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Développements méthodologiques et techniques pour le contrôle qualité en imagerie par résonance magnétique

Abstract : Magnetic Resonance Imaging (MRI) is increasingly being used in clinical routine and is frequently associated with different imaging modalities in multisite studies. Besides, MRI is becoming more complex with a growing use of phased-array coils. Hence there is a rising eagerness for quality assurance and quality control (QC). Indeed, monitoring MR systems is required in order to prevent from diagnostic errors which may be induced by drifts in the instrumentation. The ever first studies about MRI QC issue established the basis for designing test-objects and metrics which are required for monitoring the scanners. These works also resulted in two approaches for performing the testings : the first one is multi-object oriented and the second one is single-object oriented. The research conducted for this thesis are motivated by two objectives : the first one holds about designing a methodology for performing periodic monitoring of MR scanners. The procedure is required to be practical, shortly-timed, statistically robust, and system-independent. It was designed following the single-object approach promoted by the American College of Radiology. In order to fit the procedure with its specifications, all of its aspects were assessed. The resulting 10-minute weekly QC procedure was successfully tested on several MR facilities. The second goal of these works is about specifically assessing the performance of phased-array coils. Using these coils, two parameters were considered as being essential for image quality considerations, namely the sensitivity profiles and the noise covariance matrix. For monitoring these parameters, two metrics were designed in a way that they could be integrated within the weekly QC procedure. Besides, an alternative method was proposed for computing noise covariance matrices. As a matter of prospects, these doctoral works sought clinical applications which may take advantage of the techniques and methodology elaborated for QC purposes. There are interesting insights about using QC techniques in support of targeted clinical MR applications
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Submitted on : Thursday, March 29, 2018 - 12:51:48 PM
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Kwadz Anou Sewonu. Développements méthodologiques et techniques pour le contrôle qualité en imagerie par résonance magnétique. Médecine humaine et pathologie. Université de Lorraine, 2014. Français. ⟨NNT : 2014LORR0002⟩. ⟨tel-01750664⟩



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