A Review of Brain Extraction Techniques in Fetal MRI

Sonography, Maternal Serum Screening, amniocentesis, and sampling are among the techniques utilized to examine a developing fetus and diagnose fetal abnormalities in the uterus. Despite the fact that Sonography is the main technique used for imaging and monitoring, the use of Magnetic Resonance Imaging (MRI) to evaluate the fetus is growing. Moreover, MRI is used for further examinations in case of abnormalities diagnosed in the ultrasound scan. MRI, in comparison with other imaging techniques, provides the advantage of fetal brain study with higher precision and quality. The first step to study the fetal brain is its extraction from the MRI of the fetal brain. Since the maternal tissue is also present in the MRI of the fetal brain tissue, and due to the differences in the adult and fetus signals of brain tissue, it is not possible to use the adult brain extraction techniques for fetus. Given that semi-automatic segmentation is a time-consuming and tedious task, the need for automatic segmentation is highlighted. This is while the development of the stages of automatic segmentation of brain structures is still a challenge to overcome. In the present paper, we review the techniques for automatic segmentation or brain extraction of fetal MRI.