Validation of the smallest pocket echoscopic device's diagnostic capabilities in heart investigation

Pocket-sized echocardiography for screening structural heart disease: diagnostic accuracy and cost-effectiveness for population-based studies

BACKGROUND

The standard transthoracic echocardiography has some limitations in emergent and community-based situations. The emergence of pocket-sized ultrasound has led to influential advancements.

METHODS

In this prospective study, in the hospital-based phase, children with suspected structural heart diseases were enrolled. In the school-based phase, healthy children were randomly selected from six schools. All individuals were examined by experienced operators using both the standard and the pocket-sized echocardiography.

RESULTS

A total of 73 individuals with a mean age of 9.9 ± 3.2 years in the hospital-based cohort and 143 individuals with a mean age of 12.8 ± 2.9 years in the school-based cohort were examined. The agreements between the standard and the pocket-sized echocardiography were good or excellent for major CHDs in both cohorts (κ statistics > 0.61). Among valvular pathologies, agreements for tricuspid and pulmonary valves' regurgitation were moderate among school-based cohorts (0.56 [95% confidence interval 0.12-1] and 0.6 [95% confidence interval 0.28-0.91], respectively). The agreements for tricuspid and pulmonary valves' regurgitation were excellent (>0.9) among hospital-based population. Other values for valvular findings were good or excellent. The overall sensitivity and specificity were 87.5% (95% confidence interval 47.3-99.7) and 93.8% (95% confidence interval 85-98.3) among the hospital-based individuals, respectively, and those were 88% (95% confidence interval 77.8-94.7) and 68.4% (95% confidence interval 56.7-78.6) among the school-based individuals, respectively. The cost of examination was reduced by approximately 70% for an individual using the pocket-sized device.

CONCLUSIONS

When interpreted by experienced operators, the pocket-sized echocardiography can be used as screening tool among school-aged population.

Smartphone interfaced handheld echocardiography for focused assessment of ventricular function and structure in children: A pilot study

INTRODUCTION

Miniaturized echocardiographic machines improve availability and portability and can be particularly useful for underserved and resource-limited settings. The goal of this study was to compare left ventricular fractional shortening (FS) and left ventricular ejection fraction (LVEF) obtained by a newer handheld echo (HHE) machine to standard transthoracic echocardiogram (TTE) in children.

METHODS

Pediatric outpatients (Birth-18 years) undergoing TTE were prospectively enrolled. HHE protocol included 2D and M-mode images from the parasternal long, short, and apical-4 chamber views. HHE and TTE measurements were reviewed for agreement. Kappa statistic was used to analyze qualitative indices while FS and LVEF were analyzed with Lin's concordance correlation coefficient (CCC) and Bland-Altman limits of agreement (loa).

RESULTS

Sixty children were enrolled; 55 were included in the quantitative analysis. Mean age was 7.5 ± 5.5 years; 67% males; median HHE image acquisition duration was 2.3(1-5) minutes. Fractional shortening and EF by HHE showed good agreement with TTE [CCC = 0.82, 95%CI (0.73,0.90), mean bias -3.18%, loa (-7.00,6.44%) vs CCC = 0.81 (0.72,0.90), mean bias -0.87%, loa (-6.94,5.17%], respectively. In children ≤5 years, HHE FS (n = 20) and EF (n = 21) agreed with TTE measurement [0.59 (0.31, 0.88), mean bias 0.30%, loa (-8.5, 9.1%); 0.79 (0.63, 0.96), mean bias 0.10%, loa (-5.99, 6.14)]. Kappa values for RV size, function, and LV function were 1.00 (P < .05); 0.75 for LV size (P < .05) and 0.66 for pericardial effusion (P < .05).

CONCLUSION

Handheld echo demonstrates good correlation with standard TTE for focused assessment of ventricular chamber sizes and function in children.

Hand-held cardiac ultrasound examinations performed in primary care patients by nonexperts to identify reduced ejection fraction

BACKGROUND

Early identification of patients with reduced left ventricular ejection fraction (LVEF) could facilitate the care of patients with suspected heart failure (HF). We examined if (1) focused cardiac ultrasound (FCU) performed with a hand-held device (Vscan 1.2) could identify patients with LVEF < 50%, and (2) the distribution of HF types among patients with suspected HF seen at primary care clinics.

