Genetic and genomic evaluation of age at first calving in Italian Holsteins

Age at first calving (AFC) represents the nonproductive period of ∼2 yr in Holstein cows, and thus, it has a relevant effect on the cost of rearing replacements in the dairy herd. In the present study, we aimed to evaluate genetic and genomic aspects of AFC in the Italian Holstein population. Data of 4,206,218 heifers with first calving between 1996 and 2020 were used. Age at first calving averaged 26.09 ± 3.07 mo and decreased across years. Heritability was estimated using a linear animal model which included the fixed effects of herd-year-season of birth and classes of gestation length, and the random animal additive genetic effect fitted to a pedigree-based relationship matrix. The EBV and genomically EBV (GEBV) were obtained, and they were standardized to mean 100 and standard deviation 5, where animals above the mean are those contributing to reduce AFC. Heritability estimates of AFC ranged from 0.031 to 0.045. The trend of sires' GEBV was favorable and indicated a reduced AFC across years. Approximate genetic correlations between GEBV of AFC and GEBV of other economically important traits were calculated on a subset of genotyped females born after 2015. Moderate favorable associations of AFC with production traits (0.39-0.51), udder depth (0.40), interval from first to last insemination in heifer (-0.43), and longevity (0.34) were assessed. Overall, the greatest lifetime productive performances and most favorable days open in first lactation were observed when heifers calved at 22 to 23 mo. In contrast, progeny of sires with GEBV of AFC above the mean yielded more milk, fat, and protein in first lactation, and had shorter days open than progeny of sires with GEBV of AFC below the mean. Results suggested that breeding strategies to improve AFC should be pursued, also considering genetic correlations between AFC and traits which are already part of the Italian Holstein breeding objective. The inclusion of AFC in an aggregate index is expected to contribute to enhance farm income.

REDISCOVER International Guidelines on the Perioperative Care of Surgical Patients With Borderline-resectable and Locally Advanced Pancreatic Cancer

OBJECTIVE

The REDISCOVER consensus conference aimed at developing and validate guidelines on the perioperative care of patients with borderline resectable (BR-) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).

SUMMARY BACKGROUND DATA

Coupled with improvements in chemotherapy and radiation, the contemporary approach to pancreatic surgery supports resection of BR-PDAC and, to a lesser extent, LA-PDAC. Guidelines outlining the selection and perioperative care for these patients are lacking.

METHODS

The Scottish Intercollegiate Guidelines Network (SIGN) methodology was used to develop the REDISCOVER guidelines and create recommendations. The Delphi approach was used to reach consensus (agreement ≥80%) among experts. Recommendations were approved after a debate and vote among international experts in pancreatic surgery and pancreatic cancer management. A Validation Committee used the AGREE II-GRS tool to assess the methodological quality of the guidelines. Moreover, an independent multidisciplinary advisory group revised the statements to ensure adherence to non-surgical guidelines.

RESULTS

Overall, 34 recommendations were created targeting centralization, training, staging, patient selection for surgery, possibility of surgery in uncommon scenarios, timing of surgery, avoidance of vascular reconstruction, details of vascular resection/reconstruction, arterial divestment, frozen section histology of perivascular tissue, extent of lymphadenectomy, anticoagulation prophylaxis and role of minimally invasive surgery. The level of evidence was however low for 29 of 34 clinical questions. Participants agreed that the most conducive mean to promptly advance our understanding in this field is to establish an international registry addressing this patient population ( https://rediscover.unipi.it/ ).

CONCLUSIONS

The REDISCOVER guidelines provide clinical recommendations pertaining to pancreatectomy with vascular resection for patients with BR- and LA-PDAC, and serve as the basis of a new international registry for this patient population.

