Thesis (Ph.D.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Oral and Maxillofacial Surgery

This study was designed to compare the accuracy of low dose CT versus CBCT in assessment of the various maxillofacial linear measurements. Methods: 8 skulls were included in this study and 11 linear skull measurements were selected. Direct bone measurements were obtained using digital caliber then skulls were imaged once using CBCT standard protocol and 3 times with 16 slices MDCT using three low dose protocols with reduced mAs values (40, 50, 60 mAs). Mean absolute error for each whole protocol was obtained and the degree of over and underestimation for each protocol was recorded. Results: or CBCT protocol the mean absolute error was 0.167 ± 0.6461mm while for the MDCT protocols it was 0.632 ± 0.9803, 0.320 ± 0.8393, 0.166 ± 0.803mm For the first, second and third protocol respectively. First and second protocols showed a tendency for overestimation while the third MDCT protocol and CBCT protocol showed a tendency for underestimation. But all were within the range of 1mm. Conclusions: Low dose MDCT accuracy is less than that of CBCT but the difference between the two techniques is still not significant in some protocols

Issued also as CD