METHODS

FCU performed by general practitioners (GPs)/GP registrars after a training programme comprising 20 supervised FCU examinations were compared with the corresponding results from conventional cardiac ultrasound by specialists. The agreement between groups of estimated LVEF < 50%, after visual assessment of global left ventricular function, was compared. Types of HF were determined according to the outcomes from the reference examinations and serum levels of natriuretic peptides (NT-proBNP).

RESULTS

One hundred patients were examined by FCU that was performed by 1-4 independent examiners as well as by the reference method, contributing to 140 examinations (false positive rate, 19.0%; false negative rate, 52.6%; sensitivity, 47.4% [95% confidence interval [CI]: 27.3-68.3]; specificity, 81.0% [95% CI: 73.1-87.0]; Cohen's κ measure for agreement = 0.22 [95% CI: 0.03-0.40]). Among patients with false negative examinations, 1/7 had HF with LVEF < 40%, while the others had HF with LVEF 40-49% or did not meet the full criteria for HF. In patients with NT-proBNP > 125 ng/L and fulfilling the criteria for HF (68/94), HF with preserved LVEF (≥50%) predominated, followed by mid-range (40-49%) or reduced LVEF (< 40%) HF types (53.2, 11.7 and 7.4%, respectively).

CONCLUSIONS

There was poor agreement between expert examiners using standard ultrasound equipment and non-experts using a handheld ultrasound device to identify patients with reduced LVEF. Asides from possible shortcomings of the training programme, the poor performance of non-experts could be explained by their limited experience in identifying left ventricular dysfunction because of the low percentage of patients with HF and reduced ejection fraction seen in the primary care setting.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT02939157). Registered 19 October 2016.

Wireless, Real-Time Plane-Wave Coherent Compounding on an iPhone: A Feasibility Study

The processing power in commercially available hand-held devices has improved dramatically in recent years. In parallel, techniques used in high-frame-rate medical ultrasound imaging, especially plane-wave (PW) imaging, have reduced the number of ultrasound transmissions and amount of data necessary to reconstruct an ultrasound image. In combination, the processing power and data reduction allow all of the processing steps in ultrasound image formation, from raw ultrasound channel data to final rendering, to be performed on a hand-held device. In this study, we send the raw ultrasound channel data from a research scanner wirelessly to an off-the-shelf hand-held device. The hand-held unit's graphical processing unit is processing the raw ultrasound data into the final image, achieving real-time frame rates on the order of 60-90 frames per second (FPS) for a single-angle PW transmission. Higher quality images are achieved by trading off frame rate by coherently compounding multiple PW images, resulting in frame rates on the order of, e.g., 13 FPS when coherently compounding 7 PW transmissions. The presented setup has the potential of providing image quality which could be valuable for simple medical ultrasound diagnostic scans of, e.g., the carotid artery or thyroid. Also, since the computationally expensive beamforming can be done in off-the-shelf devices, this could reduce the price of hand-held ultrasound systems in the future.

Application of mobile health, telemedicine and artificial intelligence to echocardiography

The intersection of global broadband technology and miniaturized high-capability computing devices has led to a revolution in the delivery of healthcare and the birth of telemedicine and mobile health (mHealth). Rapid advances in handheld imaging devices with other mHealth devices such as smartphone apps and wearable devices are making great strides in the field of cardiovascular imaging like never before. Although these technologies offer a bright promise in cardiovascular imaging, it is far from straightforward. The massive data influx from telemedicine and mHealth including cardiovascular imaging supersedes the existing capabilities of current healthcare system and statistical software. Artificial intelligence with machine learning is the one and only way to navigate through this complex maze of the data influx through various approaches. Deep learning techniques are further expanding their role by image recognition and automated measurements. Artificial intelligence provides limitless opportunity to rigorously analyze data. As we move forward, the futures of mHealth, telemedicine and artificial intelligence are increasingly becoming intertwined to give rise to precision medicine.