Genetic and nongenetic variation of heifer fertility in Italian Holstein cattle

Excellent fertility performance is important to maximize farmers' profit and to reduce the number of culled animals. Although female fertility of adult cows has been included in Italian Holstein breeding objectives since 2009, little has been done to quantify genetic variation of heifer fertility characteristics so far. The aim of the present study was to estimate genetic parameters of 4 fertility traits in nulliparous Italian Holstein heifers and to develop an aggregate selection index to improve heifer fertility. Data were retrieved from the national fertility database and included information on insemination, calving, and pregnancy diagnosis dates. The investigated phenotypes (mean ± standard deviation) were age at first insemination (AFI, mo; 17.25 ± 2.89), nonreturn rate at 56 d from the first insemination (NRR56, binary; 0.78 ± 0.41), conception rate at first insemination (CR, binary; 0.61 ± 0.49), and interval from first to last insemination (IFL, d; 26.09 ± 51.85). Genetic parameters were estimated using a 4-trait animal model that included the following fixed effects: herd-year of birth and month of birth for AFI, and herd-year-season of birth and month-year of insemination for IFL, NRR56, and CR; the animal additive genetic effect (fitted to the pedigree-based relationship matrix) was considered as a random term. An aggregate index was developed from the estimated additive genetic (co)variance matrix by considering CR as the breeding goal and AFI, NRR56, and IFL as selection criteria. Heritability estimates from average covariance matrices ranged from 0.012 (CR) to 0.015 (IFL), with the exception of AFI (0.071). Conception rate at first insemination was strongly correlated with both IFL (-0.730) and NRR56 (0.668), and weakly to AFI (-0.065), and the relative emphasis placed on each selection criteria in the aggregate index was 10%, 47%, and 43% for AFI, IFL, and NRR56, respectively. The results of the present study suggest that heifer fertility should be considered as an additional trait in the breeding objectives of Italian Holstein.

Single feature constrained manual registration method for Augmented Reality applications in gynecological laparoscopic interventions

Augmented Reality (AR) can avoid some of the drawbacks of Minimally Invasive Surgery and may provide opportunities for developing innovative tools to assist surgeons. In laparoscopic surgery, the achievement of easy and sufficiently accurate registration is an open challenge. This is particularly true in procedures, such as laparoscopic abdominal Sacro-Colpopexy, where there is a lack of a sufficient number of visible anatomical landmarks to be used as a reference for registration. In an attempt to address the above limitations, we developed and preliminarily testes a constrained manual procedure based on the identification of a single anatomical landmark in the laparoscopic images, and the intraoperative measurement of the laparoscope orientation. Tests in a rigid in-vitro environment show good accuracy (median error 2.4 mm obtained in about 4 min) and good preliminary feedback from the technical staff who tested the system. Further experimentation in a more realistic environment is needed to validate these positive results. Clinical Relevance - This paper provides a new registration method for the development of AR educational videos and AR-based navigation systems for laparoscopic interventions.

A Rendering Engine for Integral Imaging in Augmented Reality Guided Surgery. Annu Int Conf IEEE Eng Med Biol Soc 2022;2022:2693-2696. [PMID: 36086410 DOI: 10.1109/embc48229.2022.9871806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

In the field of image-guided surgery, Augmented Reality wearable displays are a widely studied and documented technology for their ability to provide egocentric vision together with the overlap between real and virtual content. In particular, optical see-through (OST) displays have the advantage of maintaining visual perception of the real world. However, OST displays suffer from vergeance-accomodation conflict when virtual content is superimposed on real world. Furthermore, the calibration methods required to achieve geometric consistency between real and virtual are inherently error-prone. One of the solutions, already studied, to these problems is to use of integral imaging displays. In this paper we present an easy and straightforward real-time rendering strategy implemented in modern OpenGL to show the 3D image of a virtual object on a wearable OST display deploying the integral imaging approach. Clinical Relevance- The algorithm proposed open the way towards more effective AR surgical navigation in terms of comfort of the AR experience and accuracy of the AR guidance.

Augmented Reality as a Tool to Guide Patient-Specific Templates Placement in Pelvic Resections

Patient-specific templates (PST) have become a useful tool for guiding osteotomy in complex surgical scenarios such as pelvic resections. The design of the surgical template results in sharper, less jagged resection margins than freehand cuts. However, their correct placement can become difficult in some anatomical regions and cannot be verified during surgery. Conventionally, pelvic resections are performed using Computer Assisted Surgery (CAS), and in recent years Augmented Reality (AR) has been proposed in the literature as an additional tool to support PST placement. This work presents an AR task to simplify and improve the accuracy of the positioning of the template by displaying virtual content. The focus of the work is the creation of the virtual guides displayed during the AR task. The system was validated on a patient-specific phantom designed to provide a realistic setup. Encouraging results have been achieved. The use of the AR simplifies the surgical task and optimizes the correct positioning of the cutting template: an average error of 2.19 mm has been obtained, lower than obtained with state-of-the-art solutions. In addition, supporting PST placement through AR guidance is less time-consuming than the standard procedure that solely relies on anatomical landmarks as reference.

