Appropriateness of internal digital phantoms for monitoring the stability of the UBIS 5000 quantitative ultrasound device in clinical trials

In bone status assessment, proper quality assurance/quality control is crucial since changes due to disease or therapeutic treatment are very small, in the order of 2-5%. Unlike for dual X-ray absorptiometry, quality control procedures have not been extensively developed and validated for quantitative ultrasound technology, limiting its use in longitudinal monitoring. While the challenge of developing an ideal anthropometric phantom is still open, some manufacturers use the concept of the internal digital phantom mimicking human characteristics to check the stability of their device. The objective of the study was to develop a sensitive model of quality control suitable for the correction of QUS patient data. In order to achieve this goal, we simulated a longitudinal device lifetime with both correct and malfunctioning behaviors. Then, we verified the efficiency of digital phantoms in detecting those changes and subsequently established the in vitro/in vivo relationship. This is the first time that an attempt to validate an internal digital phantom has made, and that this type of validation approach is used. The digital phantom (DP) was designed to mimic normal bone (BUAP2) and osteoporotic bone (BUAP1) properties. The DP was studied using the UBIS 5000 ultrasound device (DMS, France). Diverse malfunctions of the UBIS-5000 were simulated. Several series of measurements were performed on both BUAP1 and 2 and on 12 volunteers at each grade of malfunction. The effect of each simulated malfunction on in vivo and in vitro results was presented graphically by plotting the average BUA values against the percentage change from baseline. The change from baseline in BUA was modeled using linear regression, and the in vivo/in vitro ratio was obtained from the model. All experimentations influenced the measure of BUAP1 and 2 as well as the measure of our 12 volunteers. However, the degree of significance varied as a function of the severity of the malfunction, and the results also differed substantially in magnitude between in vivo and in vitro. Indeed, the DP was about 10 times more sensitive to variations of the transfer function than was the in vivo measurement, which is very reassuring. The sensitivity of the digital phantoms was reliable in the determination of simulated malfunctions of the UBIS-5000. The digital phantoms provided an accurate evaluation of the acoustic performance of the scanner, including the fidelity of transducers. In light of these results, the QC approach of the UBIS-5000 will be extremely simple to implement compared with other devices. Indeed, since the digital phantom was automatically measured during every patient measurement, the QC approach could be built on an individual level basis rather than on an average basi

Bone loss: Quantitative imaging techniques for assessing bone mass in rheumatoid arthritis

Osteoporosis is associated with low bone mass and microarchitectural deterioration of bone tissue with clinical manifestation of low trauma fractures. Rheumatoid arthritis (RA) is a risk factor due to generalized and articular bone loss. This minireview presents past and current bone mass measurement techniques in RA. These techniques include: plain radiographs, absorptiometry, quantitative computed tomography (QCT) and ultrasound. The most widely used technique is dual x-ray absorptiometry (DXA). RA patients have lower bone mass as compared with normals and substantial bone loss may occur early after the onset of disease. Measurement of bone mineral density (BMD) at the hand using either DXA or ultrasound maybe a useful tool in the management of RA patients

The dependence of ultrasound velocity and attenuation on the material properties of cancellous bone.

There is an increasing interest in evaluating the role of ultrasound in the identification and management of osteoporosis. We may measure the velocity of ultrasound through bone and the frequency-dependent attenuation, generally referred to as broadband ultrasound attenuation (BUA). The dependence of these parameters upon osteoporotic changes in density and architecture(total loss or thinning of trabeculae width) is still not well defined. A physical model for cancellous bone was developed by introducing an array of cylindrical voids of defined diameter and configuration into polymethylmethacrylate (Perspex). Experimental studies on the cancellous bone model demonstrated that the relationship between BUA and porosity is approximately parabolic, with low BUA values obtained at both low (cortical bone) and high (bone marrow) porosities. This explains the discrepancies in the correlation between BUA and density for different bone structures reported in the literature. BUA was also found to be dependent on the number of pores and the pore distribution(structure). Velocity was found to be dependent on pore size only. BUA and velocity were also found to be temperature dependent. Permeability provides quantitative information related to structure, validated using the perspex model.In vitro studies were carried out on bovine and human cancellous bone (calcaneus and vertebrae). The relationship between Young's modulus, strength and density followed the power law predicted by theoretical models. Measurements on bovine and vertebrae samples were carried out in three orthogonal directions. Young's modulus, strength, BUA, velocity and permeability were shown to be direction dependent and hence dependent upon structure. The relationship between BUA and density followed the parabolic trend observed in the physical model, with the human samples on the rising phase and the bovine on the falling phase of the parabola. BUA in the calcaneus was found to follow a power law relationship with density (BUA = rho[1.99]). BUA was a goodpredictor of strength in both the bovine (R[2] = 74%) and calcaneus (R[2] = 75%) samples. Velocity was a good predictor of both Young's modulus and strength whenapplied to the bar wave equation (E = V[2]rho) with an R[2] of 94% and 88% respectively for the calcaneus and 91% and 92% respectively for the bovine samples. For thecalcaneus samples an R[2] of 83% and 80% for Young's modulus and strength were obtained when density in the bar wave equation was substituted by BUA. The cortical end plates have a significant offset effect on BUA in the calcaneus. Permeability was highly correlated to strength. BUA and velocity were shown to be good predictors of cancellous bone strength in vitro. Future work should concentrate upon the investigation of controlled structural models of cancellous bone and also on the extrapolation of this study to the in vivo prediction of bone strength

