Relationship between Voxel Value of Cone Beam CT and Hounsfield Unit of CT: Systematic Review and Meta-Analysis
Abstract
This systematic review aims to investigate the relationship between voxel value obtained from Cone Beam Computed Tomography (CBCT) in studies compared to Hounsfield of Multidetector Computed Tomography (MDCT) in homogeneous and heterogeneous samples. A literature search was carried out in the databases PubMed, Scopus, Embase, and Web of Science searching for relevant literature until February 2022 (updated at July 2023). A risk of bias assessment of the studies was performed using a modified checklist based on the Cochrane Collaboration’s tool and the Journal of Biomedical Informatics. The software version 20.104 of MedCalc was used to conduct the meta-analysis of correlation coefficients. Out of 4750 articles in the initial search, 13 met the eligibility criteria. Out of the articles, eight studies were included in the meta-analysis. Both heterogeneous and homogenous samples showed a strong correlation between the voxel value of CBCT and Hounsfield Unit (HU), with high heterogeneity (r=0.900 and 0.998 respectively and I2>70%). Two other meta-analyses were conducted for kVp and voxel size, which showed a high correlation. The 95% confidence interval was used to present the estimated pooled correlation. The strong correlation of voxel value and HU indicates the possible potential of CBCT in radiographic bone density measurement. However, further research is needed to obtain an accurate conversion equation for translating voxel values of CBCT to HU. Calibration of voxel values within each scan using a reference object and consideration of both linear and non-linear regression could improve accuracy.
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2. Mallya S, Lam E. White and Pharoah's Oral radiology: principles and interpretation. St. Louis, United states, Elsevier, 2019: 659.
3. Shapurian T, Damoulis PD, Reiser GM, Griffin TJ, Rand WM. Quantitative evaluation of bone density using the Hounsfield index. Int J Oral Maxillofac Implants. 2006 Mar-Apr;21(2):290-7.
4. Shahlaie M, Gantes B, Schulz E, Riggs M, Crigger M. Bone density assessments of dental implant sites: 1. Quantitative computed tomography. Int J Oral Maxillofac Implants. 2003 Mar-Apr;18(2):224-31.
5. Eguren M, Holguin A, Diaz K, Vidalon J, Linan C, Pacheco-Pereira C, et al. Can gray values be converted to Hounsfield units? A systematic review. Dentomaxillofac Radiol. 2022 Jan 1;51(1):20210140.
6. Pauwels R, Jacobs R, Singer SR, Mupparapu M. CBCT-based bone quality assessment: are Hounsfield units applicable? Dentomaxillofac Radiol. 2015;44(1):20140238.
7. Parsa A, Ibrahim N, Hassan B, Motroni A, van der Stelt P, Wismeijer D. Reliability of voxel gray values in cone beam computed tomography for preoperative implant planning assessment. Int J Oral Maxillofac Implants. 2012 Nov-Dec;27(6):1438-42.
8. Valiyaparambil JV, Yamany I, Ortiz D, Shafer DM, Pendrys D, Freilich M, et al. Bone quality evaluation: comparison of cone beam computed tomography and subjective surgical assessment. Int J Oral Maxillofac Implants. 2012 Sep-Oct;27(5):1271-7.
9. Mah P, Reeves TE, McDavid WD. Deriving Hounsfield units using grey levels in cone beam computed tomography. Dentomaxillofac Radiol. 2010 Sep;39(6):323-35.
10. Aranyarachkul P, Caruso J, Gantes B, Schulz E, Riggs M, Dus I, et al. Bone density assessments of dental implant sites: 2. Quantitative cone-beam computerized tomography. Int J Oral Maxillofac Implants. 2005 May-Jun;20(3):416-24.
11. Parsa A, Ibrahim N, Hassan B, van der Stelt P, Wismeijer D. Bone quality evaluation at dental implant site using multislice CT, micro-CT, and cone beam CT. Clin Oral Implants Res. 2015;26(1):e1-7.