Insights on Human Small Heat Shock Proteins and Their Alterations in Diseases

The family of the human small Heat Shock Proteins (HSPBs) consists of ten members of chaperones (HSPB1-HSPB10), characterized by a low molecular weight and capable of dimerization and oligomerization forming large homo- or hetero-complexes. All HSPBs possess a highly conserved centrally located α-crystallin domain and poorly conserved N- and C-terminal domains. The main feature of HSPBs is to exert cytoprotective functions by preserving proteostasis, assuring the structural maintenance of the cytoskeleton and acting in response to cellular stresses and apoptosis. HSPBs take part in cell homeostasis by acting as holdases, which is the ability to interact with a substrate preventing its aggregation. In addition, HSPBs cooperate in substrates refolding driven by other chaperones or, alternatively, promote substrate routing to degradation. Notably, while some HSPBs are ubiquitously expressed, others show peculiar tissue-specific expression. Cardiac muscle, skeletal muscle and neurons show high expression levels for a wide variety of HSPBs. Indeed, most of the mutations identified in HSPBs are associated to cardiomyopathies, myopathies, and motor neuropathies. Instead, mutations in HSPB4 and HSPB5, which are also expressed in lens, have been associated with cataract. Mutations of HSPBs family members encompass base substitutions, insertions, and deletions, resulting in single amino acid substitutions or in the generation of truncated or elongated proteins. This review will provide an updated overview of disease-related mutations in HSPBs focusing on the structural and biochemical effects of mutations and their functional consequences.

Life-threatening complications of streptococcal sepsis: a PICU contemporary series

Background

Life-threatening streptococcal sepsis nowadays represents an uncommon event in previously healthy infants and children. Critically ill patients suffering from severe streptococcal sepsis complications may present with pre-antibiotic era clinical pictures and require a timely clinical approach to achieve restitutio ad integrum.

Results

We report a series of four patient groups affected by an uncommon life-threatening streptococcal sepsis, each of them exhibiting some distinct features. Streptococcus Agalactiae sepsis was associated with cerebral thrombotic/ischaemic lesions, whereas severe cardiogenic shock was prominent in the Streptococcus Viridans group; Streptococcus Faecalis and β-hemolytic group A Streptococcus patients mostly reported lung complications.

Conclusions

Previous antibiotic treatments should not delay aggressive treatment in the intensive care setting. Early diagnostic suspicion, as well as appropriate and aggressive treatment provided within an intensive care setting are crucial for the clinical outcome.

A Systematic Review on Methods and Tools for the In Situ Fenestration of Aortic Stent-Graft

In situ fenestration of stent-graft represents a potential option for the treatment of aortic diseases in patients unsuitable for standard endovascular repair. The best fenestration strategy to restore perfusion of collateral vessels after their coverage by an endograft depends mainly on the anatomical area. Several tools are employed as fenestration devices, including needles, radiofrequency probes, and laser systems, used in conjunction with other instrumentation to provide enough support and stability during the procedure. In this systematic review, the approaches to reach the correct fenestration site both in human, animal, and in in vitro environments are described and discussed, highlighting advantages and limitations. Both commercial and dedicated solutions for the intraoperative modification of the fabric material are reported as well. The clinical interest in this procedure has so far encouraged researchers to develop and refine both methods and tools to solve the current limitations of this technique, intending to extend the indications for endovascular treatment to a broader range of patients.

Variation in neutrophil to lymphocyte ratio (NLR) as predictor of outcomes in metastatic renal cell carcinoma (mRCC) and non-small cell lung cancer (mNSCLC) patients treated with nivolumab

BACKGROUND

An elevated pre-treatment neutrophil to lymphocytes ratio (NLR) is associated with poor prognosis in various malignancies. Optimal cut-off is highly variable across studies and could not be determined individually for a patient to inform his prognosis. We hypothesize that NLR variations could be more useful than baseline NLR to predict progression-free survival (PFS) and overall survival (OS) in patients (pts) receiving anti-PD1 treatment.

