Ultrasound stethoscopy: a renaissance of the physical examination?

Assessment of Thyroid Gland in Children with Point-of-Care Ultrasound (POCUS): Radiological Performance and Feasibility of Handheld Ultrasound in Clinical Practice

Objective

Point-of-Care Ultrasound (POCUS) refers to the use of portable ultrasound machines to perform quick and focused ultrasound examinations at a patient’s bedside or point-of-care. POCUS can be performed by all health workers with specific training to use POCUS. The aim of this study was to investigate the radiological performance and feasibility of POCUS using a handheld ultrasound device (HHUSD) in children for examining the thyroid gland.

Methods

A pediatric endocrinologist performed thyroid imaging in children referred to our hospital with suspected thyroid disease using an HHUSD. The same children underwent ultrasonography (US) imaging using the same device by the first radiologist, and a second radiologist performed thyroid US using an advanced high-range ultrasound device (AHUSD) (defined as the gold-standard method) within two hours. The data obtained by the three researchers were compared with each other.

Results

This study included 105 patients [68.6% girls (n=72)] with a mean age 12.8±3.6 years. When the thyroid volume was evaluated, a strong correlation was found between the measurements of the three researchers (AA vs. MG: r=0.963, AA vs. GT: r=0.969, MG vs. GT: r=0.963, p<0.001). According to the Bland-Altman analysis for total thyroid volume, AA measured 0.43 cc [95% confidence interval (CI): -0.89-0.03] smaller than MG, and 0.11 cc (95% CI: -0.30-0.52) larger than GT, whereas MG measured 0.52 cc (95% CI: 0.09-0.94) larger than GT. When evaluated for the presence of goiter and nodules, a near-perfect agreement was found between the results of the three researchers (AA vs. GT; κ=0.863, MG vs. GT; κ=0.887, p<0.001, and AA vs. GT; κ=1.000, MG vs. GT; κ=0.972, p<0.001, respectively). When evaluated in terms of the longest axis of nodules, a high correlation was found between the measurements of the three researchers (AA vs. MG; r=0.993, AA vs. GT; r=0.996, MG vs. GT; r=0.996, p<0.001). When evaluated in terms of the final diagnosis, the evaluations of the three researchers showed excellent agreement with each other (AA vs. GT; κ=0.893, MG vs. GT; κ=0.863, p<0.001, accuracy rate AA vs. GT: 93.3%; MG vs. GT: 91.4%).

Conclusion

A pediatric endocrinologist, equipped with sufficient training in thyroid US evaluation, incorporated HHUSD examination as a routine clinical tool in an outpatient setting. It was shown that, they could effectively assess normal thyroid tissue in pediatric patients. Moreover, the HHUSD proved to be useful in detecting thyroid pathologies. However, it is important to note that for a more comprehensive evaluation of thyroid nodules, including detailed assessment and Thyroid Imaging Reporting and Data System (TIRADS) classification, patients should be referred to radiology departments equipped with AHUSD systems. These specialized devices, along with the expertise of radiologists, are essential for in-depth evaluations and accurate classification of thyroid nodules.

Portable Device to Assist With Force Control in Ultrasound Acquisition

This study presents a portable device that ensures precise contact force between a subject and a probe to improve the stability and reproducibility of ultrasound (US) acquisition. The mechanical portion of the device includes a servo motor, gears, and a ball screw linear actuator; two photoelectric switches are used to limit the stroke. A combined force and position control system is developed, and a pressure threshold is introduced to reduce the chattering of the system so that it can be applied to US examinations of tissues of different stiffness levels. Force control experiments were conducted on the device, and the results showed that the device can overcome the chattering of a physician's hand and movement caused by a subject's respiration. Additionally, the stability of the US acquisition was substantially improved. Based on clinical trials on humans, this device was observed to improve the consistency of ultrasonic results and the repeatability of images, and it assisted sonographers with maintaining suitable contact force and improving imaging quality. The device can either be handheld by a physician or easily integrated with a manipulator as an autonomous robotic US acquisition device, thereby validating its potential for US applications.

