Application of materials used in everyday life to create radiological models of human tissues

Radiological physical models (phantoms) are used for quality control, for evaluation and analysis of a given X-ray device. They are easily available, providing the X-ray technicians with consistent results and safety compared to using a live subject. Phantoms must respond in the same or similar way to human tissues and organs when exposed to radiation, and therefore must be manufactured from materials with the same or similar X-ray properties. The purpose of this report is to study materials from everyday life as suitable substitutes for human tissues in quality control tasks. In daily life, everything we come in contact with could be used as a material for a physical phantom: plastic, wood, glass, water, salt, sugar, gelatin, paraffin, and others. Due to the advantages of plastic—cheap, flexible, waterproof, and easy to manufacture, it becomes a reliable material in many fields, including 3D printing. After the physical model is printed, it should be checked whether or not it is the same or similar to the real human tissues. All results are processed by using the DICOM processing program (Digital Imaging and Communication in Medicine) by comparing the density using the Hounsfield units scal

Reverse engineering applied to biomodelling and pathological bone manufacturing using FDM technology

[EN] Reverse engineering and medical image-based modeling technologies allow manufacturing of 3D biomodels of anatomical structures of human body. These techniques are based on anatomical information from scanning data such as CT and MRI, whose scanners are used for scanning data acquisition of the external and internal geometry of anatomical structures. These 3D biomodels have many medical applications such surgical training, preoperative planning, surgical simulation, diagnosis and treatments. 3D virtual models of human body structures based on CT are increasingly being used in clinical practice. A data processing methodology is required to obtain an accurate 3D model suitable for manufacturing using AM, and specially the FDM technologies. This study shows a step-by-step methodology to process the CT information in bounded uncertainty conditions in order to obtain the STL models of the degenerated bone components, and to manufacture the 3D biomodels for surgery analysis with optimal design and details, and with an adequate accuracy to ensure proper results by surgeons analysis.The authors wish to acknowledge the support of Ms. Jerica Risent and Mr. Joan Ortiz of Ford Motor Company for his assistance in the scanning of printed models. This work was supported by the Polisabio Funding (UPV-Fisabio 2017)Laura Piles; Miguel J. Reig; Vte. Jesús Seguí; Rafael Pla; Fernando Martínez; José Miguel Seguí (2019). Reverse engineering applied to biomodelling and pathological bone manufacturing using FDM technology. Procedia Manufacturing. 41:739-746. https://doi.org/10.1016/j.promfg.2019.09.065S73974641Van Eijnatten, M., Berger, F. H., de Graaf, P., Koivisto, J., Forouzanfar, T., & Wolff, J. (2017). Influence of CT parameters on STL model accuracy. Rapid Prototyping Journal, 23(4), 678-685. doi:10.1108/rpj-07-2015-0092Lalone, E. A., Willing, R. T., Shannon, H. L., King, G. J. W., & Johnson, J. A. (2015). Accuracy assessment of 3D bone reconstructions using CT: an intro comparison. Medical Engineering & Physics, 37(8), 729-738. doi:10.1016/j.medengphy.2015.04.010Stull, K. E., Tise, M. L., Ali, Z., & Fowler, D. R. (2014). Accuracy and reliability of measurements obtained from computed tomography 3D volume rendered images. Forensic Science International, 238, 133-140. doi:10.1016/j.forsciint.2014.03.005Van Eijnatten, M., van Dijk, R., Dobbe, J., Streekstra, G., Koivisto, J., & Wolff, J. (2018). CT image segmentation methods for bone used in medical additive manufacturing. Medical Engineering & Physics, 51, 6-16. doi:10.1016/j.medengphy.2017.10.008Javaid, M., & Haleem, A. (2018). Additive manufacturing applications in medical cases: A literature based review. Alexandria Journal of Medicine, 54(4), 411-422. doi:10.1016/j.ajme.2017.09.003D.V.C. Stoffelen, K. Eraly, P. Debeer, The use of 3D printing technology in reconstruction of a severe glenoid defect: a case report with 2.5 years of follow-up, Journal of Shoulder Elbow Surgery, 24 (2015) e218-e22

Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

<p>Abstract</p> <p>Background</p> <p>A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides.</p> <p>Methods</p> <p>In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast) and preoperative (radiographic template) models, obtained by both CT and optical scanning processes.</p> <p>Results</p> <p>A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates.</p> <p>Conclusions</p> <p>The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology.</p

The evaluation of the effects of steroid treatment on the tumor and peritumoral edema by DWI and MR spectroscopy in brain tumors

Objective To investigate the effects of dexamethasone on brain tumor and peritumoral edema by different sequences of magnetic resonance imaging (MRI). Materials and methods MRI was performed in 28 patients with brain tumor. Patients were divided into the 3 groups based on the histological diagnosis; Group I: high-grade glial tumor, Group II: low-grade glial tumor, and Group III: brain metastasis. The measurements of peritumoral edema volume and apparent diffusion coefficient (ADC) values were performed while the peak areas of cerebral metabolites were measured by spectroscopy in groups I and II. The changes in edema volumes, ADC values and cholin/creatine peak areas were compared. Results The volume of peritumoral edema was decreased in groups I and II, but increased in group III after dexamethasone treatment. These changes were not statistically significant for 3 groups. ADC value was decreased in group I and increased in groups II and III. Changes in ADC values were statistically significant. Cholin/creatine peak areas were decreased after dexamethasone in groups I and II, but these changes were also not significant. Conclusion Dexamethasone has no significant effect on the volume of peritumoral edema in glial tumor and metastasis. Moreover, dexamethasone increases the fluid movements in low grade gliomas and metastases, decreases in high grade gliomas. However, more comprehensive clinical studies are needed to show the effects of dexamethasone on brain tumors and peritumoral edema

Normal computed tomographic features and reference values for the coelomic cavity in pet parrots

BACKGROUND: The increasing popularity gained by pet birds over recent decades has highlighted the role of avian medicine and surgery in the global veterinary scenario; such a need for speciality avian medical practice reflects the rising expectation for high-standard diagnostic imaging procedures. The aim of this study is to provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species. RESULTS: Contrast-enhanced computed tomographic studies of the coelomic cavity were performed in 5 blue-and-gold macaws, 4 African grey parrots and 6 monk parakeets by means of a 4-multidetector-row CT scanner. Both pre- and post-contrast scans were acquired. Anatomical reference cross-sections were obtained from 5 blue-and-gold macaw, 7 African grey parrot, and 9 monk parakeet cadavers. The specimens were stored in a −20 °C freezer until completely frozen and then sliced at 5-mm intervals by means of a band saw. All the slices were photographed on both sides. Individual anatomical structures were identified by means of the available literature. Pre- and post-contrast attenuation reference values for the main coelomic organs are reported in Hounsfield units (HU). CONCLUSIONS: The results provide an atlas of matched anatomical cross-sections and contrast-enhanced CT images of the coelomic cavity in three highly diffused psittacine species