Noninvasive Cardiac Imaging and the Prediction of Heart Failure Progression in Preclinical Stage A/B Subjects

Heart failure (HF) continues to grow as a cause of morbidity and mortality in our community and presents a significant public health problem, predominantly in individuals ≥65 years of age. Early intervention in asymptomatic HF subjects (Stage A/B) at risk of progression to symptomatic HF (Stage C/D) may provide an opportunity to halt this epidemic. The ability of cardiac imaging to assess cardiac structure and function permits early identification of those at increased risk of developing symptomatic HF. Systolic, diastolic, and structural left ventricular parameters each predict symptomatic HF, but no single parameter has sufficient sensitivity for screening to identify individuals with Stage A/B HF who are at increased risk of disease progression. Transthoracic echocardiography (TTE) has the advantage over other imaging modalities in being able to measure systolic, diastolic, and structural left ventricular parameters, and it identified at least 1 abnormal parameter in >50% of individuals with Stage A/B HF ≥65 years of age. Moreover, identification of at least 1 abnormality according to TTE in individuals with Stage A/B HF ≥65 years of age had 72% to 82% sensitivity for detection of those who subsequently developed symptomatic HF. Therefore, a case can be made for cardiac imaging by using TTE for community-dwelling populations with Stage A/B HF ≥65 years of age to identify those with increased risk of symptomatic HF who can be offered preventative therapies. Further studies are required to determine the best strategy for identifying the risk of symptomatic HF in younger individuals.

A Vector Flow Imaging Method for Portable Ultrasound Using Synthetic Aperture Sequential Beamforming

This paper presents a vector flow imaging method for the integration of quantitative blood flow imaging in portable ultrasound systems. The method combines directional transverse oscillation (TO) and synthetic aperture sequential beamforming to yield continuous velocity estimation in the whole imaging region. Six focused emissions are used to create a high-resolution image (HRI), and a dual-stage beamforming approach is used to lower the data throughput between the probe and the processing unit. The transmit/receive focal points are laterally separated to obtain a TO in the HRI that allows for the velocity estimation along the lateral and axial directions using a phase-shift estimator. The performance of the method was investigated with constant flow measurements in a flow rig system using the SARUS scanner and a 4.1-MHz linear array. A sequence was designed with interleaved B-mode and flow emissions to obtain continuous data acquisition. A parametric study was carried out to evaluate the effect of critical parameters. The vessel was placed at depths from 20 to 40 mm, with beam-to-flow angles of 65°, 75°, and 90°. For the lateral velocities at 20 mm, a bias between -5% and -6.2% was obtained, and the standard deviation (SD) was between 6% and 9.6%. The axial bias was lower than 1% with an SD around 2%. The mean estimated angles were 66.70° ± 2.86°, 72.65° ± 2.48°, and 89.13° ± 0.79° for the three cases. A proof-of-concept demonstration of the real-time processing and wireless transmission was tested in a commercial tablet obtaining a frame rate of 27 frames/s and a data rate of 14 MB/s. An in vivo measurement of a common carotid artery of a healthy volunteer was finally performed to show the potential of the method in a realistic setting. The relative SD averaged over a cardiac cycle was 4.33%.

Clinical utility and diagnostic accuracy of palm-held, mini-sized ultrasonocardiographic scanner in congenital heart disease

BACKGROUND/PURPOSE

To investigate whether a palm-held ultrasonocardiographic scanner would be useful for screening and follow-up in congenital heart disease (CHD).

METHODS

We retrospectively reviewed the echocardiographic images from June 1, 2014 to November 1, 2014. All patients underwent two ultrasonographic examinations including palm-held scanner examination and standard echocardiography. To compare the quality of the two instruments, we developed a diagnostic scoring system ranging from 1 point to 10 points, with 10 points indicating the best quality. Two experienced echocardiographers retrospectively reviewed all recorded images blindedly and gave each examination a score. Comparisons of diagnostic score between two equipments were performed.

RESULTS

A total of 262 patients' images were reviewed. All cardiac lesions could be detected with both instruments. The mean diagnostic score of palm-held scanner and standard echocardiography were 8.20±0.53 versus 9.64±0.37 (p<0.05) in color image and 7.00±1.05 versus 8.56±1.14 (p<0.05) in gray-scale two-dimensional image, respectively. When we compared the score between the two instruments in individual CHDs, we found standard echocardiography had better quality except for detecting muscular ventricular septal defect and pulmonary regurgitation.