Handheld Echocardiography in a Clinical Practice Scenario: Concordances Compared to Standard Echocardiographic Reports

BACKGROUND

The purpose of this study was to assess the utility of a handheld device (HH) used during common daily practice and its agreement with the results of a standard echocardiography study (STD) performed by experienced sonographers and echocardiographer.

METHODS

A prospective follow-up was conducted in an adult outpatient echocardiography clinic. Experienced sonographers performed the STD and an experienced echocardiographer performed the HH. STD included 2-dimensional images, Doppler and hemodynamics analysis. Hemodynamic assessment was not performed with the HH device because the HH does not include such technology. The images were interpreted by blinded echocardiographers, and the agreement between the reports was analyzed.

RESULTS

A total of 108 patients were included; and the concordance for left ventricle (LV) ejection fraction (EF), wall motion score index, LV and right ventricle (RV) function, RV size, and mitral and aortic stenosis was excellent with κ values greater than 0.80. Wall motion abnormalities had good concordance (κ value 0.78). The agreement for LV hypertrophy, mitral and aortic regurgitation was moderate, and tricuspid and pulmonary regurgitation agreements were low (κ values of 0.26 and 0.25, respectively).

CONCLUSIONS

In a daily practice scenario with experienced hands, HH demonstrated good correlation for most echocardiography indications, such as ventricular size and function assessment and stenosis valve lesion analyses.

Gated Transmit and Fresnel-Based Receive Beamforming With a Phased Array for Low-Cost Ultrasound Imaging

Low-cost ultrasound imaging systems are desired for many applications outside of radiology and cardiology departments. By making ultrasound systems smaller and lower cost, the use of ultrasound has spread from these mainstays to other areas of the hospital such as emergency departments and critical care. To further miniaturize and reduce the cost of ultrasound systems, we have investigated novel Fresnel-based beamforming methods to reduce front-end hardware requirements. Previous studies with linear and curvilinear arrays demonstrated comparable imaging performance using Fresnel-based beamforming versus delay-and-sum (DAS) beamforming. In this work, we extend Fresnel-based beamforming to phased arrays with beam steering. To accomplish this in transmit mode, we introduce a technique called a gated transmit beamformer where multicycle bursts are gated using multiplexers. In receive mode, a 64-element 2.5-MHz phased array is broken up into four 16-element subapertures, and each subaperture performs Fresnel beamforming before a final beamforming step is done. Timing errors are inevitable with Fresnel-based beamforming leading to higher sidelobe and clutter levels. To suppress sidelobe and clutter contributions, we also combine this with our previous technique, dual apodization with cross correlation (DAX) to improve contrast. Field II simulations are performed to evaluate spatial resolution and contrast-to-noise ratio and compared to standard DAS beamforming. Fresnel-based and gated transmit beamforming is also implemented using synthetic aperture data from tissue-mimicking phantoms. Lastly, a hardware proof-of-concept (PoC) Fresnel beamformer was designed, assembled, and evaluated with images from tissue-mimicking phantoms and initial in vivo images.

Stethoscope of the 21st century: dominant discourses of ultrasound in medical education

CONTEXT

In recent years, point-of-care ultrasound (POCUS) has become a widely used clinical tool in a number of clinical specialties. In response, POCUS has been incorporated into medical curricula across the learning continuum, bolstered by enthusiastic appraisals of the technology's benefits for learners, clinicians and patients. In this project, we have sought to identify and understand the effects of dominant discourses influencing the integration of POCUS into medical education.

METHODS

We conducted a Foucauldian critical discourse analysis (CDA) to identify and analyse discourses that legitimise and privilege the use of POCUS in medical education. We assembled an archive of 473 texts published between 1980 and 2017. Each article in the archive was analysed to identify frequently occurring truth statements (expressing concepts whose truths are unquestioned within particular discourses) that we used to characterise the major discourses that construct representations of POCUS in medical education.

RESULTS

We identified three dominant discourses: (i) a visuo-centric discourse prioritising the visual information as truth over other clinical data; (ii) a utilitarian discourse emphasising improvements in patient care; and (iii) a modernist discourse highlighting the current and future needs of clinicians in our technological world. These discourses overlap and converge; the core discursive effect makes the further elevation of POCUS in medical education, and the resulting attenuation of other curricular priorities, appear inevitable.