Identity restored: Nesmin's forensic facial reconstruction in context

Ljudski ostaci otkriveni arheološkim istraživanjima imaju širok hronološki i kulturni raspon, od epipaleolitskih skeleta i egipatskih mumija, preko tela iz močvara gvozdenog doba, do srednjovekovnih sahrana i ostataka starosedelaca Severne Amerike. Sem retkih izuzetaka, stotine hiljada ovih počivših ljudskih bića lišeno je identiteta, ne samo na individualnom, već često i na etničkom nivou. Neretko kontroverzna problematika tretmana ovih ostataka, prešla je dug put od depersonalizacije i desakralizacije XVIII veka, do savremenih shvatanja o njihovom moralnom statusu i viđenja po kome to nisu samo anonimni uzorci prikupljeni u svrhe medicinskih, statističkih i drugih proučavanja, već zemni ostaci nekada živih ljudskih bića, koja činom smrti ne gube pravo na lični integritet, ljudsko dostojanstvo i kulturni identitet. Izučavanje ljudskih ostataka, nesumnjivo neophodno i izuzetno važno, stoga treba vršiti uz uvažavanje i ovih činjenica, u skladu sa savremenim etičkim normama. U kontekstu staroegipatske civilizacije, ali i mnogih drugih kultura, od posebnog je značaja utvrđivanje što više elementa identiteta, kako bi se mogla formirati odgovarajuća analitička datoteka koja bi kroz komparaciju i interakciju mnoštva individualnih podataka doprinela boljem razumevanju prošlosti i potpunijoj rekonstrukciji socijalnog tkiva. Studija slučaja Beogradske mumije, staroegipatskog sveštenika Nesmina, datovane oko početka III veka pre naše ere, pokazuje tok utvrđivanja elemenata identiteta, od konstatovanja fizičkog statusa pokojnika, kulturnih i hronoloških markera, preko DNK analize, utvrđivanja mesta porekla, imena, zanimanja i korigovane genealogije, zaključno sa 3D forenzičkom rekonstrukcijom lica (sl. 1-2). Neinvazivni metod digitalne rekonstrukcije podrazumeva prethodno CT skeniranje glave, generisanje 3D modela lobanje, i aplikovanje filtera koji odstranjuju meka tkiva, platnene ovoje i smolaste materije korišćene u procesu mumifikacije. Sledi sinhrona primena više različitih softvera za rekonstrukciju lica, usklađenih sa prethodno utvrđenim polom i životnim dobom, ali i sačuvanim likovnim delima epohe kada su u pitanju boja kože i očiju. Dobijeni rezultat je rekonstrukcija, ili radije otkrivanje, lica Nesmina, finalnog vizuelnog elementa njegovog povraćenog identiteta.A wide range of archaeological human remains stay, for the most part, anonymous and are consequently treated as objects of analysis; not as dead people. With the growing availability of medical imaging and rapidly developing computer technology, 3D digital facial reconstruction, as a noninvasive form of study, offers a successful method of recreating faces from mummified human remains. Forensic facial reconstruction has been utilized for various purposes in scientific investigation, including restoring the physical appearance of the people of ancient civilizations which is an important aspect of their individual identity. Restoring the identity of the Belgrade mummy started in 1991. Along with the absolute dating, gender, age, name, rank and provenance, we also established his genealogy. The owner of Cairo stela 22053 discovered at Akhmim in 1885, and the Belgrade coffin purchased in Luxor in 1888, in which the mummy rests, have been identified as the very same person. Forensic facial reconstruction was used to reproduce, with the highest possible degree of accuracy, the facial appearance of the mummy Nesmin, ca. 300 B.C., a priest from Akhmim, when he was alive

Effects of Material Mapping Agnostic Partial Volume Correction for Subject Specific Finite Elements Simulations

Partial Volume effects are present at the boundary between any two types of material in a CT image due to the scanner's Point Spread Function, finite voxel resolution, and importantly, the discrepancy in radiodensity between the two materials. In this study a new algorithm is developed and validated that builds on previously published work to enable the correction of partial volume effects at cortical bone boundaries. Unlike past methods, this algorithm does not require pre-processing or user input to achieve the correction, and the correction is applied directly onto a set of CT images, which enables it to be used in existing computational modelling workflows. The algorithm was validated by performing experimental three point bending tests on porcine fibulae specimen and comparing the experimental results to finite element results for models created using either the original, uncorrected CT images or the partial volume corrected images. Results demonstrated that the models created using the partial volume corrected images did improved the accuracy of the surface strain predictions. Given this initial validation, this algorithm is a viable method for overcoming the challenge of partial volume effects in CT images. Thus, future work should be undertaken to further validate the algorithm with human tissues and through coupling it with a range of different finite element creation workflows to verify that it is robust and agnostic to the chosen material mapping strategy