Portable Ultrasound Research Articles

A spectral Doppler ultrasound method for estimation of skeletal muscle velocity

Skeletal muscle velocity is a key indicator of neuromuscular function, and monitoring its changes plays important role in tracking the progression of musculoskeletal diseases, injuries, and fatigue. However, existing methods for non-invasive estimation of skeletal muscle velocity primarily use B- mode ultrasound, often with processing methods that are time-consuming or computationally expensive, with varying accuracy based on tissue structure. Here, we propose a spectral Doppler envelope estimation method designed for skeletal muscle measurements. When compared to the modified signal noise slope intersection (MSNSI) method, our method reduces the overall mean absolute error by 13.9% and the mean absolute zero error by 82.1%. We validated our method using a portable ultrasound system on a benchtop setup that mimics the acoustic properties, measurement angles, and velocity patterns of skeletal muscles. Ex vivo and in vivo muscle velocity estimates of parallel and pennate muscles will be compared to those obtained using the MSNSI method and manual tracking of B-Mode images. Our proposed method could enable automated estimation of skeletal muscle velocities during dynamic activities in unconstrained environments, providing new insight into neuromuscular function and movement biomechanics, with potential applications in monitoring fatigue, disease progression, or injury recovery. [Work supported by the National Science Foundation.]

Skeletal Muscle Echo Intensity Values Differ Significantly across Ultrasound Parameter Settings.

Echo intensity determined by muscle ultrasound has been proposed as an efficient method for the assessment of muscle quality. The influence of changing ultrasound parameter settings on echo intensity values was assessed using a standardized approach. In this repeated measures cross-sectional study, sixteen repeated scans of rectus femoris, gracilis, and rectus abdominis were taken in 21 middle-aged persons with a portable Mindray M7 premium ultrasound machine equipped with a linear 5.0-10.0 MHz transducer. The settings of three parameters were fixed: gain, depth, and frequency. The settings of the following adjustable parameters were changed over their entire range: dynamic range, gray map, line density, persistence, and IClear. Repeated measures analyses were performed to evaluate the effect of changing the settings on echo intensity values. In all three muscles, dynamic range, gray map, and IClear correlated significantly (rrm-values ranging between -0.86 and 0.45) with echo intensity. In all three muscles, the echo intensity values differed significantly across the dynamic range (p < 0.013), gray map (p < 0.003), and IClear (p < 0.003). In middle-aged subjects, echo intensity values of lower limb and trunk muscles are significantly related to ultrasound parameters and significantly differ across their respective setting range. For the assessment of muscle quality through ultrasound, it is suggested to fix parameter settings within their midrange in order to minimize the effect of setting-dependent factors on EI values.

Repeatability of ultrasonographic measurement of cross‐sectional area of the multifidus muscle in the horse

SummaryBackgroundRecent studies have described techniques to acquire ultrasound measurements of the cross‐sectional area of the multifidus muscle to investigate back pain in horses and monitor the response to rehabilitation. These techniques have been extrapolated from human research but have not been clinically validated in the horse.ObjectiveThe objective of the study was to investigate whether measuring the cross‐sectional area of the multifidus muscle in horses using ultrasound is a repeatable technique.Study designCross‐sectional.MethodsUltrasound images of the articular process view and interspinous view of the multifidus muscle were acquired at T15, T18, L2 and L5 on the left and right sides. Three images were acquired at each location and each image was measured three times to give an average cross‐sectional area. Study 1 investigated the repeatability of acquiring images in a single session, and then on two separate days. Study 2 compared measurements of images acquired with a console (Philips EpiQ) and a portable (MyLab™Alpha) ultrasound machine. Study 3 investigated the repeatability of measuring the cross‐sectional area using external software, OsiriX. Intraclass correlation coefficients (ICC) were calculated for each study.ResultsRepeatability varied from good to excellent for images taken in a single session. The repeatability for measuring the images using external software was good to excellent. There was poor‐to‐moderate repeatability for images taken on two different days and poor‐to‐good repeatability when using the two different machines.Main limitationsPopulation size, study population limited to a single breed, only one operator.ConclusionsThe measurement of the multifidus muscle in horses has poor repeatability and may have limited application.