CONCLUSIONS

The three dominant discourses identified in this paper engender ideal conditions for the proliferation of POCUS in medical education through curricular guidelines, surveys of adherence to these guidelines and authoritative position statements. By identifying and analysing these dominant discourses, we can ask questions that do not take for granted the assumed truths underpinning the discourses, highlight potential pitfalls of proposed curricular changes and ensure these changes truly improve medical education.

Feasibility and Diagnostic Accuracy of Point-of-Care Abdominal Sonography by Pocket-Sized Imaging Devices, Performed by Medical Residents

OBJECTIVES

We aimed to study the feasibility and diagnostic performance of bedside ultrasound by examination of the liver, gallbladder, kidneys, and abdominal aorta performed by medical residents with limited experience in ultrasound, on emergency admissions using pocket-sized imaging devices (PSIDs).

METHODS

A total of 199 patients admitted acutely to the medical department at the non-university Levanger Hospital, Norway, during the period from April 4 to June 23, 2011, were consecutively included. Six medical residents, selected by drawing, examined these patients with a PSID at admission. Reference imaging was performed and/or judged at the Department of Radiology.

RESULTS

Each resident performed a median of 28 examinations (interquartile range 24-46). Imaging of the kidneys and liver were feasible in 85 and 82% of the cases, and the corresponding values for the gallbladder and abdominal aorta were 79 and 50%, respectively. The sensitivity of medical residents to detect organ pathology with the aid of PSID, ranged between 54% (95% confidence interval [CI]: 29-77%) and 74% (95% CI: 51-88%). Assessment of the aortic dimension showed moderate correlation, with r = 0.38.

CONCLUSIONS

Examination by PSID by inexperienced residents may allow for early detection of abdominal pathology, but do not appear to be accurate enough to rule out pathology in the abdominal organs.

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.

Hand-held cardiac ultrasound screening performed by family doctors with remote expert support interpretation

OBJECTIVE

To assess the usefulness of hand-held cardiac ultrasound (HCU) performed by family doctors (FDs) in primary care, with web-based remote expert support interpretation, in a cohort of patient with symptoms or physical examination signs suggestive of cardiovascular disease.

METHODS

This prospective observational study included 1312 consecutive patients, in three remote primary care areas, with symptoms or physical examination signs suggestive of cardiovascular disease. In 859 patients (group A), FDs had indicated conventional echocardiography (CE), and in 453 (Group B) the study was performed to complement the physical examination. HCU was carried out by 14 FDs after a short training period. The scans and preliminary FD reports were uploaded on a web-based program for remote expert support interpretation in <24 h.

RESULTS

Experts considered HCU to be inconclusive in 116 (8.8%) patients. FD and expert agreement on diagnosis was moderate (K=0.40-0.70) except in mitral stenosis (K=0.29) and in left atrial dilation (K=0.38). Diagnostic agreement between expert interpretation and CE was good (K=0.66-0.85) except in mitral stenosis (K=0.43). After remote expert interpretation, conventional echocardiograms were finally requested by FDs in only 276 (32.1%) patients, and discharges increased by 10.2%. Furthermore, significant heart diseases were diagnosed in 32 (7%) patients of group B.

CONCLUSIONS

HCU performed at the point of care by FDs with remote expert support interpretation using a web-based system is feasible, rapid and useful for detecting significant echocardiographic abnormalities and reducing the number of unnecessary echocardiographic studies.

