Use of an Online Ultrasound Simulator to Teach Basic Psychomotor Skills to Medical Students During the Initial COVID-19 Lockdown: Quality Control Study.

Teaching medical ultrasound has increased in popularity in medical schools with hands-on workshops as an essential part of teaching. However, the lockdown due to COVID-19 kept medical schools from conducting these workshops. The aim of this paper is to describe an alternative method used by our medical school to allow our students to acquire the essential psychomotor skills to produce ultrasound images. Our students took online ultrasound courses. Consequently, they had to practice ultrasound exercises on a virtual simulator, using the mouse of their computer to control a simulated transducer. Our team measured the precision reached at the completion of simulation exercises. Before and after completion of the courses and simulator's exercises, students had to complete a questionnaire dedicated to psychomotor skills. A general evaluation questionnaire was also submitted. A total of 193 students returned the precourse questionnaire. A total of 184 performed all the simulator exercises and 181 answered the postcourse questionnaire. Of the 180 general evaluation questionnaires that were sent out, 136 (76%) were returned. The average precourse score was 4.23 (SD 2.14). After exercising, the average postcourse score was 6.36 (SD 1.82), with a significant improvement (P<.001). The postcourse score was related to the accuracy with which the simulator exercises were performed (Spearman rho 0.2664; P<.001). Nearly two-thirds (n=84, 62.6%) of the students said they enjoyed working on the simulator. A total of 79 (58.0%) students felt that they had achieved the course's objective of reproducing ultrasound images. Inadequate connection speed had been a problem for 40.2% (n=54) of students. The integration of an online simulator for the practical learning of ultrasound in remote learning situations has allowed for substantial acquisitions in the psychomotor field of ultrasound diagnosis. Despite the absence of workshops, the students were able to learn and practice how to handle an ultrasound probe to reproduce standard images. This study enhances the value of online programs in medical education, even for practical skills

Learning Efficient Navigation in Vortical Flow Fields

Efficient point-to-point navigation in the presence of a background flow field is important for robotic applications such as ocean surveying. In such applications, robots may only have knowledge of their immediate surroundings or be faced with time-varying currents, which limits the use of optimal control techniques for planning trajectories. Here, we apply a novel Reinforcement Learning algorithm to discover time-efficient navigation policies to steer a fixed-speed swimmer through an unsteady two-dimensional flow field. The algorithm entails inputting environmental cues into a deep neural network that determines the swimmer's actions, and deploying Remember and Forget Experience replay. We find that the resulting swimmers successfully exploit the background flow to reach the target, but that this success depends on the type of sensed environmental cue. Surprisingly, a velocity sensing approach outperformed a bio-mimetic vorticity sensing approach by nearly two-fold in success rate. Equipped with local velocity measurements, the reinforcement learning algorithm achieved near 100% success in reaching the target locations while approaching the time-efficiency of paths found by a global optimal control planner.Comment: 6 pages, 6 figure

Gated cardiac CT in infants: What can we expect from deep learning image reconstruction algorithm?

ECG-gated cardiac CT is now widely used in infants with congenital heart disease (CHD). Deep Learning Image Reconstruction (DLIR) could improve image quality while minimizing the radiation dose. To define the potential dose reduction using DLIR with an anthropomorphic phantom. An anthropomorphic pediatric phantom was scanned with an ECG-gated cardiac CT at four dose levels. Images were reconstructed with an iterative and a deep-learning reconstruction algorithm (ASIR-V and DLIR). Detectability of high-contrast vessels were computed using a mathematical observer. Discrimination between two vessels was assessed by measuring the CT spatial resolution. The potential dose reduction while keeping a similar level of image quality was assessed. DLIR-H enhances detectability by 2.4% and discrimination performances by 20.9% in comparison with ASIR-V 50. To maintain a similar level of detection, the dose could be reduced by 64% using high-strength DLIR in comparison with ASIR-V50. DLIR offers the potential for a substantial dose reduction while preserving image quality compared to ASIR-V

How Strong a Kick Should be to Topple Northeastern's Tumbling Robot?

Rough terrain locomotion has remained one of the most challenging mobility questions. In 2022, NASA's Innovative Advanced Concepts (NIAC) Program invited US academic institutions to participate NASA's Breakthrough, Innovative \& Game-changing (BIG) Idea competition by proposing novel mobility systems that can negotiate extremely rough terrain, lunar bumpy craters. In this competition, Northeastern University won NASA's top Artemis Award award by proposing an articulated robot tumbler called COBRA (Crater Observing Bio-inspired Rolling Articulator). This report briefly explains the underlying principles that made COBRA successful in competing with other concepts ranging from cable-driven to multi-legged designs from six other participating US institutions

