Computed tomography of the cervical spine: comparison of image quality between a standard-dose and a low-dose protocol using filtered back-projection and iterative reconstruction.

OBJECTIVE: To compare image quality of a standard-dose (SD) and a low-dose (LD) cervical spine CT protocol using filtered back-projection (FBP) and iterative reconstruction (IR). MATERIALS AND METHODS: Forty patients investigated by cervical spine CT were prospectively randomised into two groups: SD (120 kVp, 275 mAs) and LD (120 kVp, 150 mAs), both applying automatic tube current modulation. Data were reconstructed using both FBP and sinogram-affirmed IR. Image noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were measured. Two radiologists independently and blindly assessed the following anatomical structures at C3-C4 and C6-C7 levels, using a four-point scale: intervertebral disc, content of neural foramina and dural sac, ligaments, soft tissues and vertebrae. They subsequently rated overall image quality using a ten-point scale. RESULTS: For both protocols and at each disc level, IR significantly decreased image noise and increased SNR and CNR, compared with FBP. SNR and CNR were statistically equivalent in LD-IR and SD-FBP protocols. Regardless of the dose and disc level, the qualitative scores with IR compared with FBP, and with LD-IR compared with SD-FBP, were significantly higher or not statistically different for intervertebral discs, neural foramina and ligaments, while significantly lower or not statistically different for soft tissues and vertebrae. The overall image quality scores were significantly higher with IR compared with FBP, and with LD-IR compared with SD-FBP. CONCLUSION: LD-IR cervical spine CT provides better image quality for intervertebral discs, neural foramina and ligaments, and worse image quality for soft tissues and vertebrae, compared with SD-FBP, while reducing radiation dose by approximately 40 %.

Superficial femoral vein as substitute for pulmonary artery reconstruction after resection for bronchovascular fistula

Post-lobectomy bronchovascular fistula (BVF) associated with massive hemoptysis is a rare but life-threatening complication. Surgical options include completion pneumonectomy or BVF resection with end-to-end anastomosis of the airways and reconstruction of the pulmonary artery (PA) by interposition of an appropriate substitute. We report PA resection and successful reconstruction by interposition of an autologous reversed superficial femoral vein (SFV) segment for this purpose.

Laparoscopic Pancreatic Enucleation With End-to-End Pancreatic Duct Reconstruction.

BACKGROUND: Laparoscopic enucleation for neuroendocrine pancreatic tumors has become a feasible technique, with a reported incidence of pancreatic fistula ranging from 13 to 29 %.1 (-) 3 This report describes the first successful case of laparoscopic pancreatic enucleation with resection of the main pancreatic duct followed by end-to-end anastomosis. METHODS: A 41-year-old woman was admitted to the authors' hospital for repeated syncope. Hypoglycemia also was noted. A contrast-enhanced computed tomography examination showed a highly enhanced tumor measuring 22 mm in diameter on the ventral side of the pancreatic body adjacent to the main pancreatic duct. The patient's blood insulin level was elevated, and her diagnosis was determined to be pancreatic insulinoma. Laparoscopic pancreatic enucleation was performed. Approximately 2 cm of the main pancreatic duct was segmentally resected, and a short stent (Silicone tube: Silastic, Dow Corning Corporation, Midland, MI) was inserted. The direct anastomosis of the main pancreatic duct was performed using four separate sutures with an absorbable monofilament (6-0 PDS). RESULTS: The operation time was 166 min, and the estimated blood loss was 100 mL. The postoperative course was uneventful, and the patient was discharged from hospital on postoperative day 7. The pathologic findings showed a well-differentiated insulinoma and a negative surgical margin. A computed tomography examination performed 1 month after the operation showed a successful anastomosis with a patent main pancreatic duct. CONCLUSIONS: Laparoscopic segmental resection of the main pancreatic duct and end-to-end anastomosis can be performed safely with the insertion of a short stent. This technique also can be used for a central pancreatectomy.

L"educació davant la societat digital: presentació

Els articles reunits en aquest monogràfic, que és una iniciativa conjunta de la revista Temps d"Educació i de la revista en línia Interactive Educational Multimedia, reflexionen sobre les conseqüències educatives de la societat digital.1 És veritat que se n"ha escrit molt, i que és només el principi dels canvis que s"estan produint: comparats a vegades amb la impremta i altres vegades amb la pròpia escriptura, molts autors acostumen a situar la revolució digital per damunt de totes les altres revolucions tecnològiques. Al costat d"aquestes tecnofilies, en determinats moments completament acrítiques, la reflexió que qüestiona els canvis ha anat minvant progressivament davant l"avenç generalitzat de les telecomunicacions i de la informàtica, potser com a resultat d"un sentiment d"inevitabilitat. Afortunadament no és el cas dels articles reunits per a aquest monogràfic que incorpora diferents treballs d"un alt contingut.