Kinder Houston Area Survey: Forty-Two Years of Measuring Perceptions and Experiences of a Resilient City

The 2023 Kinder Houston Area Survey provides a glimpse into how Houstonians are thinking about the critical challenges and issues facing their communities. This year's survey reveals the cost of housing or the economy is the biggest problem facing the area, despite the fact that jobs have rebounded since the pandemic

Is Pulp Inflammation a Prerequisite for Pulp Healing and Regeneration?

The importance of inflammation has been underestimated in pulpal healing, and in the past, it has been considered only as an undesirable effect. Associated with moderate inflammation, necrosis includes pyroptosis, apoptosis, and nemosis. There are now evidences that inflammation is a prerequisite for pulp healing, with series of events ahead of regeneration. Immunocompetent cells are recruited in the apical part. They slide along the root and migrate toward the crown. Due to the high alkalinity of the capping agent, pulp cells display mild inflammation, proliferate, and increase in number and size and initiate mineralization. Pulp fibroblasts become odontoblast-like cells producing type I collagen, alkaline phosphatase, and SPARC/osteonectin. Molecules of the SIBLING family, matrix metalloproteinases, and vascular and nerve mediators are also implicated in the formation of a reparative dentinal bridge, osteo/orthodentin closing the pulp exposure. Beneath a calciotraumatic line, a thin layer identified as reactionary dentin underlines the periphery of the pulp chamber. Inflammatory and/or noninflammatory processes contribute to produce a reparative dentinal bridge closing the pulp exposure, with minute canaliculi and large tunnel defects. Depending on the form and severity of the inflammatory and noninflammatory processes, and according to the capping agent, pulp reactions are induced specifically

Estimating the Absorbed Dose to Critical Organs During Dual X-ray Absorptiometry

Objective: The purpose of this study is to estimate a patient's organ dose (effective dose) during performance of dual X-ray absorptiometry by using the correlations derived from the surface dose and the depth doses in an anthropomorphic phantom. Materials and Methods: An anthropomorphic phantom was designed and TLDs (Thermoluminescent Dosimeters) were placed at the surface and these were also inserted at different depths of the thyroid and uterus of the anthropomorphic phantom. The absorbed doses were measured on the phantom for the spine and femur scan modes. The correlation coefficients and regression functions between the absorbed surface dose and the depth dose were determined. The derived correlation was then applied for 40 women patients to estimate the depth doses to the thyroid and uterus. Results: There was a correlation between the surface dose and depth dose of the thyroid and uterus in both scan modes. For the women's dosimetry, the average surface doses of the thyroid and uterus were 1.88 μGy and 1.81 μGy, respectively. Also, the scan center dose in the women was 5.70 μGy. There was correlation between the thyroid and uterus surface doses, and the scan center dose. Conclusion: We concluded that the effective dose to the patient's critical organs during dual X-ray absorptiometry can be estimated by the correlation derived from phantom dosimetry

What 'Home' Means to Residents in the Houston Area

The idea of “home” is a multidimensional concept that encapsulates a variety of meanings, ranging from psychological orientations and physical locations to the relationships that unfold within. In the summer of 2024, members of the Greater Houston Community Panel were surveyed and asked, “What do you think of when you hear the word ‘home’?” and given an open space to write 1-2 sentences to describe what came to mind. This snapshot explores the ways in which area residents conceptualize home. In short, residents organized their thinking into four broad categories: 1) psychological orientations/attachments, 2) geographical location/built environment, 3) social relationships, and 4) activities. Additionally, while most residents have positive associations with home, some do not feel “at home” and associate the word with negative experiences, highlighting the fluid nature of home in the context of high stress

Particularites de l’epilepsie au cours des maladies inflammatoires du systeme nerveux central

