Abstract
In this paper we propose a new methodology to support the physician both to identify automatically the nuchal region and to obtain a correct thickness measurement of the nuchal translucency. The thickness of the nuchal translucency is one of the main markers for screening of chromosomal defects such as trisomy 13, 18 and 21. Its measurement is performed during ultrasound scanning in the first trimester of pregnancy. The proposed methodology is mainly based on wavelet and multi resolution analysis. The performance of our method was analysed on 382 random frames, representing mid-sagittal sections, uniformly extracted from real clinical ultrasound videos of 12 patients. According to the ground-truth provided by an expert physician, we obtained a true positive rate equal to 99.95% with respect to the nuchal region detection and about 64% of measurements present an error equal to 1 pixel (which corresponds to 0.1 mm), respectively.
1. Introduction
Down's Syndrome (namely DS), identified in 1886 by Dr. Langdon Down, is a genetic condition that causes a variable degree of delay in mental, physical and motor development. It is caused by the presence of an extra chromosome in the nucleus of every cell (47 in comparison with a normal number of 46) in the twenty-first pair; for this reason DS is often indicated as trisomy 21. Its causes are still unknown and therefore there is no real way of prevention. Early in the 70's, the maternal age was the first element to deduce the probability for the fetus to present a chromosomal defect.
5. Conclusions
The proposed contribution introduces an automatic methodology to support physicians in the evaluation of some important chromosomal defects. It must be stressed that, according to the international acquisition protocol described in [6], only mid-sagittal sections must be considered. Indeed, our methodology relies on the selection of those frames from video sequences, due to our algorithm already described in [20]. Here we focus our attention on detecting and measuring the nuchal translucency, thus presenting a complete environment to highlight eventual diseases like trisomy 13, 18 and 21 during ultrasound scanning in the first trimester of pregnancy. We experimentally verified the correctness of our methodology on 382 random frames from 12 real examinations and compared the obtained results against the groundtruth provided by an expert physician.
