Fabrication and Testing of Breast Tissue-Mimicking Phantom for Needle Biopsy Cutting: A Pilot Study

Breast lesion tissue can be extremely stiff, e.g. calcification or soft, e.g. adipose. When performing needle biopsy, too small or scanty samples can be retrieved due to the tissue is mainly compressed instead of being cut. In order to studying the tissue cutting performance in various cutting conditions, tissue-mimicking phantoms are frequently used as a surrogate of human tissue. The advantage of using tissue phantoms is that their mechanical properties can be controlled. The stiffness of a tissue phantom can be measured by an indentation test. Previous studies have demonstrated mathematic models to estimate Young’s moduli of tissue phantoms from force-displacement data with an adjustable coefficient according to the geometry of the indenter. Tissue force reactions occurred needle insertion has been largely researched [1], but few studies investigated the tissue cutting with a rotational needle, which is a cutting method largely used in the breast needle biopsy. Research has demonstrated that the influence of rotation can significantly reduce the insertion force [2], but the experiment was conducted on a specific formula of silicone-based tissue phantoms. This paper served as a pilot study of a large-scale experiment to study the effect of rotational cutting on various cutting conditions and target materials, including artificial and biological soft tissues. Two most common types of soft tissue phantoms, biopolymers (gelatin gels and agar) and chemically synthesized polymers (polydimethylsiloxane, PDMS) were investigated. Indentation tests were performed to estimate the mechanical properties of tissue phantoms which were then verified by finite element simulations. Tissue cutting tests with and without rotation were conducted to evaluate the effect of needle rotation on the tissue force reactions.

Optimizing Emergency Department Workflow Using Radio Frequency Identification Device (RFID) Data Analytics

Emergency Department (ED) is a complex care delivery environment in a hospital that provides time sensitive urgent and lifesaving care [1]. Emergency medicine is an unscheduled practice and therefore providers experience extreme fluctuations in their workload. ED crowding is a major concern that affects the efficacy of the ED workflow, which often is challenged by long wait times, overuse of observation units, patients either leaving without being seen by a provider and non-availability of inpatient beds to accommodate patients after diagnosis [2]. Evaluating ED workflow is a challenging task due to its chaotic nature, with some success using time-motion studies and novel capacity management tools are nowadays becoming common in ED to address workflow related issues [3]. Several studies reveal that Electronic Medical Record (EMR) adoption has not resulted in significant ED workflow improvements nor reduced the cost of ED operations. Since raw EMR data does not offer operational and clinical decision making insights, advanced EMR data analytics are often sought to derive actionable intelligence from EMR data that can provide insights to improve ED workflow. Improving ED workflow has been an important topic of research because of its great potential to optimize the urgent care needed for the patients and at the same time save time and cost. Radio Frequency Identification Device (RFID) is a wireless automatic identification and data capture technology device that has the potential for improving safety, preventing errors, saving costs, and increasing security and therefore improving overall organizational performance. RFID technology use in healthcare has opened a new space in healthcare informatics research that provides novel data to identify workflow process pitfalls and provide new directions [4]. The potential advantages of RFID adoption in healthcare and especially in ED has been well recognized to save costs and improve care delivery [5]. However, the large upfront infrastructure costs, need for an integrated health information technology (HIT), advanced analytical tools for big data analysis emerging from RFID and skilled data scientists to tackle the data to derive actionable intelligence discourage many hospitals from adoption RFID technology despite its potential advantages. Our recent pilot study on the RFID data analytics demonstrated the feasibility of quantifying and analyzing two novel variables such as ‘patient alone’ time defined as the total time a patient spends alone without interaction with a health care staff in the ED and ‘provider time’ defined as the total time a patient spends interacting with any health care staff [6]. The study motivated a more comprehensive big data analytics of RFID data which can provide better insights into optimizing ED workflow which can improve the quality of care in the ED and also reduce cost. In this work, the authors attempt to describe the RFID adoption in the ED at the Saint Mary’s Hospital at Mayo Clinic, in Rochester, MN, a level one trauma center both for children and adults as a step towards optimizing ED workflow.