12. Dahiya K, Kumar N, Bajaj P, Sharma A, Sikka R, Dahiya S. Qualitative Assessment of Reliability of Cone-beam Computed Tomography in evaluating Bone Density at Posterior Mandibular Implant Site. J Contemp Dent Pract. 2018 Apr 1;19(4):426-430.
13. Scarfe WC, Angelopoulos C. Maxillofacial cone beam computed tomography: principles, techniques and clinical applications.Switzerland, Springer, 2018.
14. Silva IM, Freitas DQ, Ambrosano GM, Bóscolo FN, Almeida SM. Bone density: comparative evaluation of Hounsfield units in multislice and cone-beam computed tomography. Braz Oral Res. 2012 Nov-Dec;26(6):550-6.
15. González-García R, Monje F. The reliability of cone-beam computed tomography to assess bone density at dental implant recipient sites: a histomorphometric analysis by micro-CT. Clin Oral Implants Res. 2013 Aug;24(8):871-9.
16. Borenstein M, Hedges LV, Higgins JP, Rothstein HR. Introduction to meta-analysis. West Sussex, United Kingdom, John Wiley & Sons Ltd. Chichester, 2009: 421.
17. Pauwels R, Stamatakis H, Manousaridis G, Walker A, Michielsen K, Bosmans H, et al. Development and applicability of a quality control phantom for dental cone-beam CT. J Appl Clin Med Phys. 2011 Nov 15;12(4):3478.
18. Gaur A, Dhillon M, Puri N, Sethi Ahuja U, Rathore A. Questionable accuracy of CBCT in determining bone density: A comparative CBCT-CT in vitro study. Dent Med Probl. 2022 Jul-Sep;59(3):413-419.
19. Rostetter C, Metzler P, Schenkel JS, Seifert B, Luebbers HT. Comparison of in vivo cone-beam and multidetector computed tomographic scans by three-dimensional merging software. Br J Oral Maxillofac Surg. 2015 Dec;53(10):1021-6.
20. Razi T, Emamverdizadeh P, Nilavar N, Razi S. Comparison of the Hounsfield unit in CT scan with the gray level in cone-beam CT. J Dent Res Dent Clin Dent Prospects. 2019 Summer;13(3):177-182.
21. Pauwels R, Nackaerts O, Bellaiche N, Stamatakis H, Tsiklakis K, Walker A, et al. Variability of dental cone beam CT grey values for density estimations. Br J Radiol. 2013 Jan;86(1021):20120135.
22. Nomura Y, Watanabe H, Honda E, Kurabayashi T. Reliability of voxel values from cone-beam computed tomography for dental use in evaluating bone mineral density. Clin Oral Implants Res. 2010 May;21(5):558-62.
23. Khavid A, Sametzadeh M, Godiny M, Moarrefpour MM. Comparison of the hounsfield unit values obtained from cone-beam computed tomography (CBCT) and multidetector computed tomography (MDCT) images for different bone densities. J Contemp Med Sci. 2021 Mar;7(2):92-5.
24. Kamaruddin N, Rajion ZA, Yusof A, Aziz ME. Relationship between Hounsfield unit in CT scan and gray scale in CBCT. AIP Conf Proc. 19 December 2016; 1791 (1): 020005.
25. Haghanifar S, Yousefi S, Moudi E, Abesi F, Bijani A, Moghadamnia AA, et al. Accuracy of densitometry of two cone beam computed tomography equipment in comparison with computed tomography. Electron Physician. 2017 May 25;9(5):4384-4390.
26. Chindasombatjaroen J, Kakimoto N, Shimamoto H, Murakami S, Furukawa S. Correlation between pixel values in a cone-beam computed tomographic scanner and the computed tomographic values in a multidetector row computed tomographic scanner. J Comput Assist Tomogr. 2011 Sep-Oct;35(5):662-5.
