title: Effect of ultra-low doses, ASIR and MBIR on density and noise levels of MDCT images of dental implant sites.
abstract: OBJECTIVE
  Differences in noise and density values in MDCT images obtained using ultra-low doses with FBP, ASIR, and MBIR may possibly affect implant site density analysis. The aim of this study was to compare density and noise measurements recorded from dental implant sites using ultra-low doses combined with FBP, ASIR, and MBIR.
  
  
  METHODS
  Cadavers were scanned using a standard protocol and four low-dose protocols. Scans were reconstructed using FBP, ASIR-50, ASIR-100, and MBIR, and either a bone or standard reconstruction kernel. Density (mean Hounsfield units [HUs]) of alveolar bone and noise levels (mean standard deviation of HUs) was recorded from all datasets and measurements were compared by paired t tests and two-way ANOVA with repeated measures.
  
  
  RESULTS
  Significant differences in density and noise were found between the reference dose/FBP protocol and almost all test combinations. Maximum mean differences in HU were 178.35 (bone kernel) and 273.74 (standard kernel), and in noise, were 243.73 (bone kernel) and 153.88 (standard kernel).
  
  
  CONCLUSIONS
  Decreasing radiation dose increased density and noise regardless of reconstruction technique and kernel. The effect of reconstruction technique on density and noise depends on the reconstruction kernel used.
  
  
  CONCLUSIONS
  • Ultra-low-dose MDCT protocols allowed more than 90 % reductions in dose. • Decreasing the dose generally increased density and noise. • Effect of IRT on density and noise varies with reconstruction kernel. • Accuracy of low-dose protocols for interpretation of bony anatomy not known. • Effect of low doses on accuracy of computer-aided design models unknown.
authors.affiliation: Department of Radiology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Gerlig
authors.initials: G
authors.lastname: Widmann
authors.affiliation: Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, P. O. Box 56810, Riyadh, 11564, Kingdom of Saudi Arabia.
authors.forename: Reema
authors.initials: R
authors.lastname: Al-Shawaf
authors.affiliation: Department of Radiology, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Schullian
authors.affiliation: Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, P. O. Box 56810, Riyadh, 11564, Kingdom of Saudi Arabia.
authors.forename: Ra'ed
authors.initials: R
authors.lastname: Al-Sadhan
authors.affiliation: Division of Clinical and Functional Anatomy, Medical University of Innsbruck, Innsbruck, Austria.
authors.forename: Romed
authors.initials: R
authors.lastname: Hörmann
authors.affiliation: Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, P. O. Box 56810, Riyadh, 11564, Kingdom of Saudi Arabia. asma.alekrish@gmail.com.
authors.forename: Asma'a A
authors.initials: AA
authors.lastname: Al-Ekrish
mesh_terms: D000465:Algorithms; D002102:Cadaver; D015921:Dental Implants; D006801:Humans; D008962:Models, Theoretical; D061330:Multidetector Computed Tomography / Q000379:methods*; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods
chemical_list: D015921:Dental Implants
keywords: Algorithms; Dental implants; Image processing, computer-assisted; Multidetector computed tomography; Radiation dosage