28 research outputs found
The clinical use of 3D printing in surgery
No full textThe use of 3D printing is gaining considerable success in many medical fields including surgery. Here, the technology was introduced for increasing the level of anatomical understanding thanks to the inherent characteristics of 3D printed models: these are highly accurate and customized reproductions, being obtained from own radiological imaging of patients, and are solid graspable objects allowing for free manipulation on part of the user. The resulting tactile feedbacks significantly help the comprehension of anatomical details, especially the spatial relations between structures. In this regard, they proved to be more effective than conventional 2D imaging and 3D virtual models. To date, an increasing number of applications have been successfully tested in many surgical disciplines, extending the range of possible uses to pre-operative planning, counselling with patients, education of students and residents, surgical training, intraoperative navigation and others; in recent years, 3D printing was also employed for creating surgical tools and reproducing anatomical parts to be used, respectively, as templates or guides for specific tasks of the surgery and individualized implantable materials in reconstructive procedures. Future expectations concern on one side the reduction of manufacturing costs and time to further increase the accessibility of 3D printing, while on the other the development of novel techniques and materials suitable for 3D printing of biological structures by which recreating the architecture and functionality of real human organs and tissues
Anisotropic Adapted Meshes for Image Segmentation: Application to Three-Dimensional Medical Data
No full textThis work focuses on a variational approach to image segmentation based on the Ambrosio--Tortorelli functional. We propose an efficient algorithm, which combines the functional minimization with a smart choice of the computational mesh. With this aim, we resort to an anisotropic mesh adaptation procedure driven by an a posteriori recovery-based error analysis. We apply the proposed algorithm to a computed tomography dataset of a fractured pelvis to create a virtual model of the anatomy. The result is verified against a semiautomatic segmentation carried out using the ITK-SNAP tool. Furthermore, a physical replica of the virtual model is produced by means of fused filament fabrication technology to assess the appropriateness of the proposed solution in terms of resolution-quality balance for three-dimensional printing production
Elaboration and development of a realistic 3D printed model for training in ultrasound-guided placement of peripheral central venous catheter in children
No full textBackground: Simulation for training is becoming a trend topic worldwide, even if its applications are commonly limited to adulthood. Ultrasound-guided procedures require practice and experience-especially in the pediatric field, where the small size of the involved anatomical structures poses major problems. In this context, a realistic 3D printed pediatric phantom for training of the ultrasound-guided placement of peripheral central venous catheters in children was developed. Materials and methods: Starting from Computed Tomography scans of an 8 years-old girl, her left arm was virtually reconstructed-including bones, arteries, and veins-through a semi-automatic segmentation process. According to preliminary results, the most suitable 3D printing technologies to reproduce the different anatomical structures of interest were selected, considering both direct and indirect 3D printing techniques. Experienced operators were asked to evaluate the efficacy of the final model through a dedicated questionnaire. Results: Vessels produced through indirect 3D printing latex dipping technique exhibited the best echogenicity, thickness, and mechanical properties to mimic real children's venous vessels, while arteries-not treated and/or punctured during the procedure-were directly 3D printed through Material Jetting technology. An external mold-mimicking the arm skin-was 3D printed and a silicone-based mixture was poured to reproduce real patient's soft tissues. Twenty expert specialists were asked to perform the final model's validation. The phantom was rated as highly realistic in terms of morphology and functionality for the overall simulation, especially for what concerns vessels and soft tissues' response to puncturing. On the other hand, the involved structures' US appearance showed the lower score. Conclusions: The present work shows the feasibility of a patient-specific 3D printed phantom for simulation and training in pediatric ultrasound-guided procedures
Herschel-ATLAS : deep HST/WFC3 imaging of strongly lensed submillimetre galaxies
No full textThis work is supported by STFC (grants PP/D002400/1 and ST/G002533/1)We report on deep near-infrared observations obtained with the Wide Field Camera-3 (WFC3) onboard the Hubble Space Telescope (HST) of the first five confirmed gravitational lensing events discovered by the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). We succeed in disentangling the background galaxy from the lens to gain separate photometry of the two components. The HST data allow us to significantly improve on previous constraints of the mass in stars of the lensed galaxy and to perform accurate lens modelling of these systems, as described in the accompanying paper by Dye et al. We fit the spectral energy distributions of the background sources from near-IR to millimetre wavelengths and use the magnification factors estimated by Dye et al. to derive the intrinsic properties of the lensed galaxies. We find these galaxies to have star-formations rates (SFR) ∼ 400–2000 M⊙ yr−1, with ∼(6–25) × 1010 M⊙ of their baryonic mass already turned into stars. At these rates of star formation, all remaining molecular gas will be exhausted in less than ∼100 Myr, reaching a final mass in stars of a few 1011 M⊙. These galaxies are thus proto-ellipticals caught during their major episode of star formation, and observed at the peak epoch (z ∼ 1.5–3) of the cosmic star formation history of the Universe.Peer reviewe
Three-D-printed simulator for kidney transplantation
No full textBackground Three-Dimensional (3D) printing technology can be used to manufacture training platforms for surgeons. Kidney transplantation offers a suitable model, since it mostly entails vascular and ureteric anastomoses. Methods A new simulation platform for surgical training in kidney transplantation was realized and validated in this study. A combination of different 3-D printing technology was used to reproduce the key anatomy of lower abdomen, of pelvis, and of a kidney graft, including their mechanical properties. Results Thirty transplantations were performed by two junior trainees with no previous experience in the area. Analysis of the times required to perform the simulated transplantation showed that proficiency was reached after about ten cases, as indicated by a flattening of the respective curves that corresponded to a shortening of about 40% and 47%, respectively, of the total time initially needed to perform the whole simulated transplantation. Although an objective assessment of the technical quality of the anastomoses failed to show a significant improvement throughout the study, a growth in self-confidence with the procedure was reported by both trainees. Conclusion The quality of the presented simulation platform aimed at reproducing in the highest possible way a realistic model of the operative setting and proved effective in providing an integrated training environment where technical skills are enhanced together with a team-training experience. As a result the trainees' self-confidence with the procedure resulted enforced. Three-D--printed models can also offer pre-operative patient-specific training when anatomical variants are anticipated by medical imaging. An analysis of the costs related to the use of this platform is also provided and discussed
Hybrid 3D-Printed and Electrospun Scaffolds Loaded with Dexamethasone for Soft Tissue Applications
No full textBackground: To make the regenerative process more effective and efficient, tissue engineering (TE) strategies have been implemented. Three-dimensional scaffolds (electrospun or 3D-printed), due to their suitable designed architecture, offer the proper location of the position of cells, as well as cell adhesion and the deposition of the extracellular matrix. Moreover, the possibility to guarantee a concomitant release of drugs can promote tissue regeneration. Methods: A PLA/PCL copolymer was
used for the manufacturing of electrospun and hybrid scaffolds (composed of a 3D-printed support coated with electrospun fibers). Dexamethasone was loaded as an anti-inflammatory drug into the electrospun fibers, and the drug release kinetics and scaffold biological behavior were evaluated.
