Bony Regions Research Articles

The Prevalence and Associated Risk Factors of Pressure Injury among Adults at King Saud Medical City, Riyadh

Background: Pressure injuries rank among the top five most frequent causes of patient injury worldwide. Usually, these ulcers develop in the body's bony regions where there is a higher chance of pressure and tissue deformation. Pressure injuries are still a common and severely incapacitating ailment, even with advances in medical understanding and the development of efficient therapies and preventative measures. They result in large socioeconomic consequences since they place a heavy load on the healthcare system and the affected individuals. Objectives: To assess the occurrence rate, identify correlated risk factors, and analyze additional indicators related to pressure injuries diagnosed within the care units of King Saud Medical City throughout the study period. Methodology: A descriptive cross-sectional study was undertaken at King Saud Medical City in Riyadh during the months of August and September 2023. The study focused on patients with newly identified pre-existing pressure injury lesions. Demographic information and associated risk factors were recorded in the study's data extraction sheet after obtaining participants' consent to engage in the research. The study commenced following approval from the institutional review board of king Saud medical city research and Innovation center, Riyadh. The gathered data were analyzed using the Statistical Package for the Social Sciences (SPSS), version 26. Descriptive statistics, bivariate and multivariate logistic regression were computed to assess the statistical association, using odds ratio. Significance of statistical association was assured and tested using 95% confidence interval and P-Value of < 0.05 is considered statistically significant. Results: A total of 250 patients with pressure ulcers were identified during the study period. Most of the study participants were male, and the mean age of the participants was 59.2 years. The prevalence of pressure injuries in the hospital units included in the study was 18.8%. The sacral region was the most affected site, with 121 patients (48%) having pressure injuries in that area, while 83 patients (33%) had pressure injuries in the gluteal area. The most frequently associated comorbidities were hypertension, present in 140 patients (56%), and diabetes mellitus, present in 123 patients (49.2%). Conclusion: The prevalence of pressure ulcers was high among admitted patients at King Saud Medical City, Riyadh. Primary prevention health promotion programs should be implemented to prevent the occurrence of pressure injuries in our healthcare facilities and the community at large.

Validating a Novel 2D to 3D Knee Reconstruction Method on Preoperative Total Knee Arthroplasty Patient Anatomies.

As advanced technology continues to evolve, incorporating robotics into surgical procedures has become imperative for precision and accuracy in preoperative planning. Nevertheless, the integration of three-dimensional (3D) imaging into these processes presents both financial considerations and potential patient safety concerns. This study aims to assess the accuracy of a novel 2D-to-3D knee reconstruction solution, RSIP XPlan.ai™ (RSIP Vision, Jerusalem, Israel), on preoperative total knee arthroplasty (TKA) patient anatomies. Accuracy was calculated by measuring the Root Mean Square Error (RMSE) between X-ray-based 3D bone models generated by the algorithm and corresponding CT bone segmentations (distances of each mesh vertex to the closest vertex in the second mesh). The RMSE was computed globally for each bone, locally for eight clinically relevant bony landmark regions, and along simulated bone cut contours. In addition, the accuracies of three anatomical axes were assessed by comparing angular deviations to inter- and intra-observer baseline values. The global RMSE was 0.93 ± 0.25 mm for the femur and 0.88 ± 0.14 mm for the tibia. Local RMSE values for bony landmark regions were 0.51 ± 0.33 mm for the five femoral landmarks and 0.47 ± 0.17 mm for the three tibial landmarks. The RMSE along simulated cut contours was 0.75 ± 0.35 mm for the distal femur cut and 0.63 ± 0.27 mm for the proximal tibial cut. Anatomical axial average angular deviations were 1.89° for the trans epicondylar axis (with an inter- and intra-observer baseline of 1.43°), 1.78° for the posterior condylar axis (with a baseline of 1.71°), and 2.82° (with a baseline of 2.56°) for the medial-lateral transverse axis. The study findings demonstrate promising results regarding the accuracy of XPlan.ai™ in reconstructing 3D bone models from plain-film X-rays. The observed accuracy on real-world TKA patient anatomies in anatomically relevant regions, including bony landmarks, cut contours, and axes, suggests the potential utility of this method in various clinical scenarios. Further validation studies on larger cohorts are warranted to fully assess the reliability and generalizability of our results. Nonetheless, our findings lay the groundwork for potential advancements in future robotic arthroplasty technologies, with XPlan.ai™ offering a promising alternative to conventional CT scans in certain clinical contexts.

