Accuracy and performance of a new handheld ultrasound machine with wireless system

Utility of tele-guidance for point-of-care ultrasound: a single center prospective diagnostic study

BACKGROUND

Point-of-care-ultrasound (POCUS) improves diagnostic accuracy and expedites lifesaving procedures. Remote areas disproportionately underuse ultrasound (US) due to a dearth of US trained professionals, imaging tools, and lack of quality assurance. Handheld US probes have been approved for diagnostic imaging but there have been limited studies examining their tele-guidance features. This study investigates whether physician tele-guidance improved ultrasound image acquisition by untrained scanners.

METHODS

To determine the effectiveness of tele-guidance for ultrasound image acquisition, 30 participants (15 in each study arm: experimental and control) with no ultrasound or medical experience gathered images of the heart, right kidney, and gallbladder of a standardized patient using a handheld ultrasound probe (Butterfly iQ +). All participants watched a standardized ultrasound tutorial video and were randomized into the control or experimental group. A physician assisted the experimental group using ultrasound probe's tele-guidance feature while the control group received no assistance. Time to image acquisition was recorded for both groups, and the images were graded by 3 blinded radiologists using the RACE tool to determine image and diagnostic quality.

RESULTS

There was evidence that mean imaging time was greater in the control group for the heart, right kidney, and gallbladder (p < 0.0001, all; Cohen's DL: 2.0, 1.7, 3.0, respectively). Similarly, there was evidence that the predicted mean image quality for the heart, right kidney, and gallbladder was higher for the experimental group compared to the control group (3.46 versus 1.86, 4.49 versus 1.58, and 3.93 versus 1.5, respectively; p < 0.0001, all). There was also evidence that the diagnostic quality of images had a statistically higher predicted probability of meaningful interpretation for the experimental group for pericardial fluid, intraperitoneal fluid, and acute cholecystitis (p = 0.003, p < 0.0001, p < 0.0001, respectively).

CONCLUSIONS

Tele-guidance improves time to image acquisition and clinical applicability of ultrasound images obtained by untrained scanners.

Comparison of a handheld ultrasound device with cart-based ultrasound for the assessment of gout lesions in people with established gout

OBJECTIVES

Use of handheld portable ultrasound is increasing and would improve access for people with rheumatic disease when conventional, cart-based ultrasound is unavailable. This study compared handheld and cart-based ultrasound for the assessment of gout lesions in people with gout.

METHODS

The lower limbs of 21 participants with gout were independently scanned at six sites (1st and 2nd metatarsophalangeal joints, knee, patellar ligament, Achilles tendon, and peroneal tendons) using cart-based (LOGIQ P9) and handheld (Vscan Air™) ultrasound by two rheumatologists. One rheumatologist was randomized to scan the right or left leg first with the cart-based or handheld ultrasound. The other rheumatologist scanned the legs in the opposite order with the imaging devices reversed. Images were saved and blinded images scored for double contour, tophus, erosion and aggregates using OMERACT definitions by two rheumatologists experienced in gout ultrasound.

RESULTS

On handheld ultrasound, 90% of participants had at least one site with double contour, tophus and erosions, and 100% had at least one site with aggregates. There were similar findings using cart-based ultrasound. However, site-level inter-device analysis showed only fair-good agreement: kappa (percentage agreement) for double contour 0.22 (67%), tophus 0.46 (77%), erosion 0.63 (83%) and aggregates 0.37 (75%). There were more aggregates detected by cart-based ultrasound in joints and more tophi detected by handheld ultrasound in ligaments and tendons.

CONCLUSIONS

Handheld ultrasound can detect gout lesions in people with established gout. However, concordance between cart-based and handheld ultrasound in detection of some gout lesions is low, particularly double contour and aggregates.

An Assessment of the Imaging Performance of Hand-Held Ultrasound Scanners Using the Edinburgh Pipe Phantom

OBJECTIVE

Although hand-held ultrasound devices (HHUSDs) are currently used for a diverse range of diagnostic and interventional applications the imaging performance of such scanners is rarely considered. The aim of this study was to assess the imaging performance of a wide-range of HHUSDs and compare their imaging performance to cart-based systems utilized for the same clinical applications.

