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

Gainer R. Jasa, Mayumi Shimizu, Kazutoshi Okamura, Kenji Tokumori, Yohei Takeshita, Warangkana Weerawanich, Kazunori Yoshiura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Objectives: The purpose of this study was to clarify the effects of exposure parameters and image-processing methods when using CBCT to detect clear and unclear mandibular canals (MCs). Methods: 24 dry half mandibles were divided into 2 groups with clear and unclearMCs based on a previous CBCT study. Mandibles were scanned using a CBCT system with varying exposure parameters (tube voltages 60 kV, 70 kV and 90 kV; and tube currents 2mA, 5mA, 10mA and 15mA) to obtain a total of 144 scans. The images were processed with different slice thicknesses using ImageJ software (National Institutes of Health, Bethesda, MD). Five radiologists evaluated the cross-sectional images of the first molar region to detect the MCs. The diagnostic accuracy of varying exposure parameters and image-processing conditions was compared with the area under the curve (Az) in receiver-operating characteristic analysis. Results: The Az values for clear MCs were higher than those for unclear MCs (p<0.0001). With increasing exposure voltages and currents, Az values increased, but no significant differences were found with high voltages and currents in clear MCs (p=1.0000 and p= 0.9340). The Az values of serial images were higher than those of overlaid images (p< 0.0001), and those for thicker slices were higher than those for thinner slices (p<0.0001). Conclusions: Our findings indicate that detection of unclear MCs requires either higher exposure parameters or processing of the images with thicker slices. To detect clear MCs, lower exposure parameters can be used.

Original languageEnglish
Article number20160315
JournalDentomaxillofacial Radiology
Volume46
Issue number4
DOIs
Publication statusPublished - 2017
Externally publishedYes

Fingerprint

Cone-Beam Computed Tomography
Mandible
National Institutes of Health (U.S.)
ROC Curve
Area Under Curve
Software
Radiologists

Keywords

  • CBCT
  • Computer-assisted image processing
  • Image quality
  • Mandible

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Dentistry(all)
  • Radiology Nuclear Medicine and imaging

Cite this

Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT. / Jasa, Gainer R.; Shimizu, Mayumi; Okamura, Kazutoshi; Tokumori, Kenji; Takeshita, Yohei; Weerawanich, Warangkana; Yoshiura, Kazunori.

In: Dentomaxillofacial Radiology, Vol. 46, No. 4, 20160315, 2017.

Research output: Contribution to journalArticle

Jasa, Gainer R. ; Shimizu, Mayumi ; Okamura, Kazutoshi ; Tokumori, Kenji ; Takeshita, Yohei ; Weerawanich, Warangkana ; Yoshiura, Kazunori. / Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT. In: Dentomaxillofacial Radiology. 2017 ; Vol. 46, No. 4.
@article{aef0320f2b1542b28c38b4170751bb16,
title = "Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT",
abstract = "Objectives: The purpose of this study was to clarify the effects of exposure parameters and image-processing methods when using CBCT to detect clear and unclear mandibular canals (MCs). Methods: 24 dry half mandibles were divided into 2 groups with clear and unclearMCs based on a previous CBCT study. Mandibles were scanned using a CBCT system with varying exposure parameters (tube voltages 60 kV, 70 kV and 90 kV; and tube currents 2mA, 5mA, 10mA and 15mA) to obtain a total of 144 scans. The images were processed with different slice thicknesses using ImageJ software (National Institutes of Health, Bethesda, MD). Five radiologists evaluated the cross-sectional images of the first molar region to detect the MCs. The diagnostic accuracy of varying exposure parameters and image-processing conditions was compared with the area under the curve (Az) in receiver-operating characteristic analysis. Results: The Az values for clear MCs were higher than those for unclear MCs (p<0.0001). With increasing exposure voltages and currents, Az values increased, but no significant differences were found with high voltages and currents in clear MCs (p=1.0000 and p= 0.9340). The Az values of serial images were higher than those of overlaid images (p< 0.0001), and those for thicker slices were higher than those for thinner slices (p<0.0001). Conclusions: Our findings indicate that detection of unclear MCs requires either higher exposure parameters or processing of the images with thicker slices. To detect clear MCs, lower exposure parameters can be used.",
keywords = "CBCT, Computer-assisted image processing, Image quality, Mandible",
author = "Jasa, {Gainer R.} and Mayumi Shimizu and Kazutoshi Okamura and Kenji Tokumori and Yohei Takeshita and Warangkana Weerawanich and Kazunori Yoshiura",
year = "2017",
doi = "10.1259/dmfr.20160315",
language = "English",
volume = "46",
journal = "Dentomaxillofacial Radiology",
issn = "0250-832X",
publisher = "British Institute of Radiology",
number = "4",

