Reliability of voxel values from cone‐beam computed tomography for dental use in evaluating bone mineral density

Abstract

This study revealed that there was a high correlation between the voxel values of CBCT and the CT numbers of MSCT. Although this was an in vitro study with assumed ideal conditions for measuring voxel values, there was a clear possibility for estimating CT numbers and BMD using the voxel values from the CBCT images, but the relationship was not entirely linear and should be examined further.

Evaluating Maxilla Bone Quality Through Clinical Investigation of Voxel Grey Scale Values from Cone-Beam Computed Tomography for Dental Use

“…Linear relationship between HU values obtained in multislice computed tomography (MSCT) and CBCT grey levels was confirmed by Parsa et al who compared images made by both devices [15]. Nomura et al described the relationship between CT numbers and the grey values as non-linear [16] and pointed out poorer reproducibility of measurements performed by the CBCT, with the potential error of measuring reaching 15.7%.…”

Bone mineral density in cone beam computed tomography: Only a few shades of gray

“…Thus, CBCT has been proposed as a diagnostic method for the determination of bone mineral density [10,11,18,[34][35][36] . Gray values obtained with CBCT are used in an analog way as the HU values for the determination of mineral density [16] and show a linear relationship with the attenuation coefficients of the materials [13,15] , HU values obtained with medical CT [11,12,37,38] , and density values from DEXA [14] . Despite the correlation between gray values obtained with MSCT and CBCT, errors are expected when CBCT images are used to define the density of scanned structures [39] because these images present with inconsistencies and arbitrariness of gray values [16,40] , especially when related to abrupt changes of density in the object [41,42] , X-ray beam hardening effect [39,43] , scattered radiation [43] and projection data discontinuity-related effect [16] , making the validity of the measurements obtained questionable (Table 1).…”

Bone Quality Assessment for Dental Implants

“…In a study, (Katsumata et al, 2007), the authors found that calculated HU on a CBCT scan varied widely from a range of -1500 to over +3000 for different types of bone. However, after a correction has been applied to grey levels with the CBCT, the HU values are much similar to those one would expect in a medical CT device than to the original grey levels obtained from the CBCT scanners (Naitoh et al 2009;Nomura et al, 2010, Mah et al, 2010. The clinical utility of preoperative implant planning by use of in imaging stent that helps relate the radiographic image and its information to a precise anatomic location or a potential implant site.…”