Transmission of full-length echocardiographic images over ISDN for diagnosing congenital heart disease

The Future of Cardiac Ultrasound in the Neonatal Intensive Care Unit

Cardiac ultrasound is increasingly used to guide hemodynamic decision making in the neonatal intensive care unit (NICU). This article focuses on likely future progress in training, accreditation, digital connectivity, miniaturization, and modality development. Many documents have been published internationally to guide cardiac ultrasound training, accreditation, and implementation in the NICU, but challenges remain in providing assessments of hemodynamic status without risking missed structural diagnoses. Advances in simulation training and digital connectivity provide an opportunity to standardize approaches across institutions and continents. Development of machine learning and ultrasound modalities in turn provide huge scope for improving robustness and completeness of assessment.

Paediatric telecardiology services in Queensland: A review of three years’ experience

Videoconferencing at 384 kbit/s for the transmission of echocardiograms has proved useful for the assessment of children with suspected cardiac disease, in regional areas of Queensland. A retrospective review of patient and management outcomes was conducted on cardiac teleconsultations performed at two regional hospitals during the period November 2000 to February 2004, inclusive. There were 106 echo studies. A subset of 72 cardiac teleconsultations performed between May 2001 and February 2004 was reviewed in detail. The median age of patients at the time of consultation was 3 months (range 1 day–1 7 years). Sixteen per cent of teleconsultations were classified as urgent and were conducted on the same day as referral. Following the videoconference, 90% of patients could be managed locally and reviewed by the paediatrician or visiting paediatric cardiologist during an outreach clinic. Six children (8%) had significant cardiac lesions that were initially managed locally, with subsequent elective transfer at the appropriate time for treatment. Only one child (1%) required urgent transfer to the tertiary centre for specialist care and surgery. Telecardiology was effective in accurately identifying congenital heart disease. Paediatric telecardiology is an evolving modality of assessment and communication, and is likely to result in continued improvements in patient care, patient outcomes and parental satisfaction, in provincial centres removed from the tertiary cardiac centre.

Image quality in real-time teleultrasound of infant hip exam over low-bandwidth internet links: a transatlantic feasibility study

Evolution of communication systems, especially internet-based technologies, has probably affected Radiology more than any other medical specialty. Tremendous increase in internet bandwidth has enabled a true revolution in image transmission and easy remote viewing of the static images and real-time video stream. Previous reports of real-time telesonography, such as the ones developed for emergency situations and humanitarian work, rely on high compressions of images utilized by remote sonologist to guide and supervise the unexperienced examiner. We believe that remote sonology could be also utilized in teleultrasound exam of infant hip. We tested feasibility of a low-cost teleultrasound system for infant hip and performed data analysis on the transmitted and original images. Transmission of data was accomplished with Remote Ultrasound (RU), a software package specifically designed for teleultrasound transmission through limited internet bandwidth. While image analysis of image pairs revealed statistically significant loss of information, panel evaluation failed to recognize any clinical difference between the original saved and transmitted still images.

Impact of telemedicine on hospital transport, length of stay, and medical outcomes in infants with suspected heart disease: a multicenter study

BACKGROUND

Previous single-center studies have shown that telemedicine improves care in newborns with suspected heart disease. The aim of this study was to test the hypothesis that telemedicine would shorten time to diagnosis, prevent unnecessary transports, reduce length of stay, and decrease exposure to invasive treatments.

METHODS

Nine pediatric cardiology centers entered data prospectively on patients aged <6 weeks, matched by gestational age, weight, and diagnosis. Subjects born at hospitals with and without access to telemedicine constituted the study group and control groups, respectively. Data from patients with mild or no heart disease were analyzed.

RESULTS

Data were obtained for 337 matched pairs with mild or no heart disease. Transport to a tertiary care center (4% [n = 15] vs 10% [n = 32], P = .01), mean time to diagnosis (100 vs 147 min, P < .001), mean length of stay (1.0 vs 26 days, P = .005) and length of intensive care unit stay (0.96 vs 2.5 days, P = .024) were significantly less in the telemedicine group. Telemedicine patients were significantly farther from tertiary care hospitals than control subjects. The use of inotropic support and indomethacin was significantly less in the telemedicine group. By multivariate analysis, telemedicine patients were less likely to be transported (odds ratio, 0.44; 95% confidence interval, 0.23-0.83) and less likely to be placed on inotropic support (odds ratio, 0.16; 95% confidence interval, 0.10-0.28).

