Cutting-edge 3D image obtained through fusion of three imaging technologies.

Abstract

Three-dimensional (3D) imaging provides a lifelike view of the fetus which can enhance maternal–fetal bonding1-3. Advancement in the accuracy and image quality of 3D ultrasound (3D-US) and magnetic resonance imaging (MRI) have improved dramatically visualization within the pregnant uterus4, 5, facilitating diagnostic and therapeutic developments in fetal medicine. We describe here the creation of a maternal–fetal virtual model from the fusion of three imaging technologies: 3D-US, MRI and structured light 3D scanning. A 34-year-old primigravid woman with a normal pregnancy, was scanned transabdominally at 30 weeks' gestation using a 3D high-resolution probe with harmonic imaging (4–8-MHz transducer, Voluson E10, GE Healthcare, Zipf, Austria). On the same day, MRI examination was performed using a 1.5-Tesla scanner (Magnetom Aera, Siemens, Erlangen, Germany) with the surface coil placed on the mother's abdomen. 3D T2-weighted true fast imaging sequence with steady-state precession (true FISP) was applied in the sagittal plane (repetition time = 3.02 ms; echo time = 1.43 ms; isotropic voxel = 1.0 × 1.0 × 1.0 mm3; matrix = 256 × 256 mm; 136 slices), with a total acquisition time of 26 s. Maternal sedation was not necessary. The woman provided signed informed consent to participate in the study and for the images to be published. The pregnancy was delivered uneventfully at 40 weeks, and the neonate weighed 3420 g with 1-min and 5-min Apgar scores of 9 and 10, respectively. 3D surface scanning, which is a non-invasive method, was used to obtain the model of the mother's body. We used an Eva Lite 3D scanner (Artec 3D, Luxembourg) which consists of two cameras and a light emitter that projects a pattern on the surface. The two cameras identify these patterns and the software, by means of triangulation, identifies the distance generating the 3D surface. To construct the mother's whole body, scanning was performed in parts which were then joined using Artec Studio version 11 software (Artec 3D). The model was aligned and finalized in MeshLab v2016 software (University of Pisa, Pisa, Italy). The software mathematically compares the point clouds that form the models in search of similarities in the indicated regions, thus aligning the mother's skin in the abdominal region constructed by MRI with the same region obtained by the 3D scanner in order to acquire the actual position of the fetus within the mother's body. After the 3D-US and MRI scans, the images were exported in DICOM format and imported to 3D Slicer v4.11.10 software (Birmingham, UK). The images were segmented and the regions of interest selected (Figure 1a). The resulting 3D models were exported to the MeshLab program to correct construction imperfections. To complete the process, the models were sent to the 3ds MAX v2019 program (Mill Valley, CA, USA) which produces the final images with a better definition of colors and brightness (Figure 1b). The total time to prepare the virtual model was 4 hours. We have shown that it is possible to create accurate and high-quality 3D images of a mother with her fetus through combination and fusion of three imaging technologies using 3D software. Such images may help to promote maternal–fetal bonding, facilitate parental counseling and be used in medical education5.