital in parallel with the training dataset (Heidelberg test dataset), and 2034 MRI scans from 532 patients at 34 institutions collected between Oct 26, 2011, and Dec 3, 2015, in the EORTC-26101 study were of sufficient quality to be included in the EORTC-26101 test dataset. The ANN yielded excellent performance for accurate detection and segmentation of CE tumours and NE volumes in both longitudinal test datasets (median DICE coefficient for CE tumours 0·89 [95% CI 0·86-0·90], and for NEs 0·93 [0·92-0·94] in the Heidelberg test dataset; CE tumours 0·91 [0·90-0·92], NEs 0·93 [0·93-0·94] in the EORTC-26101 test dataset). Time to progression from quantitative ANN-based assessment of tumour response was a significantly better surrogate endpoint than central RANO assessment for predicting overall survival in the EORTC-26101 test dataset (hazard ratios ANN 2·59 [95% CI 1·86-3·60] vs central RANO 2·07 [1·46-2·92]; p<0·0001) and also yielded a 36% margin over RANO (p<0·0001) when comparing reliability values (ie, agreement in the quantitative volumetrically defined time to progression [based on radiologist ground truth vs automated assessment with ANN] of 87% [266 of 306 with sufficient data] compared with 51% [155 of 306] with local vs independent central RANO assessment). In the Heidelberg simulation dataset, which comprised 466 patients with brain tumours, with 595 MRI scans obtained between April 27, and Sept 17, 2018, automated on-demand processing of MRI scans and quantitative tumour response assessment within the simulated clinical environment required 10 min of computation time (average per scan). Overall, we found that ANN enabled objective and automated assessment of tumour response in neuro-oncology at high throughput and could ultimately serve as a blueprint for the application of ANN in radiology to improve clinical decision making. Future research should focus on prospective validation within clinical trials and application for automated high-throughput imaging biomarker discovery and extension to other diseases. Medical Faculty Heidelberg Postdoc-Program, Else Kröner-Fresenius Foundation.

Effects of CD33 Variants on Neuroimaging Biomarkers in Non-Demented Elders.

Two CD33 common variants, rs3826656 and rs3865444, have been identified to be correlated with Alzheimer's disease (AD). Our study examined the effects of the two AD-related CD33 common variants (rs3826656 and rs3865444) on the chosen AD-related brain regions (including hippocampus, amygdala, parahippocampus, middle temporal, entorhinal cortex, and total brain volume) in non-demented elders recruited from the Alzheimer's Disease Neuroimaging Initiative database at baseline and during four-year follow-up. We further tested the effects in an Aβ-positive group (including preclinical and prodromal stage of AD) and an Aβ-negative group. In the total non-demented elderly population, no associations reached significant levels after FDR correction. In the Aβ-positive group, we found that rs3826656 was associated with hippocampal and amygdala volumes (Hippocampus-R: pc = 0.0022; Amygdala-L: pc = 0.0044; Amygdala-R: pc = 0.0066), and rs3865444 was associated with right entorhinal volume (pc = 0.0286). The associations of rs3826656 with hippocampal and amygdala volumes in the Aβ-positive group were successfully replicated in the prodromal AD group (Hippocampus-R: pc = 0.0022; Amygdala-L: pc = 0.0022; Amygdala-R: pc = 0.0088). These changes became more obvious over time during four-year follow-up. No associations were found between the two CD33 variants and neuroimaging biomarkers in the Aβ-negative and preclinical AD groups after FDR correction. These results suggested that the two CD33 common variants (rs3826656 and rs3865444) influenced volumes and atrophy rates of AD-related brain regions in non-demented elders. Subgroup analyses showed the effects mainly existed in the Aβ-positive group instead of the Aβ-negative group, and the effects began in the prodromal AD stage.

