Texture analysis in cone-beam computed tomographic images of medication-related osteonecrosis of the jaw

Purpose@#The aim of this study was to evaluate changes in the trabecular bone through texture analysis and compare the texture analysis characteristics of different areas in patients with medication-related osteonecrosis of the jaw (MRONJ). @*Materials and Methods@#Cone-beam computed tomographic images of 16 patients diagnosed with MRONJ were used. In sagittal images, 3 regions were chosen: active osteonecrosis (AO); intermediate tissue (IT), which presented a zone of apparently healthy tissue adjacent to the AO area; and healthy bone tissue (HT) (control area). Texture analysis was performed evaluating 7 parameters: secondary angular momentum, contrast, correlation, sum of squares, inverse moment of difference, sum of entropies, and entropy. Data were analyzed using the Kruskal-Wallis test with a significance level of 5%. @*Results@#Comparing the areas of AO, IT, and HT, significant differences (P<0.05) were observed. The IT and AO area images showed higher values for parameters such as contrast, entropy, and secondary angular momentum than the HT area, indicating greater disorder in these tissues. @*Conclusion@#Through texture analysis, changes in the bone pattern could be observed in areas of osteonecrosis. The texture analysis demonstrated that areas visually identified and classified as IT still had necrotic tissue, thereby increasing the accuracy of delimiting the real extension of MRONJ. (Imaging Sci Dent 2023; 53: 109-15)

Characteristics of radiographic images acquired with CdTe, CCD and CMOS detectors in skull radiography

Purpose@#The purpose of this study was to evaluate the image quality, diagnostic efficacy, and radiation dose associated with the use of a cadmium telluride (CdTe) detector, compared to charge-coupled device (CCD) and complementary metal oxide semiconductor (CMOS) detectors. @*Materials and Methods@#Lateral cephalographs of a phantom (type 1) composed of synthetic polymer filled with water and another phantom (type 2) composed of human skull macerated with polymer coating were obtained with CdTe, CCD, and CMOS detectors. Dosimeters placed on the type 2 phantom were used to measure radiation. Noise levels from each image were also measured. McNamara cephalometric analysis was conducted, the dentoskeletal configurations were assessed, and a subjective evaluation of image quality was conducted. Parametric data were compared via 1-way analysis of variance with the Tukey post-hoc test, with a significance level of 5%. Subjective image quality and dentoskeletal configuration were described qualitatively. @*Results@#A statistically significant difference was found among the images obtained with the 3 detectors (P0.05) was observed, and perfect agreement was seen with regard to the classifications obtained from the images acquired using the 3 detectors. The radiation dose associated with the CMOS detector was higher than the doses associated with the CCD (P<0.05) and CdTe detectors (P<0.05). @*Conclusion@#Considering the evaluated parameters, the CdTe detector is recommended for use in clinical practice.

The influence of different scan resolutions on the detection of proximal caries lesions

PURPOSE: This study was conducted to evaluate the effect of different spatial resolutions of a photostimulable phosphor plate (PSP) radiography system on the detection of proximal caries lesions. MATERIALS AND METHODS: Forty-five extracted human permanent teeth were radiographed using a PSP system (VistaScan Perio Plus) and scanned at the 4 resolutions (10 lp/mm, 20 lp/mm, 25 lp/mm, and 40 lp/mm) available in the system. Three independent examiners scored the images for the presence and absence of proximal caries lesions using a 5-point scale. The presence or absence of caries was confirmed by histological sections of the examined teeth (defined as the gold standard). Intra- and inter-observer reproducibility was calculated by the weighted kappa test. One-way analysis of variance with the post hoc Tukey test was used to compare the area under the receiver operating characteristic curve for the classifications made with each resolution. RESULTS: For the detection of enamel lesions, the spatial resolution of 10 lp/mm was significantly superior to the other resolutions. However, the spatial resolution did not affect the detection of caries lesions in dentin (P>0.05). CONCLUSION: Spatial resolution may influence the accuracy of the detection of incipient caries lesions in radiographs with PSP plates. Images with low spatial resolution seem to be more appropriate for this purpose.

Metal artifact production and reduction in CBCT with different numbers of basis images

PURPOSE: To evaluate the effect of different numbers of basis images and the use of metal artifact reduction (MAR) on the production and reduction of artifacts in cone-beam computed tomography images. MATERIALS AND METHODS: An acrylic resin phantom with a metal alloy sample was scanned, with 450 or 720 basis images and with or without MAR. Standard deviation values for the test areas (around the metal object) were obtained as a way of measuring artifact production. Two-way analysis of variance was used with a 5% significance level. RESULTS: There was no significant difference in artifact production among the images obtained with different numbers of basis images without MAR (P=.985). MAR significantly reduced artifact production in the test areas only in the protocol using 720 basis images (P=.017). The protocol using 450 basis images with MAR showed no significant difference in artifact production when compared to the protocol using 720 basis images with MAR (P=.579). CONCLUSION: Protocols with a smaller number of basis images and with MAR activated are preferable for minimizing artifact production in tomographic images without exposing the patient to a greater radiation dose.