Assessment of CBCT gray value in different regions-of-interest and fields-of-view compared to Hounsfield unit.

Different factors can affect the discrepancy between the gray value (GV) measurements obtained from CBCT and the Hounsfield unit (HU) derived from multidetector CT (MDCT), which is considered the gold-standard density scale. This study aimed to explore the impact of region of interest (ROI) location and field of view (FOV) size on the difference between these two scales as a potential source of error. Three phantoms, each consisting of a water-filled plastic bin containing a dry dentate human skull, were prepared. CBCT scans were conducted using the NewTom VGi evo system, while MDCT scans were performed using Philips system. Three different FOV sizes (8 × 8 cm, 8 × 12 cm, and 12 × 15 cm) were used, and the GVs obtained from eight distinct ROIs were compared with the HUs from the MDCT scans. The ROIs included dental and bony regions within the anterior and posterior areas of both jaws. Statistical analyses were performed using SPSS v. 26. The GVs derived from CBCT images were significantly influenced by both ROI location and FOV size (p < 0.05 for both factors). Following the comparison between GVs and HUs, the anterior mandibular bone ROI represented the minimum error, while the posterior mandibular teeth exhibited the maximum error. Moreover, the 8 × 8 cm and 12 × 15 cm FOVs resulted in the lowest and highest degrees of GV error, respectively. The ROI location and the FOV size can significantly affect the GVs obtained from CBCT images. It is not recommended to use the GV scale within the posterior mandibular teeth region due to the potential for error. Additionally, selecting smaller FOV sizes, such as 8 × 8 cm, can provide GVs closer to the gold-standard numbers.

Characterizing the biomechanical transmission effects of elastic compression stockings on lower limb tissues by using 3D finite element modelling

Studies have primarily simulated the interface pressure and skin surface stress produced by compression textiles or garments with a single pressure level. However, only a few studies have reported the biomechanical transmission behaviors of compression fabrics from the skin to deeper soft tissues of the human body, especially within the context of compression fabrics providing multiple pressure levels. Therefore, to address this limitation, this study developed novel 3D finite element (FE) models to characterize and visualize the interface pressure exerted at the skin surface by elastic compression stockings (ECSs), a type of typical compression textiles, with either low- or high-pressure levels, and to analyze the resulting stress and stress transmission effects within lower limb tissues. The results of the validated FE models indicated that the simulated interface pressure favorably agreed with the measured pressure data. A close relationship existed between the pressure magnitudes and the lower limb surface curvatures, with the highest interface pressure occurring at the anterior and posterior bony regions of the ankle with greater surface curvatures than those of the posterior calf. The internal tissue stress distributions largely varied, which may be one of the potential causes for the inconsistency observed between the claimed pressure doses and those practically delivered inside. Overall, this study serves to improve the understanding of the working mechanisms of the ECS-lower limb system, allowing for improved functional material design and evaluation of the pressure effectiveness of compression textiles and garments used in physiotherapy.

Computed tomographic findings in dogs with multiple myeloma.

Computed tomography (CT) is considered the first-line imaging modality for human patients with suspected multiple myeloma (MM). Recently the diagnostic criteria for human MM have been updated. To describe and provide a baseline of the CT features and distribution of osseous lesions in dogs diagnosed with MM and to describe the change of initial osseous lesions after the start of treatment in a subset of dogs. Single-centre, retrospective, descriptive, case series. Dogs were included when they met the updated MM criteria and if a staging CT was performed at the time of diagnosis and prior to initiation of treatment. When available, change of osseous lesions was assessed on serial imaging studies. Thirteen dogs met the inclusion criteria. All dogs had involvement of the axial skeleton and 9/13 (69%) had concurrent involvement of the appendicular skeleton. Large (≥1cm), lytic, 'punched out' or expansile bony lesions and regions of permeative lysis were most common and mainly affected the vertebral column. Discrete intramedullary soft tissue attenuating lesions of the proximal appendicular skeleton were observed in 8/13 dogs (61%) and bilateral involvement of both humeri and femurs was seen in 4/9 dogs (44%). A subset of dogs underwent serial imaging and progressive replacement of the contrast-enhancing lesions with fat attenuating tissue was observed for all dogs, corresponding with clinical improvement. This case series provides a baseline knowledge of the initial and follow-up CT features in dogs diagnosed with MM based on updated criteria.

