A New Method for Imaging of the Unborn Fetus

By Michael G. Muhonen, M.D.
Director of Neurosurgery and Neurosciences Institute, Children's Hospital of Orange County (CHOC)

Appeared in the foundation's newsletter, LIFE~LINE, Winter 2002

I am excited to be able to share with you a new technique that we are using in the evaluation of the unborn fetus.

Many institutions, after finding a medical defect or condition on an antenatal ultrasound, the physician will refer the parents-to-be to a specialist. Antenatal findings that might be found (in the neurological field) include hydrocephalus, spina bifida, Dandy Walker Malformation, or other brain anomalies and cysts. Most of my personal counseling deals with these conditions.

Ultrasonagraphy has been the mainstay of fetal imaging for decades. Although ultrasonagraphy is the primary technique for evaluating the developing fetus, significant limitations still exist. The fetal brain anatomy cannot be full visualized, as the images are hampered by the fact that the brain is deep in the maternal pelvis.

However, recent advances in technology have allowed vast improvements in fetal diagnosis and therapy.

At Children's Hospital of Orange County (CHOC), we are now utilizing magnetic resonance imaging (MRI) to evaluate the unborn fetus. Previously, MRI's of the fetus could only be performed by temporarily paralyzing the fetus with drugs, until all bodily movements ceased. This paralysis technique is no longer necessary. The new study is called a Fast MR Image. The acquisition time is so rapid that movement of the baby does not significantly distort the pictures. The advantage of this type of study is that there are no restraints, as far as "seeing" deep structures within the brain, as there are with an ultrasound. In addition, the MRI has higher sensitivity than the ultrasound to differentiate various cerebral tissues. It is the superior spatial and contrast resolution that provides specific information for patient counseling and decision making. It also helps to identify patients who might benefit from prenatal intervention, and it aids in fetal surgical planning.

We have now utilized this technique many cases. The information has been valuable to provide a measure of confidence, not only for the physicians, but also for the families. If you are in the position to counsel mothers of infants suspected of having brain anomalies in-utero, relay this information on to them. It will add more concrete facts about the development of the fetus, and will hopefully help to diminish the feat-factor that is often overwhelming for the parents of the unborn child.