Design of a Robotic Catheterization Platform With Use of Commercial Ablation Catheter

Cardiovascular diseases including atherosclerosis, thrombosis, aneurysm and arrhythmia remain the major cause of mortality in developed countries, accounting for 34% of deaths each year [1]. Commonly used minimally invasive vascular intervention with using catheters leads to higher success rate than open surgery [2]. Integrating robotic technologies into active control of catheters in teleoperation manner has promised to reduce radiation exposure to surgeons and improve accuracy during electro-physiological (EP) procedures [1]. Common used commercial robotic EP catheter platforms such as Sensei (Hansen Medical Inc., USA) and Niobe (Stereotaxis Inc., USA) are usually composed of a catheter driver (slave side) which can be remotely controlled by a console operator (master side). However, the Sensei catheters are more rigid and bigger than standard catheters because of their two-layer-sheath structure; and Magnetic Niobe systems are huge and expensive. In this paper, we propose a mechanism of remote-driving catheterization platforms in which a commercial tip-steerable ablation catheter (St. Jude Medical Inc., USA) (Fig. 1) is manipulated by a catheter driver in three degree of freedoms (DOF) (insertion/withdrawal, rotation and tip deflection). In addition, we also present the design of the control software based on Object-Oriented Programming (OOP) method which is expected to give the other researchers a guide line during robotic catheter design.

Review of Cardiac Pacemaker Lead Designs for Computational Models in a VR Environment

An implantable cardiac pacemaker is used to modify and treat irregular heartbeats [1] and invented in 1958 [2]. Devices have no fixation or fixed to the heart wall. No fixation leads lay in the bottom of heart cavities, while fixed leads have tines (passive) or a helix screw (active) to attach to the heart. Lead geometries and material properties vary between companies, with geometric sizing based primarily on the internal mechanics of the lead. Finite element analysis (FEA), computational fluid dynamics (CFD) and bench-top simulations are used to evaluate cardiac leads. These simulations analyze only one lead and struggle to compare and test variations in lead designs. Advanced computational resources can run many computer simulations of anatomical environments, however model complexity increases the time to run each simulation. To address this issue, we present a simplified parameterized design space for cardiac pacemaker leads in the right atrium. This information will be used to run multiple simulations of leads in blood flow, for visualization in a single virtual reality (VR) environment and allow the designer to iterate through many design variations (See Figure 1).

Laparoscopic Skill Classification Using the Two-Third Power Law and the Isogony Principle

Surgical skill evaluation is a field that attempts to improve patient outcomes by accurately assessing surgeon proficiency. An important application of the information gathered from skill evaluation is providing feedback to the surgeon on their performance. The most commonly utilized methods for judging skill all depend on some type of human intervention. Expert panels are considered the gold standard for skill evaluation, but are cost prohibitive and often take weeks or months to deliver scores. The Fundamentals of Laparoscopic Surgery (FLS) is a widely adopted surgical training regime. Its scoring method is based on task time and number of task-specific errors, which currently requires a human proctor to calculate. This scoring method requires prior information on the distribution of scores among skill levels, which creates a problem any time a new training module or technique is introduced. These scores are not normally provided while training for the FLS skills test, and [1] has shown that FLS scoring does not lend any additional information over sorting skill levels based on task time. Crowd sourced methods such as those in [2] have also been used to provide feedback and have shown concordance with patient outcomes, however it still takes a few hours to generate scores after a training session. It is desired to find an assessment method that can deliver a score immediately following a training module (or even in real time) and depends neither on human intervention nor on task-specific probability distributions. It is hypothesized that isogony-based surgical tool motion analysis discerns surgical skill level independent of task time.