Hand-held echocardiography in the setting of pre-operative cardiac evaluation of patients undergoing non-cardiac surgery: results from a randomized pilot study

Transthoracic echocardiography is not a routine test in the pre-operative cardiac evaluation of patients undergoing non-cardiac surgery but may be considered in those with known heart failure and valvular heart disease or complaining cardiac symptoms. In this setting, hand-held echocardiography (HHE) could find a potential application as an alternative to standard echocardiography in selected patients; however, its utility in this context has not been investigated. The aim of this pilot study was to evaluate the conclusiveness of HHE compared to standard echocardiography in this subset of patients. 100 patients scheduled for non-cardiac surgery were randomized to receive a standard exam with a Philips Ie33 or a bedside evaluation with a pocket-size imaging device (Opti-Go, Philips Medical System). The primary endpoint was the percentage of satisfactory diagnosis at the end of the examination referred as conclusiveness. Secondary endpoints were the mean duration time and the mean waiting time to perform the exams. No significant difference in terms of conclusiveness between HHE and standard echo was found (86 vs 96%; P = 0.08). Mean duration time of the examinations was 6.1 ± 1.2 min with HHE and 13.1 ± 2.6 min with standard echocardiography (P < 0.001). HHE resulted in a consistent save of waiting time because it was performed the same day of clinical evaluation whereas patients waited 10.1 ± 6.1 days for a standard echocardiography (P < 0.001). This study suggests the potential role of HHE for pre-operative evaluation of selected patients undergoing non-cardiac surgery, since it provided similar information but it was faster and earlier performed compared to standard echocardiography.

Feasibility and reliability of point-of-care pocket-size echocardiography performed by medical residents

Aims

To study the feasibility and reliability of pocket-size hand-held echocardiography (PHHE) by medical residents with limited experience in ultrasound.

Methods and results

A total of 199 patients admitted to a non-university medical department were examined with PHHE. Six out of 14 medical residents were randomized to use a focused protocol and examine the heart, pericardium, pleural space, and abdominal large vessels. Diagnostic corrections were made and findings were confirmed by standard diagnostics. The median time consumption for the examination was 5.7 min. Each resident performed a median of 27 examinations. The left ventricle was assessed to satisfaction in 97% and the pericardium in all patients. The aortic and atrioventricular valves were assessed in at least 76% and the abdominal aorta in 50%, respectively. Global left-ventricular function, pleural, and pericardial effusion showed very strong correlation with reference method (Spearman's r ≥ 0.8). Quantification of aortic stenosis and regurgitation showed strong correlation with r = 0.7. Regurgitations in the atrioventricular valves showed moderate correlations, r = 0.5 and r = 0.6 for mitral and tricuspid regurgitation, respectively, similar to dilatation of the left atrium (r = 0.6) and detection of regional dysfunction (r = 0.6). Quantification of the abdominal aorta (aneurysmatic or not) showed strong correlation, r = 0.7, while the inferior vena cava diameter correlated moderately, r = 0.5.

Conclusion

By adding a PHHE examination to standard care, medical residents were able to obtain reliable information of important cardiovascular structures in patients admitted to a medical department. Thus, focused examinations with PHHE performed by residents after a training period have the potential to improve in-hospital diagnostic procedures.

Medical educators' perspectives of teaching physical examinations using ultrasonography at the undergraduate level

BACKGROUND

Ultrasonography is increasingly used for teaching physical examination in medical schools. This study seeks the opinions of educators as to which physical examinations would be most enhanced by the addition of ultrasonography. We also asked when ultrasound-aided physical examination teaching could have deleterious effects if used outside its intended scope.

METHODS

All of the educators from the University of Calgary Master Teacher Program were invited to complete a 22-item paper-based survey. Survey items were generated independently by two investigators, with input from an expert panel (n = 5).

RESULTS

Of the 36 educators, 27 (75%) completed the survey. Examinations identified to be potentially most useful included: measuring the size of the abdominal aorta, identifying the presence/absence of ascites, identifying the presence/absence of pleural effusions, and measuring the size of the bladder. Examinations thought to be potentially most harmful included: identifying the presence/absence of intrauterine pregnancy, measuring the size of the abdominal aorta, and identifying the presence/absence of pericardial effusion.

CONCLUSIONS

Examinations that are potentially the most useful may also be potentially the most harmful. When initiating an ultrasound curriculum for physical examinations, educators should weigh the risks and benefits of examinations chosen.

