In-situ estimation of defect volume from parameters of acoustic emission signals

By using two methods of nondestructive testing, i.e., acoustic emission (AE) measurements and X-ray computed microtomography (CT), an experimental study of defect accumulation during a uniaxial compression of a natural heterogeneous material was carried out. A joint analysis of the AE and CT data revealed a correspondence between energy characteristics of the acoustic emission accompanying defect formation and volume of defects. It is shown that the dependence of the total energy of AE signals on the defect volume is linear, which is consistent with the phenomenological dependences for earthquake focuses obtained earlier. The linear dependence was used to estimate the average defect size. It is shown that, regardless of the assumed defect shape, its average linear size does not exceed 100 μm.

Predictions of the axial tensile property of the unidirectional composite influenced by microfiber breakage defects

This paper primarily investigated the effect of fiber breakage defects on tensile properties of the unidirectional composite (UD) using the numerical simulation method. Different kinds of fiber breakage defects were firstly proved to exist in the UD according to the sub-micro computed tomography images at the microscale level. A strict random uniform distribution hypothesis was then proposed to introduce fiber breakage defects into the composite. Numerous microstructural models within random fiber breakage defects were created with the Monte Carlo method to analyze the fiber breakage defect effect on the UD. The results show that the tensile modulus of the UD was reduced by 17% when the fiber breakage defect volume fraction was only 1%, which indicates the effect of this kind of defect was very significant. The fiber volume fraction, defect volume fraction and property all have influences on the decrease of the UD caused by the fiber breakage defect. Finally, we derived a mathematical model to calculate the tensile modulus of the UD based on the numerical results. The proposed mathematical model has an application on the prediction of the axial modulus of the UD or the fiber tow containing large numbers of fiber breakage defects in the composites with complicated structure.

Acute Pulmonary Embolism Severity Assessment Evaluated with Dual Energy CT Perfusion Compared to Conventional CT Angiographic Measurements

The purpose of the study was to investigate whether Dual Energy CT (DECT) can be used as a diagnostic tool to assess the severity of acute pulmonary embolism (PE) by correlating parenchymal perfusion defect volume, obstruction score and right ventricular-to-left ventricular (RV/LV) diameter ratio using CT angiography (CTA) and DECT perfusion imaging. A total of 43 patients who underwent CTA and DECT perfusion imaging with clinical suspicion of acute PE were retrospectively included in the study. In total, 25 of these patients had acute PE findings on CTA. DECT assessed perfusion defect volume (PDvol) were automatically and semiautomatically quantified. Overall, two CTA methods for risk assessment in patients with acute PE were assessed: the RV/LV diameter ratio and the Modified Miller obstruction score. Automatic PDvol had a weak correlation (r = 0.47, p = 0.02) and semiautomatic PDvol (r = 0.68, p < 0.001) had a moderate correlation to obstruction score in patients with confirmed acute PE, while only semiautomatic PDvol (r = 0.43, p = 0.03) had a weak correlation with the RV/LV diameter ratio. Our data indicate that PDvol assessed by DECT software technique may be a helpful tool to assess the severity of acute PE when compared to obstruction score and RV/LV diameter ratio.

Use and Evaluation of a Computer-Assisted Examination Method for the Diagnosis and Analysis of Medication-Related Osteonecrosis of the Jaw

The aim of the present study was to analyze the size of the preoperatively calculated defect volume of MRONJ patients (medication-related osteonecrosis of the jaw) and to develop a computer-aided tool based on techniques of AI (artificial intelligence) that facilitates diagnostics of MRONJ. For this purpose, on the basis of 3D (three-dimensional) data sets of 175 MRONJ patients, the outline of the necrosis was marked with the software iPlan 3.0.5 (BrainLAB AG) thus determining the respective volume. The correlation of this volume with other 31 collected parameters was analyzed retrospectively. There was a significant correlation between the defect volume on the one hand, and the MRONJ stage, the number of performed operations, and the therapy invasiveness on the other hand. Furthermore, it could be shown that in one third of the cases no defects could be recognized in the 2D imaging by panoramic radiograph, while in the 3D data sets defects already had been demarcated. On the basis of these data, a computer-aided tool based on the principles of AI was developed and validated, which might allow the automated calculation of the 3D defect extension and classification of the MRONJ cases into a ranking system. In conclusion, preparation of a 3D image can be recommended for reliably making the diagnosis “MRONJ.” Moreover, knowledge of the exact defect volume serves as a decision-making aid with regard to the choice of therapy, ensures intraoperative certitude, and allows an assessment of the prognosis.

