Effect of electric potential and current on mandibular linear measurements in cone beam CT

Abstract

Objectives: The purpose of this study was to compare mandibular linear distances measured from cone beam CT (CBCT) images produced by different radiographic parameter settings (peak kilovoltage and milliampere value). Methods: 20 cadaver hemimandibles with edentulous ridges posterior to the mental foramen were embedded in clear resin blocks and scanned by a CBCT machine (CB MercuRay TM ; Hitachi Medico Technology Corp., Chiba-ken, Japan). The radiographic parameters comprised four peak kilovoltage settings (60 kVp, 80 kVp, 100 kVp and 120 kVp) and two milliampere settings (10 mA and 15 mA). A 102.4 mm field of view was chosen. Each hemimandible was scanned 8 times with 8 different parameter combinations resulting in 160 CBCT data sets. On the cross-sectional images, six linear distances were measured. To assess the intraobserver variation, the 160 data sets were remeasured after 2 weeks. The measurement precision was calculated using Dahlberg's formula. With the same peak kilovoltage, the measurements yielded by different milliampere values were compared using the paired t-test. With the same milliampere value, the measurements yielded by different peak kilovoltage were compared using analysis of variance. A significant difference was considered when p , 0.05. Results: Measurement precision varied from 0.03 mm to 0.28 mm. No significant differences in the distances were found among the different radiographic parameter combinations. Conclusions: Based upon the specific machine in the present study, low peak kilovoltage and milliampere value might be used for linear measurements in the posterior mandible.

Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT

“…In consideration of the dose reduction, they suggested that 10 mA and 60 kV should be used. In the present study, our results were similar to those of Panmekiate et al 10 for clear MCs, but relatively higher voltages and currents were needed to see unclear MCs. Neves et al 32 acquired images with a scan time of 10.8 s at 60 kV, with seven different combinations of tube currents (2 mA, 4 mA, 6.3 mA, 8 mA, 10 mA, 12 mA and 15 mA).…”

“…[6][7][8][9] However, the information it provides is only two-dimensional and the images are distorted, often resulting in miscalculation of the location of the MC. planning, 4,10,11 and both have recently been replacing conventional panoramic radiographs. 1 CBCT requires a lower exposure dose than CT 12,13 and provides adequate image quality at a lower cost and with fewer artefacts than CT. CBCT has therefore become the ideal pre-operative assessment tool for dental implant surgery.…”

“…1,10,20 Higher tube currents decrease image noise, and higher tube voltages increase the mean energy of the X-ray beam. To a greater or lesser extent, both of these exposure parameters influence the patient dose and image quality by increasing or decreasing the amount and energy of photons.…”

Influence of CBCT parameters on the output of an automatic edge-detection-based endodontic segmentation

“…Low-dose protocols presented less significant differences (one of two comparisons and two of three for high-dose protocols). Our results differ from those of Panmekiate et al 17 On mandibular linear measurements, no significant differences in the distances were found between the different combinations of peak voltage and milliamperes. Using a human mandible cadaver, Hassan et al 14 showed CBCT scan mode (exposure time) was less relevant on root canal visibility.…”

Oblique or orthoradial CBCT slices for preoperative implant planning: which one is more accurate?

“…It may result in injury to the neurovascular bundle and cause some postoperative complaints such as neuroma, paresthesia, anesthesia and hemorrhage [4][5] . It has been stated that CBCT anatomical linear measurements are accurate and reliable [6][7][8][9][10][11][12][13] . However, the inclination of the patient's head during CBCT image acquisition can cause distortion in measurements for preoperative implant planning [14][15][16][17] .…”