Comparative assessment of subjective image quality of cross-sectional cone-beam computed tomography scans

Abstract

Since the introduction of cone-beam computed tomography (CBCT), several novel systems with different technical specifications and settings have become commercially available. Therefore, it is essential to evaluate CBCT systems for differences in the subjective quality of images obtained for various dental procedures. We evaluated the subjective image quality of cross-sectional scans obtained from various CBCT systems. Images of three cadaver mandibles were obtained from four different CBCT units: 1) Veraviewepocs 3D 40 × 40 mm field of view (FOV) (voxel size: 0.125 × 0.125 × 0.125 mm), 2) Iluma, low-resolution (voxel size: 0.3 × 0.3 × 0.3 mm), 3) Kodak, 50 × 3.7 cm FOV (voxel size: 0.076 × 0.076 × 0.076 mm), and 4) Vatech 12 × 8.5cm FOV (voxel size: 0.160 × 0.160 × 0.160 mm). We assessed subjective image quality and the visibility of 10 specific features, namely, caries, amalgam restoration, final implant drill, root canal filling, metal crown, mandibular canal, mental foramen, tooth (periodontal ligament space and lamina dura), trabecular pattern, and soft tissue. Images were viewed and scored by five calibrated observers, and image quality was ranked from best to worst. The Veraviewepocs 3D had the highest quality images for most of the assessed features, whereas the Iluma low-resolution scans were rated as the lowest quality images.

Bone quality evaluation at dental implant site using multislice CT, micro‐CT, and cone beam CT

“…Voxel size in CBCT influences image quality among other factors including the unit itself, tube voltage, and FOV selection (Kamburoglu et al. ). Generally, the smaller the voxels, the higher the spatial resolution and therefore the sharper the images appear to be.…”

“…Finally, the difference in voxel size of CBCT (0.080 mm), micro-CT (0.035 mm), and MSCT (0.67 mm) can also contribute to the observed discrepancy in calculating BV/TV and bone density. Voxel size in CBCT influences image quality among other factors including the unit itself, tube voltage, and FOV selection (Kamburoglu et al 2011). Generally, the smaller the voxels, the higher the spatial resolution and therefore the sharper the images appear to be.…”

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

“…One study tested various voxel sizes used to acquire the images (0.30 and 0.25 mm) but reconstructed the images using the same final resolution (0.25 mm), neglecting a direct comparison of voxel size [14]. The other studies were excluded because no gold standard was employed [15,16] or because the evaluation was merely subjective of image quality [7].…”

“…Under clinical conditions, the subjective image quality of CBCT-based images and the ability of CBCT to display various features are influenced by a number of variables, including the unit itself, the FOV, the tube voltage and current, the voxel size, and other technical factors [7,36]. 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 clinical practice, the image quality of CBCT scans and the ability of CBCT to display anatomic features and pathology is influenced by a number of variables such as the scanning unit, the field of view (FOV), examined object, examination time, tube voltage and amperage, and also spatial resolution defined by the voxel size [7]. The size of a voxel is defined by its height, width, and depth, and CBCT voxels are generally isotropic (the three parameters are equal) [8].…”