Tomographic Assessment of Craniofacial Structures: Cleft Lip/Palate

Abstract

The purpose of the investigation was to develop software and hardware modifications for computed tomography to provide high—resolu-tion thin sections for the assessment of craniofacial anomalies in the pediatric population. Modifications were undertaken on an EMI 5005 head scanner. Section thickness of two millimeters and resolution of greater than ten lines per centimeter were achieved. Since this study was concerned with reduction of slice thickness and increase in resolution , radiation dose was not of immediate concern, but would be addressed subsequent to achievement of desired initial results. Initial results on investigation of a full-term human fetus with bilateral cleft lip, cleft of the posterior palate, and micrognathia are presented. The interrelationships of the affected structures are shown clearly. Soft tissues are Visualized which cannot be seen by conventional tomography. New developments in radiographic imag— ing make it possible to Visualize structures previously hidden from View by methods other than dissection. These developments in— clude reduction of slice thickness and increase in resolution in computed tomography. This is of particular significance in the assessment of craniofacial anomalies in the pediatric and fetal populations (Lipinski, McCreath, and Matheson, 1980). Within these populations we are concerned with small structures, and with tissue contrasts that are relatively low due to small airways and incomplete ossifi-cation of bony segments.