Case Series – Osteochondromas at Rare Locations

Osteochondromas are very common. They are typically seen in long bones and rarely seen in smaller bones. Some of the rare presentations include flat bones, the body of pelvis, scapula, skull, and small bones of the hand and foot. Their presentation also varies according to the site of presentation. We have included five cases of osteochondromas occurring at rare locations with variable presentations and their management. We have included one case of metacarpal, one case of skull exostosis, two cases of scapula exostosis, and one case of fibula exostosis. Osteochondromas can rarely occur at unusual locations. It is important to thoroughly evaluate all patients presenting with swelling and pain over bony regions to accurately diagnose osteochondromas and manage accordingly.

Degradation behavior and osseointegration of Mg-Zn-Ca screws in different bone regions of growing sheep: a pilot study.

Magnesium (Mg)-based implants are highly attractive for the orthopedic field and may replace titanium (Ti) as support for fracture healing. To determine the implant-bone interaction in different bony regions, we implanted Mg-based alloy ZX00 (Mg < 0.5 Zn < 0.5 Ca, in wt%) and Ti-screws into the distal epiphysis and distal metaphysis of sheep tibiae. The implant degradation and osseointegration were assessed in vivo and ex vivo after 4, 6 and 12 weeks, using a combination of clinical computed tomography, medium-resolution micro computed tomography (µCT) and high-resolution synchrotron radiation µCT (SRµCT). Implant volume loss, gas formation and bone growth were evaluated for both implantation sites and each bone region independently. Additionally, histological analysis of bone growth was performed on embedded hard-tissue samples. We demonstrate that in all cases, the degradation rate of ZX00-implants ranges between 0.23 and 0.75 mm/year. The highest degradation rates were found in the epiphysis. Bone-to-implant contact varied between the time points and bone types for both materials. Mostly, bone-volume-to-total-volume was higher around Ti-implants. However, we found an increased cortical thickness around the ZX00-screws when compared with the Ti-screws. Our results showed the suitability of ZX00-screws for implantation into the distal meta- and epiphysis.

Automatic detection of primary and metastatic lesions on cervicothoracic region and whole-body bone using a uniform machine-learnable approach for [18F]-FDG-PET/CT image analysis

We propose a method to detect primary and metastatic lesions with Fluorine−18 fluorodeoxyglucose (FDG) accumulation in the lung field, neck, mediastinum, and bony regions on the FDG-PET/CT images. To search for systemic lesions, various anatomical structures must be considered. The proposed method is addressed by using an extraction process for anatomical regions and a uniform lesion detection approach. The uniform approach does not utilize processes that reflect any region-specific anatomical aspects but has a machine-learnable framework. Therefore, it can work as a lesion detection process for a specific anatomical region if it machine-learns the specific region data. In this study, three lesion detection processes for the whole-body bone region, lung field, or neck-mediastinum region are obtained. These detection processes include lesion candidate detection and false positive (FP) candidate elimination. The lesion candidate detection is based on a voxel anomaly detection with a one-class support vector machine. The FP candidate elimination is performed using an AdaBoost classifier ensemble. The image features used by the ensemble are selected sequentially during training and are optimal for candidate classification. Three-fold cross-validation was used to detect performance with the 54 diseased FDG-PET/CT images. The mean sensitivity for detecting primary and metastatic lesions at 3 FPs per case was 0.89 with a 0.10 standard deviation (SD) in the bone region, 0.80 with a 0.10 SD in the lung field, and 0.87 with a 0.10 SD in the neck region. The average areas under the ROC curve were 0.887 with a 0.125 SD for detecting bone metastases, 0.900 with a 0.063 SD for detecting pulmonary lesions, and 0.927 with a 0.035 SD for detecting the neck-mediastinum lesions. These detection performances indicate that the proposed method could be applied clinically. These results also show that the uniform approach has high versatility for providing various lesion detection processes.

