Comparative ergonomic workflow and user experience analysis of MRI versus fluoroscopy-guided vascular interventions:an iliac angioplasty exemplar case study

Purpose A methodological framework is introduced to assess and compare a conventional fluoroscopy protocol for peripheral angioplasty with a new magnetic resonant imaging (MRI)-guided protocol. Different scenarios were considered during interventions on a perfused arterial phantom with regard to time-based and cognitive task analysis, user experience and ergonomics. Methods Three clinicians with different expertise performed a total of 43 simulated common iliac angioplasties (9 fluoroscopic, 34 MRI-guided) in two blocks of sessions. Six different configurations for MRI guidance were tested in the first block. Four of them were evaluated in the second block and compared to the fluoroscopy protocol. Relevant stages’ durations were collected, and interventions were audio-visually recorded from different perspectives. A cued retrospective protocol analysis (CRPA) was undertaken, including personal interviews. In addition, ergonomic constraints in the MRI suite were evaluated. Results Significant differences were found when comparing the performance between MRI configurations versus fluoroscopy. Two configurations [with times of 8.56 (0.64) and 9.48 (1.13) min] led to reduce procedure time for MRI guidance, comparable to fluoroscopy [8.49 (0.75) min]. The CRPA pointed out the main influential factors for clinical procedure performance. The ergonomic analysis quantified musculoskeletal risks for interventional radiologists when utilising MRI. Several alternatives were suggested to prevent potential low-back injuries. Conclusions This work presents a step towards the implementation of efficient operational protocols for MRI-guided procedures based on an integral and multidisciplinary framework, applicable to the assessment of current vascular protocols. The use of first-user perspective raises the possibility of establishing new forms of clinical training and education

Detection and analysis of single event upsets in noisy digital imagers with small to medium pixels

Camera sensors are shrinking, resulting in more defects seen through image analysis. Due to cosmic radiation, camera experience both permanent defects known as hot pixels and temporal defective spikes which are Single Event Upsets (SEUs). SEUs manifest themselves as temporal random bright areas in sequential dark-frame images that are taken with long exposure times. In the past, it was difficult to separate SEUs from noise in dark-frame images taken with DSLRs at high sensitivity levels (ISO) and cell phone cameras at modest sensitivity levels. However, recent software improvements in this research have enabled the analysis of defect rates in noisy digital imagers – by leveraging local area and pixel address distribution techniques. In addition, multiple experiments were performed to understand the relationship of SEUs and elevation. This study reports data from imagers with pixels ranging from 7 μm (DSLR cameras) down to 1.2 μm (cell phone cameras)

Easy Leaf Area: Automated digital image analysis for rapid and accurate measurement of leaf area.

UnlabelledPremise of the studyMeasurement of leaf areas from digital photographs has traditionally required significant user input unless backgrounds are carefully masked. Easy Leaf Area was developed to batch process hundreds of Arabidopsis rosette images in minutes, removing background artifacts and saving results to a spreadsheet-ready CSV file. •Methods and resultsEasy Leaf Area uses the color ratios of each pixel to distinguish leaves and calibration areas from their background and compares leaf pixel counts to a red calibration area to eliminate the need for camera distance calculations or manual ruler scale measurement that other software methods typically require. Leaf areas estimated by this software from images taken with a camera phone were more accurate than ImageJ estimates from flatbed scanner images. •ConclusionsEasy Leaf Area provides an easy-to-use method for rapid measurement of leaf area and nondestructive estimation of canopy area from digital images

In vitro assessment of the primary stability of the acetabular component in hip arthroplasty