Clinical and Radiographic Evaluation of Combined Treatment with Bisphosphonate Plus Platelet-Rich Fibrin versus Platelet-Rich Fibrin Alone for Severe Periodontitis with Furcation Defects

Background: This research assessed the clinical and radiographic evaluation of treatment with PRF plus bisphosphonate, compared to alone PRF in treatment of severe periodontitis with furcation defects. Methodology : This randomized, controlled radiological and clinical study enrolled 50 patients. All patients were given oral health instructions, oral prophylaxis, root planning, and relief of trauma from occlusion. The sites for therapy with PRF and PRF plus bisphosphonate were chosen randomly by the coin toss method. After they had received 6 weeks of presurgical therapy, patients underwent further clinical assessments by using different indices and assessment of level of attachment Radiographic outcomes were bone defect height, defect width, and defect depth; these were used to determine the bone defect volume. Results: This study revealed with positive results in all clinical assessments in the PRF plus bisphosphonate, as compared to PRF alone group with significant p value of less than 0.05. All radiographic parameters showed greater degrees of reduction in the parameters of platelet-rich fibrin plus bisphosphonate group, compared to the platelet-rich fibrin alone group; however, only the defect width of bone and defect volume were statistically significantly reduced in the platelet-rich fibrin plus bisphosphonate group, in comparison to the platelet-rich fibrin. Conclusion: Platelet-rich fibrin plus bisphosphonate therapy was beneficial in regeneration of periodontal ligament and improvement of periodontal status.

Comparative Effect of Calcium Phosphate Biocomposite Materials on the Healing of Experimental Defect of Compact Bone Tissue

Introduction For the treatment of bone defects, a considerably large number of biocomposite calcium-phosphate materials has been developed and used. However, in the scientific literature, there is no information about the comparative effect of biocomposite materials based on β-tricalcium phosphate, hydroxyapatite, and collagen on the dynamics of healing of the defect of compact bone tissue. Materials and Methods The experiment was performed on 48 white Wistar rats. In the middle third of the femoral shaft, a perforated defect 2.5 mm in diameter was reproduced in the bone marrow canal, which was filled with the calcium phosphate material Collapan (Intermedapatit, Moscow, Russia) (hydroxyapatite/collagen/antibiotics) in the animals of the first group, and with Guidor easy-graft Crystal (Sunstar S.A., Etoy, Switzerland) (hydroxyapatite/β-tricalcium phosphate) in the animals of the second group. Fragments of the injured bones were examined on the 15th and 30th days by light microscopy with morphometry and scanning electron microscopy. Results It was found that, in the area of implantation of Collapan and of Guidor easy-graft Crystal, signs of inflammation were not detected, and osteogenic cells exhibited high topism to biocomposite materials. The biomaterials during the entire period of the experiment are subjected to resorption and replacement by the bone tissue of the regenerate. On the 15th and 30th days of the experiment, the predominance in the rate of biomaterial resorption (of 35.04% and 53.47%, respectively) and the formation of regenerate bone tissue (of 58.67% and 50.47%, respectively) was in the area of implantation of Collapan. Conclusion The biocomposite materials tested exhibit a high biocompatibility, osteoconductive properties, and good integration with the tissues of the regenerate. However, the biocomposite material Collapan undergoes resorption and replacement by the bone tissue of the regenerate much faster, and Guidor easy-graft Crystal provides stability of the defect volume of compact bone tissue due to full resorption and good integration with the tissues of the regenerate.

Evidence of Negative Effects of Defect Size and Older Patient Age by Quantitative CT-Based 3D Image Analysis in Ultraporous Beta-Tricalcium Phosphate Grafted Extremity Bone Defects at One Year

Introduction. Synthetic bone graft materials are commonly used to fill defects after curettage of benign bone lesions. Ultraporous beta tricalcium phosphate (TCP) is a popular synthetic compound used in this situation. Prior clinical studies based on plain X-ray analysis suggest incorporation of TCP is incomplete, even when combined with bone marrow (BMA). Purpose. The purpose was to analyze volumetric CT-based changes in defects grafted with TCP with/without BMA in a completed prospective RCT to objectively determine (1) relationship between size and age versus TCP incorporation and (2) whether there is an advantage to addition of BMA. Methods. Twenty-one patients with CT scans at ≥1 year follow-up available for digital analysis (TCP=10, TCP w/BMA =11) form the study population. CT image stacks were evaluated by creating volumetric masks using MIMICS imaging software for total defect, graft remaining, and graft incorporated volumes graft incorporation endpoints. Results. Overall, there was significant (p=0.0029) negative correlation (r2 = 0.38) between defect size and ratio of incorporated bone to defect size. This relationship remained strong (r2 = 0.56) particularly for defects > 20 cc but not for smaller defects. Bone width was also a significantly related factor (r2 = 0.94), with less graft incorporation in larger bone sites, in part likely due to the linear relationship between defect size and bone width. Relationship with age was complex and closely tied to defect volume. For larger defect volumes, younger patients were more successful at graft incorporation. Although age itself was not an independently significant factor, as defect volume increased, advanced age more negatively impacted new bone formation. Conclusions. Larger size defect and affected bone and advancing age appear to be important negative factors in synthetic graft incorporation. Results showed no advantage to addition of BMA to TCP.