METHODS

The grayscale imaging performances of 19 HHUSDs from eight different manufacturers, manufactured between 2016 and 2021, were measured using a figure-of-merit known as the resolution integral. The imaging performance of the HHUSDs were compared to 142 cart-based ultrasound scanners.

RESULTS

The HHUSD with the overall highest resolution integral (66) was a Butterfly (Burlington, MA, USA) wired phased array for small parts applications, followed by a Philips (Bothell, WA, USA) Lumify wired curvilinear transducer (57) for abdominal applications, a Butterfly wired phased array (56) for abdominal applications, a GE (Freiburg, Baden-Wurttemberg, Germany) VScan Air wireless linear array (56) for small parts applications, and a Healcerion (Seoul, Korea) Sonon 300L wireless linear array (56) for small parts applications. A GE VScan Extend wired phased array had the highest resolution integral (44) for cardiac applications.

CONCLUSIONS

The Butterfly phased array had the highest resolution integral of all the 19 HHUSDs, although this value is still less than the majority of cart-based cardiac and abdominal ultrasound scanners manufactured from 2010 to 2017. Clinical users of HHUSDs should be mindful of the limitations in imaging performance of hand-held ultrasound devices.

Reliability of Ultrasound Measurements of the Median Nerve in Asymptomatic Subjects Using a Handheld Device

This study investigated the reliability of measuring the median nerve cross-sectional area (CSA) at the carpal tunnel inlet using a handheld ultrasound device (HUD) compared to a standard ultrasound system, focusing on intra- and inter-operator reproducibility among novice and expert operators. Employing a prospective cross-sectional design, 37 asymptomatic adults were assessed using both devices, with measurements taken by an expert with over five years of experience and a novice with less than six months. The CSA was determined using manual tracing and ellipse methods, with reproducibility evaluated through intraclass correlation coefficients (ICCs) and agreement assessed via Bland-Altman plots. Results showed a high degree of agreement between the devices, with excellent intra-operator reproducibility (ICC > 0.80) for the expert, and moderate reproducibility for the novice (ICCs ranging from 0.539 to 0.841). Inter-operator reliability was generally moderate, indicating acceptable consistency across different experience levels. The study concludes that HUDs are comparable to standard ultrasound systems for assessing median nerve CSA in asymptomatic subjects, with both devices providing reliable measurements. This supports the use of HUDs in diverse clinical environments, particularly where access to traditional ultrasound is limited. Further research with a larger sample and symptomatic patients is recommended to validate these findings.

Application of Deep Learning for Real-Time Ablation Zone Measurement in Ultrasound Imaging

BACKGROUND

The accurate delineation of ablation zones (AZs) is crucial for assessing radiofrequency ablation (RFA) therapy's efficacy. Manual measurement, the current standard, is subject to variability and potential inaccuracies.

AIM

This study aims to assess the effectiveness of Artificial Intelligence (AI) in automating AZ measurements in ultrasound images and compare its accuracy with manual measurements in ultrasound images.

METHODS

An in vitro study was conducted using chicken breast and liver samples subjected to bipolar RFA. Ultrasound images were captured every 15 s, with the AI model Mask2Former trained for AZ segmentation. The measurements were compared across all methods, focusing on short-axis (SA) metrics.

RESULTS

We performed 308 RFA procedures, generating 7275 ultrasound images across liver and chicken breast tissues. Manual and AI measurement comparisons for ablation zone diameters revealed no significant differences, with correlation coefficients exceeding 0.96 in both tissues (p < 0.001). Bland-Altman plots and a Deming regression analysis demonstrated a very close alignment between AI predictions and manual measurements, with the average difference between the two methods being -0.259 and -0.243 mm, for bovine liver and chicken breast tissue, respectively.

CONCLUSION

The study validates the Mask2Former model as a promising tool for automating AZ measurement in RFA research, offering a significant step towards reducing manual measurement variability.