Validity and reliability of portable A-mode ultrasound in measuring body fat percentage: A systematic review with meta-analysis.

The present Systematic Review with Meta-analysis study aimed to evaluate the validity and reliability of the Portable A-mode Ultrasound (P-US) for measuring body fat percentage (BF%). Only studies with participants of both genders which had assessed BF% using P-US compared to the reference standard were selected. Publications up until May 31, 2022 were searched in the MEDLINE, COCHRANE, Science Direct, Web of Science, LILACS, SciELO, PEDro, SPORT Discus, CINAHL and SCOPUS databases. QUADAS-2 was used to assess the risk of bias in the validity studies and QAREL was used for the methodological quality of reliability studies. The JAMOVI software program synthesized the results, from which the Pearson Correlation Coefficient (r) or the square root of the Multiple Linear Regression Determination Coefficient (R2) were extracted for the validity studies, and the Mean of Errors of the Bland-Altman Test (ME) and the Confidence Interval (95%CI) with Upper and Lower Limits for the reliability studies. A total of 13 studies were included, generating 26 results for the quantitative synthesis, 14 for validity and 12 for reliability. Regarding the validity results, a strong correlation was identified between the equipment (r = 0.870 [0.845-0.895], P<0.001), with moderate and true heterogeneity (I2 = 53.47%, P = 0.003), presenting publication bias. A small effect size was identified regarding the reliability results, overestimating the results due to chance between the devices (ME = 0.207 [-0.798-1.212], P = 0.686), with low heterogeneity also due to chance (I2 = 19.44%, P = 0.253), with no publication bias. All of the evaluated studies showed some violation of the instruments, confirming the high risk of bias and the low methodological quality. There is concern with heterogeneity for the validity results explained by the subgroups' analysis. The P-US associated with anthropometric perimeters satisfactorily measures the BF% with samples greater than 100 participants, and males. The results in the reliability assessment show high agreement and high variability, greatly expanding the confidence interval, which should be viewed with reservations. This review received financial support from the Brazilian Air Force. The study was registered with PROSPERO under the number CRD42020166617.

Ultrasound diagnostics in solving situational problems in the discipline of clinical pathophysiology

Aim. Тo train future specialists to effectively apply the methods of pathophysiological research (ultrasound diagnostics) in solving situational problems within the course of clinical pathophysiology.Materials and methods. The 2nd and 3rd year students were trained to use stationary and portable ultrasound machines Phillips CX50 and Chison Sonotouch 80. The students were trained to master ultrasound B and M modes, Doppler ultrasonography, as well as elastography of the most common diseases of the endocrine, digestive, and urinary systems. At the first stage, students worked in tandem with the lecture, observing the process of sensor manipulation. At the second stage, each student conducted a study on his or her fellow student.Results. When conducting ultrasound scanning of the hepatoduodenal zone and kidneys, 65% and 55% of students, respectively, failed to obtain an optimal image and to measure anatomical structures during the assigned time interval. Echocardioscopy was established to be the most difficult method to master when solving situational problems within the topic of “Impaired Systemic Circulation”. This task was successfully performed only by 20% of the students. The optimal student-lecturer ratio was established to be 6:1.Conclusion. The use of new ultrasound technologies in the training process is important for forming students’ professional competencies and increasing their motivation.

Automatic Diagnosis of Carotid Atherosclerosis Using a Portable Freehand 3-D Ultrasound Imaging System.

The objective of this study is to develop a deep-learning-based detection and diagnosis technique for carotid atherosclerosis (CA) using a portable freehand 3-D ultrasound (US) imaging system. A total of 127 3-D carotid artery scans were acquired using a portable 3-D US system, which consisted of a handheld US scanner and an electromagnetic (EM) tracking system. A U-Net segmentation network was first applied to extract the carotid artery on 2-D transverse frame, and then, a novel 3-D reconstruction algorithm using fast dot projection (FDP) method with position regularization was proposed to reconstruct the carotid artery volume. Furthermore, a convolutional neural network (CNN) was used to classify healthy and diseased cases qualitatively. Three-dimensional volume analysis methods, including longitudinal image acquisition and stenosis grade measurement, were developed to obtain the clinical metrics quantitatively. The proposed system achieved a sensitivity of 0.71, a specificity of 0.85, and an accuracy of 0.80 for diagnosis of CA. The automatically measured stenosis grade illustrated a good correlation ( r = 0.76) with the experienced expert measurement. The developed technique based on 3-D US imaging can be applied to the automatic diagnosis of CA. The proposed deep-learning-based technique was specially designed for a portable 3-D freehand US system, which can provide a more convenient CA examination and decrease the dependence on the clinician's experience.

