Fetal vertebral structure detected by three-dimensional ultrasound

The spinal cord is an important part of the central nervous system as well as the brain. The vertebral structure develops remarkably early during embryonal and fetal periods. As the cranium develops from early pregnancy with ossification and gradual closure of the fontanelles and sutures, the vertebral bony structure is also formed with ossification and gradual closure of the neural arches during the fetal period. Open spina bifida, which results from a failure of neural arch closure, has been demonstrated by ultrasound and magnetic resonance imaging in utero. Postnatal neurological deficit is greatly dependent on the lesion level of spina bifida and the condition of the exposed spinal cord. Therefore, accurate detection of the lesion level and spinal cord appearance before birth has an important role in predicting neurological prognosis. Because it is hard to demonstrate fetal bony structure including vertebral arches and ribs on a single image by two-dimensional (2D) ultrasound, precise diagnosis of spinal lesion is difficult for examiners. Several reports have been published on two-dimensional detection of the spinal lesion level. After introduction of three-dimensional (3D) ultrasound technology in the field of fetal neuroimaging diagnosis, however, more accurate, objective and comprehensive information has been added on fetal vertebra/spine development and spine lesion such as open spina bifida even in the first and early second trimesters. Multiplanar image analysis and rendering of bony structure by 3D ultrasound technology have contributed greatly to the precise demonstration of normal/abnormal vertebra and spinal cord. Exact and objective diagnosis of spina bifida during pregnancy leads to the prediction of postnatal neurological deficit and to proper management.