Diagnostic accuracy of Tuned Aperture Computed Tomography (TACT)

The diagnostic accuracy of Tuned Aperture Computed Tomography (TACT) was evaluated for a variety of diagnostic tasks. Drawbacks of 2D radiography, lack of accessibility and high cost associated with advanced imaging modalities prompted these studies. Mechanically induced vertical/oblique radicular fractures (VRF) on unrestored and endodontically treated teeth were imaged using 2D radiography, unprocessed and TACT-IR images. The effect of iterative restoration on diagnostic accuracy was studied in association with detection tasks such as VRF and mandibular fractures, as also with quantification efforts associated with osseous healing studied in vivo. Iterative restoration deblurring of TACT produced consistently higher diagnostic quality than the other two image types. The effect of observer training and previous experience with viewing TACT indicated that observers with prior experience performed better. It was also noted that fractures extending beyond the middle third of the roots were more accurately detected. The effect of the number of basis images on diagnostic accuracy of TACT radiographs for mandibular fractures showed that reconstructions using 16 basis images that had been iteratively restored performed significantly better. In the in vivo study, quantitative evaluation of healing of osseous defects subjected to different types of grafts using TACT indicates that the most optimal healing occurred with osteoblast-polymer matrix combination. TACT-IR correlated most with histomorphometric data. Increases in gray values corresponding to bone formation were notable during the early period following surgery. These studies indicate that there is enough justification for TACT to find applications in many clinical situations where an ordinary dental x-ray source and a digital sensor/film are currently being used.