Comparisons of Preoperative Three-Dimensional Planning and Surgical Reconstruction in Primary Cementless Total Hip Arthroplasty

La planification scanographique (3D) a démontré son utilité pour une reconstruction anatomique plus précise de la hanche (longueur du fémur, centre de rotation, offset, antéversion et rétroversion). Des études ont montré que lors de la planification 2D 50% seulement correspondaient à l'implant définitif du fémur alors que dans une autre étude ce taux s'élevait à 94% pour une planification 3D. Les erreurs étaient liées à l'agrandissement des radiographies. L'erreur sur la taille de la tige est liée à l'estimation inadéquate de la morphologie osseuse ainsi qu'à la densité osseuse. L'erreur de l'antéversion, augmentée par l'inclinaison du bassin, a pu être éliminée par la planification 3D et l'offset restauré dans 98%. Cette étude est basée sur une nouvelle technique de planification scanographique en trois dimensions pour une meilleure précision de la reconstruction de la hanche. Le but de cette étude est de comparer l'anatomie post-opératoire à celle préopératoire en comparant les tailles d'implant prévu lors de la planification 3D à celle réellement utilisée lors de l'opération afin de déterminer l'exactitude de la restauration anatomique avec étude des différents paramètres (centre de rotation, densité osseuse, L'offset fémoral, rotations des implants, longueur du membre) à l'aide du Logiciel HIP-PLAN (Symbios) avec évaluation de la reproductibilité de notre planification 3D dans une série prospective de 50 patients subissant une prothèse totale de hanche non cimentée primaire par voie antérieure. La planification pré-opératoire a été comparée à un CTscan postopératoire par fusion d'images. CONCLUSION ET PRESPECTIVE Les résultats obtenus sont les suivants : La taille de l'implant a été prédit correctement dans 100% des tiges, 94% des cupules et 88% des têtes (longueur). La différence entre le prévu et la longueur de la jambe postopératoire était de 0,3+2,3 mm. Les valeurs de décalage global, antéversion fémorale, inclinaison et antéversion de la cupule étaient 1,4 mm ± 3,1, 0,6 ± 3,3 0 -0,4 0 ± 5 et 6,9 ° ± 11,4, respectivement. Cette planification permet de prévoir la taille de l'implant précis. Position de la tige et de l'inclinaison de la cupule sont exactement reproductible. La planification scanographique préopératoire 3D permet une évaluation précise de l'anatomie individuelle des patients subissant une prothèse totale de hanche. La prédiction de la taille de l'implant est fiable et la précision du positionnement de la tige est excellente. Toutefois, aucun avantage n'est observée en termes d'orientation de la cupule par rapport aux études impliquant une planification 2D ou la navigation. De plus amples recherches comparant les différentes techniques de planification pré-opératoire à la navigation sont nécessaire.

Model-based iterative reconstruction in pediatric chest CT: assessment of image quality in a prospective study of children with cystic fibrosis.

BACKGROUND: The potential effects of ionizing radiation are of particular concern in children. The model-based iterative reconstruction VEO(TM) is a technique commercialized to improve image quality and reduce noise compared with the filtered back-projection (FBP) method. OBJECTIVE: To evaluate the potential of VEO(TM) on diagnostic image quality and dose reduction in pediatric chest CT examinations. MATERIALS AND METHODS: Twenty children (mean 11.4 years) with cystic fibrosis underwent either a standard CT or a moderately reduced-dose CT plus a minimum-dose CT performed at 100 kVp. Reduced-dose CT examinations consisted of two consecutive acquisitions: one moderately reduced-dose CT with increased noise index (NI = 70) and one minimum-dose CT at CTDIvol 0.14 mGy. Standard CTs were reconstructed using the FBP method while low-dose CTs were reconstructed using FBP and VEO. Two senior radiologists evaluated diagnostic image quality independently by scoring anatomical structures using a four-point scale (1 = excellent, 2 = clear, 3 = diminished, 4 = non-diagnostic). Standard deviation (SD) and signal-to-noise ratio (SNR) were also computed. RESULTS: At moderately reduced doses, VEO images had significantly lower SD (P < 0.001) and higher SNR (P < 0.05) in comparison to filtered back-projection images. Further improvements were obtained at minimum-dose CT. The best diagnostic image quality was obtained with VEO at minimum-dose CT for the small structures (subpleural vessels and lung fissures) (P < 0.001). The potential for dose reduction was dependent on the diagnostic task because of the modification of the image texture produced by this reconstruction. CONCLUSIONS: At minimum-dose CT, VEO enables important dose reduction depending on the clinical indication and makes visible certain small structures that were not perceptible with filtered back-projection.

digital¡. 5è Pla estratègic de les Biblioteques UPC. 2012-2014

Postprint (published version)

digital¡. 5º Plan estratégico de las bibliotecas UPC. 2012-2014

Postprint (published version)

The temporoparietal fascia flap: a versatile tool in head and neck reconstruction.