Echocardiography: frontier imaging in cardiology

This article reviews the recent developments in echocardiography that have maintained this technology at the forefront of day-to-day imaging in clinical cardiology. The primary reason for most requests for imaging in cardiovascular medicine is to assess left ventricular structure and function. As our understanding of left ventricular mechanics has become more intricate, tissue Doppler and speckle tracking modalities have been developed that deliver greater insights into diagnosis of cardiomyopathy and earlier warning of ventricular dysfunction. Increased accuracy has been achieved with the dissemination of real-time three-dimensional echocardiography, which has also acquired a central role in the pre-operative assessment of patients prior to reparative valvular surgery. The use of contrast has broadened the indications for transthoracic echocardiography and has increased the accuracy of stress echocardiography, while reducing the number of patients who cannot be scanned because of a limited acoustic window. Finally, echocardiography will be seen in the future not only as a diagnostic tool in those affected by cardiovascular disease but also as a method for prediction of risk and perhaps activation of targeted treatment.

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.

Ultrasound pleural effusion sign as a useful marker for identifying heart failure worsening in established heart failure patients during follow-up

Clinical significance of UltraSound Pleural Effusion (US-PLE) and test characteristics of this sign for identifying worsening heart failure (HF) during follow-up of HF patients are unclear. Clinical records of 83 established HF patients were examined. The diagnosis of worsening HF was classified as "highly certain,""probable,""uncertain," or "no" based on the combination of the changes in symptoms/signs and B-type natriuretic peptide (BNP). Routine test included searching for the US-PLE sign. During a follow-up of 652±456 days, 1826 visits were evaluated. Among the 83 study patients, 78 had at least one of the following: worsening symptom(s), HF-related sign(s), and/or elevated BNP levels (≥3-fold increase) at one or more clinic visits. The US-PLE sign was present at 83 visits of 49 study patients. Its appearance was associated with the presence of HF-related symptom(s)/sign(s) and BNP elevation (odds ratio, 53-177, P<.0001 each). The test characteristics of the US-PLE sign for diagnosis of high possibility of worsening HF status fulfilling the "highly certain" or "probable" criteria were: sensitivity (76.6%), specificity (98.6%), positive predictive value (71.1%), and negative predictive value (99.0%). The US-PLE sign has high diagnostic accuracy for identifying worsening HF, including asymptomatic events, in HF patients during follow-up.

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.

Diagnostic utility and clinical usefulness of the pocket echocardiographic device

BACKGROUND

The pocket echocardiograph (PE) with color Doppler imaging belongs to a new class of diagnostic tools, the feasibility and accuracy of which is not well established. The aim of this study was to assess the feasibility and diagnostic value of transthoracic echocardiography (TTE) performed with the use of PE by a cardiology resident (2nd year of training) and by an experienced cardiologist.

METHODS

The study population comprised 220 consecutive patients (142 men, mean age 63 ± 8 years), 110 of whom were admitted to our intensive cardiac care unit (ICU) and 110 patients referred for TTE from the outpatient clinic. All patients had PE TTE performed by a resident (60 ICU patients, 60 outpatients) or a cardiologist (50 ICU patients, 50 outpatients). Within 24 h of PE TTE, all subjects had a standard TTE (sTTE) performed by an experienced echocardiographer.

RESULTS

96% of patients had echocardiographic measurements completed by both PE TTE and sTTE. The dimensions measured with PE TTE by the resident and the cardiologist showed good to excellent correlation with sTTE (r = 0.64-0.96, P < 0.001). The agreement in detection of various pathologies between PE TTE performed by the resident and sTTE examinations was moderate to very good, whereas it was good to excellent if PE TTE was performed by the experienced cardiologist.

CONCLUSION

The diagnostic accuracy of the PE in basic assessment of cardiac morphology and function as compared to standard echocardiography is moderate to very good for a cardiology resident and good to excellent for an experienced cardiologist. (Echocardiography 2012;29:1-6).

Is pocket mobile echocardiography the next-generation stethoscope? A cross-sectional comparison of rapidly acquired images with standard transthoracic echocardiography

BACKGROUND

A pocket mobile echocardiography (PME) device is commercially available for clinical use, but public data documenting its accuracy compared with standard transthoracic echocardiography (TTE) are not available.