Domain-aware contrastive learning for ultrasound hip image analysis

Early diagnosis of Developmental Dysplasia of Hip (DDH) using ultrasound can result in simpler and more effective treatment options. Handheld ultrasound probes are ideally suited for such screening due to their low cost and portability. However, images from the pocket-sized probes are of lower quality than conventional probes. Image quality can be enhanced by image translation techniques that generate a pseudo-image mimicking the image quality of conventional probes. This can also help in generalizing the performance of AI-based automatic interpretation techniques to multiple probes. We develop a new domain-aware contrastive unpaired translation (D-CUT) technique for translating between images acquired from different ultrasound probes. Our approach embeds a Bone Probability Map (BPM) as part of the loss function which enforces higher structural similarity around bony regions in the image. Using the D-CUT model we translated 575 images acquired from a Philips Lumify handheld probe to generate pseudo-3D ultrasound (3DUS) images similar (Fréchet Inception Distance = 92) to those acquired from a conventional ultrasound probe (Philips iU22). The pseudo-3DUS images showed high structural similarity (SSIM = 0.68, Cosine Similarity = 0.65) with the original images and improved the contrast around the bony regions. This study establishes the feasibility of using D-CUT to improve the quality of data acquired from handheld ultrasound probes. Among other potential applications, clinical use of this tool could result in wider use of ultrasound for DDH screening programs.

The Morphometric analysis of accessory sutural bones with an emphasis on association with parietal emissary foramina

Background: The sutural bones and fontanelle of the skull display unique morphological characters. Sutural bones are also called supernumerary bones or ossicles or Wormian bones (WB). These are irregular and develop from the independent ossification centers present along the cranial sutures. They appear on periosteal and endosteal surfaces of the skull with variations in size, number, shape, and location. In the present study, we aimed to determine the morphological characteristics of sutural bones and emphasize the significance of the same. One interesting entity of skull near the posterior fontanelle is the presence of Inca bones. Methods: The present study was done on 128 dry human skulls by a convenient sampling method. The skulls were collected from the Department of Anatomy and significant characteristic features of Inca and Wormian bones like shape, number, size and location were recorded. Results: Of the 128 dry skulls examined Wormian bones were seen in 13.2 % of skulls and Inca bones in 5.4 % of skulls. Incorporation of Wormian bones in lambdoid suture was noted in 12.5 % in sagittal suture in 0.7 % skulls respectively. The Wormian bones were found frequently on the left side (n=12) as compared to the right side (n=5). The morphometry of the accessory bones showed quadrilateral as the most common shape (n=9, 37.5 %) followed by triangular (n=4, 16.6 %). Radiological examination of all 24 skulls with accessory bones showed a zigzag pattern of accessory suture lines. Conclusions: The presence of Wormian and Inca bones can be easily confused with fractures of the related bony regions. The surgeons need to be aware of this fact in order to make a proper and accurate diagnosis. The knowledge regarding these bones is highly beneficial to the clinician, radiologist, and neurosurgeon.

Primary site and survival in ewing sarcoma: A National Cancer Database (NCDB) analysis.

e23510 Background: Ewing sarcoma is the one of the most common primary malignancies of bone, with an incidence of about 1 case per million in the United States. Ewing sarcoma typically affects the pelvis, axial skeleton, and femur. However, this cancer can affect other bony regions and, to the author’s knowledge, all possible primary sites have not been investigated in-depth in regards to tumor location and the effect it may have on outcomes. The aim of this study is to conduct such an investigation to see whether or not the primary site of the tumor in osteosarcoma patients may have an effect on survival. Methods: Using the NCDB, patients diagnosed with Ewing sarcoma between 2004-2018 were identified using ICD-O-3 histology code 9260. The cohort was analyzed to investigate survival outcomes in different primary sites. Univariate analysis was then performed assessing patient length of survival for each primary site subtype. Data was analyzed using SPSS and statistical significance was set at α = 0.05. Results: A total of 4284 patients with known primary site that had survival data were included. The sites with the best survival were the skull, face, and mandible and upper limb. Patients with primary tumor of the skull, face, and mandible survived significantly longer than all groups other than the upper limb (all p &lt; .01). Upper limb patients survived significantly longer than all groups other than the skull, face, and mandible and lower limb (all p &lt; .05). The labeled primary site with the lowest survival was the pelvis, sacrum, and coccyx and significantly lower than the lower limb, vertebral column, and ribs, sternum, and clavicle (all p &lt; .01). Survival of patients with primary site of the upper limb versus lower limb, and vertebral column versus ribs, sternum, and clavicle did not differ (each p &gt; .05). Conclusions: This study found numerous survival differences between patients diagnosed with Ewing sarcoma of different primary sites. Labeled primary sites of the skull, face, and mandible and upper limb were associated with best survival while the pelvis, sacrum, and coccyx were associated with worst survival. Future studies may benefit from investigations into variables that may impact the survival differences we have presented including staging, treatments, time from diagnosis to treatment, and insurance status.[Table: see text]