CONCLUSIONS

Telemedicine shortened the time to diagnosis and significantly decreased the need for transport of infants with mild or no heart disease. The length of hospitalization and intensive care stay and use of indomethacin and inotropic support were less in telemedicine patients.

Validation of an automatic tool for the assessment of image quality in digital tele-echocardiography

We investigated a novel tool for assessing image degradation in tele-echocardiography. Different video recordings from an echocardiographic examination were transmitted using commercial videoconferencing equipment via a local area network. Different compression schemes were selected, ranging from MPEG 1 to MPEG 4, with transmission at different bit rates ranging from 1.0 to 4.5 Mbit/s. Three methods were used to compare the transmitted and received video sequences: the peak signal to noise ratio, the Double Stimulus Impairment Scale (DSIS) and the National Telecommunication and Information Administration Virtual Quality Metric (VQM). The results showed that the most useful grading procedure was the subjective DSIS. There was a high correlation between the DSIS results and the VQM. The VQM could be thus an effective tool for evaluating tele-echocardiography transmission systems, avoiding the costs and times associated with conducting subjective tests in repeatable conditions.

Diagnosis of congenital heart disease in neonates by videoconferencing: an eight-year experience

Summary

Over an eight-year period, echocardiograms were transmitted by ISDN at 384 kbit/s for a total of 132 patients suspected of having congenital heart disease (CHD). Five transmitted scans were inadequate. Hands-on echocardiograms were performed subsequently on 116 of the remaining 127 cases (91%). Major CHD was diagnosed in 42 of the 116 infants (36%) and minor CHD in 49 (42%). The telemedicine diagnosis was accurate in 97% of the cases (kappa = 0.90). There were four diagnostic errors. Transfer to the regional unit was avoided in 95 patients (72%). The present study shows that high diagnostic accuracy is possible using a telemedicine link to transmit images obtained with the assistance of real-time guidance by a paediatric cardiologist. The results also demonstrate the importance of an expert interpreting the echocardiographic images, since the accuracy of diagnosis was considerably improved (the kappa coefficient increased from 0.14 to 0.90).

The role of telemedicine in fostering health-care innovations to address problems of access, specialty shortages and changing patient care needs

The integration of advanced technologies into health-care services promises to aid society in its transition to a coordinated, systems approach which is focused on disease prevention, enhanced wellness, chronic disease management, decision support, quality and patient safety. By incorporating such technologies, clinicians will be able to manage the growing volumes of medical information, research and decision support analytical tools. The deployment of advanced technologies will minimize the barriers of distance and geography to enhance access and facilitate the delivery of integrated health care. This will support and enhance the goals of the US federal Healthy People 2010 initiative.

Forward and store telemedicine using Motion Pictures Expert Group: a novel approach to pediatric tele-echocardiography

BACKGROUND

Live transmission of echocardiograms over integrated services digital network lines is accurate and has led to improvements in the delivery of pediatric cardiology care. Permanent archiving of the live studies has not previously been reported. Specific obstacles to permanent storage of telemedicine files have included the ability to produce accurate images without a significant increase in storage requirements.

OBJECTIVE

We evaluated the accuracy of Motion Pictures Expert Group (MPEG) digitization of incoming video streams and assessed the storage requirements of these files for infants in a real-time pediatric tele-echocardiography program.

RESULTS

All major cardiac diagnoses were correctly diagnosed by review of MPEG images. MPEG file size ranged from 11.1 to 182 MB (56.5 +/- 29.9 MB).

CONCLUSIONS

MPEG digitization during live neonatal telemedicine is accurate and provides an efficient method for storage. This modality has acceptable storage requirements; file sizes are comparable to other digital modalities.