(187) Associations between Pain Interference and Brain Volume in Community-Dwelling Older Adults

Pain is common in older individuals often interfering with daily function, and pain interference is a common proxy for measuring physical functioning in this population. Although both pain and aging are associated with changes to brain volume, relatively few studies have examined the association between pain interference and brain volume among older individuals. As part of the Neuromodulatory Examination of Pain Across the Lifespan (NEPAL) study at the University of Florida, older individuals 60 to 93 years old (n=49, 69% female) filled out demographic and pain questionnaires followed by a structural 3-Tesla MRI scan. FreeSurfer 6.0.0 was used for preprocessing, quality control, and for volumetric parcellation generation. FreeSurfer Query, Design, Estimate, Contrast (QDEC) processing stream was used for statistical analysis controlling for multiple comparisons with gender as a nuisance covariate. Higher pain interference was associated with smaller volume in the lateral orbitofrontal cortex, rostral middle frontal cortex, post-central cortex, superior temporal cortex, and precuneus but larger volume in the superior frontal and parstriangularis cortices (False Discovery Rate p's

Associations between vascular risk factors and brain MRI indices in UK Biobank.

AimsSeveral factors are known to increase risk for cerebrovascular disease and dementia, but there is limited evidence on associations between multiple vascular risk factors (VRFs) and detailed aspects of brain macrostructure and microstructure in large community-dwelling populations across middle and older age.Methods and resultsAssociations between VRFs (smoking, hypertension, pulse pressure, diabetes, hypercholesterolaemia, body mass index, and waist–hip ratio) and brain structural and diffusion MRI markers were examined in UK Biobank (N = 9722, age range 44–79 years). A larger number of VRFs was associated with greater brain atrophy, lower grey matter volume, and poorer white matter health. Effect sizes were small (brain structural R2 ≤1.8%). Higher aggregate vascular risk was related to multiple regional MRI hallmarks associated with dementia risk: lower frontal and temporal cortical volumes, lower subcortical volumes, higher white matter hyperintensity volumes, and poorer white matter microstructure in association and thalamic pathways. Smoking pack years, hypertension and diabetes showed the most consistent associations across all brain measures. Hypercholesterolaemia was not uniquely associated with any MRI marker.ConclusionHigher levels of VRFs were associated with poorer brain health across grey and white matter macrostructure and microstructure. Effects are mainly additive, converging upon frontal and temporal cortex, subcortical structures, and specific classes of white matter fibres. Though effect sizes were small, these results emphasize the vulnerability of brain health to vascular factors even in relatively healthy middle and older age, and the potential to partly ameliorate cognitive decline by addressing these malleable risk factors.

Wireless Wearable Ultrasound Sensor on a Paper Substrate to Characterize Respiratory Behavior.

Respiratory behavior contains crucial parameters to feature lung functionality, including respiratory rate, profile, and volume. The current well-adopted method to characterize respiratory behavior is spirometry using a spirometer, which is bulky, heavy, expensive, requires a trained provider to operate, and is incapable of continuous monitoring of respiratory behavior, which is often critical to assess chronic respiratory diseases. This work presents a wireless wearable sensor on a paper substrate that is capable of continuous monitoring of respiratory behavior and delivering the clinically relevant respiratory information to a smartphone. The wireless wearable sensor was attached on the midway of the xiphoid process and the costal margin, corresponding to the abdomen-apposed rib cage, based on the anatomical and experimental analysis. The sensor, with a footprint of 40 × 35 × 6 mm3 and weighing 6.5 g, including a 2.7 g battery, consists of three subsystems, (i) ultrasound emitter, (ii) ultrasound receiver, and (iii) data acquisition and wireless transmitter. The sensor converts the linear strain at the wearing site to the lung volume change by measuring the change in ultrasound pressure as a function of the distance between the emitter and the receiver. The temporal lung volume change data, directly converted from the ultrasound pressure, is wirelessly transmitted to a smartphone where a custom-designed app computes to show volume-time and flow rate-volume loop graphs, standard respiratory analysis plots. The app analyzes the plots to show the clinically relevant respiratory behavioral parameters, such as forced vital capacity (FVC) and forced expiratory volume delivered in the first second (FEV1). Potential user-induced error on sensor placement and temperature sensitivity were studied to demonstrate the sensor maintains its performance within a reasonable range of those variables. Eight volunteers were recruited to evaluate the sensor, which showed the mean deviation of the FEV1/FVC ratio in the range of 0.00-4.25% when benchmarked by the spirometer. The continuous measurement of respiratory behavioral parameters helps track the progression of the respiratory diseases, including asthma progression to provide alerts to relevant caregivers to seek needed timely treatment.