Measuring the dose in bone for spine stereotactic body radiotherapy.

Current quality assurance of radiotherapy involving bony regions generally utilises homogeneous phantoms and dose calculations, ignoring the challenges of heterogeneities with dosimetry problems likely occurring around bone. Anthropomorphic phantoms with synthetic bony materials enable realistic end-to-end testing in clinical scenarios. This work reports on measurements and calculated corrections required to directly report dose in bony materials in the context of comprehensive end-to-end dosimetry audit measurements (63 plans, 6 planning systems). Radiochromic film and microDiamond measurements were performed in an anthropomorphic spine phantom containing bone equivalent materials. Medium dependent correction factors, kmed, were established using 6MV and 10MV Linear Accelerator Monte Carlo simulations to account for the detectors being calibrated in water, but measuring in regions of bony material. Both cortical and trabecular bony material were investigated for verification of dose calculations in dose-to-medium (Dm,m) and dose-to-water (Dw,w) scenarios. For Dm,m calculations, modelled correction factors for cortical and trabecular bone in film measurements, and for trabecular bone in microDiamond measurements were 0.875(±0.1%), 0.953(±0.3%) and 0.962(±0.4%), respectively. For Dw,w calculations, the corrections were 0.920(±0.1%), 0.982(±0.3%) and 0.993(±0.4%), respectively. In the audit, application of the correction factors improves the mean agreement between treatment plans and measured microDiamond dose from -2.4%(±3.9%) to 0.4%(±3.7%). Monte Carlo simulations provide a method for correcting the dose measured in bony materials allowing more accurate comparison with treatment planning system doses. In verification measurements, algorithm specific correction factors should be applied to account for variations in bony material for calculations based on Dm,m and Dw,w.

Assessment of Bone Electron Density Effects on Dose Calculation and Optimization Accuracy for MRI-Only Treatment Planning for Cervical Carcinoma in 1.5 T MR-Linac

For cervical patients planning, conventionally only part of the bony regions like femoral head will be contoured, which can lead to the misinterpretation for the undelineated bones on the bulk electron density (ED) assigned MRI-only planning. This study aims to assess the impact of these undelinated bone regions on dose calculation and optimization results of MRI-only based cervical IMRT plans. Five retrospective cervix patients who were treated on the 1.5T MR-Linac with their original CT and MRI datasets were used for the study. Both of the IMRT plans on CT and MRI images were created using TPS Monaco 5.40. After registration of the MRI with the original CT, the synthetic CT (s-CT) for MRI was generated using bulk ED assignment according to the mean ED values of the delineated structures from the original planning CT. To investigate the dosimetric impact of bone electron density on MRI-only planning, another set of s-CT was generated with fully delineation of all the bone regions. The adaptive plans for the two s-CT sets, which denote as “BoneRC-MRI” and “NoBoneRC-MRI” respectively, were created by copying from the original CT and recalculating final dose without optimization. To account for the influence from planning optimization process, the above s-CT based adaptive plans were copied and reoptimized using the method of optimizing shapes, which denote as “BoneRO-MRI” and “NoBoneRO-MRI”. All the adaptive plans were recalculated on the original CT for comparison. The dose-volume-parameters (DVPs), Homogeneity Index, Conformity Index and Gamma analysis were implemented for assessment. In comparison of the recalculation plans on two s-CT sets, NoBoneRC-MRI plans significantly increase PTV dose (Dmean: BoneRC-MRI vs NoBoneRC-MRI, p＜0.001). Comparing the recalculation plans on original CT and s-CT, the result showed that the BoneRC-MRI plans lead to smaller dose effect than NoBoneRC-MRI by comparing RC-CT, with the difference being 0.7% and 1.2% respectively. And gamma pass rate (GPR) of BoneRC-MRI was higher than NoBoneRC-MRI (BoneRC-MRI vs NoBoneRC-MRI, p = 0.049). In addition, comparing the reoptimized plans on two s-CT sets, the DVPs were no significantly difference (PTV Dmean: BoneRO-MRI vs NoBoneRO-MRI, p = 0.572). However, in comparison of reoptimized plans on original CT and s-CT, the result showed that the BoneRO-MRI plans also lead to smaller dose effect than NoBoneRO-MRI by comparing BoneRO-CT and NoBoneRO-CT, with the difference being 0.7% and 1.2% respectively. And the GPR of BoneRO-MRI was higher than NoBoneRO-MRI (BoneRO-MRI vs NoBoneRO-MRI, p = 0.008). The commonly used bulk ED assignment with only part of bone delineation may not be sufficient for cervical cancer MRI-only planning. Fully delineation of the bones and considering the effect of bone electron density have the potential to reduce the error of s-CT generation.

