Optimization of exposure parameters and relationship between subjective and technical image quality in cone-beam computed tomography
10.5624/isd.2019.49.2.139
- Author:
Ha Na PARK
1
;
Chang Ki MIN
;
Kyoung A KIM
;
Kwang Joon KOH
Author Information
1. Department of Oral and Maxillofacial Radiology, School of Dentistry, Chonbuk National University, Jeonju, Korea. kkj1512@jbnu.ac.kr
- Publication Type:Original Article
- Keywords:
Optimization;
Image Quality;
Cone-Beam Computed Tomography
- MeSH:
Artifacts;
Cone-Beam Computed Tomography;
Diagnosis;
Noise;
ROC Curve;
Skull
- From:Imaging Science in Dentistry
2019;49(2):139-151
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: This study was performed to investigate the effect of exposure parameters on image quality obtained using a cone-beam computed tomography (CBCT) scanner and the relationship between physical factors and clinical image quality depending on the diagnostic task. MATERIALS AND METHODS: CBCT images of a SedentexCT IQ phantom and a real skull phantom were obtained under different combinations of tube voltage and tube current (Alphard 3030 CBCT scanner, 78–90 kVp and 2–8 mA). The images obtained using a SedentexCT IQ phantom were analyzed technically, and the physical factors of image noise, contrast resolution, spatial resolution, and metal artifacts were measured. The images obtained using a real skull phantom were evaluated for each diagnostic task by 6 oral and maxillofacial radiologists, and each setting was classified as acceptable or unacceptable based on those evaluations. A statistical analysis of the relationships of exposure parameters and physical factors with observer scores was conducted. RESULTS: For periapical diagnosis and implant planning, the tube current of the acceptable images was significantly higher than that of the unacceptable images. Image noise, the contrast-to-noise ratio (CNR), the line pair chart on the Z axis, and modulation transfer function (MTF) values showed statistically significant differences between the acceptable and unacceptable image groups. The cut-off values obtained using receiver operating characteristic curves for CNR and MTF 10 were useful for determining acceptability. CONCLUSION: Tube current had a major influence on clinical image quality. CNR and MTF 10 were useful physical factors that showed significantly associations with clinical image quality.