The role of age on tau PET uptake and gray matter atrophy in atypical Alzheimer's disease

IntroductionLittle is known about the role of age on neurodegeneration and protein deposition in atypical variants of Alzheimer's disease (AD). MethodsRegional tau and β-amyloid positron emission tomography standard uptake value ratios and gray matter volumes were calculated in a cohort of 42 participants with atypical AD. The relationship between regional metrics and age was modeled using a Bayesian hierarchical linear model. ResultsAge was strongly associated with tau uptake across all cortical regions, particularly parietal, with greater uptake in younger participants. Younger age was associated with smaller parietal and lateral temporal volumes. Regional β-amyloid differed little by age. Age showed a stronger association with tau than volume and β-amyloid in all cortical regions. Age was not associated with cognitive performance. DiscussionAge is an important determinant of severity of cortical tau uptake in atypical AD, with young participants more likely to show widespread and severe cortical tau uptake.

The Association of Depressive Symptoms With Brain Volume Is Stronger Among Diabetic Elderly Carriers of the Haptoglobin 1-1 Genotype Compared to Non-carriers.

Aim: Depression is highly prevalent in type 2 diabetes and is associated with lower adherence to medical treatments, worse glycemic control, and increased risk for diabetes-related complications. The mechanisms underlying depression in type 2 diabetes are unclear. The haptoglobin (Hp) genotype is associated with type 2 diabetes related complications including increased risk for cerebrovascular pathology and worse cognitive performance. Its relationship with depression is unknown. We investigated the role of Hp genotype on the association of depression with brain and white matter hyperintensities (WMH) volumes.Methods: Depressive symptoms (measured with the 15-item Geriatric Depression Scale), brain MRI, and Hp genotypes, were examined in elderly subjects with type 2 diabetes [29 (13.8%) Hp 1–1 carriers and 181 (86.2%) non-carriers]. The interaction of Hp genotype with number of depressive symptoms on regional brain measures was assessed using regression analyses.Results: The significant interactions were such that in Hp 1–1 carriers but not in non-carriers, number of depressive symptoms was associated with overall frontal cortex (p = 0.01) and WMH (p = 0.04) volumes but not with middle temporal gyrus volume (p = 0.43).Conclusions: These results suggest that subjects with type 2 diabetes carrying the Hp 1–1 genotype may have higher susceptibility to depression in the context of white matter damage and frontal lobe atrophy. The mechanisms underlying depression in diabetes may differ by Hp genotype.

COMT-Val158Met polymorphism modulates antipsychotic effects on auditory verbal hallucinations and temporal lobe gray matter volumes in healthy individuals\u2014symptom relief accompanied by worrisome volume reductions

Investigation of auditory verbal hallucinations (AVHs) in schizophrenics is complicated by psychiatric symptoms. Investigating healthy individuals with AVHs (H-AVHs) can obviate such confounding factors. The objective of this study was to explore the effects of antipsychotic treatment on AVHs and gray matter volumes (GMVs) in H-AVH subjects and whether such are effects are influenced by COMT-Val158Met genotype. Magnetic resonance imaging (MRI) and genotyping studies were completed for 42 H-AVH subjects and 42 well-matched healthy controls (HCs). COMT-Met/Met homozygotes (158th codon) were identified as COMT-Met genotype; COMT-Met/Val heterozygotes and COMT-Val/Val homozygotes were identified as COMT-Val genotype. Data were compared across groups (H-AVH vs. HC, and between genotypes) with two-sample t-tests. The H-AVH COMT-Met group showed a stronger response to antipsychotic treatment than the H-AVH COMT-Val group (p < 0.001). Both H-AVH genotype groups exhibited temporal lobe GMV reductions after treatment, and relative to their respective genotype-matched HC groups. Antipsychotic treatment effects in H-AVH subjects were influenced by COMT-Val158Met genotype and associated with widespread GMV reductions. These findings provide clues for further exploration of treatment targets for AVHs. Treatment associated GMV reductions, however, raise concerns about use of antipsychotics in H-AVH subjects.

