Search results for "imagin."
showing 10 items of 7170 documents
Probabilistic liver atlas construction
2017
Background Anatomical atlases are 3D volumes or shapes representing an organ or structure of the human body. They contain either the prototypical shape of the object of interest together with other shapes representing its statistical variations (statistical atlas) or a probability map of belonging to the object (probabilistic atlas). Probabilistic atlases are mostly built with simple estimations only involving the data at each spatial location. Results A new method for probabilistic atlas construction that uses a generalized linear model is proposed. This method aims to improve the estimation of the probability to be covered by the liver. Furthermore, all methods to build an atlas involve p…
Post-extraction mesio-distal gap reduction assessment by confocal laser scanning microscopy - a clinical 3-month follow-up study
2017
[EN] AimThe aim of this 3-month follow-up study is to quantify the reduction in the mesio-distal gap dimension (MDGD) that occurs after tooth extraction through image analysis of three-dimensional images obtained with the confocal laser scanning microscopy (CLSM) technique. Materials and MethodsFollowing tooth extraction, impressions of 79 patients 1month and 72 patients 3months after tooth extraction were obtained. Cast models were processed by CLSM, and MDGD changes between time points were measured. ResultsThe mean mesio-distal gap reduction 1month after tooth extraction was 343.4m and 3months after tooth extraction was 672.3m. The daily mean gap reduction rate during the first term (bet…
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…
Sialographic findings in Wharton duct evagination
2009
Ductal evagination is a rare condition affecting the Wharton duct. The aim of this study was to establish the incidence, imaging features and clinical significance of ductal evagination in patients undergoing submandibular gland sialography. The sialographic findings and reports of 322 patients undergoing submandibular gland sialography during the period 1998-2007 were retrospectively reviewed. Ductal evagination was identified on sialograms as a unique diverticulum, filled with contrast medium, of the Wharton duct, with a narrow neck and a blind end. A ductal evagination was found in 5/322 patients with swelling and pain in the submandibular gland. It was always located in the middle tract…
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 < .…
The effect of amifostine or IMRT to preserve the parotid function after radiotherapy of the head and neck region measured by quantitative salivary gl…
2008
Purpose: In this retrospective study, two approaches to preserve the parotid function after radiotherapy (RT) were compared: application of the radioprotective agent amifostine during RT and parotid sparing intensity-modulated radiotherapy (IMRT). Patients and methods: Patients were qualified for this analysis if (1) both parotid glands received a radiation dose of P50 Gy using conventional radiotherapy techniques (cRT) or if they received a parotid sparing IMRT as alternative, if (2) salivary gland scintigraphies before and after RT were performed, and if (3) a normal parotid function was present before RT. Quantitative salivary gland scintigraphy was used to assess the parotid gland funct…
Results of oral implant–supported prostheses after mandibular vertical alveolar ridge distraction: a propos of 54 sites
2012
Objective The aim of this study was to present retrospective long-term results of oral implant–supported prostheses after mandibular vertical alveolar ridge distraction. Study Design Patients who had alveolar mandibular distraction before oral rehabilitation from 1999 to 2009 were retrospectively reviewed. Results Fifty-four distractions were performed in 25 women and 12 men with a mean age of 51.7 years. Seventeen patients had bilateral distraction. Most of the distracted sites were posterior. Global major complications were major misdirection (3.7%), fracture (3.7%), and permanent alveolar nerve paresthesia (1 patient). All of the patients experienced osseous improvement. Mean height of t…
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…