In Europa, più di 700'000 interventi di artroplastica d’anca vengono effettuati annualmente. Il tasso di fallimento della chirurgia è del 2-8 % (a 10 anni). Di questo, più del 50% è dovuto alla mobilizzazione asettica della componente acetabolare (più che ad un fallimento legato alla componente femorale). Lo scopo centrale di questo progetto di tesi è quello di creare un pilot-test per la valutazione in vitro della stabilità primaria di una componente acetabolare commerciale, impiantata in una emipelvi sintetica (senza cemento, attraverso la procedura chirurgica press-fit). La valutazione dei micromovimenti prevede un approccio multiplo, costituito dall’utilizzo della Digital Image Correlation (DIC) e di sensori lineari di spostamento. Per adeguare e migliorare le prestazioni dei due strumenti di misura, lo studio prevede: (1.a) l’ottimizzazione delle misure ottenute dalla correlazione di immagini, (1.b) creare ed effettuare la procedura di calibrazione interna dei sensori di spostamento e l’ottimizzazione delle misure ottenute dai sensori stessi come monitor dell’intero pilot-test. La seconda parte del lavoro si prone di implementare una metodologia affidabile per il calcolo delle roto-traslazioni relative tra coppa e osso. La creazione di un algoritmo dedicato, prevede, quindi, di valutare: (2.a) la migrazione permanente e (2.b) i micromovimenti inducibili dai picchi di carico.L’utilizzo della correlazione di immagini è risultato un gran punto di forza dello studio. Grazie al potere della DIC nell’elaborare spostamenti e deformazioni a tutto campo, senza contatto e in stereofotogrammetria, per la prima volta è stato possibile ottenere informazioni 3D del vettore migrazione della coppa. Inoltre, creando una procedura ottimizzata dell’allineamento del provino sotto la macchina, si sono potute riferire tutte le misure ottenute dal pilot-test, all’Aneterior Pelvic Plane (sistema di riferimento di rilevanza clinica)

In vitro biomechanical testing of the stability of primary and revision hip acetabular implants

Hip acetabular stability is the capability of acetabular implants to resist to the forces acting in the acetabulum during patient activities after surgery. If implant motions are sufficiently low, primary stability is achieved and the osteointegration process between the implant and the surrounding bone may occur. In this context, measuring implant motions is essential to predict the implant failure. In clinical practise, these measurements are limited to implant migration, while elastic motions and periacetabular strains are not monitored. So far, to obtain a complete set of stability measurements in vitro testing is the most reliable option. Despite the importance of the experimental analysis, a general consensus about the application of biomechanical tools to solve clinical problems is still missing. The aim of my Ph.D project was to develop and apply reliable in vitro methods to assess the hip acetabular stability in case of primary and revision reconstructions. First, two methodological studies were conducted (1) to define and implement a robust reference frame for the human hemipelvis based on a morphological analysis of this anatomical district and (2) to create a robust procedure to measure the implant motions and the periacetabular strains with the Digital Image Correlation technique. Secondly, I applied these methods to answer the following clinical questions: 1. How do changes in the motor task affect the cup stability and the periacetabular strains? 2. Does the cup medialization affect implant stability? 3. Which is the effect on cup stability of defect reconstructions with an innovative synthetic bone substitute or with human bone graft in revision surgery? All these clinical questions were answered in three experimental studies. In conclusion, this project provided a reliable set of in vitro methods to perform biomechanical testing on human hemipelvis and to assess the stability of acetabular reconstructions by mean of Digital Image Correlation

Development of An In Vivo Robotic Camera for Dexterous Manipulation and Clear Imaging

Minimally invasive surgeriy (MIS) techniques are becoming more popular as replacements for traditional open surgeries. These methods benefit patients with lowering blood loss and post-operative pain, reducing recovery period and hospital stay time, decreasing surgical area scarring and cosmetic issues, and lessening the treatment costs, hence greater patient satisfaction would be earned. Manipulating surgical instruments from outside of abdomen and performing surgery needs precise hand-eye coordination which is provided by insertable cameras. The traditional MIS insertable cameras suffer from port complexity and reduced manipulation dexterity, which leads to defection in Hand-eye coordination and surgical flow. Fully insertable robotic camera systems emerged as a promising solution in MIS. Implementing robotic camera systems faces multiple challenges in fixation, manipulation, orientation control, tool-tissue interaction, in vivo illumination and clear imaging.In this dissertation a novel actuation and control mechanism is developed and validated for an insertable laparoscopic camera. This design uses permanent magnets and coils as force/torque generators in an external control unit to manipulate an in vivo camera capsule. The motorless design of this capsule reduces the, wight, size and power consumption of the driven unit. In order to guarantee the smooth motion of the camera inside the abdominal cavity, an interaction force control method was proposed and validated.Optimizing the system\u27s design, through minimizing the control unit size and power consumption and extending maneuverability of insertable camera, was achieved by a novel transformable design, which uses a single permanent magnet in the control unit. The camera robot uses a permanent magnet as fixation and translation unit, and two embedded motor for tilt motion actuation, as well as illumination actuation. Transformable design provides superior imaging quality through an optimized illumination unit and a cleaning module. The illumination module uses freeform optical lenses to control light beams from the LEDs to achieve optimized illumination over surgical zone. The cleaning module prevents lens contamination through a pump actuated debris prevention system, while mechanically wipes the lens in case of contamination. The performance of transformable design and its modules have been assessed experimentally

