M. Clarke

Reversible watermarking for authentication of DICOM images

We propose a watermarking scheme that can recover the original image from the watermarked one. The purpose is to verify the integrity and authenticity of DICOM images. We used 800x600x8 bits ultrasound (US) images in our experiment. SHA-256 of the whole image is embedded in the least significant bits of the RONI (Region of Non-Interest). If the image has not been altered, the watermark will be extracted and the original image will be recovered. SHA-256 of the recovered image will be compared with the extracted watermark for authentication.

Optimum delivery of telemedicine over low bandwidth satellite links

Telemedicine is frequently used to support the delivery of medicine to remote regions, but it can often be the case that these areas are poorly served by communications. The AIDMAN project investigates the delivery of telemedicine in remote regions of Greece using satellite. However the high cost of such links can severely limit the bandwidth available to applications. In addition the satellite link is a clear channel and may be configured to emulate any protocol. This presents a problem of determining which protocol may best support the applications. We have modelled the. three types of link protocol, circuit switched (ISDN), packet switched (TCP/IP) and cell switched (ATM) to determine how their characteristics affect the performance when bandwidth is severely restricted. We further investigate how performance may be optimised when the link is used to carry mixed traffic of real-time video conference and image transfer. Our simulation shows that TCP/IP can support telemedicine applications reasonably well, so long as the number of simultaneous image transfers are restricted. Furthermore, 1Pv6, which supports prioritisation of traffic, can overcome this restriction. Use of TCP/IP has further advantage, in that it permits integration of wider networks, is cheap, widely available and supports virtually all telemedicine applications. Real-time measurements using the virtual consultation workstations developed for the AIDMAN project on a low bandwidth link Implemented on routers connected using ISDN to simulate a link with 128 kbps and on the GALENOS satellite network confirms the findings of the simulation.

Reversible Watermarking Surviving JPEG Compression

This paper will discuss the properties of watermarking medical images. We will also discuss the possibility of such images being compressed by JPEG and give an overview of JPEG compression. We will then propose a watermarking scheme that is reversible and robust to JPEG compression. The purpose is to verify the integrity and authenticity of medical images. We used 800times600times8 bits ultrasound (US) images in our experiment. SHA-256 of the image is then embedded in the least significant bits (LSB) of an 8times8 block in the region of non interest (RONI). The image is then compressed using JPEG and decompressed using Photoshop 6.0. If the image has not been altered, the watermark extracted will match the hash (SHA256) of the original image. The result shown that the embedded watermark is robust to JPEG compression up to image quality 60 (~91% compressed)

A Telemonitoring Architecture to Support Chronic Disease Management and Acute Episode Monitoring

We describe a telemonitoring architecture designed to support the dual role of chronic disease management and acute episode monitoring. In the former, measurements of parameters such as weight and blood pressure are taken periodically and are used to determine a change in the condition of a patient and thus prompt intervention in therapy. However, such patients can deteriorate rapidly and enter a phase where constant monitoring of vital signs is required. In these conditions, our system monitors ECG, SpO2 and temperature continuously and transmits data on preset events or at preset times. To date such monitoring has required two systems; we have developed a single system to fulfil both roles. Transmission and control protocol are designed along principles of the 11073 standard. We show how such monitoring can manage patients with acute conditions such as unstable angina and heart failure

Integrated Selective Heart Disease Screening

Integrated selective heart disease screening is based on the concept of selective screening procedures, passing through one sieve to the next as a result of a high score in risk factor assessment. Coarse sieves at the start of the system are based on simple, low cost techniques (e.g. age), but are, nevertheless, most effective at screening out large numbers of people with extremely low probabilities of having the disease.

New use cases for remote control and configuration of interoperable medical devices

The newest branch of the ISO/IEEE 11073 (X73) standard for Personal Health Devices (X73PHD), allow the development of interoperable personal health ecosystems. At the moment of this writing, more than 11 specializations have been successfully published by the Personal Health Device (PHD) Working Group (PHD WG). Nevertheless, some recent specializations at draft stage show the need for a procedure to control configuration parameters. As a solution, some ad-hoc methods have been elaborated to deal with it, but, the aim of the PHD WG is to standardize a general procedure, valid for longer term. Then it is needed to identify use cases requiring remote configuration services. This work identifies and studies new use cases that employ remote configuration services. The resulting use cases, discussed within the PHD WG to get the maximum consensus, are within the scope of the Basic Electrocardiograph (X73-10406), the Sleep Apnea Breathing Therapy Equipment (X73-10424), and the Medication Monitor (X73-10472) specializations. In addition, a classification of the findings is proposed for each use case. These findings could be the basis for the new remote configuration extension.

A Systematic Review of Technical Evaluation in Telemedicine Systems

We conducted a systematic review of the literature to critically analyse the evaluation and assessment frameworks that have been applied to telemedicine systems. Subjective methods were predominantly used for technical evaluation (59 %), e.g. Likert scale. Those including objective measurements (41%) were restricted to simple metrics such as network time delays. Only three papers included a rigorous standards based objective approach. Our investigation has been unable to determine a definitive standards-based telemedicine evaluation framework that exists in the literature that may be applied systematically to assess and compare telemedicine systems. We conclude that work needs to be done to address this deficiency. We have therefore developed a framework that has been used to evaluate videoconferencing systems telemedicine applications. Our method seeks to be simple to allow relatively inexperienced users to make measurements, is objective and repeatable, is standards based, is inexpensive and requires little specialist equipment. We use the EIA 1956 broadcast test card to assess resolution, grey scale and for astigmatism. Colour discrimination is assessed with the TE 106 and Ishihara 24 colour scale chart. Network protocol analysis software is used to assess network performance (throughput, delay, jitter, packet loss).

Optimum Design for Teleconsultation Systems

We analyse the clinical process of patient referral developed and in routine use for over 5 year at Chorleywood Health Centre, UK. The system combines diagnostics performed in primary care with results forwarded to the consultant in electronic form. Patients may then be referred for teleconsultation between patient and local health care professional and distant consultant. By ensuring diagnostic information is gained in advance, we have determined that the teleconsultation may concentrate on management, and as a result is more efficient and effective. We further analyse the processes and determine the functional characteristics of the teleconsultation and the functional requirements of the teleconsultation system that may support the process in an optimum way

Ultrasonic Endoscope Based On A Low Cost Personal Computer

We present details of an ultrasonic endoscope based on a low cost personal computer. The system has been designed for use in intravascular imaging, for which high quality, high resolution images are required. A PVDF-2 transducer, chosen for its small size and high bandwidth, is mounted at the end of a Bowden cable, and is rotated by a stepper moter. Ultrasound echoes are digitized at 7.5MHz with 6 bit accuracy, and transferred to a low cost IBM AT compatible computer, at a rate of 50 echos per revolution. Radial scan images may be produced in real time, or data may be captured to memory at higher resolution and higher sampling rate.

Future trends in Picture Archiving and Communication System (PACS).

This research investigates the opinions of radiologists regards requirements for improving current Picture Archiving and Communication System (PACS). Responses to a questionnaire were collected from 120 of the 200 radiologists in five governmental hospitals of Kuwait. The study the determines the importance of the solutions for future PACS from the radiologists point of view as: PACS must be integrated with other hospital information systems (100%); there must be multi hospital PACS access across different organizations (99%); web based PACS solutions (97%) and PACS applications in mobile phones (97%) are seen as an improved solution for future PACS. Whereas, the radiologists expressed strong concerns over the barriers for implementing web PACS solutions including: technical issues (91%); lack of training (85%); and cost (76%).