Comparisons of image quality factors for phase aberration correction with diffuse and point targets: theory and experiments

1991 ◽  
Vol 38 (2) ◽  
pp. 125-132 ◽  
Author(s):  
D. Zhao ◽  
G.E. Trahey
Keyword(s):  
Image Quality ◽  
Aberration Correction ◽  
Quality Factors ◽  
Phase Aberration ◽  
Theory And Experiments

scholarly journals Correlation of objective image quality and working length measurements in different CBCT machines: An ex vivo study

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
T. G. Wolf ◽  
F. Fischer ◽  
R. K. W. Schulze
Keyword(s):  
Image Quality ◽  
Ex Vivo ◽  
Quality Factors ◽  
Study Objective ◽  
Intra Class Correlation ◽  
Working Length ◽  
Length Determination ◽  
Image Quality Measures ◽  
Operator Reproducibility ◽  
Ex Vivo Study

Abstract To investigate potential correlations between objective CBCT image parameters and accuracy in endodontic working length determination ex vivo. Contrast-to-noise ratio (CNR) and spatial resolution (SR) as fundamental objective image parameters were examined using specific phantoms in seven different CBCT machines. Seven experienced observers were instructed and calibrated. The order of the CBCTs was randomized for each observer and observation. To assess intra-operator reproducibility, the procedure was repeated within six weeks with a randomized order of CBCT images. Multivariate analysis (MANOVA) did not reveal any influence of the combined image quality factors CNR and SR on measurement accuracy. Inter-operator reproducibility as assessed between the two observations was poor, with a mean intra-class correlation (ICC) of 0.48 (95%-CI  0.38, 0.59) for observation No. 1. and 0.40 (95%-CI 0.30, 0.51) for observation No. 2. Intra-operator reproducibility pooled over all observers between both observations was only moderate, with a mean ICC of 0.58 (95%-CI 0.52 to 0.64). Within the limitations of the study, objective image quality measures and exposure parameters seem not to have a significant influence on accuracy in determining endodontic root canal lengths in CBCT scans. The main factor of variance is the observer.

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