Effect of Ultra-low Doses and ASIR and MBIR on Density and Noise Levels of MDCT Images of Dental Implant Sites
Journal Article
Widmann, Gerlig . 2016
رابط المنشور على الويب:
المجلة \ الصحيفة:
European Radiology
رقم العدد:
5
رقم الإصدار السنوي:
27
الصفحات:
2225-2234
مستخلص المنشور:
Objectives
Differences in noise and density values in multidetector CT (MDCT) images obtained using ultra-low doses combined with filtered backprojection (FBP), Adaptive Statistical Iterative Reconstruction (ASIR), and Model Based Iterative Reconstruction (MBIR) may possibly affect implant site density analysis and computer guided surgery. Therefore the aim of this study was to compare the objective density and noise measurements recorded from dental implant sites using ultra-low doses combined with FBP, ASIR, and MBIR.
Methods
Cadavers were scanned using an MDCT standard protocol and four low dose protocols. All 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) were recorded from all datasets and the measurements compared by Paired T-test and Two-way ANOVA with Repeated Measures.
Results
A significant difference in density (P< 0.021) and noise (P< 0.033) was found between the reference dose/FBP protocol and almost all the test combinations. The 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 the reconstruction technique and kernel. The effect of reconstruction technique on density and noise depends on the reconstruction kernel used.
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