Search results for "Scanner"
showing 10 items of 170 documents
Cognitive reserve and cognitive performance of patients with focal frontal lesions.
2016
The Cognitive reserve (CR) hypothesis was put forward to account for the variability in cognitive performance of patients with similar degrees of brain pathology. Compensatory neural activity within the frontal lobes has often been associated with CR. For the first time we investigated the independent effects of two CR proxies, education and NART IQ, on measures of executive function, fluid intelligence, speed of information processing, verbal short term memory (vSTM), naming, and perception in a sample of 86 patients with focal, unilateral frontal lesions and 142 healthy controls. We fitted multiple linear regression models for each of the cognitive measures and found that only NART IQ pre…
Radiomic Machine Learning Classifiers in Spine Bone Tumors: A Multi-Software, Multi-Scanner Study
2021
Purpose: Spinal lesion differential diagnosis remains challenging even in MRI. Radiomics and machine learning (ML) have proven useful even in absence of a standardized data mining pipeline. We aimed to assess ML diagnostic performance in spinal lesion differential diagnosis, employing radiomic data extracted by different software. Methods: Patients undergoing MRI for a vertebral lesion were retrospectively analyzed (n = 146, 67 males, 79 females; mean age 63 ± 16 years, range 8-89 years) and constituted the train (n = 100) and internal test cohorts (n = 46). Part of the latter had additional prior exams which constituted a multi-scanner, external test cohort (n = 35). Lesions were la…
Detection of intracranial circulatory arrest in brain death using cranial CT-angiography.
2011
Background and purpose Computed tomographic-angiography (CT-A) is becoming more accepted in detecting intracranial circulatory arrest in brain death (BD). An international consensus about the use and the parameters of this technique is currently not established. We examined intracranial contrast enhancement in CT-A after clinically confirmed BD, compared the results with electroencephalography (EEG) and Transcranial Doppler Ultrasonography (TCD) findings and developed a commonly applicable CT-A protocol. Methods Prospective, monocentric study between April 2008 and October 2011. EEG, TCD and CT-A were performed in 63 patients aged between 18 and 88 years (mean, 55 years) who fulfilled clini…
First experiences with a high-resolution ultrasonic scanner in the diagnosis of malignant melanomas
1983
The use of high-resolution ultrasonic instruments with transducer frequencies above 8 MHz makes it possible to visualize malignant melanomas of a thickness of more than 0.7 mm. While the sonolucent structure has not permitted the dignity of a lesion to be judged to date, it is easy to determine the maximal tumor thickness as well as infiltration of the subcutis. Thus "low-risk" and "high-risk" melanomas may be differentiated preoperatively according to these parameters. The results are of great use for the operator to plan the extent of his intervention, as well as to select patients for prophylactic regional lymphonodectomy.
Il rilievo con scanner laser del Tempio "G" di Selinunte. Elaborazione delle scansioni e metodo per l'anastilosi virtuale di una colonna
2007
La possibilità di misurare in un tempo relativamente ridotto le coordinate tridimensionali di un elevato numero di punti rende i sistemi laser scanner particolarmente idonei al rilievo di frammenti erratici; la disponibilità di dati metrici accurati e puntuali, difficilmente ottenibili con le tecniche tradizionali del rilevamento architettonico, rende possibile condurre processi di discretizzazione e razionalizzazione della morfologia dei singoli frammenti. In questa sede vengono esposte le fasi di lavoro relative all’orientamento relativo ed assoluto delle scansioni laser del Tempio “G” di Selinunte, ed all’anastilosi virtuale dei rocchi di una colonna del fronte nord del tempio; obiettivo…
Levantamiento 3D para el estudio arqueológico y la reconstrucción virtual del Santuario de Isis en la antigua Lilybaeum (Italia)
2020
[EN] In recent years, the use of three-dimensional (3D) models in cultural and archaeological heritage for documentation and dissemination purposes has increased. New geomatics technologies have significantly reduced the time spent on fieldwork surveys and data processing. The archaeological remains can be documented and reconstructed in a digital 3D environment thanks to the new 3D survey technologies. Furthermore, the products generated by modern surveying technologies can be reconstructed in a virtual environment on effective archaeological bases and hypotheses coming from a detailed 3D data analysis. However, the choice of technologies that should be used to get the best results for dif…
Study of ambient light influence for three-dimensional scanners based on structured light
2007
Ambient light in a scene can introduce errors into range data from most commercial three-dimensional range scanners, particularly scanners that are based on projected patterns and structured lighting. We study the effects of ambient light on a specific commercial scanner. We further present a method for characterizing the range accuracy as a function of ambient light distortions. After a brief review of related research, we first describe the capabilities of the scanner we used and define the experimental setup for our study. Then we present the results of the range characterization relative to ambient light. In these results, we note a systematic error source that appears to be an artifact…
Recovering Surface Temperature and Emissivity from Thermal Infrared Multispectral Data
1998
Abstract In 1992 Thermal Infrared Multispectral Scanner (TIMS) data were acquired from the NASA C-130 aircraft over the Sahelian region of West Africa as part of the Hydrological and Atmospheric Pilot Experiment in the Sahel (HAPEX). TIMS measures the radiation from the surface modified by the atmosphere in six channels located between 8 mm and 12.5 μm in the thermal infrared. By using a variety of techniques it is possible to extract both the surface temperature and surface emissivity from the areas over which TIMS data were acquired. One such technique was tested with the data acquired during this experiment. Several TIMS images of both the east and west central sites on 2 and 4 September…
PET: Theoretical Background and Practical Aspects
2012
Positron emission tomography (PET) is a nuclear medicine imaging tool utilized for investigation of physiological processes in vivo. PET uses the decay characteristics of positron-emitting radionuclides which are produced in a cyclotron and then used to label compounds involved in physiological processes. Usually, the labeled compound—the tracer—is administered intravenously and distributed in the tissue. The radionuclide decays and the emitted photons are detected by the PET scanner. PET then offers the possibility to compute three-dimensional images of the biodistribution and kinetics of the regional radioactivity concentration. There are several options to analyze reconstructed PET image…
Rilievo integrato presso Borgo Schirò (PA)
2013
Il lavoro presentato consiste in un rilievo integrato (Topografico/GPS statico/NRTK/Laser) di un piccolo contesto extraurbano siciliano noto per le vicende storiche che portarono alla sua costruzione. Il caso studio è quello di Borgo Schirò, un borgo rurale costruito nel territorio di Monreale (Palermo) a seguito dell’emanazione della legge n.1 del 2 gennaio 1940 che, nel tentativo di superare le politiche del latifondo, offriva ai contadini un luogo vicino ai campi di lavoro nel quale vivere. Il borgo, servito ed attraversato dalla Strada Provinciale n. 99 (di collegamento tra Camporeale, con Corleone e San Cipirrello), in provincia di Palermo, è costituito da sei corpi di fabbrica prospic…