PATIENTS AND METHODS

All pts with metastatic renal cell carcinoma (mRCC) and metastatic non-small cell lung cancer (mNSCLC) who received anti-PD1 nivolumab monotherapy in second-line setting or later were included in this French multicentric retrospective study. NLR values were prospectively collected prior to each nivolumab administration. Clinical characteristics were recorded. Associations between baseline NLR, NLR variations and survival outcomes were determined using Kaplan-Meier's method and multivariable Cox regression models.

RESULTS

161 pts (86 mRCC and 75 mNSCLC) were included with a median follow-up of 18 months. On the whole cohort, any NLR increase at week 6 was significantly associated with worse outcomes compared to NLR decrease, with a median PFS of 11 months vs 3.7 months (p < 0.0001), and a median OS of 28.5 months vs. 18 months (p = 0.013), respectively. In multivariate analysis, NLR increase was significantly associated with worse PFS (HR 2.2; p = 6.10^-5) and OS (HR 2.1; p = 0.005). Consistent results were observed in each cohort when analyzed separately.

CONCLUSION

Any NLR increase at week 6 was associated with worse PFS and OS outcomes. NLR variation is an inexpensive and dynamic marker easily obtained to monitor anti-PD1 efficacy.

Quartz Crystal Resonator Sensor With Printed-on-Crystal Coil for Dual-Harmonic Electromagnetic Contactless Interrogation

A novel quartz crystal resonator (QCR) sensor with a printed-on-crystal conductive coil, named sensor coil, is presented. The sensor coil electromagnetically coupled to an external readout coil allow to perform contactless interrogation of the QCR working as a stand-alone sensor unit. A frequency-domain readout technique is adopted that allows dual-harmonic operation by detecting the QCR frequencies of the fundamental and third harmonic, and offers first-order independence from the stand-off distance between the sensor and the readout unit. The QCR electrodes and sensor coil have been printed on a 330- [Formula: see text]-thick bare AT-cut quartz crystal exploiting the aerosol jet printing technology. The fabricated QCR sensor has reference values of the fundamental and third harmonic frequencies at 4.77 and 14.22 MHz, respectively. Distance-independent contactless operation has been demonstrated for distances up to 12 mm. The readout frequencies deviate from reference values less than 10 and 90 ppm for the fundamental and third harmonic, respectively, thus validating the proposed principle.

Novel EM Guided Endovascular Instrumentation for In Situ Endograft Fenestration

Objective: This work aims at providing novel endovascular instrumentation to overcome current technical limitations of in situ endograft fenestration including challenges in targeting the fenestration site under fluoroscopic control and supplying mechanical support during endograft perforation. Technology: Novel electromagnetically trackable instruments were developed to facilitate the navigation of the fenestration device and its stabilization at the target site. In vitro trials were performed to preliminary evaluate the proposed instrumentation for the antegrade in situ fenestration of an aortic endograft, using a laser guidewire designed ad hoc and the sharp end of a commercial endovascular guidewire. Results: In situ fenestration was successfully performed in 22 trials. A total of two laser tools were employed since an over bending of laser guidewire tip, due to its manufacturing, caused the damage of the sensor in the first device used. Conclusions: Preliminary in vitro trials demonstrate the feasibility of the proposed instrumentation which could widespread the procedure for in situ fenestration. The results obtained should be validated performing animal studies. Clinical Impact: The proposed instrumentation has the potential to expand indications for standard endovascular aneurysm repair to cases of acute syndromes.

The inaccuracy of LaFarge equations estimating the oxygen consumption in children under 3 years age

Accurate oxygen consumption measurement (VO₂), is essential to obtain a reliable hemodynamic assessment, particularly in patients with congenital heart diseases undergoing cardiac catheterization. LaFarge equations can be unreliable in predicting VO₂, particularly in the pediatric population. In a clinical setting, these inaccurate estimates can lead to important hemodynamic parameter miscalculations, with possible therapeutic or diagnostic consequences. Our aim is to validate LaFarge equations (the most widely used for estimating VO₂) and compare them with direct measurement in children during cardiac catheterization in the cath lab. We performed a prospective observational study in 21 patients (0-3 years of age) with different congenital cardiac diseases, scheduled for diagnostic cardiac catheterization. Under general anesthesia and mechanical ventilation, VO₂ was measured directly with a metabolic module in our cath lab, and also estimated using LaFarge equations. Statistical analysis included Bland-Altman plots, Pearson coefficient and percentage error, among others. LaFarge equations overestimated VO₂ values in all study patients. Therefore, in pediatric patients under 3 years of age, the use of direct VO₂ measurement methods are more accurate and acceptable than LaFarge equations.

