Search results for "RESONANCE"
showing 10 items of 6625 documents
Digital assessment of MRI for lumbar disc desiccation. A comparison of digital versus subjective assessments and digital intensity profiles versus di…
1994
During magnetic resonance imaging, a vast amount of digital data on anatomic structures is translated into images, which are then assessed subjectively. The development of an objective, sensitive method to directly assess the digital data would have clear benefits, particularly for clinical research on disc degeneration. The study goals were to develop a method of digital assessment of disc desiccation and to compare digital signal intensity profiles with discographic patterns and macroanatomic findings. Proton density-weighted MRIs were obtained from 45 males (9-77 years) and digital analysis was done with a freely selectable region of interest facility. The adjacent cerebrospinal fluid (C…
Expanding the clinical phenotype of patients with a ZDHHC9 mutation.
2013
In 2007, 250 families with X-linked intellectual disability (XLID) were screened for mutations in genes on the X-chromosome, and in 4 of these families, mutations in the ZDHHC9 gene were identified. The ID was either isolated or associated with a marfanoid habitus. ZDHHC9 encodes a palmitoyl transferase that catalyzes the posttranslational modification of NRAS and HRAS. Since this first description, no additional patient with a ZDHHC9 mutation has been reported in the literature. Here, we describe a large family in which we identified a novel pathogenic ZDHHC9 nonsense mutation (p.Arg298*) by parallel sequencing of all X-chromosome exons. The mutation cosegregated with the clinical phenotyp…
Left insular cortex and left SFG underlie prismatic adaptation effects on time perception: Evidence from fMRI
2014
Prismatic adaptation (PA) has been shown to affect left-to-right spatial representations of temporal durations. A leftward aftereffect usually distorts time representation toward an underestimation, while rightward aftereffect usually results in an overestimation of temporal durations. Here, we used functional magnetic resonance imaging (fMRI) to study the neural mechanisms that underlie PA effects on time perception. Additionally, we investigated whether the effect of PA on time is transient or stable and, in the case of stability, which cortical areas are responsible of its maintenance. Functional brain images were acquired while participants (n = 17) performed a time reproduction task an…
Bone marrow after autologous blood stem cell transplantation and total body irradiation: magnetic resonance and chemical shift imaging.
1993
Magnetic resonance studies of the lumbar, pelvic, and femoral bone marrow were performed in 10 patients after autologous blood stem cell transplantation, including total body irradiation and myeloablative chemotherapy. The posttreatment interval varied between 2 and 6 yr. The appearance on T1-weighted images and the quantitative data obtained from chemical shift imaging (relative fat signal) were compared to 10 age-matched healthy volunteers. The classification of the T1-weighted images yielded no significant differences between the two groups. Chemical shift imaging by determination of the relative fat signal was able to detect a significant fatty replacement of the patients' lumbar (p < .…
Prediction of the hemoglobin level in hemodialysis patients using machine learning techniques
2013
HighlightsDifferent prediction algorithms were used to predict Hb levels in CRF patients.Prediction errors in the validation cohorts of patients were around 0.6g/dl.Difficulty to obtain lower errors due to the measuring machine precision (0.2g/dl).Relevance analysis of features have been applied for each predictor. Patients who suffer from chronic renal failure (CRF) tend to suffer from an associated anemia as well. Therefore, it is essential to know the hemoglobin (Hb) levels in these patients. The aim of this paper is to predict the hemoglobin (Hb) value using a database of European hemodialysis patients provided by Fresenius Medical Care (FMC) for improving the treatment of this kind of …
Physical Activity Predicts Population-Level Age-Related Differences in Frontal White Matter
2020
Physical activity has positive effects on brain health and cognitive function throughout the life span. Thus far, few studies have examined the effects of physical activity on white matter microstructure and psychomotor speed within the same, population-based sample (critical if conclusions are to extend to the wider population). Here, using diffusion tensor imaging and a simple reaction time task within a relatively large population-derived sample (N = 399; 18–87 years) from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN), we demonstrate that physical activity mediates the effect of age on white matter integrity, measured with fractional anisotropy. Higher self-reported daily ph…
Differential effects of age on subcomponents of response inhibition.
2013
Inhibitory deficits contribute to cognitive decline in the aging brain. Separating subcomponents of response inhibition may help to resolve contradictions in the existing literature. A total of 49 healthy participants underwent functional magnetic resonance imaging (fMRI) while performing a Go/no-go-, a Simon-, and a Stop-signal task. Regression analyses were conducted to identify correlations of age and activation patterns. Imaging results revealed a differential effect of age on subcomponents of response inhibition. In a simple Go/no-go task (no spatial discrimination), aging was associated with increased activation of the core inhibitory network and parietal areas. In the Simon task, whi…
Towards a unified analysis of cerebellum maturation and aging across the entire lifespan: A MRI analysis
2021
[EN] Previous literature about the structural characterization of the human cerebellum is related to the context of a specific pathology or focused in a restricted age range. In fact, studies about the cerebellum maturation across the lifespan are scarce and most of them considered the cerebellum as a whole without investigating each lobule. This lack of study can be explained by the lack of both accurate segmentation methods and data availability. Fortunately, during the last years, several cerebellum segmenta- tion methods have been developed and many databases comprising subjects of dif- ferent ages have been made publically available. This fact opens an opportunity window to obtain a mo…
Physical Activity Predicts Population-Level Age-Related Differences in Frontal White Matter
2018
Physical activity has positive effects on brain health and cognitive function throughout the life span. Thus far, few studies have examined the effects of physical activity on white matter microstructure and psychomotor speed within the same, population-based sample (critical if conclusions are to extend to the wider population). Here, using diffusion tensor imaging and a simple reaction time task within a relatively large population-derived sample (N = 399; 18–87 years) from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN), we demonstrate that physical activity mediates the effect of age on white matter integrity, measured with fractional anisotropy. Higher self-reported daily ph…
Ageing‐related changes in the cortical processing of otolith information in humans
2017
Acoustic short tone bursts (STB) trigger ocular and cervical vestibular-evoked myogenic potentials (oVEMPs/cVEMPs) by activating irregular otolith afferents. Simultaneously, STBs introduce an artificial net acceleration signal of otolith origin into the vestibular network. VEMP parameters as diagnostic otolith processing markers have been shown to decline after the age of thirty. To delineate the differential effects of healthy ageing on the cortical vestibular subnetwork processing otolith information, we measured cVEMPs and the differential effects of unilateral STB in three age groups (20-40, 40-60 and 60+; n = 42) using functional neuroimaging. STB evoked responses in the main vestibula…