Results: The encapsulation efficiency (EE%) was higher than 80%. DXM embedding into the electrospun fibers resulted in a slowed drug release rate, and a slower release was seen in the hybrid scaffolds. The fibers maintained their nanometric dimensions (less than 800 nm) even after deposition on the 3D-printed supports. Cell adhesion and proliferation was favored in the DXM-loading hybrid
scaffolds.
Conclusions: The hybrid scaffolds that were developed in this study can be optimized as a versatile platform for soft tissue regeneration
Right coronary artery atresia in an athlete presenting with cardiac arrest: a case report
No full text“She parted the curtains; she looked”: finestre spalancate su realtà apparentemente inconciliabili in Mrs Dalloway di Virginia Woolf
No full textMrs Dalloway is probably the most multifaceted and complex novel by Virginia Woolf; this complexity derives from the writer’s desire to represent life seen both from the points of view of the insane and the sane: “the world seen by the sane and the insane side by side” (D2, 14 ottobre 1922, p. 207). The novel, thus, is structured on two main plots, whose protagonists are Mrs Dalloway on one side (representing the ‘sane truth’) and the veteran Septimus Warren-Smith on the other (representing the ‘insane truth’). During one single day, the stories of the protagonists develop without intersecting in the city of London. In such a complex design, the window becomes a strong symbol of communication and connection between these two worlds which only seem to be detached and independent. Not only that, but since the beginning of the novel the window symbolises also the passage from a time frame to another, from the present moment to a more or less distant past, thus permitting the author to linger on the past of the characters, revealing aspects of their personalities that, otherwise, would remain unknown. This essay then will present the symbology of the window in Virginia Woolf’s novel through the analysis of the most effective episodes of Mrs Dalloway, where this object becomes a mean of communication between apparently disconnected realities like sanity and madness, youth and adulthood, past and present and life and death
Colour matters: the effects of lensing on the positional offsets between optical and submillimetre galaxies in Herschel★-ATLAS
No full textWe report an unexpected variation in the positional offset distributions between Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) submillimetre (submm) sources and their optical associations, depending on both 250-mu m signal-to-noise ratio and 250/350-mu m colour. We show that redder and brighter submm sources have optical associations with a broader distribution of positional offsets than would be expected if these offsets were due to random positional errors in the source extraction. The observation can be explained by two possible effects: either red submm sources trace a more clustered population than blue ones, and their positional errors are increased by confusion, or red submm sources are generally at high redshifts and are frequently associated with low-redshift lensing structures which are identified as false counterparts. We perform various analyses of the data, including the multiplicity of optical associations, the redshift and magnitude distributions in H-ATLAS in comparison to HerMES, and simulations of weak lensing, and we conclude that the effects are most likely to be explained by widespread weak lensing of Herschel-SPIRE sources by foreground structures. This has important consequences for counterpart identification and derived redshift distributions and luminosity functions of submm surveys.</p
Assessment of different manufacturing techniques for the production of bioartificial scaffolds as soft organ transplant substitutes
No full textIntroduction: The problem of organs’ shortage for transplantation is widely known: different manufacturing techniques such as Solvent casting, Electrospinning and 3D Printing were considered to produce bioartificial scaffolds for tissue engineering purposes and possible transplantation substitutes. The advantages of manufacturing techniques’ combination to develop hybrid scaffolds with increased performing properties was also evaluated.Methods: Scaffolds were produced using poly-L-lactide-co-caprolactone (PLA-PCL) copolymer and characterized for their morphological, biological, and mechanical features.Results: Hybrid scaffolds showed the best properties in terms of viability (>100%) and cell adhesion. Furthermore, their mechanical properties were found to be comparable with the reference values for soft tissues (range 1–10 MPa).Discussion: The created hybrid scaffolds pave the way for the future development of more complex systems capable of supporting, from a morphological, mechanical, and biological standpoint, the physiological needs of the tissues/organs to be transplanted