In Vitro Evaluation of Coating Performance of Guidewire Surrogates

Vascular guidewires are commonly used during interventional surgery to help introduce and position intravascular catheters at the treatment site. Nitinol (NiTi) and stainless steel are the most commonly used alloys in guidewires and a thin layer of polymer coating is usually applied on the guidewire surface to reduce friction within the lumen of blood vessels. Hydrophobic (e.g. PTFE) or hydrophilic (e.g., hyaluronic acid (HA), polyvinylpyrrolidone (PVP), etc.) coatings may be used for this purpose, but coating separation/flaking has been reported from intravascular medical devices [1]. Coating fragments may cause serious adverse events in patients, including pulmonary embolism and infarction, myocardial embolism, necrosis, and death. Hydrophilic polymer emboli in patients has also been reported [2][3][4]. By 2015, the Environmental Protection Agency (EPA) required device manufacturers to phase out the use of the surfactant, perfluorooctanoic acid (PFOA), a potential carcinogen during polytetrafluoroethylene (PTFE) coating manufacturing [5]. Such changes in manufacturing processes need to be evaluated for their effects on coating performance. Of special concern is flaking of coatings, a multifactorial phenomenon that may be related to changes in device design, manufacturing, pre-conditioning, storage, and/or clinical use. There is no comprehensive standard for assessment of coating performance on guidewires. The objective of this study was to evaluate hydrophilic coating integrity and durability during in vitro soaking and bending stress tests.

Toward Inkjet Additive Manufacturing Directly Onto Human Anatomy

Bioprinting technology has been rapidly increasing in popularity in the field of tissue engineering. Potential applications include tissue or organ regeneration, creation of biometric multi-layered skin tissue, and burn wound treatment [1]. Recent work has shown that living cells can be successfully applied using inkjet heads without damaging the cells [2]. Electrostatically driven inkjet systems have the benefit of not generating significant heat and therefore do not damage the cell structure. Inkjets have the additional benefit of depositing small droplets with micrometer resolution and therefore can be used to build up tissue like structures. Previous attempts at tracking and drawing on a hand include either direct contact with the hand [3] or tracking the hand only in two degrees of freedom [4]. In this work we present an approach to track a hand with three degrees of freedom and accurately apply a substance contact free to the hand in a desired pattern using a bioprinting compatible inkjet. The third degree of freedom, in this case depth from the hand surface, provides improved control over the distance between the inkjet head and object, thus increasing deposition accuracy.

Skin Self-Screening Camera for Veterans With Spinal Cord Injury

Veterans with spinal cord injury (SCI) are at high risk for developing debilitating pressure injuries, particularly to their seated areas (e.g. coccyx, sacral and gluteal) [1]. To prevent development of a pressure injury the Veteran with SCI is encouraged to invoke multiple prevention strategies [2]. One recommended prevention strategy is to conduct twice daily skin self-screenings. Skin self-screening is usually conducted in the bed, prior to arising in the morning and prior to sleep in the evening. The current method to conduct skin self-screening utilizes a mirror at the end of a long handle. The Veteran with SCI examines at-risk areas for changes in their skin integrity such as discoloration, swelling, or changes in skin texture. This method can take up to 20 minutes to complete. In the event there is a change to skin integrity, the pressure injury prevention protocol advises the Veteran with SCI to off-load that particular area for at least 24 hours [3]. Further, he/she is advised to consult with their skin specialist if the area does not resolve to normal color or texture within that next 24 hour period. The consequences of ignoring an early stage pressure injury can be serious e.g. weeks to months of hospitalization attempting to heal the injury, tens to hundreds of thousands of dollars in healthcare costs, possible surgery to close the wound and possibly death [4]. Informal interviews with Veterans with SCI clarified and validated that conducting skin screening with the mirror could be very challenging due to barriers such as: not having a baseline image to compare to; the mirror image not being viewable to the user due to lack of user flexibility or body habitus; the mirror does not easily allow a complete view of all the at-risk areas; the user not being able to discern what he/she is actually viewing possibly due to mirror image distortion and limited visual acuity. The need for a better skin self-screening device was evidenced by the advanced pressure injuries Veterans presented to their healthcare providers. Finding a pressure injury in the early stages of development and intervening immediately, such as repositioning, can improve the trajectory of the injury [5]. Therefore the project goal was to offer a better tool for and improve the efficacy of skin self-screening for the Veterans with SCI. To overcome the identified barriers, our team of VA clinicians and engineers of the Minneapolis Adaptive Design & Engineering (MADE) program invented such a device at the Minneapolis VA. This paper presents the patient centered iterative process that was used to develop a skin self-screening device and the future directions for this technology.