Is there a specific memory signature associated with Aβ-PET positivity in patients with amnestic mild cognitive impairment?

Amnestic mild cognitive impairment (aMCI) is a clinical entity with various potential etiologies including but not limited to Alzheimer's disease. We examined whether a positive ([18F]Florbetapir) beta amyloid positron emission tomography scan, supporting underlying Alzheimer's disease pathophysiology, was associated with specific memory deficits in 48 patients with aMCI (33 beta amyloid positive, 15 beta amyloid negative). Memory was evaluated using an autobiographical fluency task and a word-list learning task with 2 different encoding types (shallow/incidental versus deep/intentional). Compared with 40 beta amyloid–negative controls, both aMCI subgroups demonstrated severe deficits in the global memory score and in most subscores of both tasks. Finer-grained analyses of memory tests showed subtle association with beta amyloid status, revealing a stronger impairment of the primacy effect in beta amyloid–positive patients. Structural magnetic resonance imaging showed that both aMCI subgroups exhibited comparable atrophy patterns, with similar degrees of medial temporal volume loss compared with controls. Specifically assessing the primacy effect might complement global memory scores in identifying beta amyloid–positive patients with aMCI.

Stability, thermophysical properties and performance assessment of alumina–water nanofluid with emphasis on ultrasonication and storage period

Owing to the improvements in thermophysical properties, nanofluids are considered advantageous over pure fluids in heat transfer applications. However, these improvements may be regarded as meaningful for applications provided that optimum dispersion of nanoparticles is ensured throughout the process, which mostly depend on preparation technique. In this study, alumina (Al2O3)–water nanofluids of 0.5 vol% were prepared using ultrasonication (up to 5 h) and stored at stationary condition until 30 days. We have evaluated stability as temporal volume fraction by measuring density. Further, thermal conductivity and viscosity were measured, and heat transfer performance was analyzed for the case of fully developed laminar flow inside a tube. All the measurements were conducted at 25 °C temperature. Results revealed that longer ultrasonication reduces sedimentation of nanoparticles and hence, increases stability of nanofluids. Thermal conductivity increased, while viscosity decreased with increasing sonication time. Moreover, these thermophysical properties decreased with storage periods. It was observed, until 30 days of storage that ultrasonication process for different durations induced significant changes in viscosity, although those in thermal conductivity was not as pronounced. All the prepared samples were determined beneficial as heat transfer fluids over water, even after 30 days from preparation.

Low-cost, high-resolution stemflow sensing

This study develops and evaluates a sensing system capable of measuring stemflow at high temporal resolutions. Leveraging affordable hobbyist grade electronics has allowed for the development of a system which is low-cost, easy to reproduce and adaptable. Eschewing classic stemflow measurement techniques, the system demonstrated herein utilizes a sensing payload which includes a wetness sensor and ultrasonic rangefinder. Combined, these sensors are capable of determining precise stemflow initiation and cessation times as well as capturing high temporal resolution stemflow volume measurements at 10 s intervals. A case study focusing on stemflow data collected by the sensing system from an isolated green ash (Fraxinus pennsylvanica Marshall) during a May 2016 rainfall event in Kamloops, British Columbia is used to evaluate the performance of the sensing system, demonstrating the accuracy of the collected data and the potential research questions that can be addressed by large scale deployment of the sensor system.