Journal of Cranio-Maxillofacial Surgery (2005) 33, 19–23 r 2004 European Association for Cranio-Maxillofacial Surgery doi:10.1016/j.jcms.2004.07.004, available online at http://www.sciencedirect.com Evaluation of quality of reformatted images from two cone-beam computed tomographic systems Dirk SCHULZE 1 , Max HEILAND 2 , Felix BLAKE 2 , Uwe ROTHER 3 , Rainer SCHMELZLE 2 1 Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. R. Schmelzeisen), University Hospital Freiburg, Freiburg, Germany; 2 Department of Oral and Maxillofacial Surgery (Head: Prof. Dr. Dr. R. Schmelzle), University Hospital Hamburg-Eppendorf, Hamburg, Germany; 3 Department of Oral Radiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany SUMMARY. Purpose: The aim of the study was to compare image quality of two different systems based on cone-beam computed tomography (CBCT). Study design: Primary and secondary reconstructions were performed from data sets of the Siremobil Iso-C 3D (Siemens Medical Solutions, Erlangen, Germany) and the NewTom 9000 (NIM s.r.l., Verona, Italy) using a dried human skull. Using defined anatomical structures, image quality was analysed by 10 examiners using a ranking scale. Results: Regarding image quality there was no statistically significant difference between the two systems compared. Conclusion: The preliminary results show, that imaging of the facial skeleton using the Siremobil Iso-C 3D can be performed with a quality comparable to the NewTom 9000. r 2004 European Association for Cranio-Maxillofacial Surgery Keywords: Cone-beam computed tomography; C-arm; Midfacial imaging INTRODUCTION Three-dimensional imaging of the recipient bones plays an increasingly important role in the planning of complex implant prosthetics with endosseous fixtures in the vicinity of delicate anatomical struc- tures. Whereas in routine cases, the panoramic radiograph will usually suffice, being sufficiently accurate (Tal and Moses, 1991), for determining the width of the alveolar ridge, transverse slice images are necessary (Tammisalo et al., 1992). Andersson and Kurol (1987) inaugurated the use of computed tomography (CT) for three-dimensional visualization of the maxilla using sagittal and coronal reconstruc- tions. This imaging modality has been more and more accepted in conjunction with dental implantation due to the introduction of user friendly, specific planning software. This allows image reconstructions that are comparable with conventional radiographic projections (Casselman et al., 1991; King et al., 1992; Besimo et al., 1995). Furthermore, a special cone- beam computed tomography (CBCT, also known as true volumetric computed tomography TVCT) designed for use in dental imaging of osseous structures has been introduced (Mozzo et al., 1998). It enables diagnostic details in a CT-like quality with reduced radiation exposure. It proved suitable for planning implantation, especially in the maxilla, where attention has to be paid to the positioning of the primary reconstruction, and ensuring optimal alignment in the area of interest (Mo¨bes et al., 1999). Furthermore, in third molar surgery, CBCT is superior to conventional panoramic views regarding the depiction of the inferior alveolar nerve (Pawelzik et al., 2002). The principle of this type of cone-beam tomography has been implemented for the development and improvement of radiotherapy simulators since the mid 1970s (Harrison and Farmer, 1976, 1978; Webb et al., 1977). These systems (e.g. Simtomix tomographic scanner) should be able to generate cross-sectional images without additional CT (Kijewski et al., 1984; Leach et al., 1985). The first available and now well-established CBCT system was the NewTom 9000 (NIM s.r.l., Verona, Italy; Mozzo et al., 1998). In addition to this, another new and portable system is available now, the Siremobil Iso-C 3D (Siemens Medical Solutions, Erlangen, Germany), which is also based on the cone-beam tomography and is designed for intraoperative imaging. The Siremobil Iso-C 3D was primarily used for intraoperative imaging of the limbs. As a result, most of the publica- tions pertaining to this system refer to typical projections taken during fracture treatments (Euler et al., 2001; Kotsianos et al., 2001; Rock et al., 2001 and 2002). In previous studies, it was possible to visualize the facial skeleton three-dimensionally using the Siremobil Iso-C 3D and no statistically significant difference regarding visualization of anatomical landmarks from standard CT-scans could be ob- served (Heiland et al., 2003). The object of this study was to compare the image quality of these two systems, which are based on the same physical principle. ARTICLE IN PRESS 19