A system for the automatic measurement of the nuchal translucency thickness from ultrasound video stream of the foetus A. Anzalone 1 , G. Fusco 2 , F. Isgr` o 3 , E. Orlandi 4 , R. Prevete 3 , G. Sciortino 5 , D. Tegolo 5 , C. Valenti 5 1 IASF, National Institute of Astrophysics, Palermo, Italy 2 Dipartimento di Informatica, Bioingegneria, Robotica e Ingegneria dei Sistemi, Universit` a di Genova, Italy 3 Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Universit` a di Napoli Federico II, Italy 4 Azienda Ospedaliera Universitaria Policlinico Paolo Giaccone di Palermo,, Italy 5 Dipartimento di Matematica e Informatica, Universit` a di Palermo, Italy Abstract Nowadays the measurement of the nuchal translucency thickness is being used as part of routine ultrasound scan- ning during the end of the first trimester of pregnancy, for the screening of chromosomal defects, as trisomy 21. Cur- rently, the measurement is being performed manually by physicians. The measurement can take a long time for be- ing accomplished, needs to be performed by highly skilled operators, and is prone to errors. Semi-automated methods requires that the user manually selects a region of the image containing the nuchal translucency, procedure that is some- what time consuming. In this paper we present a complete system prototype that is able to perform the measurement of the nuchal translucency thickness without any manual in- tervention from the operator, operating on the video stream coming out from the ultrasound machine. 1. Introduction Despite the fact that no definitive non-invasive diagnosis is available at the moment, it is still possible to calculate a risk for chromosomal defects for the foetus considering both patient-specific information and foetus related data. Among the former, maternal age and the presence of pre- vious affected pregnancies are the most significative. For the latter indicative data are the thickness of nuchal translu- cency (measured during the first trimester of pregnancy) and/or the absence of the nose [10]. Nuchal translucency (henceforth NT) is the subcuta- neous fluid-filled space between the back of the neck of a foetus and the overlying skin [10]. The NT thickness is de- fined as the maximum thickness of the translucent space, that is the dark area between the two echogenic lines, the white borders delimiting the NT (see figure 1). Currently manual measurement is being performed mostly by physi- cians using electronic callipers placed on the two echogenic lines on the screen of the sonograph [2]. A semi-automated system has been presented recently in [9]. To distinguish between the skin and the amniotic fluid is a hard task, since in the prenatal phase both the structures appear as thin membranes. The complexity of the exam is also demonstrated in [12], in which the authors state that given the first measurement, new measurements on the same patient both made by the same or a new operator may differ from the reference measure by a value between 0.54 mm and 0.62mm in 95% of the cases, where the average nuchal thickness is of 2.18mm. Also in [11] the same type of variability is shown to affect the repeatability of the caliper placement. We can then conclude that the main cause in the measurement variation is due to the difficulties in placing the caliper more than the ability of the operator in acquir- ing ultrasound (US) images. Thus in this context it appears useful to rely on an automated system capable in detecting the NT in US images and measure its thickness, aiming at increasing the repeatability of this kind of exam. Figure 1. Ultrasound image of the foetus. Both ROI containing the NT and manual mea- surement of the thickness are highlighted. The research work presented in this paper aims to design and develop appropriate software tools capable to make the 978-1-4799-1053-3/13/$31.00 c 2013 IEEE CBMS 2013 239