Musculoskeletal ultrasound: a technical and historical perspective

During the past four decades, musculoskeletal ultrasound has become popular as an imaging modality due to its low cost, accessibility, and lack of ionizing radiation. The development of ultrasound technology was possible in large part due to concomitant advances in both solid-state electronics and signal processing. The invention of the transistor and digital computer in the late 1940s was integral in its development. Moore's prediction that the number of microprocessors on a chip would grow exponentially, resulting in progressive miniaturization in chip design and therefore increased computational power, added to these capabilities. The development of musculoskeletal ultrasound has paralleled technical advances in diagnostic ultrasound. The appearance of a large variety of transducer capabilities and rapid image processing along with the ability to assess vascularity and tissue properties has expanded and continues to expand the role of musculoskeletal ultrasound. It should also be noted that these developments have in large part been due to a number of individuals who had the insight to see the potential applications of this developing technology to a host of relevant clinical musculoskeletal problems. Exquisite high-resolution images of both deep and small superficial musculoskeletal anatomy, assessment of vascularity on a capillary level and tissue mechanical properties can be obtained. Ultrasound has also been recognized as the method of choice to perform a large variety of interventional procedures. A brief review of these technical developments, the timeline over which these improvements occurred, and the impact on musculoskeletal ultrasound is presented below.

Physicians' perceptions of the daily use of a handheld ultrasound device in the labor room

OBJECTIVE

The objective of our study was to describe the perception of physicians who use a handheld ultrasound (US) device in an intensive perinatal care unit.

METHODS

We conducted a prospective observational study in the labor ward of an intensive perinatal care unit between November 2021 and May 2022. Obstetrics & Gynecology residents in rotation in our department during this time were recruited as participants in this study. All the participants were provided with a handheld US device Vscan Air™ (GE Healthcare, Zipf, Austria) to use during their normal days and nights practice in labor ward. At the end of their 6 months rotation, participants completed an anonymous surveys about their perceptions of the handheld US device. The survey included questions about the ease of use in clinical situations, the amount of time of initial diagnosis, performances of the device, feasibility to use, and patient's satisfaction with the use of the device.

RESULTS

6 residents in their last year of residency were included. All the participants were satisfied with the device and would like to use it in their future practice. They all agreed that the probe was easy to handle and that the mobile application was easy to use. Image quality was always considered good by the participants and 5/6 of them declared that the handheld US device was always sufficient and did not require any confirmation with a conventional US machine. 5/6 of the participants considered that the handheld US device allowed them to gain time for clinical decision but half of them did not estimate that the use of the handheld US device improved their ability to make a clinical diagnosis.

CONCLUSION

Our study suggests that the Vscan Air™ is easy to use, with a good quality image and reduces the amount of time to make a clinical diagnosis. Handheld US device could be useful in the daily practice in maternity hospital.

Three-Dimensional Imaging of Commonly Performed Peripheral Blocks: Using a Handheld Point-of-Care Ultrasound System

Background

Handheld ultrasound devices have become popular among clinicians due to their affordability and compatibility with tablets and smartphones. Several handheld ultrasound devices have the capability to construct three-dimensional (3D) images using a traditional two-dimensional (2D) ultrasound transducer.

Objectives

The current study aimed to construct 3D images of common peripheral nerve and fascial plane blocks using a handheld ultrasound device with a 2D ultrasound probe.

Methods

A total of 10 patients who were scheduled to receive ultrasound-guided peripheral nerve blocks for outpatient surgery and classified as the American Society of Anesthesiologists physical status I or II with a body mass index of ≤ 30 kg/m² were included in the study. Patients who presented with anatomical variations during the initial ultrasound scanning were excluded.

Results

This study successfully constructed 3D images of 10 peripheral nerve blocks. The average time to complete each 3D scan was less than 5 seconds per attempt, with fascial plane blocks requiring twice the amount of time to complete. All the nerve blocks provided effective postoperative analgesia without complications. The 3D images were successfully captured in all patients.

Conclusions

The 3D images provide clinicians with valuable information on the anatomical boundaries of the injectate that can further direct needle direction and placement of local anesthetic to achieve visual confidence of anesthetic spread.

Comparison of four handheld point-of-care ultrasound devices by expert users

Background

Point-of-care ultrasound (POCUS) is rapidly becoming ubiquitous across healthcare specialties. This is due to several factors including its portability, immediacy of results to guide clinical decision-making, and lack of radiation exposure to patients. The recent growth of handheld ultrasound devices has improved access to ultrasound for many clinicians. Few studies have directly compared different handheld ultrasound devices among themselves or to cart-based ultrasound machines. We conducted a prospective observational study comparing four common handheld ultrasound devices for ease of use, image quality, and overall satisfaction. Twenty-four POCUS experts utilized four handheld devices (Butterfly iQ+™ by Butterfly Network Inc., Kosmos™ by EchoNous, Vscan Air™ by General Electric, and Lumify™ by Philips Healthcare) to obtain three ultrasound views on the same standardized patients using high- and low-frequency probes.

