Comparison beetween Two-and Three-Dimensional ultrasound in visualization of corpus callosum during second trimester routin scan: our experience

Visualization of the corpus callosum by ultrasound is not always easy because of fetal head position and movements as well as echogenicity of maternal abdominal tissues. Additionally, it cannot be visualized in standard axial and coronal planes because of its ‘comma’ shape. In the mid-trimester, a basic imaging of the most common malformations of the fetal brain can be done using the three standard axial planes as defined by ISUOG (International Society of Ultrasound in Obstetrics and Gynecology) [1] . For a correct diagnosis of anomalies of the corpus callosum, an examination of a mid-sagittal plane of fetal brain is necessary, which can be difficult. The use of three-dimensional (3D) ultrasound for the reconstruction of sagittal planes has been proposed as a valid alternative method for the evaluation of midline structures [2, 3] . The advantage of 3D ultrasound is the velocity at which the volume is acquired that allows an off-line analysis and reconstruction of planes using a multiplanar technique, reducing limitations due to fetal movements. It has to be considered that the corpus callosum has a different appearance in 2D imaging (hypoechoic) compared with 3D imaging (hyperechoic) [4] . The aim of our study is to determine the effectiveness of 2D and 3D imaging in the visualization of the fetal corpus callosum, comparing the efficacy of the two techniques.