Cryoablation for the Treatment of Lymph Node Metastasis

Background: Lymph Node Metastasis (LNM) is often treated preventively during the initial management of the primary tumor, by chemotherapy-radiotherapy-surgical excision. However, few options exist for the treatment of loco-regional LNM at the time of recurrence. Objective: This study aims to assess the efficacy, safety, and the loco-regional disease control of Cryoablation (CA) as a removal option for LNM. Patients/methods: The clinical records of 9 patients, (5 male and 4 female, median age 60), treated by CA at the department of interventional radiology, CHUV, between May 2014 and December 2016 were retrospectively and consecutively reviewed. Permission from the Swiss Ethics Committee was obtained. Nine patients bearing 17 LNM from various primary tumors were treated by CA. CA was performed by using 2 median freezing cycles, (sd=0), with a median duration of 9 minutes for the first freezing cycle (± 3.3min) and 6 minutes for the second freezing cycle (± 2.7min). The median duration of the total of freezing cycles was 15 minutes (± 5.7min). The number of probes ranged from 1 to 10, (median 2). After CA, the patients were followed up by imagery (PET-CT, CT, MRI) at intervals of 1-3 months, 6 months, 9 months, 12 months, 24 months, etc., for as long as follow-up was available. Both PERCIST and RECIST 1.1 criteria were applied to evaluate the effectiveness of CA, by measuring SUVmax and diameter of lesion respectively. Results: A total of 13 CA procedures were performed on 17 LNM. All procedures were technically successful resulting in a satisfactory ablation zone. Minor immediate and periprocedural complications were observed (SIR classification). Using PERCIST, out of the 14 hypercaptant target lesions, at the end of the PET-CT follow-up available for each lesion (13.8 months mean), 14% (n=2) had Complete Response, 64% (n=9) had Partial Response, 21% (n=3) were in Stable Disease, and 0% (n=0) showed Progressive Disease. Mean SUVmax decrease was -51%, for a mean follow up time of 13.8 months. Using RECIST 1.1 criteria, out of the 17 target lymph nodes, at the end of the MRI follow-up available for each lesion (15.6 months mean),29% (n= 5) showed CR, 41% (n=7) had PR, 24% (n=4) were in SD, and 6% (n=1) was Not Evaluated. Mean volume decrease was -72% for a mean follow up of 15.6 months. At the end of follow up 44% (p=4) patients showed global disease control for 11.2 months mean, 11% (p=1) had local disease control for 20 months with pre-existing distant tumour deposits at time of CA treatment, and 44% (p=4) patients showed locoregional or distant disease progression at 8.2 months mean. Conclusion: Our study shows that CA of LNM is a safe and effective method, with minimal complications, and satisfactory locoregional disease control rate. All treated lesions were controlled 15.6 months mean, and 44% of the patients showed global disease control 11.2 months mean

Salvage Lymph-Node Percutaneous Cryoablation: Safety Profile and Oncologic Outcomes.

Purpose To evaluate the technical feasibility and safety of percutaneous cryoablation (CA) for the treatment of single/oligometastatic lymph-node (LN) relapse in different anatomic regions. This is a retrospective study of all patients who underwent percutaneous CA of LN metastases (May 2014-April 2019). Eighteen patients with a total of 27 LNs were treated with CT-guided CA (Galil Medical, Israel). One patient was excluded since no follow-up was available. The mean LN diameter was 11 mm (range 4-28 mm). Thirteen patients had a history of previous treatment for locoregional lymphadenopathy. In 21 LNs, a supplementary thermal insulation-displacement technique was used (hydrodissection = 12; carbodissection = 6; both = 3). According to the RECIST criteria, 8 LNs had a complete response, 8 stable disease, 8 partial response and 1 progressive disease. In the subgroup of patients with prostate cancer relapse, the mean PSA level before treatment was 5.5 ngr/ml (range 0.6-36 ngr/ml) and reduced to 0.32 (range 0-1.1 ngr/ml) and 0.3 (range 0-0.6 ngr/ml) at 3- and 6-month follow-up, respectively. Six patients presented distant tumor deposits on follow-up that were further treated with systemic (5 patients: hormone/chemo/immunotherapy) and local therapies (1 patient: CA of bone oligometastatic disease). No major complication was noted. Two patients with obturator LN presented transient obturator nerve paresis. Mean follow-up was 15 months (range 1-56 months). In this series of patients, we have shown that metastatic LNs can be safely treated with image-guided CA. Caution should be paid, and additional measures should be taken when treating LNs near thermal-sensible structures

Preoperative CT-Based Skeletal Muscle Mass Depletion and Outcomes after Total Laryngectomy.

To assess the role of preoperative CT-based skeletal muscle mass depletion on postoperative clinical outcomes and survival in patients who underwent total laryngectomy for cancer. Patients operated on between January 2011 and March 2020 were retrospectively included. Skeletal muscle area and intra- and inter-muscular fat accumulation were measured at the third lumbar vertebral level on preoperative CT scans. Skeletal muscle mass depletion was defined based on pre-established cut-off values. Their association with postoperative morbidity, length of stay (LOS), costs, and survival was assessed. A total of 84 patients were included, of which 37 (44%) had preoperative skeletal muscle mass depletion. The rate of postoperative fistula (23% vs. 35%, p = 0.348), cutaneous cervical dehiscence (17% vs. 11%, p = 0.629), superficial incisional surgical site infections (SSI) (12% vs. 10%, p = 1.000), and unplanned reoperation (38% vs. 37%, p = 1.000) were comparable between the two patient groups. No difference in median LOS was observed (41 vs. 33 days, p = 0.295), nor in treatment costs (119,976 vs. 109,402 CHF, p = 0.585). The median overall survival was comparable between the two groups (3.43 vs. 4.95 years, p = 0.09). Skeletal muscle mass depletion alone had no significant impact on postoperative clinical outcomes or survival