CONCLUSION

The diagnostic sensitivity of palm-held scanner in detecting CHD was very good. Despite both instruments having a high diagnostic score in detecting CHD, standard echocardiography had better quality. Traditional echocardiography is still the standard tool for CHD evaluation. However, the palm-held scanner can support physical examination for initial screening and follow-up, and offer cardiologists an opportunity to visualize and listen to the heart at any time.

Focused cardiac ultrasound by unselected residents-the challenges

Background

Focus Cardiac Ultrasound (FoCUS) performed by internal medicine residents on call with 2 h of training can provide a means for ruling out cardiac disease, but with poor sensitivity. The purpose of the present study was to evaluate diagnostic usefulness as well as diagnostic accuracy of FoCUS following 4 h of training.

Methods

All residents on call were given a 4-h training course with an additional one-hour training course after 6 months. They were asked to provide a pre- and post-FoCUS diagnosis, with the final diagnosis at discharge as reference.

Results

During a 7 month period 113 FoCUS examinations were reported; after 53 were excluded this left 60 for evaluation with a standard echocardiogram performed on average 11.5 h after FoCUS. Examinations were performed on the basis of chest pain and dyspnoea/edema. The best sensitivity was found in terms of the detection of reduced left ventricular (LV) ejection fraction (EF) (92%), LV dilatation (85%) and pericardial effusion (100%). High values were noted for negative predictive values, although false positives were seen. A kappa > 0.6 was observed for reduced LVEF, right ventricular area fraction and dilatation of LV and left atrium. In 48% of patients pre- and post-FoCUS diagnoses were identical and concordant with the final diagnosis. Importantly, in 30% examinations FoCUS correctly changed the pre-FoCUS diagnosis.

Conclusions

A FoCUS protocol with a 4-h training program gained clinical usefulness in one third of examinations. False positive findings represented the major challenge.

Impact of Point-of-Care Ultrasound Examination on Triage of Patients With Suspected Cardiac Disease

Complementing the physical examination with a point-of-care ultrasound study (POCUS) can improve patient triage. We aimed to study the impact of POCUS on the diagnosis and management of outpatients and hospitalized patients with suspected cardiac disease. In this multicenter study, a pocket-sized device was used to perform POCUS when the diagnosis or patient management was unclear based on anamnesis, physical examination, and basic diagnostic testing. Eighteen physicians (cardiac fellows 49%, cardiologists 30%, and echocardiographers 21%) performed physical examinations extended by POCUS on 207 patients (inpatients 83% and outpatients 17%). POCUS findings resulted in a change in the primary diagnosis in 14% of patients. In patients whose diagnosis remained unchanged, POCUS results reinforced the initial diagnosis in 48% of the cases. In 39% of the patients, the diagnostic plan was altered, including referral (16%) or deferral (23%) to other diagnostic techniques. Alteration in medical treatment (drug discontinuation or initiation) occurred in 11% of the patients, and in 7% POCUS results influenced the decision whether to perform a therapeutic procedure. Hospitalization or discharge was determined after POCUS in 11% of the patients. In conclusion, during patient triage, extension of the physical examination by POCUS can cause physicians to alter their initial diagnosis, resulting in an immediate change of diagnostic and therapeutic procedures. Based on POCUS results, physicians altered the diagnostic plan either by avoiding or referring patients to other diagnostic procedures in almost half of the studied population.

A futuristic vision of pocket ultrasound machines: watch this space

Introduction: Australian medical ultrasound started in 1959 with the establishment of the Ultrasonics Institute. Since then the technology has advanced tremendously. We are now not only able to obtain clearer images on high specification ultrasound machines but also on pocket‐sized ultrasound machines that are compact, lightweight and affordable.

Method: The following descriptive review will examine the indication for use of pocket ultrasound machines in different clinical settings as well as provide evidence of its image clarity and accuracy. Potentially eligible studies were sought primarily through searches of the electronic databases PubMed, Medline (1996–Present), Embase (1996–Present) and Cochrane Library.

Conclusion: Pocket ultrasound machines, with appropriate ultrasound knowledge and training, can be incorporated successfully in patient management. The addition of point‐of‐care ultrasound has been shown to improve management recommendations and outcomes.