Improving Automatic Control of an Ankle-Foot Prosthesis Using Machine Learning Algorithms

Most commercially available lower-limb prostheses are designed for walking, not for standing. The Minneapolis VA Health Care System has developed a bimodal prosthetic ankle-foot system with distinct modes for walking and standing [1]. With this device, a prosthesis user can select standing or walking mode in order to maximize standing stability or walking functionality, depending on the activity and context. Additionally, the prosthesis was designed to allow for an “automatic mode” to switch between standing and walking modes based on readings from an onboard Inertial Measurement Unit (IMU) without requiring user interaction to manually switch modes. A smartphone app was also developed to facilitate changing between walking, standing and automatic modes. The prosthesis described in [1] was used in a pilot study with 18 Veterans with lower-limb amputations to test static, dynamic, and functional postural stability. As part of the study, 17 Veterans were asked for qualitative feedback on the bimodal ankle-foot system (Table 1). The majority of participants (82%) expressed an interest in having an automatic mode. The participants also indicated that the automatic mode would need to reach walking mode on their first step and to lock the ankle quickly once the standing position was achieved. When asked about how they wanted to control the modes of the prosthesis, 82% wanted to use a physical switch and only 12% wanted to use a smartphone app. The results indicated that the following major design changes would be needed: 1) A fast and accurate automatic mode 2) A physical switch for mode changes This paper describes the use of machine learning algorithms to create an improved automatic mode and the use of stakeholder feedback to design a physical switch for the bimodal ankle-foot system.

Defining the Relationship of Magnetohydrodynamic Voltages and Magnetic Field Strength

The magnetohydrodynamic (MHD) effect is observed in flowing electrolytic fluids and their interactions with magnetic fields. The magnetic field (B0), when perpendicular with the electrolytic fluid flow (μ), causes the shift of the charged particles in the fluid to shift across the length of the vessel (L) normal to the plane of B0 and flow, creating a voltage (VMHD) observable through voltage potential measurements across the flow (Eqn. 1)[1].(1)VMHD=∫0Lu⇀×B0⇀·dL⇀In the medical field, this phenomenon is commonly encountered inside of a human body inside of an MRI machine (Fig. 1). The effect appears most prominently inside the aortic arch due to orientation and size, and is a large contributing factor to noise observed in intra-MRI ECGs [2, 3]. Traditionally, this MHD induced voltage (VMHD) was filtered out to obtain clean intra-MRI ECGs, but recent studies have shown that the VMHD induced in a vessel is related to the blood flow through it (stroke volume in the case of the aortic arch) [4]. Further proof of this relationship can be shown from the increase in VMHD measured from periphery blood vessels during periods of elevated heart rate from exercise stress, when compared to baseline state [5]. Previously, a portable device was built to utilize induced VMHD as an indicator of flow [6]. The device was capable of showing change in blood flow, utilizing a blood flow metric obtained from VMHD, however a quantitative relationship between VMHD and blood flow has yet to be established. This study aims to define the relationship between induced VMHD and magnetic field strength in a controlled setting. Through modulating the distance between a pair of magnets around a flow channel, we hope to better realize the relationship between magnetic field strength and induced VMHD with constant flow and electrolytic solution concentration.