967P Metastases harbored in the maxillofacial region: A retrospective review of patient and tumour characteristics

Maxillofacial metastases from distal primary sites are rare, accounting for less than 1% of all newly diagnosed cancer in the head and neck region. Clinical manifestation is non-specific and lesions are often misdiagnosed as benign or inflammatory conditions. The purpose of this study was to thoroughly describe cases of maxillofacial metastases, evaluating both patient and tumor characteristics, and to explore associations with treatment delivered. In this retrospective review, we collected data from the hospital registry of patients diagnosed with cancer in the maxillofacial region over a ten year period (from 2008 to 2018). Patients with a metastatic lesion that was supported radiologically and verified histologically were included in the study. Our initial cohort included 350 patients diagnosed with cancer in the maxillofacial region. Of these, 10 patients (7 men, 3 women) were shown to have metastatic lesions. Mean patient age was 60.7 and ranged between 48 to 73. Presenting symptoms included trismus and masseteric hypertrophy in 40% of cases. Primary malignancies most commonly originated in the lung, breast, and prostate, respectively, and the majority (80%) of tumors were adenocarcinomas. Non of these metastases were the presenting lesion of a systemic cancer. Tumors were more frequently located in the mandible than other maxillofacial sites (50%), and appeared in both bony and soft tissue regions. Radiological changes to the periosteum were most commonly observed. In 20% of cases, treatment was delayed due to misdiagnoses as acute infection or osteomyelitis. Suggestive clinical presentation should alert a physician to a potential metastatic lesion in the head and neck region, and prompt a biopsy procedure. Misdiagnosis may lead to delayed or missed treatment, whereas timely management promotes improved patient outcomes.

Characterization of bony anatomic regions in pediatric and adult healthy volunteers using diffuse optical spectroscopic imaging.

.Significance: Diffuse optical spectroscopic imaging (DOSI) measures quantitative functional and molecular information in thick tissue in a noninvasive manner using near-infrared light. DOSI may be useful for diagnosis and prognosis of bone pathologies including osteosarcoma and Ewing’s sarcoma, but little is currently known about DOSI-derived parameters in bony anatomic locations where this disease occurs.Aim: Our goal is to quantify the optical characteristics and chromophore content of bony anatomic locations of healthy volunteers and assess differences due to anatomic region, age, sex, ethnicity, race, and body fat.Approach: Fifty-five healthy volunteers aged 4 to 72 were enrolled in the study. The optical properties and quantitative tissue concentrations of oxyhemoglobin, deoxyhemoglobin, water, and lipids were assessed at the distal humerus, distal femur, and proximal tibia. Body fat was assessed using skinfold calipers. One volunteer underwent a more comprehensive body scan from neck to foot to explore chromophore distributions within an individual. Regression analysis was used to identify the most important sources of variation in the measured data set.Results: Statistical differences between bony locations were found for scattering, water, and lipids, but not for hemoglobin. All chromophores had statistical differences with sex, but there were no significant age-related correlations. Regression analysis revealed that body fat measured with skinfold calipers was the most important predictor of oxy-, deoxy-, total hemoglobin, and lipids. Hemoglobin and lipid levels were highly correlated () over the subject population and within the single-subject body scan.Conclusions: DOSI can successfully measure bony anatomic sites where osteosarcomas and Ewing’s sarcomas commonly occur. Future studies of bone pathology using DOSI should account for the variation caused by anatomic region, sex, race and ethnicity, and body fat as these cause substantial variations in DOSI-derived metrics.

