Editing Radiology (section)

=== Plain, or general, radiography ===

The basic technique is optical density evaluation (i.e. histogram analysis). It is then described that a region has a different optical density, e.g. a cancer metastasis to bone can cause radiolucency. The development of this is the digital radiological subtraction. It consists in overlapping two radiographs of the same examined region and subtracting the optical densities [https://doi.org/10.1259/dmfr.20130235 Comparison of changes in dental and bone radiographic densities in the presence of different soft-tissue simulators using pixel intensity and digital subtraction analyses]. The resultant image only contains the time-dependent differences between the two examined radiographs. The advantage of this technique is the precise determination of the dynamics of density changes and the place of their occurrence. However, beforehand the geometrical adjustment and general alignment of optical density should be done [https://doi.org/10.1259/dmfr/22185098 Noise in subtraction images made from pairs of intraoral radiographs: a comparison between four methods of geometric alignment].
Another possibility of radiographic image analysis is to study second order features, e.g. digital texture analysis [https://doi.org/10.5114/AOMS.2013.33557 Basic research Textural entropy as a potential feature for quantitative assessment of jaw bone healing process] [http://www.dmp.umed.wroc.pl/en/article/2010/47/1/23/ Comparative Analysis of Three Bone Substitute Materials Based on Co-Occurrence Matrix] or fractal dimension [https://doi.org/10.2478/s11536-013-0197-y Using fractal dimension to evaluate alveolar bone defects treated with various bone substitute materials]. On this basis, it is possible to assess the places where bio-materials are implanted into the bone for the purpose of guided bone regeneration. They take an intact bone image sample (region of interest, ROI, reference site) and a sample of the implantation site (second ROI, test site) can be assessed numerically/objectively to what extent the implantation site imitates a healthy bone and how advanced is the process of bone regeneration [https://doi.org/10.3390/ma13173854 Fast-Versus Slow-Resorbable Calcium Phosphate Bone Substitute Materials—Texture Analysis after 12 Months of Observation] [https://doi.org/10.3390/ma13132935 New Oral Surgery Materials for Bone Reconstruction—A Comparison of Five Bone Substitute Materials for Dentoalveolar Augmentation]. It is also possible to check whether the bone healing process is influenced by some systemic factors [https://doi.org/10.3390/ma13163649 Influence of General Mineral Condition on Collagen-Guided Alveolar Crest Augmentation].