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Study of the Robustness of Mean Transit Time with Respect to Gain and Dynamic Range Changes in Ultrasound Scanners

出版	Universitat Politècnica de Catalunya. Escola Tècnica Superior d'Enginyeria de Telecomunicació de Barcelona. Departament de Teoria del Senyal i Comunicacions, 2013 (Enginyeria de Telecomunicació), 2013
URL	http://books.google.com.hk/books?id=fHkeywEACAAJ&hl=&source=gbs_api

註釋[ANGLÈS] Pulmonary blood volume (PBV) has become a crucial indicator for cardiologists in order to assess the gravity of a cardiovascular disease. Indicator dilution theory has become a ?gold-standard? in order to calculate perfusion parameters to obtain PBV. The improvements of contrast enhanced ultrasound technology have allowed the clinical community to avoid invasiveness in PBV calculations. However, some settings in the ultrasound scanners can influence perfusion parameters such as mean transit time (MTT). Software for modeling the influence of gain and dynamic range settings in ultrasound images was developed, and an in-vitro experiment was carried out. We propose a solution to reduce the influence of gain and dynamic range on mean transit time. Gain normalization in log-compression functions in the ultrasound machine makes a smart adaptation of the scanners to different dynamic ranges and avoids saturation of the images and the indicator dilution curves obtained. With this new technique and with a dynamic range set above 40 dB, cardiologists could work safely knowing that their measurements in MTT will be reliable with very low errors (0.25%).