}

TY - JOUR

T1 - Effects of exposure parameters and slice thickness on detecting clear and unclear mandibular canals using cone beam CT

AU - Jasa, Gainer R.

AU - Shimizu, Mayumi

AU - Okamura, Kazutoshi

AU - Tokumori, Kenji

AU - Takeshita, Yohei

AU - Weerawanich, Warangkana

AU - Yoshiura, Kazunori

PY - 2017

Y1 - 2017

N2 - Objectives: The purpose of this study was to clarify the effects of exposure parameters and image-processing methods when using CBCT to detect clear and unclear mandibular canals (MCs). Methods: 24 dry half mandibles were divided into 2 groups with clear and unclearMCs based on a previous CBCT study. Mandibles were scanned using a CBCT system with varying exposure parameters (tube voltages 60 kV, 70 kV and 90 kV; and tube currents 2mA, 5mA, 10mA and 15mA) to obtain a total of 144 scans. The images were processed with different slice thicknesses using ImageJ software (National Institutes of Health, Bethesda, MD). Five radiologists evaluated the cross-sectional images of the first molar region to detect the MCs. The diagnostic accuracy of varying exposure parameters and image-processing conditions was compared with the area under the curve (Az) in receiver-operating characteristic analysis. Results: The Az values for clear MCs were higher than those for unclear MCs (p<0.0001). With increasing exposure voltages and currents, Az values increased, but no significant differences were found with high voltages and currents in clear MCs (p=1.0000 and p= 0.9340). The Az values of serial images were higher than those of overlaid images (p< 0.0001), and those for thicker slices were higher than those for thinner slices (p<0.0001). Conclusions: Our findings indicate that detection of unclear MCs requires either higher exposure parameters or processing of the images with thicker slices. To detect clear MCs, lower exposure parameters can be used.

AB - Objectives: The purpose of this study was to clarify the effects of exposure parameters and image-processing methods when using CBCT to detect clear and unclear mandibular canals (MCs). Methods: 24 dry half mandibles were divided into 2 groups with clear and unclearMCs based on a previous CBCT study. Mandibles were scanned using a CBCT system with varying exposure parameters (tube voltages 60 kV, 70 kV and 90 kV; and tube currents 2mA, 5mA, 10mA and 15mA) to obtain a total of 144 scans. The images were processed with different slice thicknesses using ImageJ software (National Institutes of Health, Bethesda, MD). Five radiologists evaluated the cross-sectional images of the first molar region to detect the MCs. The diagnostic accuracy of varying exposure parameters and image-processing conditions was compared with the area under the curve (Az) in receiver-operating characteristic analysis. Results: The Az values for clear MCs were higher than those for unclear MCs (p<0.0001). With increasing exposure voltages and currents, Az values increased, but no significant differences were found with high voltages and currents in clear MCs (p=1.0000 and p= 0.9340). The Az values of serial images were higher than those of overlaid images (p< 0.0001), and those for thicker slices were higher than those for thinner slices (p<0.0001). Conclusions: Our findings indicate that detection of unclear MCs requires either higher exposure parameters or processing of the images with thicker slices. To detect clear MCs, lower exposure parameters can be used.

KW - CBCT

KW - Computer-assisted image processing

KW - Image quality

KW - Mandible

UR - http://www.scopus.com/inward/record.url?scp=85019899660&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85019899660&partnerID=8YFLogxK

U2 - 10.1259/dmfr.20160315

DO - 10.1259/dmfr.20160315

M3 - Article

C2 - 28125294

AN - SCOPUS:85019899660

VL - 46

JO - Dentomaxillofacial Radiology

JF - Dentomaxillofacial Radiology

SN - 0250-832X

IS - 4

M1 - 20160315

ER -