Forearm lengthening and prosthetic management in children with transverse congenital forearm deficiency

In cases of transverse congenital forearm deficiency, achieving a good prosthesis fit during childhood remains a challenge. Ulnar lengthening is a treatment option for improving the prosthesis fit. The objective of this study was to evaluate surgical ulnar lengthening and the subsequent prosthesis fit. We reviewed four cases of ulnar lengthening in children with transverse congenital forearm deficiency. The procedure was evaluated in terms of the duration of lengthening, increase in ulnar length and healing index. The elbow range of motion, functional outcome (Prosthetic Upper Extremity Functional Index, PUFI) and time spent using the prosthesis per day were evaluated. The mean age at the time of the lengthening procedure was 3.5 years, the mean duration of lengthening was 58.3 days, the mean length gain was 21 mm, and the mean healing index was 70.1 days/cm. Elbow range of motion was restricted in one patient (100°-140°) and full in the other three patients. Based on the PUFI, 88.4% of activities were performed without the prosthesis. Children only used their prosthesis to perform specific tasks. Given the high complication rate and the lack of prosthesis use during daily activities, the main indication for forearm lengthening is a very short forearm that prevents prosthesis fitting. This procedure should be performed later in life - in adolescence.

Guidance on validation and qualification of processes and operations involving radiopharmaceuticals

BACKGROUND

Validation and qualification activities are nowadays an integral part of the day by day routine work in a radiopharmacy. This document is meant as an Appendix of Part B of the EANM "Guidelines on Good Radiopharmacy Practice (GRPP)" issued by the Radiopharmacy Committee of the EANM, covering the qualification and validation aspects related to the small-scale "in house" preparation of radiopharmaceuticals. The aim is to provide more detailed and practice-oriented guidance to those who are involved in the small-scale preparation of radiopharmaceuticals which are not intended for commercial purposes or distribution.

RESULTS

The present guideline covers the validation and qualification activities following the well-known "validation chain", that begins with editing the general Validation Master Plan document, includes all the required documentation (e.g. User Requirement Specification, Qualification protocols, etc.), and leads to the qualification of the equipment used in the preparation and quality control of radiopharmaceuticals, until the final step of Process Validation.

CONCLUSIONS

A specific guidance to the qualification and validation activities specifically addressed to small-scale hospital/academia radiopharmacies is here provided. Additional information, including practical examples, are also available.

Automatic carotid centerline extraction from three-dimensional ultrasound Doppler images

Vessel lumen centerline extraction is an important issue for the intra-operative guidance of endovascular instruments; furthermore, vessel centerline is often used as a reference position in many hemodynamic studies, especially in carotid arteries. In this work we propose an innovative method for the extraction of carotid vessels centerline from three-dimensional Color Doppler ultrasound images. The method was tested on carotid Color Doppler images of eighteen healthy subjects and validated by calculating the Euclidean distances between the centerlines detected by the algorithm and those manually annotated by two experts in the corresponding original US volumes. The results show that the proposed approach can accurately estimate the actual centerline with an average error of 1.08 ± 0.54 mm. Furthermore, the method is completely automatic and therefore suitable for the aforementioned purposes.

Augmented reality system for freehand guide of magnetic endovascular devices

Magnetic guide of endovascular devices or magnetized therapeutic microparticles to the specific target in the arterial tree is increasingly studied, since it could improve treatment efficacy and reduce side effects. Most proposed systems use external permanent magnets attached to robotic manipulators or magnetic resonance imaging (MRI) systems to guide internal carriers to the region of treatment. We aim to simplify this type of procedures, avoiding or reducing the need of robotic arms and MRI systems in the surgical scenario. On account of this we investigated the use of a wearable stereoscopic video see-through augmented reality system to show the hidden vessel to the surgeon; in this way, the surgeon is able to freely move the external magnet, following the showed path, to lead the endovascular magnetic device towards the desired position. In this preliminary study, we investigated the feasibility of such an approach trying to guide a magnetic capsule inside a vascular mannequin. The high rate of success and the positive evaluation provided by the operators represent a good starting point for further developments of the system.