Implanting telehealth network for paediatric cardiology: learning from the Quebec experience

The implementation committee of the Quebec Child Telehealth Network was formed in 1997, with a mandate to build a network dedicated to the diagnosis of congenital cardiac disease via telemedicine. We devised criterions for selection to determine which peripheral centres would be linked by telemedicine to the university-based services for paediatric cardiology provided in the Canadian Province of Quebec. The criterions included: distance from a university centre, number of births per year, and presence of an already-established outreach clinic for paediatric cardiology. The Quebec Network became operational in 2000, and was composed of 32 peripheral centres and 4 university centres. A total of 363 transmissions of echocardiograms occurred over a 3-year period from January 2000 to December 2002. Peripheral centres located at a distance greater than 100 kilometres from a university centre were 8.5 times more likely to use the network. Criterions other than distance did not influence whether or not a peripheral centre used the network. Cardiac abnormalities were identified in almost two-thirds of the transmissions. The use of the Quebec Network resulted in the avoidance of transfers or clinic visits to university hospitals in seven-tenths of cases. We conclude that distance greater than 100 kilometres from a centre offering subspecialty services in paediatric cardiology is the most important criterion for choosing the peripheral centres that are most likely to use a telehealth network. In its first three years of operation, the telehealth network had a major impact on the delivery of paediatric cardiac care, improving access to subspecialty services across the province.

The effect of bandwidth on the quality of transmitted pediatric echocardiograms

BACKGROUND

Remote access to pediatric cardiology diagnostic services is enabled by real-time transmission of echocardiographic images. Several transmission bandwidths have been used but there has been little analysis of image quality provided by different bandwidths. We designed a study of the quality of transmitted images at various bandwidths.

METHODS

Two echocardiographers viewed randomly a series of 13 recorded pediatric echocardiographic images either directly or after transmission using 1 of 4 bandwidths: 256; 384; 512; or 768 kbps. An image clarity scoring scale was used to assess image quality of cardiac structures.

RESULTS

Measurable differences were found in image quality with different transmission bandwidths; 512 kbps was the minimum for consistently clear imaging of all cardiac structures examined.

CONCLUSION

Bandwidth greater than 512 kbps confers sharper images subjectively although this could not be quantified by our methods.

Outcomes and Methods in Telemedicine Evaluation

One hundred and four articles, published from 1966 to 2000, were reviewed to investigate telemedicine evaluation studies in terms of methods and outcomes. A total of 112 evaluations were reported in these 104 articles. Two types of evaluations were evaluated: clinical and nonclinical. Within the clinical evaluations, three were on clinical effectiveness, 26 on patient satisfaction, 49 on diagnostic accuracy, and nine on cost. In the non-clinical evaluations, 15 articles discussed technical issues relating to digital images, such as bandwidth, resolution, and color, and 10 articles assessed management issues concerning efficiency of care, such as avoiding unnecessary patient transfer, or saving time. Of the 112 evaluations, 72 were descriptive in nature. The main methods used in the remaining 40 articles used quantitative methods. Nineteen articles employed statistical techniques, such as receiver operating characteristics curve (three evaluations) and kappa values (seven evaluations). Only one article utilized a qualitative approach to describe a telemedicine system. Currently, there are a number of good reports on diagnostic accuracy, satisfaction, and technological evaluation. However, clinical effectiveness and cost-effectiveness are important parameters, and they have received limited attention. Since telemedicine evaluations tend to explore various outcomes, it may be appropriate to evaluate from a multidisciplinary perspective, and to utilize various methodologies.

Realtime fetal ultrasound by telemedicine in Queensland. A successful venture?

We have established a realtime fetal tele-ultrasound consultation service in Queensland, which has been integrated into our routine clinical practice. The service, which uses ISDN transmission at 384 kbit/s, allows patients in Townsville to be examined by subspecialists in Brisbane, 1500 km away. For the 90 tele-ultrasound consultations performed for the first 71 patients, 90% of the babies have been delivered, and outcome data have been received on all the pregnancies. All significant anomalies and diagnoses have been confirmed. The referring clinicians would have physically referred 24 of the 71 patients to Brisbane in the absence of telemedicine. A crude cost-benefit calculation suggests that the tele-ultrasound service resulted in a net saving of A$6340, and at the same time enabled almost four times the number of consultations to be carried out.