Results

Data were collected from 24 POCUS experts using all 4 handheld devices. No single ultrasound device was superior in all categories. For overall ease of use, the Vscan Air™ was rated highest, followed by the Lumify™. For overall image quality, Lumify™ was rated highest, followed by Kosmos™. The Lumify™ device was rated highest for overall satisfaction, while the Vscan Air™ was rated as the most likely to be purchased personally and carried in one’s coat pocket. The top 5 characteristics of handheld ultrasound devices rated as being “very important” were image quality, ease of use, portability, total costs, and availability of different probes.

Conclusions

In a comparison of four common handheld ultrasound devices in the United States, no single handheld ultrasound device was perceived to have all desired characteristics. POCUS experts rated the Lumify™ highest for image quality and Vscan Air™ highest for ease of use. Overall satisfaction was highest with the Lumify™ device, while the most likely to be purchased as a pocket device was the Vscan Air™. Image quality was felt to be the most important characteristic in evaluating handheld ultrasound devices.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13089-022-00274-6.

Ultrasound assessment of SARS-CoV-2 pneumonia: a literature review for the primary care physician

The SARS-CoV-2 pandemic is considered one of the most critical global health emergencies in the last century. The diagnostic approach to the novel coronavirus disease (COVID-19) and its possible complications through a point-of-care-ultrasound (POCUS) evaluation could represent a good solution in the primary care setting. POCUS is a non-invasive technique that can be used outside hospitals to screen COVID-19 patients and their complications safely. Moreover, it offers several applications of diagnostic evaluation not only on lung parenchyma but also to search disease complications, such as the cardiovascular system, even at the patients' home. This narrative review aims to analyse the literature and provide data to primary care physicians engaged in monitoring and treating patients with SARS-CoV-2 infection. Key MessagesPOCUS is an important tool for the diagnostic approach in the primary care setting already before the start of the SARS-CoV-2 pandemic.Portable devices are useful in monitoring the clinical evolution of patients with infection from SARS-CoV-2 at home.The ultrasonographic features can help the general practice physicians to evaluate the presence of lung involvement and to diagnose complications from the SARS-CoV-2 infection involving districts such as the cardiovascular system.

Use of a wireless ultrasound probe as a portable, noninvasive method for studying reproductive biology in the asp viper, Vipera aspis

In this study, we investigated the use of wireless ultrasonography as an imaging system to study the reproductive ecology of the asp viper (Vipera aspis), a viviparous snake found in southwestern Europe. Female vipers were captured during the summer and immediately scanned to obtain an estimate of the number of embryos. Ultrasound imaging was performed with a pocket‐sized wireless ultrasound probe interfaced with a tablet with a dedicated app. Vipers were then released at the exact capture site after collecting data on body size and weight. We validate wireless ultrasonography as a non‐destructive, effective tool for ultrasonic investigations in the field. Wireless probes are light and compact, which facilitates carriage in rugged terrain. Moreover, the absence of cables simplifies the maneuvers to be made on a small, potentially dangerous snake. Importantly, ultrasound scans can be performed at the capture site, thus minimizing restraint time and handling of gravid females.

We establish wireless ultrasonography as an effective tool for animal fieldwork.

Wireless ultrasound scanners are light and flexible and can be used in harsh environments where power sources are not accessible.

Accuracy Report on a Handheld 3D Ultrasound Scanner Prototype Based on a Standard Ultrasound Machine and a Spatial Pose Reading Sensor

The aim of this study was to develop and evaluate a 3D ultrasound scanning method. The main requirements were the freehand architecture of the scanner and high accuracy of the reconstructions. A quantitative evaluation of a freehand 3D ultrasound scanner prototype was performed, comparing the ultrasonographic reconstructions with the CAD (computer-aided design) model of the scanned object, to determine the accuracy of the result. For six consecutive scans, the 3D ultrasonographic reconstructions were scaled and aligned with the model. The mean distance between the 3D objects ranged between 0.019 and 0.05 mm and the standard deviation between 0.287 mm and 0.565 mm. Despite some inherent limitations of our study, the quantitative evaluation of the 3D ultrasonographic reconstructions showed comparable results to other studies performed on smaller areas of the scanned objects, demonstrating the future potential of the developed prototype.