Benefits of iterative metal artifact reduction and dual-energy CT towards mitigating artifact in the setting of total shoulder prostheses.

To determine the utility of iterative metal artifact reduction and 130keV dual-energy virtual monoenergetic images to improve bone and soft tissue visualization in CT scans affected by metal artifacts. Thirteen females and 6 males with a history of total shoulder prosthesis who underwent dual-energy shoulder CT were included. Four sets of images were reconstructed for each patient: (1) original polychromatic kV images reconstructed with weighted filtered back projection; (2) polychromatic kV images with iterative metal artifact reduction; (3) 130keV dual-energy virtual monoenergetic; (4) combined iterative metal artifact reduction and 130keV dual-energy virtual monoenergetic. Three readers blindly reviewed all image sets and graded the extent of artifact and image quality. Mean artifact score and median overall image quality score were better in 130keV dual-energy virtual monoenergetic with iterative metal artifact reduction compared with those in original polychromatic kV images (3.02 vs 4.28, P < 0.001 and 3.00 vs 4.33, P < 0.001, respectively). The median difference in CT numbers between regions affected by artifacts and normal regions was lowest in 130keV dual-energy virtual monoenergetic with iterative metal artifact reduction compared with that in original polychromatic kV images (72.28 vs 252.08, P < 0.001 for bony regions and 15.09 vs 324.38, P < 0.001 for soft tissue). In patients with metal artifacts due to shoulder replacement surgery, the use of dual-energy monoenergetic images and iterative metal artifact reduction reconstruction significantly improves both subjective and objective indicators of image quality.

Nanotechnological approach and bio-inspired materials to face degenerative diseases in aging.

The aging of the world population is increasingly claimed as an alarming situation, since an ever-raising number of persons in advanced age but still physically active is expected to suffer from invalidating and degenerative diseases. The impairment of the endogenous healing potential provoked by the aging requires the development of more effective and personalized therapies, based on new biomaterials and devices able to direct the cell fate to stimulate and sustain the regrowth of damaged or diseased tissues. To obtain satisfactory results, also in cases where the cell senescence, typical of the elderly, makes the regeneration process harder and longer, the new solutions have to possess excellent ability to mimic the physiological extracellular environment and thus exert biomimetic stimuli on stem cells. To this purpose, the "biomimetic concept" is today recognized as elective to fabricate bioactive and bioresorbable devices such as hybrid osteochondral scaffolds and bioactive bone cements closely resembling the natural hard tissues and with enhanced regenerative ability. The review will illustrate some recent results related to these new biomimetic materials developed for application in different districts of the musculoskeletal system, namely bony, osteochondral and periodontal regions, and the spine. Further, it will be shown how new bioactive and superparamagnetic calcium phosphate nanoparticles can give enhanced results in cardiac regeneration and cancer therapy. Since tissue regeneration will be a major demand in the incoming decades, the high potential of biomimetic materials and devices is promising to significantly increase the healing rate and improve the clinical outcomes even in aged patients.

