Resources of modern radiation diagnostics of sarcoidosis (review)

Introduction. Sarcoidosis is a significant social and medical problem. Diagnosis is based on consistency of the clinical picture, histological evidence of granulomatous inflammation, exclusion of alternative diseases, and evidence of systemic involvement. There is no “gold” diagnostic standard for sarcoidosis. Aim. Review of the latest world literature data on the possibilities of modern radiation diagnosis of sarcoidosis. Materials and methods. The review summarizes data from literature published mainly over the past five years in PubMed and eLibrary. Earlier publications were also included as necessary. Results. In the literature review, modern medical imaging methods used to diagnose sarcoidosis, which in some cases can avoid biopsy, are considered. First of all, these are X-ray methods. Today, high-resolution multispiral computed tomography with three-dimensional imaging, as the method with the highest sensitivity, plays a decisive role in the diagnosis and monitoring of sarcoidosis. The use of magnetic resonance imaging and low-dose computed tomography is not well understood in patients with sarcoidosis. Quantitative computed tomography and radiomics techniques have only been partially tested in sarcoidosis. Conclusion. The imaging of sarcoidosis is the subject of a large number of publications that provide detailed descriptions of X-ray and computed tomography techniques. Nevertheless, despite the introduction of new computerized tools for the analysis of chest imaging, traditional X-ray techniques still remain an important role in both the diagnostic and prognostic assessment of changes characteristic of sarcoidosis

Evaluation of Bone Marrow Texture and Trabecular Changes With Quantitative DCE-MRI and QCT in Alloxan-Induced Diabetic Rabbit Models

PurposeTo investigate whether the microvascular permeability of lumbar marrow and bone trabecular changes in early-stage diabetic rabbits can be quantitatively evaluated using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), quantitative computed tomography, and texture-analyzed permeability parameter Ktrans map of DCE-MRI.Materials and MethodsThis prospective study included 24 rabbits that were randomly assigned to diabetic (n = 14) and control (n = 10) groups. All rabbits underwent sagittal MRI of the lumbar region at 0, 4, 8, 12, and 16 weeks after alloxan injection. Pearson correlation coefficient was performed to determine the correlation between permeability parameter and bone mineral density (BMD). Repeated-measures ANOVA was used to analyze the changes in lumbar BMD over time in each group and the texture parameters of diabetic rabbit lumbar marrow at different time points. Mann–Whitney U rank sum test was used to compare the differences of each index between the two groups and calculate the area under the curve (AUC).ResultsBMD was correlated with Ktrans, Kep, and Ve but not with Vp. At weeks 0–16, the BMD of the rabbits in the diabetic and normal groups was not statistically significant, but the change in BMD showed an overall downward trend. For texture analysis, entropy, energy, and Uniformized positive pixel (UPP) parameters extracted from the Ktrans map showed significant differences from week 0 to 16 between the two groups. The identification ability at 8–12 weeks was higher than that at 12–16 weeks, and the AUCs were 0.734, 0.766, and 0.734, respectively (P < 0.05 for all).ConclusionsThe changes in BMD measured using quantitative computed tomography occurred later than those measured using bone trabecular morphometry. Texture analysis parameters based on DCE-MRI quantitative parameter Ktrans map are feasible to identify early changes in lumbar marrow structure in diabetic rabbits.

Quantitative Computed Tomography, modern data. Review

In the review we discussed about the method of quantitative computed tomography (QCT, quantitative computed tomography). In QCT, X-ray density (HU) is converted to bone mineral density (BMD mg / ml) using linear relationships obtained by scanning calibration standards (phantoms). When compared with the normative age data, it is possible to diagnose osteoporosis (OP). The review presents various QCT techniques and their diagnostic capabilities in accordance with the positions of ISCD 2019 - (International Society for Clinical Densitometry). The results of comparison of QCT and conventional dual-energy X-ray absorptiometry (DXA) are considered. It is noted that in the study of the proximal femur (PF), the results of the methods are well comparable, according to the results of both methods, it is possible to diagnose OP by the T-score. However, when examining the spine QCT, the volume BMD of the trabecular bone of the vertebral bodies is assessed, and with DXA, the projection BMD is assessed. The approaches to the interpretation of the results are also different - diagnosis of OP in DXA of the spine based on the T-score, but in QCT, the ACR (American College of Radiology) criteria are used.We describe the phantoms used in QCT, as well as provide data on radiation exposure during QCT and DXA.The article describes an approach to opportunistic screening of osteoporosis by the QCT based on the results of previously performed CT scans, including its automated work-flow using artificial intelligence technologies. These promising techniques are attractive due to the large number of CT examinations performed and the exclusion of additional examinations.

How relevant is lumbar bone mineral density for the stability of symphyseal implants? A biomechanical cadaver study

Purpose Osteoporotic bone tissue appears to be an important risk factor for implant loosening, compromising the stability of surgical implants. However, it is unclear whether lumbar measured bone mineral density (BMD) is of any predictive value for stability of surgical implants at the pubic symphysis. This study examines the fixation strength of cortical screws in human cadaver specimens with different BMDs. Methods The lumbar BMD of ten human specimens was measured using quantitative computed tomography (qCT). A cut-off BMD was set at 120 mg Ca-Ha/mL, dividing the specimens into two groups. One cortical screw was drilled into each superior pubic ramus. The screw was withdrawn in an axial direction with a steady speed and considered failed when a force decrease was detected. Required force (N) and pull-out distance (mm) were constantly tracked. Results The median peak force of group 1 was 231.88 N and 228.08 N in group 2. While BMD values differed significantly (p < 0.01), a comparison of peak forces between both groups showed no significant difference (p = 0.481). Conclusion Higher lumbar BMD did not result in significantly higher pull-out forces at the symphysis. The high proportion of cortical bone near the symphyseal joint allows an increased contact of pubic screws and could explain sufficient fixation. This condition is not reflected by a compromised lumbar BMD in a qCT scan. Therefore, site-specific BMD measurement could improve individual fracture management.