Towards robots reasoning about group behavior of museum visitors: leader detection and group tracking

The final publication is available at IOS Press through http://dx.doi.org/10.3233/AIS-170467Peer ReviewedPostprint (author's final draft

The use of digital image correlation in the biomechanical area: a review

This paper offers an overview of the potentialities and limitations of digital image correlation (DIC) as a technique for measuring displacements and strain in biomechanical applications. This review is mainly intended for biomechanists who are not yet familiar with DIC. This review includes over 150 papers and covers different dimensional scales, from the microscopic level (tissue level) up to macroscopic one (organ level). As DIC involves a high degree of computation, and of operator- dependent decisions, reliability of displacement and strain measurements by means of DIC cannot be taken for granted. Methodological problems and existing solutions are summarized and compared, whilst open issues are addressed. Topics addressed include: preparation methods for the speckle pattern on different tissues; software settings; systematic and random error associated with DIC measurement. Applications to hard and soft tissues at different dimensional scales are described and analyzed in terms of strengths and limitations. The potentialities and limitations of DIC are highlighted, also in comparison with other experimental techniques (strain gauges, other optical techniques, digital volume correlation) and numerical methods (finite element analysis), where synergies and complementarities are discussed. In order to provide an overview accessible to different scientists working in the field of biomechanics, this paper intentionally does not report details of the algorithms and codes used in the different studies

Video guidance, landing, and imaging systems

The adaptive potential of video guidance technology for earth orbital and interplanetary missions was explored. The application of video acquisition, pointing, tracking, and navigation technology was considered to three primary missions: planetary landing, earth resources satellite, and spacecraft rendezvous and docking. It was found that an imaging system can be mechanized to provide a spacecraft or satellite with a considerable amount of adaptability with respect to its environment. It also provides a level of autonomy essential to many future missions and enhances their data gathering ability. The feasibility of an autonomous video guidance system capable of observing a planetary surface during terminal descent and selecting the most acceptable landing site was successfully demonstrated in the laboratory. The techniques developed for acquisition, pointing, and tracking show promise for recognizing and tracking coastlines, rivers, and other constituents of interest. Routines were written and checked for rendezvous, docking, and station-keeping functions

Inverse method for stiffness determination of impact damage in composites

The limited knowledge of stiffness reductions is a major problem in reliably predicting the post-impact strength of composite structures. This work describes development and application of a non-destructive approach for evaluation of the inplane stiffness of impact damage in composites. The approach combines an inverse method linked to a finite element model and non-contact full-field measurements. The material parameters of impact damage are determined by iteratively matching the finite element model to displacement fields measured optically during post-impact loading. A first order, gradient optimization technique coupled with a modified quadratic algorithm is employed. The method is validated on a reference finite element model with axisymmetric damage containing several concentric zones having different properties, and the influence of measurement noise is examined. The approach is applied to in-house experiments with impacted carbon/epoxy laminates to determine their quasi-isotropic mechanical properties in tension and compression. The resulting stiffness distributions are presented and the corresponding nonlinear behaviour of the damage is described. To examine the effect of the type of damage on the mechanical properties a thorough fractographic analysis of the impacted specimens was undertaken. The tensile stiffness is found to be mainly affected by fibre fracture, while the compressive stiffness is strongly linked to delamination buckling. The approach has further been extended for detection and evaluation of multiple impact damage zones at arbitrary locations as well as for stiffness identification of the damage in orthotropic laminates. The accuracy of both extensions is presented and discussed. Finally, possible future applications of the approach are considered