Exploring CBCT-Based DICOM Files. A Systematic Review on the Properties of Images Used to Evaluate Maxillofacial Bone Grafts

Abstract

Previous studies suggests that cone beam computerized tomography (CBCT) images could provide reliable information regarding the fate of bone grafts in the maxillofacial region, but no systematic information regarding the standardization of CBCT settings and properties is available, i.e., there is a lack of information on how the images were generated, exported, and analyzed when bone grafts were evaluated. The aim of this study was to (1) do a systematic review on which type of CBCT-based DICOM images have been used for the evaluation of the fate of bone grafts in humans and (2) use a software suggested in the literature to test DICOM-based data sets, exemplifying the effect of variation in selected parameters (windowing/contrast control, plane definition, slice thickness, and number of measured slices) on the final image characteristics. The results from review identified three publications that used CBCT to evaluate maxillofacial bone grafts in humans, and in which the methodology/results comprised at least one of the expected outcomes (image acquisition protocol, image reconstruction, and image generation information). The experimental shows how the influence of information that was missing in the retrieved papers, can influence the reproducibility and the validity of image measurements. Although the use of CBCT-based images for the evaluation of bone grafts in humans has become more common, this does not reflect on a better standardization of the developed studies. Parameters regarding image acquisition and reconstruction, while important, are not addressed in the proper way in the literature, compromising the reproducibility and scientific impact of the studies.

Impact of Voxel Size Variation on CBCT-Based Diagnostic Outcome in Dentistry: a Systematic Review

“…Many of these parameters can be varied according to the diagnostic task, but still no protocols have been established for specific diagnostic tasks in dentistry. In this way, the selection of parameters related to image generation and manipulation in CBCT imaging, including the selection of voxel resolution, seems to have been performed almost arbitrarily ("best guess" or availability in the equipment) [37,38]. In opposition to that, protocols standardizing the selection of these parameters would have a direct impact on the radiation dose that the patient receives during examination (since they interfere with the scanning time), and a better definition would be essential in respecting the "ALARA" [39].…”

Vertical bone measurements from cone beam computed tomography images using different software packages

“…The implication is that there are many possibilities for treating and analyzing images that can influence the final image, i.e., the secondary reconstruction process, the gray scale value, the windowing/contrast control, plane definition, slice thickness and number of slices measured. 1,20 Nevertheless, a major problem is that the selection of parameters related to image generation and manipulation in CBCT imaging, as well as the selection of software packages, seems to be performed almost arbitrarily. 21 In the present study, we obtained the images from the i-CAT Next Generation, using a 0.2 mm voxel size.…”

Validation of a windowing protocol for accurate in vivo tooth segmentation using i-CAT cone beam computed tomography

“…2). 17 Moreover, during manual segmentation, we encountered various parameters that may directly affect the qualitative and quantitative aspects of manual segmentation. These parameters may explain why the measurements were different between the 2 observers, and why the measurements were different when using different windowing protocols.…”

“…We wanted to compare the 2 protocols found in the literature with 2 proposed by our research team: 1. automatic adjustment of the windowing by the 3D Slicer software AUTO protocol, and 2. a mixed approach based on the protocols found in the literature: 1131/4095. 17,18 The null hypothesis was that all 4 windowing protocols were equivalent for in vivo tooth volume measurement from CBCT.…”

“…Spin-Neto et al suggested a 1131/1858 protocol for the best tooth visualization. 17 Lee et al used a 2224/4095 protocol to generate 3D virtual surface models of the maxillary and mandibular dental arches that include whole with the roots. 18 However, the protocols by Spin-Neto et al and Lee et al have not been validated.…”