Effectiveness of Ultrasound Cardiovascular Images in Teaching Anatomy: A Pilot Study of an Eight-Hour Training Exposure

The present study aimed to evaluate the students’ progress in evaluating ultrasound (US) and cadaveric cardiac images and long-time retention of information. First-year medical students were invited to participate in four two-hour online lectures during one week voluntarily. The students were trained to recognize cardiovascular anatomical structures on US and cadaveric images during the intervention. The participants’ abilities to identify specific anatomical structures were tested before, immediately after and six months after the training. A group of second-year students without US training participated as a control group and filled the same test once. Ninety-one first-year students agreed to participate, and forty-nine completed all three tests. The performances in the correct identification of cardiovascular structures on the US images significantly improved after the training but significantly decreased after six months. In the intervention group, the accurate identification of cardiovascular structures was significantly higher on cadaveric images (80% vs. 53%, p-value < 0.0001, n = 91 at post-training; 70% vs. 33%, p-value < 0.0001, n = 49 at 6 months after training). The correct answers percentage score in the control group varied from 6.7% to 66.7% for US cardiovascular anatomical without a significant difference than the intervention group (p-value = 0.7651). First-year students’ knowledge of heart US anatomy proved less effective than cadaveric images, significantly improved after training and decreased over time, indicating the need for repetition reinforcement.

Performance of a Handheld Ultrasound Device to Assess Articular and Periarticular Pathologies in Patients with Inflammatory Arthritis

The purpose of this study was to assess the accuracy and performance of a new handheld ultrasound (HHUS) machine in comparison to a conventional cart-based sonographic machine in patients with inflammatory arthritis (IA). IA patients with at least one tender and swollen joint count were enrolled. US was performed on the clinically affected joints using a cart-based sonographic device (Samsung HS40) and a HHUS device (Butterfly iQ). One blinded reader scored all images for the presence of erosions, bony enlargement, synovial hypertrophy, joint effusion, bursitis, tenosynovitis, and enthesitis. Synovitis was graded (B mode and power Doppler (PD)) by the 4-level EULAR-OMERACT scale. To avoid bias by the blinded reader, we included 67 joints of two healthy volunteers in the evaluation. We calculated the overall concordance and the concordance by type of joint and pathological finding. We also measured the time required for the US examination per joint with both devices. Thirty-two patients (20 with RA, 10 with PsA, and one each with gout and SLE-associated arthritis) were included, and 186 joints were examined. The overall raw concordance in B mode was 97% (κappa 0.90, 95% CI (0.89, 0.94)). In B mode, no significant differences were found in relation to type of joint or pathological finding examined. The PD mode of the HHUS device did not detect any PD signal, whereas the cart-based device detected a PD signal in 61 joints (33%). The portable device did not offer any time savings compared to the cart-based device (47.0 versus 46.3 s). The HHUS device was accurate in the assessment of structural damage and inflammation in patients with IA, but only in the B mode. Significant improvements are still needed for HHUS to reliably demonstrate blood flow detection in PD mode.

The Use of Handheld Ultrasound Devices in Emergency Medicine

Purpose of Review

Ultraportable handheld ultrasound (HHU) devices are being rapidly adopted by emergency medicine (EM) physicians. Though knowledge of the breadth of their utility and functionality is still limited compared to cart-based systems, these machines are becoming more common due to ease-of-use, extreme affordability, and improving technology.

Recent Findings

Images obtained with HHU are comparable to those obtained with traditional machines but create unique issues regarding billing and data management. HHU devices are increasingly used successfully to augment the education of practitioners-in-training, by emergency physicians in austere environments, and in the burgeoning fields of "tele-ultrasound" and augmented reality scanning.

Summary

This review seeks to describe the current state of use of HHU devices in the emergency department (ED) including device overview, institutional concerns, unique areas of use, recent literature since their adoption into clinical EM, and their future potential.