High Performance Wearable Ultrasound as a Human-Machine Interface for Wrist and Hand Kinematic Tracking.

Non-invasive human machine interfaces (HMIs) have high potential in medical, entertainment, and industrial applications. Traditionally, surface electromyography (sEMG) has been used to track muscular activity and infer motor intention. Ultrasound (US) has received increasing attention as an alternative to sEMG-based HMIs. Here, we developed a portable US armband system with 24 channels and a multiple receiver approach, and compared it with existing sEMG- and US-based HMIs on movement intention decoding. US and motion capture data was recorded while participants performed wrist and hand movements of four degrees of freedom (DoFs) and their combinations. A linear regression model was used to offline predict hand kinematics from the US (or sEMG, for comparison) features. The method was further validated in real-time for a 3-DoF target reaching task. In the offline analysis, the wearable US system achieved an average [Formula: see text] of 0.94 in the prediction of four DoFs of the wrist and hand while sEMG reached a performance of [Formula: see text]= 0.60. In online control, the participants achieved an average 93% completion rate of the targets. When tailored for HMIs, the proposed US A-mode system and processing pipeline can successfully regress hand kinematics both in offline and online settings with performances comparable or superior to previously published interfaces. Wearable US technology may provide a new generation of HMIs that use muscular deformation to estimate limb movements. The wearable US system allowed for robust proportional and simultaneous control over multiple DoFs in both offline and online settings.

Spontaneous splenic rupture associated with scrub typhus: a case report

BackgroundScrub typhus, an acute febrile disease with mild to severe, life-threatening manifestations, potentially presents with a variety of complications, including pneumonia, acute respiratory distress syndrome, cardiac arrhythmias (such as atrial fibrillation), myocarditis, shock, peptic ulcer, gastrointestinal bleeding, meningitis, encephalitis, and renal failure. Of the various complications associated with scrub typhus, splenic rupture has rarely been reported, and its mechanisms are unknown. This study reports a case of scrub typhus-related spontaneous splenic rupture and identifies possible mechanisms through the gross and histopathologic findings.Case presentationA 78-year-old man presented to our emergency room with a 5-day history of fever and skin rash. On physical examination, eschar was observed on the left upper abdominal quadrant. The abdomen was not tender, and there was no history of trauma. The Orientia tsutsugamushi antibody titer using the indirect immunofluorescent antibody test was 1:640. On Day 6 of hospitalization, he complained of sudden-onset left upper abdominal quadrant pain and showed mental changes. His vital signs were a blood pressure of 70/40 mmHg, a heart rate pf 140 beats per min, and a respiratory rate of 20 breaths per min, with a temperature of 36.8 °C. There were no signs of gastrointestinal bleeding, such as hematemesis, melena, or hematochezia. Grey Turner's sign was suspected during an abdominal examination. Portable ultrasonography showed retroperitoneal bleeding, so an emergency exploratory laparotomy was performed, leading to a diagnosis of hemoperitoneum due to splenic rupture and a splenectomy. The patient had been taking oral doxycycline (100 mg twice daily) for 6 days; after surgery, this was discontinued, and intravenous azithromycin (500 mg daily) was administered. No arrhythmia associated with azithromycin was observed. However, renal failure with hemodialysis, persistent hyperbilirubinemia, and multiorgan failure occurred. The patient did not recover and died on the fifty-sixth day of hospitalization.ConclusionsClinicians should consider the possibility of splenic rupture in patients with scrub typhus who display sudden-onset abdominal pain and unstable vital signs. In addition, splenic capsular rupture and extra-capsular hemorrhage are thought to be caused by splenomegaly and capsular distention resulting from red blood cell congestion in the red pulp destroying the splenic sinus.Graphical abstract