OBJECTIVE

To compare the accuracy of rapidly acquired PME images with those acquired by standard TTE.

DESIGN

Cross-sectional study. At the time of referral for TTE, ultrasonographers acquired PME images first in 5 minutes or less. Ultrasonographers were not blinded to the clinical indication for imaging or to the PME image results when obtaining standard TTE images. Two experienced echocardiographers and 2 cardiology fellows who were blinded to the indication for the study and TTE results but not to the device source interpreted the PME images.

SETTING

Scripps Clinic Torrey Pines and Scripps Green Hospital, La Jolla, California.

PATIENTS

Convenience sample of 97 patients consecutively referred for echocardiography.

MEASUREMENTS

Visualizability and accuracy (the sum of proportions of true-positive and true-negative readings and observer variability) for ejection fraction, wall-motion abnormalities, left ventricular end-diastolic dimension, inferior vena cava size, aortic and mitral valve pathology, and pericardial effusion.

RESULTS

Physician-readers could visualize some but not all echocardiographic measurements obtained with the PME device in every patient (highest proportions were for ejection fraction and left ventricular end-diastolic dimension [95% each]; the lowest proportion was for inferior vena cava size [75%]). Accuracy also varied by measurement (aortic valve was 96% [highest] and inferior vena cava size was 78% [lowest]) and decreased when nonvisualizability was accounted for (aortic valve was 91% and inferior vena cava size was 58%). Observer agreement was fair to moderate for some measurements among less-experienced readers.

LIMITATION

The study was conducted at a single setting, there was no formal estimate of accuracy given the small convenience sample of patients, and few abnormal echocardiographic measurements occurred.

CONCLUSION

The rapid acquisition of images by skilled ultrasonographers who use PME yields accurate assessments of ejection fraction and some but not all cardiac structures in many patients. Further testing of the device in larger patient cohorts with diverse cardiac abnormalities and with untrained clinicians obtaining and interpreting images is required before wide dissemination of its use can be recommended.

PRIMARY FUNDING SOURCE

National Institutes of Health.

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

We hypothesized that, based on greyscale imaging and color Doppler capabilities, a new pocket ultrasound device (PUD) could accurately record cardiologic diagnostic findings. One hundred patients referred for conventional clinical indications underwent a standard echocardiography. Subsequently, a second physician blinded to the results performed an evaluation using the PUD on the same patients. Study end-points were echocardiographic window quality; left ventricular (LV) morphology; function; hypertrophy; right ventricular, atrial and vena caval morphologies; aortic and mitral valvulopathies; and pericardial structure. Using a scale of three grades, concordance in image quality proved good with a kappa coefficient (κ) of 0.71. Concordances between systems were excellent for LV function and morphology (κ = 0.91 and 0.96). Concordance for LV hypertrophy was good (κ = 0.74). Concordances for mitral regurgitation grades were 0.90, 0.95 and 1.00, respectively. In conclusion, a new PUD enabled scanning examinations, which showed good concordance of basic and qualitative diagnostic capability to standard echocardiographic instruments.

Fresnel-based beamforming for low-cost portable ultrasound

In this paper, we propose a modified electronic Fresnel-based beamforming method for low-cost portable ultrasound systems. This method uses a unique combination of analog and digital beamforming methods. Two versions of Fresnel beamforming are presented in this paper: 4-phase (4 different time delays or phase shifts) and 8-phase (8 different time delays or phase shifts). The advantage of this method is that a system with 4 to 8 transmit channels and 2 receive channels with a network of switches can be used to focus an array with 64 to 128 elements. The simulation and experimental results show that Fresnel beamforming image quality is comparable to traditional delay-and-sum (DAS) beamforming in terms of spatial resolution and contrast-to-noise ratio (CNR) under certain system parameters. With an f-number of 2 and 50% signal bandwidth, the experimental lateral beamwidths are 0.54, 0.67, and 0.66 mm and the axial pulse lengths are 0.50, 0.51, and 0.50 mm for DAS, 8-phase, and 4-phase Fresnel beamforming, respectively. The experimental CNRs are 4.66, 4.42, and 3.98, respectively. These experimental results are in good agreement with simulation results.