Position paper on requirements for toxicological studies in the specific case of radiopharmaceuticals

This is a position paper of the Radiopharmacy Committee of the EANM (European Association of Nuclear Medicine) addressing toxicology studies for application of new diagnostic and therapeutic radiopharmaceuticals (RP) that are not approved (i.e., not having a marketing authorization or a monograph in the European Pharmacopoeia), excluding endogenous and ubiquitous substances in humans. This paper discusses the requirements for clinical trials with radiopharmaceuticals for clinical research applications, not necessarily intended to aim at a marketing authorization. If marketing authorization is intended, scientific advice of the competent authorities is mandatory and cannot be replaced by this position paper. The position paper reflects the view of the Radiopharmacy Committee of the EANM and can be used as a basis for discussions with the responsible authorities.

Basic Endovascular Skills Trainer: A surgical simulator for the training of novice practitioners of endovascular procedures

In recent years the clinical interest for structured training in endovascular procedures has increased. Such procedures respect the physical integrity of the patient and at the same time ensure good therapeutic results. This study describes the development and testing of the B.E.S.T. (Basic Endovascular Skills Trainer) simulator. The B.E.S.T is an innovative physical endovascular simulator to learn basic skills of endovascular surgery. The simulator was tested by 25 clinicians with different levels of experience: novices, intermediates, and experts. All clinicians agree on affirming the importance of training in endovascular surgery; in particular they consider the B.E.S.T a valid simulator to learn specific basic skills of vascular surgery.

New training methods based on mixed reality for interventional ultrasound: Design and validation

Currently the learning model for ultrasound imaging diagnosis and intervention follows a traditional approach based on learning by doing but this model exposes the patient to the whole learning curve of the novice. In order to enable training in a safe environment without compromising patient's health we have developed and demonstrated face, content and construct validity of a hybrid simulator for ultrasound-guided biopsy. This hybrid simulator is able to provide a support to acquire skills in term of 3D perception and hand-eye coordination thanks to a mixed reality visualization that allows accurate and easy planning of probe position/orientation and needle trajectory to reach the target.

A 3D sparse motion field filtering for quantitative analysis of fascial layers mobility based on 3D ultrasound scans

In the last few years, there has been an increasing interest in the role of deep fascia mobility in musculoskeletal dynamics and chronic pain mechanisms. In a previous paper we presented an innovative semiautomatic approach to evaluate the 3D motion of the fascia using ultrasound (US) imaging, generating a sparse deformation vector field. This paper presents an improvement of our original method, focusing on the filtering of the sparse vector field and its validation. Moreover, in order to evaluate the performance of the algorithm, a method is proposed to generate synthetic deformation vector fields, including: expansion, rotation, horizontal shear, and oblique shear components. Preliminary tests on the final synthetic deformation vector fields showed promising results. Further experiments are required in order to optimize the tuning of the algorithm.

Hybrid simulation using mixed reality for interventional ultrasound imaging training

PURPOSE

Ultrasound (US) imaging offers advantages over other imaging modalities and has become the most widespread modality for many diagnostic and interventional procedures. However, traditional 2D US requires a long training period, especially to learn how to manipulate the probe. A hybrid interactive system based on mixed reality was designed, implemented and tested for hand-eye coordination training in diagnostic and interventional US.

METHODS

A hybrid simulator was developed integrating a physical US phantom and a software application with a 3D virtual scene. In this scene, a 3D model of the probe with its relative scan plane is coherently displayed with a 3D representation of the phantom internal structures. An evaluation study of the diagnostic module was performed by recruiting thirty-six novices and four experts. The performances of the hybrid (HG) versus physical (PG) simulator were compared. After the training session, each novice was required to visualize a particular target structure. The four experts completed a 5-point Likert scale questionnaire.