Intra- and inter-rater reliability of muscle and fat thickness measurements obtained using portable ultrasonography in older adults

Ultrasonography (US) is a promising tool for assessing body composition, offering accuracy and accessibility. However, technician skills and equipment characteristics can impact measurement reliability. We aimed to evaluate the intra- and inter-rater reliability of two evaluators using A-mode Portable Ultrasound to measure muscle and fat thickness in Brazilian older adults. Quantitative cross-sectional study carried out with 150 community-dwelling older adults of Campinas-SP-Brazil, recruited in a retirement preparation program and a geriatric outpatient care unit. Scans of nine anatomical points were performed using the portable ultrasound in A-mode (BodyMetrix Pro System BX2000; Livermore, CA), with 6 scans per location and 3 measurements taken by each evaluator. After the selection and analysis of the generated images, muscle and fat thickness were measured. Reliability estimates between measures of the same evaluator (intra-rater) and between evaluators (inter-rater) were assessed using intraclass correlation coefficients (ICC), and differences within and between technicians were assessed using one-way ANOVA. Analyses were carried out for the overall sample and stratified by sex and by nutritional status. Excellent ICC values (>0.90) were found for subcutaneous fat thickness in intra- and inter-rater reliability analyses. The lowest ICC values were observed for deep abdominal fat thickness measured by evaluator 1 (ICC=0.90) and evaluator 2 (ICC=0.87), as well as in the inter-rater analysis (ICC=0.85). Muscle thickness measurements had satisfactory ICC values for triceps, biceps, anterior thigh, and calf, ranging from moderate to good (ICC 0.50-0.90). A portable A-mode ultrasound demonstrates excellent reliability among both intra- and inter-raters for assessing fat thickness but only moderate for muscle thickness in older adults. Hence, this could prompt inquiries regarding the sole reliance on this tool for quantifying muscle mass and examining sarcopenia in older adults. To our knowledge, this study represents the first assessment of reliability for a portable A-mode ultrasound device conducted with older adults.

Wavenumber Beamforming With Sub-Nyquist Sampling for Focus-Beam Ultrasound Imaging.

Conventional medical ultrasound systems utilizing focus-beam imaging generally acquire multichannel echoes at frequencies in tens of megahertz after each transmission, resulting in significant data volumes for digital beamforming. Furthermore, integrating state-of-the-art beamformers with transmission compounding substantially increases the beamforming complexity. Except for upgrading the hardware system for better computing performance, an alternative strategy for accelerating ultrasound data processing is the wavenumber beamforming algorithm, which has not been effectively extended to synthetic focus-beam transmission imaging. In this study, we propose a novel wavenumber beamforming algorithm to efficiently reduce the computational complexity of traditional focus-beam ultrasound imaging. We further integrate the wavenumber beamformer with a sub-Nyquist sampling framework, enabling ultrasonic systems to acquire echoes within the active bandwidth at significantly reduced rates. Simulation and experimental results indicate that the proposed beamformer offers image quality comparable to the state-of-the-art spatiotemporal beamformer while reducing the sampling rate and runtime by nearly ninefold and fourfold, respectively. The proposed approach would potentially help the development of low-power consumption and portable ultrasound systems.

Assessment of anatomic variations of the brachial artery bifurcation using vascular Doppler ultrasound: a cross-sectional study.

Anatomical variations in arteries of the upper limb, such as presence of an accessory brachial artery, are common and widely described in the literature, mainly in cadaveric studies, but it is now possible to diagnose them using vascular Doppler ultrasound. To identify the incidence of accessory brachial artery using vascular Doppler ultrasound and compare the findings with cadaveric studies. This was a prospective study that examined 500 upper limbs of 250 volunteers assessed with vascular Doppler ultrasound using the Sonosite Titan portable ultrasound machine. 15.6% of the participants in our study had the accessory brachial artery anatomical variation. Our percentage is in line with the average rates found in cadaveric studies, which ranged from 0.2% to 22%. Being aware of this variation is fundamental in procedures such as peripheral venipuncture, arteriovenous fistula creation, catheterization, forearm flaps, emergency surgeries on the limb and even correction of fractures by cast. The accessory brachial artery is a frequent variant in the upper limb. The percentage of individuals with an accessory brachial artery in our study was 15.6%, which agrees with data from the literature on cadaveric studies.