Usefulness of a new miniaturized echocardiographic system in outpatient cardiology consultations as an extension of physical examination

BACKGROUND

The aim of this study was to assess the usefulness of a new miniaturized echocardiographic system (MS) to perform bedside echocardiography in initial outpatient cardiology consultations, in addition to physical examination.

METHODS

One hundred eighty-nine patients referred for initial cardiology outpatient consultations at two tertiary hospitals in two countries were studied. Each patient was submitted to physical examination followed by MS assessment. Scanning time, the number of examinations with abnormal results after physical examination and the MS, and the information obtained by physical examination alone and followed by the MS (in terms of its importance in reaching a diagnosis, in the necessity of performing routine echocardiography, and in the decision to release the patient from the outpatient clinic) were assessed.

RESULTS

The scanning time with the MS was 180 ± 86 seconds. Its use after physical examination led to diagnoses in 141 patients (74.6%) and to an additional 37 patients (19.6%) being released from the outpatient clinic. After physical examination followed by MS assessment, only 64 patients (33.9%) were sent to the echocardiography lab. The MS modified the decision of whether to send a patient to the echocardiography lab, with referral determined by the MS in 27 patients (14.3%) and no referral determined by the MS in 58 patients (30.7%).

CONCLUSIONS

The new MS caused a negligible increase in the duration of consultations. It showed additive clinical value over physical examination, increasing the number of diagnoses, reducing the use of unnecessary routine echocardiography, increasing the number of adequate echocardiographic studies, and determining a large number of releases from the outpatient clinic.

Value of a cardiovascular limited ultrasound examination using a hand-carried ultrasound device on clinical management in an outpatient medical clinic

Limited ultrasound imaging studies using hand-carried ultrasound devices at the point of care have individually shown feasibility in the detection of carotid atheroma, left ventricular systolic dysfunction, left atrial enlargement, and abdominal aortic aneurysm. To evaluate the utility of a specific cardiovascular limited ultrasound examination (CLUE) designed to detect all 4 entities in patients seen in an outpatient medical clinic. One hundred ninety-six patients underwent coronary heart disease risk stratification by National Cholesterol Education Program guidelines and CLUE with a hand-carried ultrasound device with cardiac and vascular transducers. CLUE included brief imaging of the carotid arteries, the heart, and the intra-abdominal aorta. The prevalence of abnormal CLUE results and their effect on clinical management were tabulated and stratified by coronary heart disease risk class. Patient age (mean +/- SD) was 56 +/- 14 years (range 22 to 95), and 32.1% were at low risk, 30.6% at intermediate risk, and 37.2% at high risk. Of the 196 CLUEs, abnormalities were present in 37.2% (32.7% had carotid atheroma, 3.1% had systolic dysfunction, 6.1% had left atrial enlargement, and 1.0% had abdominal aortic aneurysm) and were related to age, increasing coronary heart disease risk, and male gender. Overall, CLUE resulted in new management recommendations in 20% of patients, primarily in coronary heart disease risk prevention. In patients at intermediate risk or aged 60 to 69 years, CLUE resulted in new recommendations in 39% and 37%, respectively. In conclusion, when applied to a clinic population, brief cardiovascular ultrasound exams frequently demonstrate unsuspected findings that can change management.

Hand-held echocardiography: its use and usefulness

In recent years, several echocardiographic hand-held devices have been developed and are now available for a growing number of cardiologists. After the first clinical use 25 years ago, hand-held echocardiography (HHE) is now earning important commercial positions. Their transportability permits echo performance out the echo-labs and offers the possibility to make diagnosis in intensive care unit, emergency room, outpatient clinic, at the bedside, and even in ambulance. Experiences in the clinical setting have demonstrated the ability of HHE to detect multiple diseases including abdominal aortic aneurysms, left ventricular hypertrophy, regional wall motion abnormalities, pericardial and pleural effusions. At the present time, four varieties of HHE have to be recognized: the first includes high-cost, miniaturized machines, similar to the most advanced instrumentations, provided by new tools and imaging transfer systems; a second intermediate, middle-cost variety encompasses devices corresponding to standard echocardiography, but not miniaturized; according to the definition of the American Society of Echocardiography, a third and a fourth category comprise machines of weight lower than 2.7 kg, battery supplied and appropriately defined as "portable cardioschopes", which can be utilized as a technical refinement of physical examination. The use of HHE opens main controversy concerning their diagnostic accuracy, the opportunity to establish in which clinical settings they should be used and the identification of both potential users and required competence level. Preliminary experiences show the possibility to improve and anticipate diagnosis of several cardiovascular diseases but also the need to plan specific ultrasound training to avoid incorrect use of HHE.

