Search results for "tomography"
showing 10 items of 2332 documents
Measurement of body composition in cancer patients using CT planning scan at the third lumbar vertebra
2019
Objective: the main objective was to assess body composition in terms of skeletal muscle index (SMI), myosteatosis, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and intermuscular adipose tissue (IMAT) as an adjunct of information provided by radiotherapy CT planning scan. Material and methods: a sample of 49 patients with lung and digestive cancers underwent a CT scan for radiotherapy treatment, which included measurements at the L3 region. Images were analyzed with a radiotherapy contouring software, using different Hounsfield Unit (HU) settings. Cross-sectional areas (cm2) were automatically computed by summing tissue pixels and multiplying by pixel surface area. Low …
A semi-automatic approach for epicardial adipose tissue segmentation and quantification on cardiac CT scans
2019
Abstract Many studies have shown that epicardial fat is associated with a higher risk of heart diseases. Accurate epicardial adipose tissue quantification is still an open research issue. Considering that manual approaches are generally user-dependent and time-consuming, computer-assisted tools can considerably improve the result repeatability as well as reduce the time required for performing an accurate segmentation. Unfortunately, fully automatic strategies might not always identify the Region of Interest (ROI) correctly. Moreover, they could require user interaction for handling unexpected events. This paper proposes a semi-automatic method for Epicardial Fat Volume (EFV) segmentation a…
Radiological anatomy assessment of the fissura pterygomaxillaris for a surgical approach to ganglion pterygopalatinum
2017
The ganglion pterygopalatinum has become a therapeutic target to treat various pain syndromes in recent years. It is located in the fossa pterygopalatina, and the fissura pterygomaxillaris is the main access to surgically approach this structure. Recently, the neuromodulation of the ganglion pterygopalatinum by microstimulator implantation has become the first therapeutic line in refractory cluster headache treatment. This invasive technique is performed transorally through the fissura pterygomaxillaris, and is limited by the size of the implantation device, which requires an opening of at least 2 mm. Therefore, extensive knowledge about the anatomy of the fissura pterygomaxillaris prior to…
The assesment of relationship between the angulation of impacted mandibular third molar teeth and the thickness of lingual bone: A prospective clinic…
2018
Background Our purpose was to investigate the relationship between the angulation of mandibular third molars and the thickness of the lingual bone, which can affect the risk of lingual nerve damage during lower third molars surgical extraction. Material and Methods This study consisted of 104 patients (42 males and 62 females), aged between 18-42 years (24.67 ± 6.11 years). Cone Beam Computed Tomography (CBCT) images were taken for preoperative assessment. The teeth were divided into four groups according to their positions: mesioangular, distoangular, vertical and horizontal. Lingual bone thickness around impacted teeth were measured at three points: cementoenamel junction (CEJ) of the man…
Diagnosis of pre-sarcopenia from a single selectional crosscut at C3 region, using CT scans before radiotherapy
2019
espanolProposito: el proposito de este estudio fue diagnosticar la presarcopenia en pacientes con cancer que no disponen de imagenes por tomografia computarizada (TC) a nivel abdominal mediante un metodo novedoso basado en cortes a nivel cervical. Material y metodos: se analizaron y se compararon mediante unidades la masa muscular y la masa muscular esqueletica en 37 pacientes con cancer de pulmon y neoplasias del aparato digestivo superior que incluian cortes en la TC de planificacion a nivel de C3 y L3. La presarcopenia se identifico de acuerdo con los puntos de corte establecidos actualmente: ≤ 41 cm2/m2 para mujeres, ≤ 43 cm2/m2 en hombres con un IMC ≤ 25 kg/m2 y ≤ 53 cm2/m2 en hombres …
Direction-dependent activation of the insular cortex during vertical and horizontal hand movements
2016
International audience; The planning of any motor action requires a complex multisensory processing by the brain. Gravity - immutable on Earth - has been shown to be a key input to these mechanisms. Seminal fMRI studies performed during visual perception of falling objects and self-motion demonstrated that humans represent the action of gravity in parts of the cortical vestibular system; in particular, the insular cortex and the cerebellum. However, little is known as to whether a specific neural network is engaged when processing non-visual signals relevant to gravity. We asked participants to perform vertical and horizontal hand movements without visual control, while lying in a 3T-MRI sc…
Cephalometric measurements from 3D reconstructed images compared with conventional 2D images
2011
Abstract Objective: To assess whether the values of different measurements taken on three-dimensional (3D) reconstructions from cone-beam computed tomography (CBCT) are comparable with those taken on two-dimensional (2D) images from conventional lateral cephalometric radiographs (LCRs) and to examine if there are differences between the different types of CBCT software when taking those measurements. Material and Methods: Eight patients were selected who had both an LRC and a CBCT. The 3D reconstructions of each patient in the CBCT were evaluated using two different software packages, NemoCeph 3D and InVivo5. An observer took 10 angular and 3 linear measurements on each of the three types o…
Influence of Software Tool and Methodological Aspects of Total Metabolic Tumor Volume Calculation on Baseline [18F]FDG PET to Predict Survival in Hod…
2015
Aim To investigate the respective influence of software tool and total metabolic tumor volume (TMTV0) calculation method on prognostic stratification of baseline 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography ([18F]FDG-PET) in newly diagnosed Hodgkin lymphoma (HL). Methods 59 patients with newly diagnosed HL were retrospectively included. [18F]FDG-PET was performed before any treatment. Four sets of TMTV0 were calculated with Beth Israel (BI) software: based on an absolute threshold selecting voxel with standardized uptake value (SUV) >2.5 (TMTV02.5), applying a per-lesion threshold of 41% of the SUVmax (TMTV041) and using a per-patient adapted threshold based on SUVmax of the…
Evaluation of the prognostic role of tumour-associated macrophages in newly diagnosed classical hodgkin lymphoma and correlation with early FDG-PET a…
2017
In Hodgkin Lymphoma (HL), about 20% of patients still have relapsed/refractory disease and late toxic effects rate continue to rise with time. 'Early FDG-PET' and tissue macrophage infiltration (TAM) emerged as powerful prognostic predictors. The primary endpoint was to investigate the prognostic role of both early FDG-PET and TAM; the secondary endpoint was to test if early FDG-PET positivity could correlate with high TAM score. A cohort of 200 HL patients was analysed. Induction treatment plan consisted of two to six courses of ABVD and, if indicated, involved field radiation therapy. All patients repeated CT scan and FDG-PET after two cycles and after the completion of therapy. TAM in di…
CT maxillary sinus evaluation: a retrospective cohort study
2015
Background: Proximity of the dental roots to the sinus floor makes dental disease a probable cause of maxillary sinusitis. The aim of this study was to find out if maxillary sinus pathologic changes were more prevalent in patients with dental disease and to evaluate the performance of computed tomography (CT) in analyzing and detecting apical periodontitis and other odontogenic causes on the maxillary sinusitis etiology in a Portuguese Caucasian population.Material and Methods: Retrospective cohort study. The total sample of 504 patients and their CT was included in this study. The patients were from a private dental clinic, specializing in oral surgery, where the first complaint was not di…