Analysis and Design of a Multiplex, Delay‐and‐Sum (MDAS) Beamformer Architecture to Implement a Fixed‐Focus Receive Beamformer for Portable Ultrasound Imaging Systems

A multiplex, delay‐and‐sum (MDAS) architecture is proposed to implement a fixed‐focus receive beamformer such as the first stage of the synthetic aperture sequential beamforming (P‐SASB) and synthetic transmit beams combined with the P‐SASB (STB‐P‐SASB) beamforming methods. The output image of this architecture has a resolution and contrast‐to‐noise ratio (CNR) almost similar to that of the delay‐and‐sum (DAS) architecture. In the analog part of this architecture, there is no need to use any analog memory and in the digital part, the need to use high‐speed memories and interpolation filter is eliminated. In this architecture for each input channel, the power consumption in the mixed‐signal part is increased by approximately 1.14 mW in comparison to that of the DAS architecture. On the other hand, due to the elimination of the power consumption related to the interpolation filter in the digital part, the total power consumption of the MDAS architecture increases by a maximum of 9.2% compared to the DAS architecture. Also, the silicon area required to implement the mixed‐signal part of the MDAS architecture when implementing the first stage of P‐SASB and STB‐P‐SASB beamforming methods is reduced by about 3 times and increased by a maximum of 25%, respectively, compared to that of the DAS architecture.

Response: Using Handheld Portable Ultrasound in Bedside Assessment of Post-Stroke Hemiplegic Shoulders: Early Detection of Glenohumeral Subluxation

Response: Using Handheld Portable Ultrasound in Bedside Assessment of Post-Stroke Hemiplegic Shoulders: Early Detection of Glenohumeral Subluxation

Using Handheld Portable Ultrasound in Bedside Assessment of Post-Stroke Hemiplegic Shoulders: Early Detection of Glenohumeral Subluxation

Using Handheld Portable Ultrasound in Bedside Assessment of Post-Stroke Hemiplegic Shoulders: Early Detection of Glenohumeral Subluxation

Functional Imaging of the Knee-A Comprehensive Review.

Knee pain is a common presenting problem in the general population. Radiographs and magnetic resonance imaging (MRI) are the cornerstones of imaging in current clinical practice. With advancements in technology, there has been increasing utilization of other modalities to evaluate knee disorders. Dynamic assessment utilizing computed tomography and portable ultrasounds have demonstrated the capacity to accurately assess and reproducibly quantify kinematics of knee disorders. Cartilage physiology can be evaluated with MRI. Emerging research has even demonstrated novel musculoskeletal applications of positron emission tomography to evaluate anterior cruciate ligament graft metabolic activity following reconstruction. As technology continues to evolve and traditional ways are improved upon, future comparative studies will elucidate the distinct advantages of the various modalities. Although radiology is still primarily an anatomic specialty, there is immense potential for functional imaging to be the standard of care. This review focuses on the most common musculoskeletal applications of functional imaging as well as future utilization.

Performance evaluation of pocket echo using an ultrasonic accuracy control phantom

In addition to being used in hospitals, ultrasound systems are used in many other medical settings such as disaster relief and home care. In these types of settings, it is important to be able to perform a large number of examinations easily and efficiently. Portable ultrasound systems can be used to meet such needs. The evaluation of ultrasound systems has been driven by the development of accuracy control methods used in breast examinations. This study aimed to evaluate the performance of portable ultrasound systems that have not yet been fully investigated. The performance of two ultrasound systems was evaluated using three measures. For physical evaluation, the change in the mean pixel value of the target and the contrast-to-noise ratio were obtained for each ultrasound system. Statistical analyses were performed to compare these measures between the two systems. For visual evaluation, a receiver operating characteristic analysis was performed. The results of the physical and visual evaluations showed no statistically significant differences between the portable ultrasound systems we evaluated and those that are commonly used in clinical practice.