The Use of Hand-carried Ultrasound in the Hospital Setting-A Cost-effective Analysis

OBJECTIVES

We sought to assess the accuracy of hand-carried ultrasound (HCU) in the prediction of a normal study, and its cost-effectiveness in reducing the number of standard departmental echocardiograms (SDE) performed on hospital inpatients.

METHODS

The setting was a district general hospital. Participants were 157 consecutive inpatients, mean age 68 (range: 18-97) years, 95 men (61%), referred for SDE. HCU was performed at the bedside as part of the clinical assessment. SDE was performed routinely. Main outcome measures were: (1) assessment of the accuracy of HCU in detection of a normal or abnormal study as determined by SDE; and (2) a cost-effectiveness analysis.

RESULTS

Indications for echocardiography were: left ventricular (LV) function assessment, n = 101 (64.3%); valvular abnormalities, n = 11 (7%); arrhythmia, n = 4 (2.6%); miscellaneous, n = 10 (6.4%); and no reason stated, 31 (19.7%). The sensitivity, specificity, and positive and negative predictive values of HCU predicting a completely normal scan were 74%, 96%, 94%, and 81%, respectively, and of predicting normal LV function in requests specific for LV function assessment were 81%, 100%, 100%, and 77%, respectively. If either all inpatients or those with requests for LV function assessment underwent HCU initially, and only those with abnormal scans underwent further SDE, there would be a 29% and 22% reduction in departmental workload and a cost saving of pound sterling 23,000 and pound sterling 30,000, respectively.

CONCLUSION

HCU is an accurate method of identifying patients with normal hearts as determined by SDE. Its routine use is cost-effective and can significantly reduce the number of SDE that need be performed.

Hand-held echocardiography: added value in clinical cardiological assessment

BACKGROUND

The ultrasonic industry has recently produced echocardiographic Hand Held Devices (miniaturized, compact and battery-equipped echocardiographic systems). Their potential usefulness has been successfully assessed in a wide range of clinical conditions. The aim of the study was to verify if the routine use of a basic model of echocardiographic Hand Held Device (HHD) could be an important diagnostic tool during outpatient cardiologic consulting or in non-cardiologic hospital sections.

METHODS

87 consecutive patients were included in this study; they underwent routine physical examination, resting ECG and echocardiographic evaluation using a basic model of HHD performed by trained echocardiographists; the cardiologist, whenever possible, formulated a diagnosis. The percentage of subjects in whom the findings were judged reasonably adequate for final diagnostic and therapeutic conclusions was used to quantify the "conclusiveness" of HHD evaluation. Successively, all patients underwent a second echocardiographic evaluation, by an examiner with similar echocardiographic experience, performed using a Standard Echo Device (SED). The agreement between the first and the second echocardiographic exam was also assessed.

RESULTS

Mean examination time was 6.7 +/- 1.5 min. using HHD vs. 13.6 +/- 2.4 min. using SED. The echocardiographic examination performed using HHD was considered satisfactory in 74/87 patients (85.1% conclusiveness). Among the 74 patients for whom the examination was conclusive, the diagnosis was concordant with that obtained with the SED examination in 62 cases (83.8% agreement).

CONCLUSION

HHD may generally allow a reliable cardiologic basic evaluation of outpatient or subjects admitted to non-cardiologic sections, more specifically in particular subgroups of patients, with a gain in terms of time, shortening patient waiting lists and reducing healthy costs.