The utility of pocket-sized echocardiography to assess left ventricular systolic function prior to permanent pacemaker implantation

Background

A subset of patients receiving first-time permanent pacemakers (PPM) may also benefit from an implantable cardioverter defibrillator (ICD) based on the presence of left ventricular systolic dysfunction (LVSD). Routine screening using pocket-sized echocardiography (PSE) may be useful in identifying such patients.

Objective

To determine whether PSE can be used by an inexperienced sonographer to adequately screen for LVSD in a patient population receiving a first-time PPM.

Methods

A sonographic trainee (medical student) acquired images using PSE, which were then evaluated by an experienced echocardiologist for both image quality and presence of LVSD. The sensitivity and specificity of assessment by the inexperienced sonographer was compared to the level 3 echocardiologist.

Results

The patient population included 71 individuals (66% male, mean age 77 ± 12 years). Interpretable images where left ventricular ejection fraction (LVEF) could be adequately assessed were obtained in 93% of the patient population. As compared with the echocardiologist, the sonographic trainee had a sensitivity of 60% and a specificity of 98% in detecting LVSD.

Conclusions

For patients receiving first-time PPM, the use of PSE by a sonographic trainee combined with interpretation by an experienced imaging cardiologist can triage for the need to perform standard transthoracic echocardiography (sTTE) by determining the presence of LVSD.

Pocket-sized focused cardiac ultrasound: strengths and limitations

Focused cardiac ultrasound (FCU) has emerged in recent years and has created new possibilities in the clinical assessment of patients both in and out of hospital. The increasing portability of echocardiographic devices, with some now only the size of a smartphone, has widened the spectrum of potential indications and users, from the senior cardiologist to the medical student. However, many issues still need to be addressed, especially the acknowledgment of the advantages and limitations of using such devices for FCU, and the extent of training required in this rapidly evolving field. In recent years, an increasing number of studies involving FCU have been published with variable results. This review outlines the evidence for the use of FCU with pocket-echo to address specific questions in daily clinical practice.

Point-of-care cardiac ultrasound in acute medicine--the quick scan

The optimum management of acute medical patients requires prompt and accurate diagnosis, monitoring and treatment. The clinical history and physical examination remain central to diagnosis, but often need supplementation by laboratory testing or imaging. Echocardiographic assessment of cardiac structure and function provides valuable information that can aid diagnosis and assess clinical progress. It has many advantages as an imaging modality, and recent technological advances have resulted in hand-held, battery-powered ultrasound devices that provide high-quality images. Three broad applications of cardiac ultrasound now exist: conventional echocardiography, focussed echocardiography and the quick-scan. A quick-scan using a hand-held ultrasound device is readily integrated into the bedside clinical assessment, providing information that can be used immediately in diagnostic reasoning; it can also guide pericardiocentesis. Hand-held ultrasound devices can also be used in acute situations, as well as geographically remote areas or special situations (eg disaster zones) where other imaging is not available. However, the diagnostic yield of echocardiography is user dependent, and training is required for its benefits to be realised, adding to the hardware costs. More data are needed on the incremental value of hand-held ultrasonography and a quick-scan over conventional methods of assessment, their impact on clinical outcomes, and cost effectiveness.

Diagnostic accuracy and cost-effectiveness of a pocket-sized transthoracic echocardiographic imaging device

BACKGROUND

The recently introduced pocket-sized portable transthoracic echocardiography (pTTE) is accurate for measurement of cardiac chamber size and function as well as for assessment of valvular regurgitation. This study aimed to compare the diagnostic accuracy of the pocket-sized pTTE with the standard TTE (sTTE) and assess its cost-effectiveness.

HYPOTHESIS

The use of pocket-sized pTTE, as an initial screening tool, may be feasible, accurate and cost-effective in the diagnostic strategy of cardiac abnormalities.

METHODS

The study subjects were 200 patients scheduled for sTTE and an electrocardiogram (ECG). Each patient underwent pTTE examination with the Vscan (GE Medical Systems, Milwaukee, WI) immediately after sTTE. The findings of pTTE and the ECG were compared with the results of sTTE. Cost-effectiveness was calculated.

