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

Abstract

The objective of this study was to make a systematic review on the impact of voxel size in cone beam computed tomography (CBCT)-based image acquisition, retrieving evidence regarding the diagnostic outcome of those images. The MEDLINE bibliographic database was searched from 1950 to June 2012 for reports comparing diverse CBCT voxel sizes. The search strategy was limited to English-language publications using the following combined terms in the search strategy: (voxel or FOV or field of view or resolution) and (CBCT or cone beam CT). The results from the review identified 20 publications that qualitatively or quantitatively assessed the influence of voxel size on CBCT-based diagnostic outcome, and in which the methodology/results comprised at least one of the expected parameters (image acquisition, reconstruction protocols, type of diagnostic task, and presence of a gold standard). The diagnostic task assessed in the studies was diverse, including the detection of root fractures, the detection of caries lesions, and accuracy of 3D surface reconstruction and of bony measurements, among others. From the studies assessed, it is clear that no general protocol can be yet defined for CBCT examination of specific diagnostic tasks in dentistry. Rationale in this direction is an important step to define the utility of CBCT imaging.

Efficacy of CBCT for assessment of impacted mandibular third molars: a review – based on a hierarchical model of evidence

“…28,30,31 Apart from the parameters that influence the quality of two-dimensional (2D) images, such as the examined object, tube voltage, amperage and spatial resolution, the image quality of CBCT images is also influenced by the scanned tissue volume, the so-called field of view (FOV) and the resolution defined by the voxel size. 32,33 The size of a voxel is defined by its height, width and depth. The spatial resolution (number of voxels) is defined in the unit, and for each FOV, more than one resolution may be offered.…”

Comparison of the influence of FOV sizes and different voxel resolutions for the assessment of periodontal defects

“…The influence of voxel size on image resolution has been widely confirmed in the literature, especially in relation to the diagnosis of different diseases. 13 Small voxel sizes generate images with high diagnostic power that can detect several changes such as root fractures, canals and root resorption.…”

Alveolar Ridge Preservation as a Way to Reduce the Need for Bone Augmentation: Implementation of a New, Non-invasive Method of Measuring Bone Preservation: Study Protocol of a Randomized Controlled Clinical Trial and Feasibility Testing Results

“…The precision of reversible hydrocolloid impressions after extractions is considered sufficient. The margin of error, which has been given as ± 130 μm [43], is higher than the precision of the CBCT [42] .…”

“…Also, CBCT images can be influenced by artifacts mostly metal artifacts and by the imaging parameters chosen. However, the choice of voxel size has only a minor influence on the linear measurement of defined distances [42]. The precision of reversible hydrocolloid impressions after extractions is considered sufficient.…”