Adaptive AR and Neurofuzzy Approaches: Access to Cerebral Particle Signatures

International audienceIn recent years, a relationship has been suggested between the occurrence of cerebral embolism and stroke. Ultrasound has therefore become essential in the detection of emboli when monitoring cerebral vascular disorders and forms part of ultrasound brain-imaging techniques. Such detection is based on investigating the middle cerebral artery using a TransCranial Doppler (TCD) system, and analyzing the Doppler signal of the embolism. Most of the emboli detected in practical experiments are large emboli because their signatures are easy to recognize in the TCD signal. However, detection of small emboli remains a challenge. Various approaches have been proposed to solve the problem, ranging from the exclusive use of expert human knowledge to automated collection of signal parameters. Many studies have recently been performed using time-frequency distributions and classical parameter modeling for automatic detection of emboli. It has been shown that autoregressive (AR) modeling associated with an abrupt change detection technique is one of the best methods for detection of microemboli. One alternative to this is a technique based on taking expert knowledge into account. This paper aims to unite these two approaches using AR modeling and expert knowledge through a neurofuzzy approach. The originality of this approach lies in combining these two techniques and then proposing a parameter referred to as score ranging from 0 to 1. Unlike classical techniques, this score is not only a measure of confidence of detection but also a tool enabling the final detection of the presence or absence of microemboli to be performed by the practitioner. Finally, this paper provides performance evaluation and comparison with an automated technique, i.e., AR modeling used in vitr

Etude de la cyclostationnarité du signal Doppler sanguin pour la détection de micro-emboles : étude préliminaire

Ce papier traite de la détection ultrasonore de micro-emboles par un système Doppler transcrânien. L'originalité de ce travail réside dans le fait que nous utilisons les propriétés cyclostationnaires du signal Doppler ultrasonore sanguin pour détecter des micro-emboles, depuis lors, masqués dans les phases de systoles-diastoles du cycle cardiaque. Dans cette étude nous évaluons théoriquement, à partir d'un modèle réaliste du signal Doppler sanguin, le spectre de corrélation. Nous proposons un paramètre informatif permettant la détection de micro-emboles et nous quantifions les performances du détecteur associé pour le comparer à un détecteur standard

Comparaison de l'angiographie par résonance magnétique en temps de vol 3D sans et avec injection de gadolinium et de l'artériographie numérisée dans la surveillance des anévrysmes intracrâniens traités par voie endovasculaire

TOURS-BU Médecine (372612103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Traitement par Ultrasons Focalisés guidés par IRM (MRgFUS) des léiomyomes utérins (résultats cliniques et radiologiques à 6 mois de la première expérience française au CHRU de Tours)

TOURS-BU Médecine (372612103) / SudocSudocFranceF

Spectral correlation of the embolic blood Doppler signal

(poster session)International audienceIn a previous study we have shown that take into account the quasi-cyclostationary properties of the blood Doppler signal is useful to detect embolus (red blood cell aggregates). In this latter approach, we have first considered a simple "off-line" synchronous detector. As results were very interesting, we have thought that the correlation spectrum could be an interesting alternative to the synchronous detection. As the correlation spectrum of in vivo signal seems to be too complicated, we propose here to elucidate this apparent complexity by analytically computing the correlation spectrum of Doppler signal model with or without embolus

Statistical and Neuro-fuzzy approaches for emboli detection

International audienceRelation between cerebral emboli occurrence and stroke has been suggested these last years. Emboli detection has then become a constant concern while monitoring cerebral vascular pathologies. This detection is based on analysis of embolic TransCranial Doppler (TCD) signal. In practical experiments, most of detected emboli are big-size emboli ones, because of their easy-to-recognize signature in the TCD signal. The problem of small size emboli detection is an opened one and remains a challenge. Different approaches have been proposed to solve this problem. They use exclusively human expert knowledge or automatic collection of signal parameters. In this paper we propose to used both expert knowledge and automatic processing through neuro-fuzzy approach. Performances evaluation and comparison with high performance micro-emboli detection technique, namely Autoregressive (AR) modelling are provided, using in vitro in this work

Etude de la cyclostationnarité du signal Doppler sanguin ultrasonore pour la détection de micro-emboles étude préliminaire

International audienceThis paper deals with the ultrasonic detection of micro-emboli by means of a transcranial doppler system. Theoriginality of this word is that we use the cyclostationnary properties of the blood ultrasonic Doppler signal to detect micro-embolus energeticaly masked in the different cardiac phases. In this study, we evaluate theoretically the correlation spectrum ofa realistic blood Doppler signal model. We propose a parameter allowing the detection of masked micro-emboli and quantify theperformances of this detector and compare it to a standard detector.Ce papier traite de la détection ultrasonore de micro-emboles par un système Doppler transcrânien. L'originalité de ce travail réside dans le fait que nous utilisons les propriétés cyclostationnaires du signal Doppler ultrasonore sanguin pour détecter des micro-emboles, depuis lors, masqués dans les phases de systoles-diastoles du cycle cardiaque. Dans cette étude nous évaluons théoriquement, à partir d'un modèle réaliste du signal Doppler sanguin, le spectre de corrélation. Nous proposons un paramètre informatif permettant la détection de micro-emboles et nous quantifions les performances du détecteur associé pour le comparer à un détecteur standard

Chest computed tomography signs associated with pejorative evolution in COVID-19 patients

Purpose: The aim of this study was to evaluate how chest computed tomography (CT) can predict pejorative evolution in COVID-19 patients. Material and methods: Data on 349 consecutive patients who underwent a chest CT either for severe suspected COVID-19 pneumonia or clinical aggravation and with COVID-19 were retrospectively analysed. In total, 109 had laboratory-confirmed COVID-19 infection by a positive reverse-transcription polymerase chain reaction (RT-PCR) and were included. The main outcomes for pejorative evolution were death and the need for invasive endotracheal ventilation (IEV). All the CT images were retrospectively reviewed, to analyse the CT signs and semiologic patterns of pulmonary involvement. Results: Among the 109 COVID-19 patients, 73 (67%) had severe symptoms of COVID-19, 28 (25.7%) needed an IEV, and 11 (10.1%) died. The following signs were significantly associated with both mortality and need for IEV: traction bronchiectasis and total affected lung volume ≥ 50% (p < 10-3). Other CT signs were only associated with the need of IEV: vascular dilatation, air bubble sign, peribronchovascular thickening, interlobular thickening, and number of involved lobes ≥ 4 (p < 10-3). Conclusions: On a chest CT performed during the first week of the symptoms, the presence of traction bronchiectasis and high values of affected lung volume are associated with the need for IEV, and with mortality, in COVID-19 patients