Portable Wireless Handheld Ultrasound Linear Series UProbe-L5 and Hitachi Aloka F37 Ultrasound Reliability Test

Portable Wireless Handheld Ultrasound Linear Series UProbe-L5 and Hitachi Aloka F37 Ultrasound Reliability Test

Agreement and Reliability of Patient-measured Postvoid Residual Bladder Volumes

BackgroundPost-void residual bladder volume (PVR) measurement in the non-healthcare setting is a valuable opportunity for remote monitoring of voiding dysfunction patients. We hypothesized that PVR self-measurement using a smart-device portable ultrasound system with artificial intelligence would demonstrate high reliability, strong agreement with provider measurement, and be preferred over provider measurements. MethodsPatients were enrolled during outpatient Urology visits. PVRs were measured in triplicate by providers using each of the following: an FDA-cleared (standard) bladder scanner, the portable ultrasound probe using ultrasound images (ButterflyTM US image mode), and the portable ultrasound probe using abstract images (ButterflyTM abstract mode). Subjects self-measured PVRs in triplicate using both imaging modes and reported their experiences via questionnaire. Reliability was assessed via intraclass correlation (ICC). Agreement between methods was assessed via Bland-Altman analyses using a clinically acceptable difference threshold of 50 mL. Results50 patients were enrolled. ICCs ranged from 0.95-0.98 for each method. 95% limits of agreement between standard bladder scanner and patient self-measurement were -71.73 mL and 86.73 mL using ButterflyTM US image mode and -93.84 mL and 112.52 mL using ButterflyTM abstract mode, respectively. Most patients preferred self-measurement over provider measurement (74% vs 26%, respectively). ConclusionsPatient self-measurement of PVR using smart-device integrated portable ultrasound probes is feasible, reliable, and preferred by patients. Limits of agreement between patient self-measurement and standard bladder scanner measurements exceeded our clinically acceptable difference threshold, though the inherent error of ultrasound-based bladder volume measurements should be considered. Longitudinal PVR assessments in non-healthcare settings may facilitate remote monitoring of voiding dysfunction patients.

3D Synthetic Aperture Imaging Method in Spectrum Domain for Low-Cost Portable Ultrasound Systems

3D Synthetic Aperture Imaging Method in Spectrum Domain for Low-Cost Portable Ultrasound Systems

Point of Care Ultrasound in Pediatric Surgery across the European Region-European Pediatric Surgery Association Endorsed Survey.

Our purpose was to assess the state of training, clinical practice, and barriers to use point-of-care ultrasound (POCUS) in pediatric surgery in Europe. An electronic survey was disseminated among European pediatric surgeons utilizing the European Pediatric Surgery Association network and other existing networks. There were 186 respondents from 27 European countries and 7 non-European countries. In most countries (86.6%; N = 161), the initial ultrasound for acute admissions is performed by radiologists, with 1 to 6 hours turnover in 62.9% (N = 117) of urgent cases. Ultrasound by pediatric surgeons (point-of-care ultrasound/POCUS) is performed by 48.4% (N = 90) of respondents, with 29% (N = 54) using it at least once per week. The most common indications for POCUS include abdominal focused abdominal sonography in trauma (53.8%; N = 100), diagnosis of appendicitis (41.9%; N = 78), and intussusception (44.6%; N = 84). In malrotation-volvulus, 28.5% (N = 53) used ultrasound for its diagnosis, while 27.5% (N = 51) would not see an indication here. Training in POCUS occurred informally for 55.4% (N = 103) of participants, while 31.2% (N = 58) attended formal training courses. Almost all respondents wanted to attain further POCUS training (89.3%; N = 166), only 7% (N = 13) did not think this would be useful. For 73.1% (N = 136), POCUS is not currently part of the pediatric surgery training curriculum in their country. Perceived barriers to POCUS use include a lack of training opportunities (26.3% [N = 49]) and a paucity of portable ultrasound machines (17.8% [N = 33]). There is a wide spectrum of POCUS use in pediatric surgery across Europe. For those surgeons who practice POCUS, it is most used for the diagnosis of abdominal conditions. There are differing views among clinicians concerning the most useful applications of POCUS. The extent to which ultrasound is taught during pediatric surgery training differs substantially across European curricula.