Introduction : Les crises épileptiques (CE) font partie des manifestations neurologiques des maladies inflammatoires (MI). Elles constituent un tournant évolutif grave de la maladie. Objectifs : Nous avons évalué les particularités sémiologiques, électriques, radiologiques, thérapeutiques et évolutives de l’épilepsie au cours des MI du système nerveux central (SNC). Nous avons également discuté les mécanismes physiopathologiques de l’épilepsie ainsi que les facteurs prédictifs de survenue de CE chez ces patients. Méthodes : C’est une étude rétrospective incluant les patients suivis pour épilepsie dans le cadre d’une MI du SNC. Tous nos patients ont bénéficié d’une imagerie cérébrale. Résultat : Nous avons colligé 32 patients (11 avec sclérose en plaque, 6 avec maladie de Behcet et 15 avec lupus érythémateux disséminé). Le délai des CE au cours des MI était de 3,2 ans. Elles étaient généralisées dans 62,5 % des cas. L’IRM a montré des lésions sous corticales et des lésions du tronc cérébral respectivement dans 71,8 % et 25% des cas. Une thrombose veineuse cérébrale était diagnostiquée chez 3 malades. L’EEG a objectivé des ondes lentes dans 34% des cas, et des anomalies paroxystiques chez 3 patients. Le phénobarbital était le traitement le plus prescrit. Le contrôle des CE était obtenu dans la majorité des cas. Conclusion : La survenue des CE au cours des MI pose un problème de prise en charge. Un diagnostic précoce et un traitement de l’épilepsie permettent de contrôler ces crises afin d’éviter les états de mal épileptiques qui mettent en jeu le pronostic vital des patients. Mots clés: Epilepsie, Facteurs de risque, Maladies inflammatoires  Particularities of epilepsy associated with inflammatory diseases of the central nervous systemIntroduction: The frequency of the central nervous system involvement in autoimmune disorders is very variable. Seizures are among the most common neurological manifestations, and can be occasionally the presenting symptom.Methods: All files of 32 patients with autoimmune disorder diagnosed with epilepsy were evaluated retrospectively (11 with multiple sclerosis, 6 with Behcet disease, and 15 systemic lupus erythematosus). The demographic data, clinical findings including seizures, EEG and neuroimaging findings were reviewed. Results: The sex ratio was 0.45 (10H / 22F). Seizures started 3.2 years after the onset of the inflammatory diseases. They were during either the first or following neurological attacks in 68.7% of cases. 20 patients (62,5%) had only generalized tonic-clonic seizures. Brain magnetic resonance imaging (MRI) was performed to all patients. Sub-cortical and brainstem lesions were identified respectively in 71,8 % and 25%. MRI revealed cerebral sinus thrombosis in three patients. The EEG revealed focal epileptiform discharges in three patients. In 12 patients (34%) slow waves were seen. Antiepileptic drugs were prescribed in all cases (phenobarbital :53%, valproic acid: 31%, Carbamazepine: 15%). A sufficient control of seizures was obtained in most cases. Conclusion: Seizures often complicate systemic autoimmune disorders through a variety of mechanisms. A better understanding of the mechanisms of epileptogenesis in those patients could lead to targeted treatments and better outcomes. Key words: Epilepsy, inflammatory disease, risk factor

The impact of a radiologist-led workshop on MRI target volume delineation for radiotherapy

Introduction: Magnetic resonance imaging (MRI) is increasingly used for target volume delineation in radiotherapy due to its superior soft tissue visualisation compared to computed tomography (CT). The aim of this study was to assess the impact of a radiologist-led workshop on inter-observer variability in volume delineation on MRI. Methods: Data from three separate studies evaluating the impact of MRI in lung, breast and cervix were collated. At pre-workshop evaluation, observers involved in each clinical site were instructed to delineate specified volumes. Radiologists specialising in each cancer site conducted an interactive workshop on interpretation of images and anatomy for each clinical site. At post-workshop evaluation, observers repeated delineation a minimum of 2 weeks after the workshops. Inter-observer variability was evaluated using dice similarity coefficient (DSC) and volume similarity (VOLSIM) index comparing reference and observer volumes. Results: Post-workshop primary gross tumour volumes (GTV) were smaller than pre-workshop volumes for lung with a mean percentage reduction of 10.4%. Breast clinical target volumes (CTV) were similar but seroma volumes were smaller post-workshop on both supine (65% reduction) and prone MRI (73% reduction). Based on DSC scores, improvement in inter-observer variability was seen for the seroma cavity volume on prone MRI with a reduction in DSC score range from 0.4-0.8 to 0.7-0.9. Breast CTV demonstrated good inter-observer variability scores (mean DSC 0.9) for both pre- and post-workshop. Post-workshop observer delineated cervix GTV was smaller than pre-workshop by 26.9%. Conclusion: A radiologist-led workshop did not significantly reduce inter-observer variability in volume delineation for the three clinical sites. However, some improvement was noted in delineation of breast CTV, seroma volumes and cervix GTV