RESULTS

There was a strong agreement in the detection of abnormal findings between pTTE and sTTE (agreement = 90%), whereas the agreement between the ECG and sTTE was 65%. When pTTE or the ECG was used as an initial screening tool prior to sTTE, similar cost reduction was obtained (approximately 30%) by reducing the number of referrals for sTTE. However, the negative predictive value of a diagnostic strategy with pTTE (92%) was superior to that with an ECG (67%).

CONCLUSIONS

This study demonstrates that the pocket-sized pTTE provides accurate detection of cardiac structural and functional abnormalities beyond the ECG. In addition, the use of pTTE as an initial screening tool prior to sTTE is cost-effective, suggesting that the pocket-sized pTTE is poised to alter the current diagnostic strategy in clinical practice.

Evaluation of a new pocket echoscopic device for focused cardiac ultrasonography in an emergency setting

Introduction

In the emergency setting, focused cardiac ultrasound has become a fundamental tool for diagnostic, initial emergency treatment and triage decisions. A new ultra-miniaturized pocket ultrasound device (PUD) may be suited to this specific setting. Therefore, we aimed to compare the diagnostic ability of an ultra-miniaturized ultrasound device (Vscan™, GE Healthcare, Wauwatosa, WI) and of a conventional high-quality echocardiography system (Vivid S5™, GE Healthcare) for a cardiac focused ultrasonography in patients admitted to the emergency department.

Methods

During 4 months, patients admitted to our emergency department and requiring transthoracic echocardiography (TTE) were included in this single-center, prospective and observational study. Patients underwent TTE using a PUD and a conventional echocardiography system. Each examination was performed independently by a physician experienced in echocardiography, unaware of the results found by the alternative device. During the focused cardiac echocardiography, the following parameters were assessed: global cardiac systolic function, identification of ventricular enlargement or hypertrophy, assessment for pericardial effusion and estimation of the size and the respiratory changes of the inferior vena cava (IVC) diameter.

Results

One hundred fifty-one (151) patients were analyzed. With the tested PUD, the image quality was sufficient to perform focused cardiac ultrasonography in all patients. Examination using PUD adequately qualified with a very good agreement global left ventricular systolic dysfunction (κ = 0.87; 95%CI: 0.76-0.97), severe right ventricular dilation (κ = 0.87; 95%CI: 0.71-1.00), inferior vena cava dilation (κ = 0.90; 95%CI: 0.80-1.00), respiratory-induced variations in inferior vena cava size in spontaneous breathing (κ = 0.84; 95%CI: 0.71-0.98), pericardial effusion (κ = 0.75; 95%CI: 0.55-0.95) and compressive pericardial effusion (κ = 1.00; 95%CI: 1.00-1.00).

Conclusions

In an emergency setting, this new ultraportable echoscope (PUD) was reliable for the real-time detection of focused cardiac abnormalities.

Routinely adding ultrasound examinations by pocket-sized ultrasound devices improves inpatient diagnostics in a medical department

BACKGROUND

We aimed to investigate the potential benefit of adding a routine cardiac and abdominal diagnostic examination by pocket-sized ultrasound device in patients admitted to a medical department.

METHODS

A random sample of 196 patients admitted to the medical department at a non-university hospital in Norway between March and September 2010 was studied. The patients underwent cardiac and abdominal screening with a pocket-sized ultrasound device with B-mode and color flow imaging after a principal diagnosis was set. Three internists/cardiologists experienced in ultrasonography performed the examinations. Diagnostic corrections were made and findings were confirmed by high-end echocardiography and examinations at the radiologic department.

RESULTS

196 patients were included (male=56.6%, mean±SD; 68.1±15.0 years old). The time spent doing the ultrasound screening was mean±SD 4.3±1.6 min for the cardiac screening and 2.5±1.1 min for the abdominal screening. In 36 (18.4%) patients this examination resulted in a major change in the primary diagnosis. In 38 (19.4%) patients the diagnosis was verified and in 18 (9.2%) patients an important additional diagnosis was made.

CONCLUSION

By adding a pocket-sized ultrasound examination of <10 min to usual care, we corrected the diagnosis in almost 1 of 5 patients admitted to a medical department, resulting in a completely different treatment strategy without delay in many of the patients. Routinely adding a cardiac and abdominal ultrasound screening has the potential to rearrange inpatients workflow and diagnosis.