27. Cassetta M, Stefanelli LV, Pacifici A, Pacifici L, Barbato E. How accurate is CBCT in measuring bone density? A comparative CBCT-CT in vitro study. Clin Implant Dent Relat Res. 2014 Aug;16(4):471-8.
28. Parsa A, Ibrahim N, Hassan B, Motroni A, van der Stelt P, Wismeijer D. Influence of cone beam CT scanning parameters on grey value measurements at an implant site. Dentomaxillofac Radiol. 2013;42(3):79884780.
29. El-Tabarany KS, Aboulfotouh MM, Ashmawy MS. VALIDITY OF CONE BEAM COMPUTED TOMOGRAPHY VOXEL DENSITY VALUES: A REVIEW. Int J Adv. Res. 2018 Sep; 6(9):103-121.
30. Vasconcelos TV, Leandro Nascimento EH, Bechara BB, Freitas DQ, Noujeim M. Influence of Cone Beam Computed Tomography Settings on Implant Artifact Production: Zirconia and Titanium. Int J Oral Maxillofac Implants. 2019 Sep/Oct;34(5):1114-1120.
31. Molteni R. Prospects and challenges of rendering tissue density in Hounsfield units for cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013 Jul;116(1):105-19.
32. Reeves TE, Mah P, McDavid WD. Deriving Hounsfield units using grey levels in cone beam CT: a clinical application. Dentomaxillofac Radiol. 2012 Sep;41(6):500-8.
33. Komori M, Miuchi S, Hyodo J, Kobayashi T, Hyodo M. The gray scale value of ear tissues undergoing volume-rendering high-resolution cone-beam computed tomography. Auris Nasus Larynx. 2018 Oct;45(5):971-979.
34. Selvaraj A, Jain RK, Nagi R, Balasubramaniam A. Correlation between gray values of cone-beam computed tomograms and Hounsfield units of computed tomograms: A systematic review and meta-analysis. Imaging Sci Dent. 2022 Jun;52(2):133-140.
35. Schulze R, Heil U, Gross D, Bruellmann DD, Dranischnikow E, Schwanecke U, et al. Artefacts in CBCT: a review. Dentomaxillofac Radiol. 2011 Jul;40(5):265-73.
36. Resnik R. Misch's contemporary implant dentistry. 4th ed. St. Louis, United states: Elsevier; 2020 2021. 1241 p.
37. Etöz M, Amuk M, Avcı F, Yabacı A. Investigation of the effectiveness of CBCT and gray scale values in the differential diagnosis of apical cysts and granulomas. Oral Radiol. 2021 Jan;37(1):109-117.
2. Mallya S, Lam E. White and Pharoah's Oral radiology: principles and interpretation. St. Louis, United states, Elsevier, 2019: 659.
3. Shapurian T, Damoulis PD, Reiser GM, Griffin TJ, Rand WM. Quantitative evaluation of bone density using the Hounsfield index. Int J Oral Maxillofac Implants. 2006 Mar-Apr;21(2):290-7.
4. Shahlaie M, Gantes B, Schulz E, Riggs M, Crigger M. Bone density assessments of dental implant sites: 1. Quantitative computed tomography. Int J Oral Maxillofac Implants. 2003 Mar-Apr;18(2):224-31.
5. Eguren M, Holguin A, Diaz K, Vidalon J, Linan C, Pacheco-Pereira C, et al. Can gray values be converted to Hounsfield units? A systematic review. Dentomaxillofac Radiol. 2022 Jan 1;51(1):20210140.
6. Pauwels R, Jacobs R, Singer SR, Mupparapu M. CBCT-based bone quality assessment: are Hounsfield units applicable? Dentomaxillofac Radiol. 2015;44(1):20140238.
7. Parsa A, Ibrahim N, Hassan B, Motroni A, van der Stelt P, Wismeijer D. Reliability of voxel gray values in cone beam computed tomography for preoperative implant planning assessment. Int J Oral Maxillofac Implants. 2012 Nov-Dec;27(6):1438-42.