PURPOSE OF REVIEW: The article reviews recent significant advances and current applications of the temporoparietal fascia flap (TPFF) in head and neck surgery. RECENT FINDINGS: The recent literature describes a wide span of new applications of the TPFF in many areas. Significant developments and refinements in the reconstruction of orbitomaxillary composite defects and orbital exenteration cavities are reported. The TPFF combined with alloplastic framework is gaining in importance in external ear reconstruction. Innovative prefabricated skin or soft-tissue grafts based on the TPFF are used to restore facial contour or in the reconstruction of complex facial defects. The free TPFF finds a role in laryngotracheal reconstruction as a vascular carrier to support cartilage grafts. SUMMARY: Owing to its reliability and unequalled structural properties, the TPFF still plays a central role in facial reconstruction. Future investigation will likely incorporate the free TPFF as a vascular carrier of bioengineered tissues, such as cartilage and mucosa, for various head and neck indications.

A forensic science perspective on the role of images in crime investigation and reconstruction

This article presents a global vision of images in forensic science. The proliferation of perspectives on the use of images throughout criminal investigations and the increasing demand for research on this topic seem to demand a forensic science-based analysis. In this study, the definitions of and concepts related to material traces are revisited and applied to images, and a structured approach is used to persuade the scientific community to extend and improve the use of images as traces in criminal investigations. Current research efforts focus on technical issues and evidence assessment. This article provides a sound foundation for rationalising and explaining the processes involved in the production of clues from trace images. For example, the mechanisms through which these visual traces become clues of presence or action are described. An extensive literature review of forensic image analysis emphasises the existing guidelines and knowledge available for answering investigative questions (who, what, where, when and how). However, complementary developments are still necessary to demystify many aspects of image analysis in forensic science, including how to review and select images or use them to reconstruct an event or assist intelligence efforts. The hypothetico-deductive reasoning pathway used to discover unknown elements of an event or crime can also help scientists understand the underlying processes involved in their decision making. An analysis of a single image in an investigative or probative context is used to demonstrate the highly informative potential of images as traces and/or clues. Research efforts should be directed toward formalising the extraction and combination of clues from images. An appropriate methodology is key to expanding the use of images in forensic science.

Surface reconstruction from microscopic images in optical lithography.

This paper presents a method to reconstruct 3D surfaces of silicon wafers from 2D images of printed circuits taken with a scanning electron microscope. Our reconstruction method combines the physical model of the optical acquisition system with prior knowledge about the shapes of the patterns in the circuit; the result is a shape-from-shading technique with a shape prior. The reconstruction of the surface is formulated as an optimization problem with an objective functional that combines a data-fidelity term on the microscopic image with two prior terms on the surface. The data term models the acquisition system through the irradiance equation characteristic of the microscope; the first prior is a smoothness penalty on the reconstructed surface, and the second prior constrains the shape of the surface to agree with the expected shape of the pattern in the circuit. In order to account for the variability of the manufacturing process, this second prior includes a deformation field that allows a nonlinear elastic deformation between the expected pattern and the reconstructed surface. As a result, the minimization problem has two unknowns, and the reconstruction method provides two outputs: 1) a reconstructed surface and 2) a deformation field. The reconstructed surface is derived from the shading observed in the image and the prior knowledge about the pattern in the circuit, while the deformation field produces a mapping between the expected shape and the reconstructed surface that provides a measure of deviation between the circuit design models and the real manufacturing process.

Turistes mobiltzats : el turisme cultural a la societat digital mòbil

L’impacte de la societat en xarxa en el turisme està transformant els models de negoci pel canvi en el flux i en les dinàmiques d’accés a la informació. La irrupció dels mitjans socials i la revolució mòbil canvien la manera de planificar, experimentar i compartir el viatge. Si fa uns anys es parlava de la revolució d’Internet, avui podem dir que estem assistint a la Revolució Mòbil. No es tracta d’una evolució de la primera, sinó d’un fet que té les seves pròpies característiques, els seus protagonistes i la seva implicació en la indústria del turisme i la cultura. El gadget de referència en l’impuls de la Internet social està sent el mòbil, un sensor d’ubiqüitat i polièdric. L’accés a la informació, el consum de continguts i la compra de serveis ja no es limita a una actitud relaxada davant una pantalla, sinó que es produeix al llarg de tot el dia i en qualsevol lloc. Això fa que la mobilitat afecti tot el cicle del viatge, és a dir, l’abans, el durant i el després