Quantitative analysis of spiral computed tomography for craniofacial clinical applications

To determine the relative accuracy of craniofacial measurements obtained from volumetric spiral computed tomography (CT) in two-dimensional (2D) and three-dimensional (3D) reconstructions.

Nine cadaver heads were examined with spiral CT at 3 mm collimation with 2 mm/s table feed. The CT data, stored on optical disks to allow full retrospective review of any image, were transferred to a networked computer workstation for off-line visualization, measurement and analysis. Three-dimensional surface images (3DCT) were generated from spiral CT scans (2DCT). Measurements (n = 28) were made from (both unique and conventional craniometric anatomical) landmarks (n = 23) identified in 2DCT and 3DCT images by two observers twice. The soft tissues were then removed from the cadavers and the measurements performed with an electromagnetic digitizer.

The accuracy for 3DCT was higher than 2DCT images for seven of 28 measurements. Twenty five per cent of the 2DCT measurements were found to be significantly different from the physical measurements. All measurements with 3DCT were found to have satisfactory accuracy in comparison with physical measurements.

Three-dimensional spiral CT can distinguish craniofacial anatomy more accurately with some measurements.