8. Valiyaparambil JV, Yamany I, Ortiz D, Shafer DM, Pendrys D, Freilich M, et al. Bone quality evaluation: comparison of cone beam computed tomography and subjective surgical assessment. Int J Oral Maxillofac Implants. 2012 Sep-Oct;27(5):1271-7.
9. Mah P, Reeves TE, McDavid WD. Deriving Hounsfield units using grey levels in cone beam computed tomography. Dentomaxillofac Radiol. 2010 Sep;39(6):323-35.
10. Aranyarachkul P, Caruso J, Gantes B, Schulz E, Riggs M, Dus I, et al. Bone density assessments of dental implant sites: 2. Quantitative cone-beam computerized tomography. Int J Oral Maxillofac Implants. 2005 May-Jun;20(3):416-24.
11. Parsa A, Ibrahim N, Hassan B, van der Stelt P, Wismeijer D. Bone quality evaluation at dental implant site using multislice CT, micro-CT, and cone beam CT. Clin Oral Implants Res. 2015;26(1):e1-7.
12. Dahiya K, Kumar N, Bajaj P, Sharma A, Sikka R, Dahiya S. Qualitative Assessment of Reliability of Cone-beam Computed Tomography in evaluating Bone Density at Posterior Mandibular Implant Site. J Contemp Dent Pract. 2018 Apr 1;19(4):426-430.
13. Scarfe WC, Angelopoulos C. Maxillofacial cone beam computed tomography: principles, techniques and clinical applications.Switzerland, Springer, 2018.
14. Silva IM, Freitas DQ, Ambrosano GM, Bóscolo FN, Almeida SM. Bone density: comparative evaluation of Hounsfield units in multislice and cone-beam computed tomography. Braz Oral Res. 2012 Nov-Dec;26(6):550-6.
15. González-García R, Monje F. The reliability of cone-beam computed tomography to assess bone density at dental implant recipient sites: a histomorphometric analysis by micro-CT. Clin Oral Implants Res. 2013 Aug;24(8):871-9.
16. Borenstein M, Hedges LV, Higgins JP, Rothstein HR. Introduction to meta-analysis. West Sussex, United Kingdom, John Wiley & Sons Ltd. Chichester, 2009: 421.
17. Pauwels R, Stamatakis H, Manousaridis G, Walker A, Michielsen K, Bosmans H, et al. Development and applicability of a quality control phantom for dental cone-beam CT. J Appl Clin Med Phys. 2011 Nov 15;12(4):3478.
18. Gaur A, Dhillon M, Puri N, Sethi Ahuja U, Rathore A. Questionable accuracy of CBCT in determining bone density: A comparative CBCT-CT in vitro study. Dent Med Probl. 2022 Jul-Sep;59(3):413-419.
19. Rostetter C, Metzler P, Schenkel JS, Seifert B, Luebbers HT. Comparison of in vivo cone-beam and multidetector computed tomographic scans by three-dimensional merging software. Br J Oral Maxillofac Surg. 2015 Dec;53(10):1021-6.
20. Razi T, Emamverdizadeh P, Nilavar N, Razi S. Comparison of the Hounsfield unit in CT scan with the gray level in cone-beam CT. J Dent Res Dent Clin Dent Prospects. 2019 Summer;13(3):177-182.
21. Pauwels R, Nackaerts O, Bellaiche N, Stamatakis H, Tsiklakis K, Walker A, et al. Variability of dental cone beam CT grey values for density estimations. Br J Radiol. 2013 Jan;86(1021):20120135.
22. Nomura Y, Watanabe H, Honda E, Kurabayashi T. Reliability of voxel values from cone-beam computed tomography for dental use in evaluating bone mineral density. Clin Oral Implants Res. 2010 May;21(5):558-62.
23. Khavid A, Sametzadeh M, Godiny M, Moarrefpour MM. Comparison of the hounsfield unit values obtained from cone-beam computed tomography (CBCT) and multidetector computed tomography (MDCT) images for different bone densities. J Contemp Med Sci. 2021 Mar;7(2):92-5.
