Search results for "ULTRASOUND"

Is trans-cranial MR-guided Focused UltraSound a repeatable treatment option? Report of a successfully re-treated patient

2018

Background: In recent years, transcranial Magnetic Resonance-guided Focused UltraSounds (tcMRgFUS) treatments for functional neurological disorders are giving a new thrust to the field of therapeutic brain lesioning. This technique has been proven safe and effective in selected patients. Here we present the case of a patient affected by tremor combined with parkinsonism who underwent a second tcMRgFUS thalamotomy because of relapsing tremor after a few months from the first tcMRgFUS treatment. Materials and Methods: A 72-year-old, right-handed man, who came to our observation because of a disabling tremor affecting mainly his upper right limb and refusing any invasive surgical procedure. Hi…

LESIONI FOCALI RENALI (LFR): RUOLO DELLA CEUS NELLA CARATTERIZZAZIONE DI LESIONI BENIGNE E MALIGNE

2018

SCROTO ACUTO: DIAGNOSI DIFFERENZIALE DI UN'EMERGENZA MEDICO-CHIRURGICA NELL'IMAGING ECOGRAFICO

2018

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Automatic differentiation of melanoma from dysplastic nevi.

2015

International audience; Malignant melanoma causes the majority of deaths related to skin cancer. Nevertheless, it is the most treatable one, depending on its early diagnosis. The early prognosis is a challenging task for both clinicians and dermatologist, due to the characteristic similarities of melanoma with other skin lesions such as dysplastic nevi. In the past decades, several computerized lesion analysis algorithms have been proposed by the research community for detection of melanoma. These algorithms mostly focus on differentiating melanoma from benign lesions and few have considered the case of melanoma against dysplastic nevi. In this paper, we consider the most challenging task a…

Application of High Energy Shock Waves to Single Cells

1989

Extracorporeal shock wave lithotripsy has been in clinical use since 1980 with several hundred thousand patients treated to date. Striking complications, like perirenal hematomas, are rare with a range of approximately 0.5%–1.5%. High dose applications in pigs and dogs have shown devastating effects on renal parenchyma with intrarenal hemorrhage and later fibrosis (Muschter et al. 1987). However, very little is known about shock wave effects on single cells like cellular blood components. Chaussy and coworkers (Chaussy 1982; Eisenberger et al. 1977) could show an increase of free hemoglobin after exposing canine erythrocytes to shock waves. Russo and associates (1986) found a profound influ…

Occiput-spine relationship: shoulders are more important than head.

2017

BACKGROUND:To understand the role of fetal spine position in determining a fetal head position at the time of birth and modality of delivery. PATIENTS AND METHODS: This was a multicenter prospective observational study. Fetal occiput and spine position were evaluated by intrapartum ultrasound. Eighty-six women were eligible for inclusion in the study. Occiput rotational movements and modality of delivery in relation to the fetal spine position were investigated. RESULTS: At the beginning of labor, fetal occiput was in a posterior position in 52.3% of cases and, in 81.5% of cases the spine was in an anterior transverse position. At birth, occiput and spine were both in an anterior position i…

A probabilistic compressive sensing framework with applications to ultrasound signal processing

2019

Abstract The field of Compressive Sensing (CS) has provided algorithms to reconstruct signals from a much lower number of measurements than specified by the Nyquist-Shannon theorem. There are two fundamental concepts underpinning the field of CS. The first is the use of random transformations to project high-dimensional measurements onto a much lower-dimensional domain. The second is the use of sparse regression to reconstruct the original signal. This assumes that a sparse representation exists for this signal in some known domain, manifested by a dictionary. The original formulation for CS specifies the use of an l 1 penalised regression method, the Lasso. Whilst this has worked well in l…

Timing performance of the silicon PET insert probe

2010

Simulation indicates that PET image could be improved by upgrading a conventional ring with a probe placed close to the imaged object. In this paper, timing issues related to a PET probe using high-resistivity silicon as a detector material are addressed. The final probe will consist of several (four to eight) 1-mm thick layers of silicon detectors, segmented into 1 x 1 mm(2) pads, each pad equivalent to an independent p + nn+ diode. A proper matching of events in silicon with events of the external ring can be achieved with a good timing resolution. To estimate the timing performance, measurements were performed on a simplified model probe, consisting of a single 1-mm thick detector with 2…

Correction factors for ionization chamber measurements with the ‘Valencia’ and ‘large field Valencia’ brachytherapy applicators

2018

Treatment of small skin lesions using HDR brachytherapy applicators is a widely used technique. The shielded applicators currently available in clinical practice are based on a tungsten-alloy cup that collimates the source-emitted radiation into a small region, hence protecting nearby tissues. The goal of this manuscript is to evaluate the correction factors required for dose measurements with a plane-parallel ionization chamber typically used in clinical brachytherapy for the 'Valencia' and 'large field Valencia' shielded applicators. Monte Carlo simulations have been performed using the PENELOPE-2014 system to determine the absorbed dose deposited in a water phantom and in the chamber act…

Assessment of image quality of intracoronary ultrasound systems with tissue-equivalent vessel phantoms

2002

Imaging of vascular structures by intracoronary ultrasound (ICUS) is finding more and more applications in coronary diagnosis and in the assessment of interventional access. The authors describe a method for easy and quick production of tissue-equivalent vessel phantoms from a special hydrocolloid. The mechanical tolerance is less than 3/100 mm. With these phantoms the authors tested the calibration and measured the resolution properties of the SONOS intravascular ultrasonic system (Hewlett Packard). The measurements revealed a slight space related underestimation of diameters up to 280 /spl mu/m. Using cross correlation and auto correlation functions the authors analyzed digitized ultrason…