RESULTS

Seventy-eight percentage of the HG novices successfully visualized the target structure, whereas only 45% of the PG reached this goal. The mean scores from the questionnaires were 5.00 for usefulness, 4.25 for ease of use, 4.75 for 3D perception, and 3.25 for phantom realism.

CONCLUSIONS

The hybrid US training simulator provides ease of use and is effective as a hand-eye coordination teaching tool. Mixed reality can improve US probe manipulation training.

An optimal design for patient-specific templates for pedicle spine screws placement

BACKGROUND

Currently, pedicle screws are positioned using a free-hand technique or under fluoroscopic guidance, with error in the range 10-40%, depending on the skill of the surgeon.

METHODS

After spine CT acquisition, each vertebra is segmented and the surgeon plans screw positioning in a virtual environment, then the template is designed around the chosen trajectories. This design is based on surgical and mechanical considerations to obtain an optimal solution to guarantee template stability, simple positioning and minimized intervention invasiveness. In vitro evaluation on synthetic spine models and ex vivo animal tests on porcine specimens were performed, with the insertion of 28 Kirschner wires.

RESULTS

During the in vitro tests, all the surgeons rendered positive evaluations regarding the device and considered template placement to be easy. Ex vivo tests were evaluated by CT examination, which showed that 96.5% of the Kirschner wires had been correctly inserted.

CONCLUSIONS

The proposed solution is a promising, simple, highly precise, low-cost solution to safely performing posterior stabilization. Such a solution would be of interest even in hospitals in which a few spine interventions are performed per year, and for which it is not reasonable to purchase the equipment required for robotic or navigated approaches.

Electromagnetic navigation platform for endovascular surgery: how to develop sensorized catheters and guidewires

BACKGROUND

Endovascular procedures are nowadays limited by difficulties arising from the use of 2D images and are associated with dangerous X-ray exposure and the injection of nephrotoxic contrast medium.

METHODS

An electromagnetic navigator is proposed to guide endovascular procedures with reduced radiation dose and contrast medium injection. Five DOF electromagnetic sensors are calibrated and used to track in real time the positions and orientation of endovascular catheters and guidewires, while intraoperative 3D rotational angiography is used to acquire 3D models of patient anatomy. A preliminary prototype is developed to prove the feasibility of the system using an anthropomorphic phantom.

RESULTS

The spatial accuracy of the system was evaluated during 70 targeting trials obtaining an overall accuracy of 1.2 ± 0.3 mm; system usability was positively evaluated by three surgeons.

CONCLUSIONS

The strategy proposed to sensorize endovascular instruments paves the way for the development of surgical strategies with reduced radiation dose and contrast medium injection. Further in vitro, animal and clinical experiments are necessary for complete surgical validation.

Co-doped ceria: tendency towards ferromagnetism driven by oxygen vacancies

We perform an electronic structure study for cerium oxide homogeneously doped with cobalt impurities, focusing on the role played by oxygen vacancies and structural relaxation. By means of full-potential ab initio methods, we explore the possibility of ferromagnetism as observed in recent experiments. Our results indicate that oxygen vacancies seem to be crucial for the appearance of a ferromagnetic alignment among Co impurities, obtaining an increasing tendency towards ferromagnetism with growing vacancy concentration. However, the estimated couplings cannot explain the experimentally observed room-temperature ferromagnetism. In this systematic study, we draw relevant conclusions regarding the location of the oxygen vacancies and the magnetic couplings involved. In particular, we find that oxygen vacancies tend to nucleate in the neighborhood of Co impurities and we get a remarkably strong ferromagnetic coupling between Co atoms and the Ce(3+) neighboring ions. The calculated magnetic moments per cell depend on the degree of reduction, which could explain the wide spread in the magnetization values observed in the experiments.

Ultrasound guided robotic biopsy using augmented reality and human-robot cooperative control

Ultrasound-guided biopsy is a proficient mininvasive approach for tumors staging but requires very long training and particular manual and 3D space perception abilities of the physician, for the planning of the needle trajectory and the execution of the procedure. In order to simplify this difficult task, we have developed an integrated system that provides the clinician two types of assistance: an augmented reality visualization allows accurate and easy planning of needle trajectory and target reaching verification; a robot arm with a six-degree-of-freedom force sensor allows the precise positioning of the needle holder and allows the clinician to adjust the planned trajectory (cooperative control) to overcome needle deflection and target motion. Preliminary tests have been executed on an ultrasound phantom showing high precision of the system in static conditions and the utility and usability of the cooperative control in simulated no-rigid conditions.