Diffuse reflectance spectroscopy and Raman spectroscopy for label-free molecular characterization and automated detection of human cartilage and subchondral bone

Optical technologies hold potential for bio-medical research as well as the clinical routine, since they allow contact-free, non-destructive access to several clinically relevant features of tissues. In this study, diffuse reflectance spectroscopy and spontaneous Raman spectroscopy have been applied to human hip samples in order to characterize differences between cartilage and adjacent subchondral bone tissue. Mathematical decomposition of absorption and scattering properties is an important aspect in diffuse reflectance data analysis. Here, we present the novel application of Bayesian statistics to this analysis, which can extract probability density spectra of the absorption coefficient and the scattering coefficient. Using this concept of a Bayesian decomposition algorithm for the spectral decomposition, it was possible to find characteristic differences in the relative concentration of melanin and haemoglobin as well as in scattering properties. Furthermore, this allowed a reconstruction of probability density plots for scattering coefficient and absorption coefficient instead of singular values. Complemented by the results of Raman spectroscopy, it was further possible to detect significant differences in the ratio of minerals (such as hydroxyl apatite) to bio-molecules (such as proteins) when comparing bony tissue regions to the surrounding cartilage. Finally, it was possible to use these molecular contrast mechanisms for highly-accurate, automated tissue classification using machine learning algorithms on the level of individual patients.

Pair-wise vs group-wise registration in statistical shape model construction: representation of physiological and pathological variability of bony surface morphology

Statistical shape models (SSM) of bony surfaces have been widely proposed in orthopedics, especially for anatomical bone modeling, joint kinematic analysis, staging of morphological abnormality, and pre- and intra-operative shape reconstruction. In the SSM computation, reference shape selection, shape registration and point correspondence computation are fundamental aspects determining the quality (generality, specificity and compactness) of the SSM. Such procedures can be made critical by the presence of large morphological dissimilarities within the surfaces, not only because of anthropometrical variability but also mainly due to pathological abnormalities. In this work, we proposed a SW pipeline for SSM construction based on pair-wise (PW) shape registration, which requires the a-priori selection of the reference shape, and on a custom iterative point correspondence algorithm. We addressed large morphological deformations in five different bony surface sets, namely proximal femur, distal femur, patella, proximal fibula and proximal tibia, extracted from a retrospective patient dataset. The technique was compared to a method from the literature, based on group-wise (GW) shape registration. As a main finding, the proposed technique provided generalization and specificity median errors, for all the five bony regions, lower than 2 mm. The comparative analysis provided basically similar results. Particularly, for the distal femur that was the shape affected by the largest pathological deformations, the differences in generalization, specificity and compactness were lower than 0.5 mm, 0.5 mm, and 1%, respectively. We can argue the proposed pipeline, along with the robust correspondence algorithm, is able to compute high-quality SSM of bony shapes, even affected by large morphological variability.

Densitometric Radiographic Imaging With Contour Sensors

We present the technical/physical foundations of a new imaging technique that combines ordinary radiographic information (generated by conventional X-ray settings) with the patient’s volume to derive densitometric images . Traditionally, these images provide quantitative information about tissues densities. In our approach, they graphically enhance either soft or bony regions. After measuring the patient’s volume with contour recognition devices, the physical traversed lengths within it (as the Roentgen beam intersects the patient) are calculated and pixel-wise associated with the original radiograph ( $\mathcal {X}$ ). In order to derive this map of lengths ( $\mathcal {L}$ ), the camera equations of the X-ray system and the contour sensor are determined. The patient’s surface is also translated to the point-of-view of the X-ray beam and all its entrance/exit points are sought with the help of ray-casting methods. The derived $\mathcal {L}$ is applied to $\mathcal {X}$ as a physical operation (subtraction), obtaining soft tissue- ( $\mathcal {D}_{S}$ ) or bone-enhanced ( $\mathcal {D}'_{B}$ ) figures. In the $\mathcal {D}_{S}$ type, the contained graphical information can be linearly mapped to the average electronic density (traversed by the X-ray beam). This feature represents an interesting proof-of-concept of associating density data to radiographs, but most important, their intensity histogram is objectively compressed, i.e., the dynamic range is more shrunk (compared against the corresponding $\mathcal {X}$ ). This leads to other advantages: improvement in the visibility of border/edge areas (high gradient), extended manual window level/width manipulations during screening, and immediate correction of underexposed $\mathcal {X}$ instances. In the $\mathcal {D}'_{B}$ type, high-density elements are highlighted and easier to discern. All these results can be achieved with low-energy beam exposures, saving costs and dose. Future work will deepen this clinical side of our research. In contrast with other image-based modifiers, the proposed method is grounded on the measurement of a physical entity: the span of the X-ray beam within a body while undertaking a radiographic examination.