Crystal Vue technique for imaging fetal spine and ribs
New ways of assessing the fetus are now possible owing to the introduction of three dimensional (3D) ultrasound over a decade ago1. 3D ultrasound has been used as an easy to perform and accurate technique to image the fetal skeleton1 6. Garjian et al. demonstrated that 3D ultrasound can provide more information than does conventional two dimensional (2D) imaging in the diagnosis of skeletal abnormalities, both in multiplanar and volume rendered methods. This is particularly true when assessing short ribs and chest hypoplasias as the entire body region can be visualized and offline volume reconstruction can be performed3. Classical 2D ultrasound examination of long bones, ribs and vertebrae frequently gives insufficiently detailed images for assessment of bone contour, thickness and mineralization. Crystal Vue is a new technique based on image contrast enhancement that can be used for processing and rendering of acquired 3D volumes. Our recent experience with Crystal Vue, specifically when imaging the bone/soft tissue interface, has led us to believe that it may offer new opportunities for prenatal imaging, particularly of the skeletal system but also of the face and brain. Here we present and compare images of the spine and ribs in a third trimester normal fetus and those in a fetus with suspected skeletal dysplasia, examined using a Samsung WS80 Elite system (Samsung Medison Co. Ltd. Seoul, South Korea) with Crystal Vue and Realistic Vue software applications. A 39 year old pregnant woman who had five previous healthy pregnancies was followed up at 20 weeks' gestation after spontaneous resolution of pleural effusion and echogenic bowel. Amniotic fluid polymerase chain reaction and array were negative as was TORCH and cystic fibrosis testing. Ultrasound examination was performed at 29 4 weeks' gestation (Figure 1) On 2D imaging, the spine and ribs appeared normal with normal fetal movements and amniotic fluid. Using Crystal Vue postprocessing on a saved 3D volume, the rib/vertebral interface was seen clearly and rib mineralization appeared normal; we were able to identify 12 ribs.
Ultrasound in obstetrics gynecology the official journal of the International Society of Ultrasound in Obstetrics and Gynecology