24. Kamaruddin N, Rajion ZA, Yusof A, Aziz ME. Relationship between Hounsfield unit in CT scan and gray scale in CBCT. AIP Conf Proc. 19 December 2016; 1791 (1): 020005.
25. Haghanifar S, Yousefi S, Moudi E, Abesi F, Bijani A, Moghadamnia AA, et al. Accuracy of densitometry of two cone beam computed tomography equipment in comparison with computed tomography. Electron Physician. 2017 May 25;9(5):4384-4390.
26. Chindasombatjaroen J, Kakimoto N, Shimamoto H, Murakami S, Furukawa S. Correlation between pixel values in a cone-beam computed tomographic scanner and the computed tomographic values in a multidetector row computed tomographic scanner. J Comput Assist Tomogr. 2011 Sep-Oct;35(5):662-5.
27. Cassetta M, Stefanelli LV, Pacifici A, Pacifici L, Barbato E. How accurate is CBCT in measuring bone density? A comparative CBCT-CT in vitro study. Clin Implant Dent Relat Res. 2014 Aug;16(4):471-8.
28. Parsa A, Ibrahim N, Hassan B, Motroni A, van der Stelt P, Wismeijer D. Influence of cone beam CT scanning parameters on grey value measurements at an implant site. Dentomaxillofac Radiol. 2013;42(3):79884780.
29. El-Tabarany KS, Aboulfotouh MM, Ashmawy MS. VALIDITY OF CONE BEAM COMPUTED TOMOGRAPHY VOXEL DENSITY VALUES: A REVIEW. Int J Adv. Res. 2018 Sep; 6(9):103-121.
30. Vasconcelos TV, Leandro Nascimento EH, Bechara BB, Freitas DQ, Noujeim M. Influence of Cone Beam Computed Tomography Settings on Implant Artifact Production: Zirconia and Titanium. Int J Oral Maxillofac Implants. 2019 Sep/Oct;34(5):1114-1120.
31. Molteni R. Prospects and challenges of rendering tissue density in Hounsfield units for cone beam computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol. 2013 Jul;116(1):105-19.
32. Reeves TE, Mah P, McDavid WD. Deriving Hounsfield units using grey levels in cone beam CT: a clinical application. Dentomaxillofac Radiol. 2012 Sep;41(6):500-8.
33. Komori M, Miuchi S, Hyodo J, Kobayashi T, Hyodo M. The gray scale value of ear tissues undergoing volume-rendering high-resolution cone-beam computed tomography. Auris Nasus Larynx. 2018 Oct;45(5):971-979.
34. Selvaraj A, Jain RK, Nagi R, Balasubramaniam A. Correlation between gray values of cone-beam computed tomograms and Hounsfield units of computed tomograms: A systematic review and meta-analysis. Imaging Sci Dent. 2022 Jun;52(2):133-140.
35. Schulze R, Heil U, Gross D, Bruellmann DD, Dranischnikow E, Schwanecke U, et al. Artefacts in CBCT: a review. Dentomaxillofac Radiol. 2011 Jul;40(5):265-73.
36. Resnik R. Misch's contemporary implant dentistry. 4th ed. St. Louis, United states: Elsevier; 2020 2021. 1241 p.
37. Etöz M, Amuk M, Avcı F, Yabacı A. Investigation of the effectiveness of CBCT and gray scale values in the differential diagnosis of apical cysts and granulomas. Oral Radiol. 2021 Jan;37(1):109-117.
| Issue | Vol 23 (Continuously Published Article-Based) | |
| Section | Review Article | |
| Keywords | ||
| Cone-Beam Computed Tomography Hounsfield Unit Voxel Value Gray Scale | ||
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How to Cite
1.
Goodarzipour D, Shamshiri AR, Khodadadi Z. Relationship between Voxel Value of Cone Beam CT and Hounsfield Unit of CT: Systematic Review and Meta-Analysis. Front Dent. 2026;23.
