Prenatal visualization of cranial sutures and fontanelles with three-dimensional ultrasonography

The anatomy of the cranial sutures and fontanelles in the developing fetus is difficult to evaluate using conventional two-dimensional ultrasonography (2DUS). Three-dimensional sonographic imaging (3DUS) was performed on eight normal volunteer pregnant patients after informed consent with conventional 2DUS equipment that had been adapted to obtain 3DUS images. 3DUS images of the cranium were evaluated for the presence of specific cranial sutures and fontanelles. Cranial sutures and fontanelles were identified with 3DUS in all fetuses scanned. The sutures most commonly identified included coronal, lambdoidal, and squamosal. The fontanelles most often identified included anterior, posterior, mastoid, and sphenoid. 3DUS offers the capability of identifying cranial sutures and fontanelles more clearly because volume rendered images show the cranial surface in its entirely rather than as a cross-sectional slice, offering the potential to identify pathologic cranial lesions currently not seen with 2DUS.