Characterisation of the guinea pig model of osteoarthritis by in vivo three-dimensional magnetic resonance imaging

AbstractObjective: To characterise longitudinal changes in joint integrity and cartilage volume in vivo in the guinea pig spontaneous osteoarthritis (OA) model by magnetic resonance imaging (MRI).Methods: Guinea pigs knee were imaged in vivo by high-resolution three-dimensional (3D) MRI between the ages of 3 and 12 months. Image analysis was performed to assess qualitative knee joint changes between 3 and 12 months (n=16) and quantitative volumetric changes of the medial tibial cartilage between 9 and 12 months (n=7). After imaging, animals were killed and knees were assessed macroscopically and histologically.Results: From 3 to 6 months qualitative observation by MRI and histopathology indicated localised cartilage swelling on the medial tibial plateau. At 6 months, bone cysts had developed in the epiphysis. At 9 months, we observed by MRI and histopathology, fragmentation of the medial tibial cartilage in areas not protected by the meniscus. Cartilage degeneration had intensified at 12 months with evidence of widespread loss of cartilage throughout the tibial plateau. Segmentation of the MR cartilage images showed a 36% loss of volume between 9 and 12 months.Conclusions: We have achieved 3D image acquisition and segmentation of knee cartilage in a guinea pig model of chronic OA, which permits measurements previously only possible in man. High resolution and short acquisition time allowed qualitative longitudinal characterisation of the entire knee joint and enabled us to quantify for the first time longitudinal tibial cartilage volume loss associated with disease progression

UV and EUV Instruments

We describe telescopes and instruments that were developed and used for astronomical research in the ultraviolet (UV) and extreme ultraviolet (EUV) regions of the electromagnetic spectrum. The wavelength ranges covered by these bands are not uniquely defined. We use the following convention here: The EUV and UV span the regions ~100-912 and 912-3000 Angstroem respectively. The limitation between both ranges is a natural choice, because the hydrogen Lyman absorption edge is located at 912 Angstroem. At smaller wavelengths, astronomical sources are strongly absorbed by the interstellar medium. It also marks a technical limit, because telescopes and instruments are of different design. In the EUV range, the technology is strongly related to that utilized in X-ray astronomy, while in the UV range the instruments in many cases have their roots in optical astronomy. We will, therefore, describe the UV and EUV instruments in appropriate conciseness and refer to the respective chapters of this volume for more technical details.Comment: To appear in: Landolt-Boernstein, New Series VI/4A, Astronomy, Astrophysics, and Cosmology; Instruments and Methods, ed. J.E. Truemper, Springer-Verlag, Berlin, 201

Feasibility Study of Vascular Access and REBOA Placement in Quick Response Team Firefighters.

Early hemorrhage control using resuscitative endovascular balloon occlusion of the aorta (REBOA) can save lives. This study was designed to evaluate the ability to train Quick Response Team Fire Fighters (QRT-FF) to gain percutaneous femoral artery access and place a REBOA catheter in a model, using a comprehensive theoretical and practical training program.Six QRT-FF participated in the training. SOF medics from a previous training served as the control group. A formalized training curriculum included basic anatomy and endovascular materials for percutaneous access and REBOA placement. Key skills included (1) preparation of an endovascular toolkit, (2) achieving vascular access in the model, and (3) placement and positioning of REBOA.QRT-FF had significantly better scores compared with medics using endovascular materials (P = .003) and performing the procedure without unnecessary attempts (P = .032). Basic surgical anatomy scores for QRT-FF were significantly better than SOF medics (P = .048). QRT-FF subjects demonstrated a significantly higher overall technical skills point score than medics (P = .030). QRT-FF had a median total time from start of the procedure to REBOA inflation of 3:23 minutes, and medics, 5:05 minutes. All six QRT-FF subjects improved their procedure times-as did four of the five medics.Our training program using a task training model can be utilized for percutaneous femoral access and REBOA placement training of QRT-FF without prior ultrasound or endovascular experience. Training the use of advanced bleeding control options such as REBOA, as a secondary occupational task, has the potential to improve outcomes for severely bleeding casualties in the field

Vascular access training for REBOA placement: a feasibility study in a live tissue-simulator hybrid porcine model

Background The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) in patients with severe haemorrhagic shock is increasing. Obtaining vascular access is a necessary prerequisite for REBOA placement in these situations.Methods During the EVTM workshop (September 2017, Orebro, Sweden), 21 individuals participated in this study, 16 participants and five instructors. A formalised curriculum was constructed including basic anatomy of the femoral region and basic training in access materials for REBOA placement in zone 1. Key skills: (1) preparation of endovascular toolkit, (2) achieving vascular access in the model and (3) bleeding control with REBOA. Scoring ranged from 0 to 5 for non-anatomical skills. Identification of anatomical structures was either sufficient (score=1) or insufficient (score=0). Five consultants performed a second identical procedure as a post test.Results Consultants had significantly better overall technical skills in comparison with residents (p=0.005), while understanding of surgical anatomy showed no difference. Procedure times differed significantly (p<0.01), with residents having a median procedure time of 3 min and 24 s, consultants 2:33 and instructors 1:09.Conclusion This comprehensive training model using a live tissue-simulator hybrid porcine model can be used for femoral access and REBOA placement training in medical personnel with different prior training levels. Higher levels of training are associated with faster procedure times. Further research in open and percutaneous access training is necessary to simulate real-life situations. This training method can be used in a multistep training programme, in combination with realistic moulage and perfused cadaver models.Vascular Surger