Improved electronic interfaces for AT-cut quartz crystal microbalance sensors under variable damping and parallel capacitance conditions

A new configuration of automatic capacitance compensation (ACC) technique based on an oscillatorlike working interface, which permits the tracking of the series resonant frequency and the monitoring of the motional resistance and the parallel capacitance of a thickness-shear mode quartz crystal microbalance sensor, is introduced. The new configuration permits an easier calibration of the system which, in principle, improves the accuracy. Experimental results are reported with 9 and 10 MHz crystals in liquids with different parallel capacitances which demonstrate the effectiveness of the capacitance compensation. Some frequency deviations from the exact series resonant frequency, measured by an impedance analyzer, are explained by the specific nonideal behavior of the circuit components. A tentative approach is proposed to solve this problem that is also common to previous ACC systems.

Treatment of Paget's disease of bone: a survey of clinical practice in Australia

Consensus guidelines for the treatment of Paget's disease of bone have been published, but it is not known how closely these reflect clinical practice. We conducted a multi-centre, stratified, retrospective review of case notes of 531 subjects treated for Paget's disease of bone between 2000 and 2005 in 29 Australian centres. The subjects received 1072 courses of bisphosphonate treatment (pamidronate 363, alendronate 324, risedronate 208, tiludronate 103, zoledronic acid 69, and etidronate 5). The most recent treatment received was oral therapy in 57% of patients (alendronate 29%, risedronate 24%, and tiludronate 4%) and intravenous in 43% (pamidronate 33%, and zoledronic acid 10%). For oral bisphosphonates, the percentages of courses which were at the recommended dosage and duration were: alendronate 33%, risedronate 60% and tiludronate 29%. Pamidronate was administered in a wide range of dosing schedules, most commonly 60 mg every 3 months (18%), 6 months (17%) or annually (12%), whereas zoledronic acid was mainly given as a 4 mg infusion (98%) as a single dose (52%) or annually (19%). Most clinicians reported taking into account symptoms, plasma alkaline phosphatase activity and anatomical location of disease in determining the need for treatment. Patient preference, intolerance of oral therapy and compliance were ranked highest in determining the choice between oral and intravenous therapy. We conclude that oral and intravenous bisphosphonate dosing regimens are both commonly used to treat Paget's disease of bone in Australia. Only a minority of courses of oral bisphosphonate treatment are at the recommended dosage and duration, and there is a lack of consensus on regimens for intravenous treatment.

Groups of adjacent contour segments for object detection

We present a family of scale-invariant local shape features formed by chains of k connected, roughly straight contour segments (kAS), and their use for object class detection. kAS are able to cleanly encode pure fragments of an object boundary, without including nearby clutter. Moreover, they offer an attractive compromise between information content and repeatability, and encompass a wide variety of local shape structures. We also define a translation and scale invariant descriptor encoding the geometric configuration of the segments within a kAS, making kAS easy to reuse in other frameworks, for example as a replacement or addition to interest points. Software for detecting and describing kAS is released on lear.inrialpes.fr/software. We demonstrate the high performance of kAS within a simple but powerful sliding-window object detection scheme. Through extensive evaluations, involving eight diverse object classes and more than 1400 images, we 1) study the evolution of performance as the degree of feature complexity k varies and determine the best degree; 2) show that kAS substantially outperform interest points for detecting shape-based classes; 3) compare our object detector to the recent, state-of-the-art system by Dalal and Triggs [4].

Ferrodistortive instability at the (001) surface of half-metallic manganites

We present the structure of the fully relaxed (001) surface of the half-metallic manganite La0.7Sr0.3MnO3, calculated using density functional theory. Two relevant ferroelastic order parameters are identified and characterized. The known tilting of the oxygen octahedra, which is present in the bulk phase, decreases towards the surface. A ferrodistortive Mn off-centering, triggered by the surface and not reported before, decays monotonically into the bulk. This distortion affects neither the half-metallicity nor the zero-temperature magnetization, but does change the effective spin-spin interactions, and thus the temperature dependence of the magnetic properties.