Methods of measurement of image quality in teleultrasound

In recent years, teleultrasound has emerged as a potentially effective method of provision of ultrasound services to remote areas of the community. Transmission of teleultrasound, however, requires a high degree of compression when utilizing the relatively low bandwidth ISDN connections available within the UK. The actual amount of compression occurring varies both with the connection and the image content, often on a frame to frame basis. For this reason, traditional measurements of image quality using test tools are ineffective. Most studies to date have assessed equipment performance by testing diagnostic performance. Although this is the most important method of assessing the results of image degradation, few studies have attempted to perform physical measurements of degradation. The aims of this study were to measure the amount of degradation within a teleultrasound system and, using a number of methods, to ascertain the most useful indicators of loss of image quality. Groups of successive abdominal ultrasound images were captured and digitized both before and after degradation via an ISDN6 teleultrasound system. Normalized mean squared error (NMSE), pixel histograms, line and surface plots, Fourier spectra and contrast measurements were carried out on regions of interest in both sets of images. The NMSE was most sensitive to degradation, with alterations in the NMSE value depending on image content and degree of degradation. Fourier analysis was also indicative, showing consistent changes in high frequency content again varying with image content.

Clinical and basic laboratory assessment of children for possible congenital heart disease

Accurate and cost-effective detection of congenital heart disease is a priority for the primary care physician, but there are many diagnostic modalities and strategies available. Within the past year, investigators have reported factors that contribute to the failure to diagnose congenital heart disease before autopsy. Recent research also highlights the strengths and weaknesses of the clinical evaluation by the primary care physician. An examination by a pediatric cardiologist is a more specific discriminator between heart disease and innocent murmur and can, in many instances, eliminate the expense of relying on echocardiography for diagnosis. Current reports document substantial limitations of diagnostic utility of electrocardiography and chest roentgenography. Suspicions that echocardiography can be misleading when performed in laboratories without expertise in congenital heart disease are confirmed in recent organized comparisons of accuracy. High-quality, well-designed tele-echocardiography programs are shown to be effective solutions when maldistribution of pediatric cardiology services hampers diagnostic efficiency.

Clinical consultations using store-and-forward telemedicine technology

OBJECTIVE

To investigate the potential role of a store-and-forward (SAF) telemedicine system in specialty consultations initiated by primary care physicians.

MATERIALS AND METHODS

In this pilot telemedicine study, patients needing consultations in cardiology, dermatology, endocrinology, and orthopedics had both standard face-to-face (FTF) consultations and SAF consultations.

RESULTS

Fifteen patients had both FTF and SAF consultations, 4 had echocardiograms transmitted for an SAF consultation only, and 1 had an SAF consultation but no FTF appointment. Of 19 diagnoses made, all were essentially the same in both types of consultations; 14 of 15 FTF consultations and 15 of 19 SAF consultations resulted in additional treatment recommendations.

CONCLUSIONS

While it was possible to develop a desktop system for SAF consultations, the equipment was not adequately integrated. Without total digital input, including electronic patient medical records, packaging of information is laborious and impractical. Seamlessly adapting to existing clinical practice is vital. Issues such as increasing work for the physicians or office staff, gathering adequate patient information, and designing a referral process were more difficult than we had anticipated. Patient acceptance was high, but the clinical pilot had very small numbers.

Telemedicine: a useful tool for the pediatric cardiologist

OBJECTIVE

To determine if the Georgia Statewide Academic and Medical System Telemedicine Network can deliver subspecialty pediatric care to rural areas of Georgia.

MATERIALS AND METHODS

A retrospective review was conducted of a clinical experience, over a 30-month period from November 1993 through June 1996, involving 13 pediatric cardiology-related encounters in seven male and six female patients. Patients' ages ranged from 5 days to 16 years. Eleven encounters were initiated because of a suspicion of congenital heart disease (CHD); two encounters involved postoperative evaluations in patients who had recently undergone cardiac surgery at the Medical College of Georgia (MCG).

RESULTS

Of the 11 patients suspected to have CHD, five had CHD documented during the telemedicine evaluation, of whom two were transferred to MCG for further invasive evaluation and surgical correction. Three others with CHD, and the remaining six patients who required no further subspecialty follow-up, were followed in their home communities by their primary care physicians.

CONCLUSIONS

Telemedicine is a useful tool for the evaluation of infants and children with suspected CHD.

Design of mobile telemedicine systems using GSM and IS-54 cellular telephone standards

This paper presents an overview of the design of mobile telemedical systems using cellular telephone channels. A mobile telemedicine communication system was studied using both the GSM and the IS-54 standards, which are the most widely used commercial cellular telephone systems in Europe and North America, respectively. A simulation using a photoplethesmography signal showed successful transmission of data with bit error rates of less than 10(-7) at the receiver for the IS-54 standard and less than 10(-5) for the GSM standard, depending on the mobile channel conditions used.