Three-dimensional ultrasound STIC-HDlive rendering: new technique to assessing of fetal heart

Abstract

Congenital heart diseases (CHD) are the most common fetal congenital malformations, corresponding to an inci-dence six higher than chromosome anomalies and four high -er than neural tube defects [1]. The prevalence of CHD in newborns ranges from 0.6% to 5% [2]. It’s too known that the prenatal diagnosis can modify the outcome of some types of CHD [3,4]. The two-dimensional echocardiography is the “gold standard” exam to the diagnosis of CHD; however, it is operator-depending and only is realized in high risk preg-nancies [5]. Although, the majority of CHD cases occurring in low risk pregnancies [6], being necessary appropriate screening in the second trimester ultrasound scan.Due the high incidence of CDH in low risk pregnancies, several international associations tried to incorporate the “ex -tended basic” cardiac scan in the second trimester ultrasound exam. In other words, the “extended basic” would be the in-clusion of ventricles outflows in the four chamber view [7,8]. The incorporation of medical ultrasound obstetrics educa-tion has proved to be an effective method to improve the de-tection rate of CHD [9]. Despite of these improvements in the fetal cardiac screening, the second trimester ultrasound scan continues being operator-depending and time-consuming.In the begging of 2000, a new software named spatio-tem -poral image correlation (STIC) has been available in sever-al three-dimensional ultrasound machines. STIC enables acquisition of fetal heart volume and vascular connection data. The images generated by this software can be evaluated both in multiplanar and in rendering modes. They can also be evaluated both statically and in movement (4D) through a cineloop sequence that simulates an entire cardiac cycle [10,11]. The advantages of STIC for fetal heart evaluation are the following: lower dependency on the operator’s experience, in obtaining diagnostic planes; shorter time taken to perform the examination, without the patient’s presence during the volume analysis; possibility of evaluating structures through the render mode with assessment of their morphology and function [12]; and the capacity to send volumes for analysis at other fetal cardiology reference centers via an internet link [13]. Nowadays, the STIC has been utilized in the rendering mode to assess the atrioventricular valves [14,15]and inter-ventricular septum [16]. STIC and virtual-organ comput-er-aided analysis (VOCAL) has been used to assess the fetal cardiac function by means heart stroke, cardiac output and ejection fraction [17,18]. In relation to screening of CHD, the isolated use of STIC still remains controversial. Some studies have shown advantages of two-echocardiography under STIC in the screening of CHD [19,20]; however, one study showed a great accuracy of STIC in the diagnosis of CHD in a high risk pregnancies [21]. Its necessary new multicenter studies with large samples both low and high risk obtaining definitive results [22].Recently, a new software named HD