Papers by Sotiri Pavlopoulos
IEEE Transactions on Information Technology in Biomedicine, 2006
Information technology advances have brought forth new challenges in healthcare information manag... more Information technology advances have brought forth new challenges in healthcare information management, due to the vast amount of medical data that needs to be efficiently stored, retrieved, and distributed, and the increased security threats that explicitly have to be addressed. The paper discusses the perspectives of digital watermarking in a range of medical data management and distribution issues, and proposes a complementary and/or alternative tool that simultaneously addresses medical data protection, archiving, and retrieval, as well as source and data authentication. The scheme imperceptibly embeds in medical images multiple watermarks conveying patient's personal and examination data, keywords for information retrieval, the physician's digital signature for authentication, and a reference message for data integrity control. Experimental results indicate the efficiency and transparency of the scheme, which conforms to the strict requirements that apply to regions of diagnostic significance.
Topics in Biomedical Engineering, 2006
... Efthyvoulos Kyriacou * , Sotiris Pavlopoulos, and Dimitris Koutsouris ... The protocol was ba... more ... Efthyvoulos Kyriacou * , Sotiris Pavlopoulos, and Dimitris Koutsouris ... The protocol was based on the experience gained from the creation of an extended codification scheme based on the Vital and DICOM standards which were developed (Anagnostaki, A. et al. ...
IEEE Transactions on Information Technology in Biomedicine, 1998
Recent studies conclude that early and specialized prehospital management contributes to emergenc... more Recent studies conclude that early and specialized prehospital management contributes to emergency case survival. We have developed a portable medical device that allows telediagnosis, long distance support and teleconsultation of mobile health care providers by expert physicians. The device allows the transmission of vital biosignals and still images of the patient from the emergency site to the consultation site using the GSM mobile telephony network. The device can telematically "bring" an expert specialist doctor at the site of the medical emergency, allow him to evaluate patient data and issue directions to the emergency personnel on treatment procedures until the patient is brought to hospital. Legal reasons mandated the inclusion at the consultation site of a multimedia database able to store and manage the data collected by the system. The performance of the system has been validated in four different countries using a controlled medical protocol and a set of 100 patients per country treated has been collected and analyzed.
Proceedings of the 20th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Vol.20 Biomedical Engineering Towards the Year 2000 and Beyond (Cat. No.98CH36286), 1998
ABSTRACT Medical institutions have felt the need for a well structured computer-based patient rec... more ABSTRACT Medical institutions have felt the need for a well structured computer-based patient record (CPR) for at least 20 years now. Hospital information systems (HIS) were conceived to serve that purpose. A pilot application is being developed to serve the needs of management of inpatient and outpatient medical record, the mechanism of patients' visits and bed reservation from the GPs (general practitioners) as well as the management of the drug store. Having these needs in mind we developed an intranet Web client-server application. The developed system provides a user-friendly graphical interface and features such as Internet access, access to complete electronic patient records, remote access, etc. The whole application was developed as an ActiveX Document that can be downloaded from a Web server and run from within a Web browser. The scope of this intranet based hospital information system is to improve the quality of health care provision, to minimise the institution's costs, to ameliorate time management, to increase training capabilities and to improve remote patient record access. This system will increase patient satisfaction by reducing waiting times and staff morale through high quality information systems and infrastructure
The 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2004
... and between care organizations is just one of the major impediments in the health care busine... more ... and between care organizations is just one of the major impediments in the health care business's progress ... REGIONAL HEALTHCARE INFORMATION SYSTEM ... Using (A)PDUs to exchangeinformation between systems bring a number of distinct advantages: 1. All systems can ...
Dynamic 18F-fluorodeoxyglucose positron emission tomography (PET) studies can successfully be use... more Dynamic 18F-fluorodeoxyglucose positron emission tomography (PET) studies can successfully be used for diagnosis, therapy planning and monitoring in oncology. Using similarity mapping, we assessed the accuracy of anatomical localization of lesions and the detectability of metastases. 17 patients with co- lorectal cancer and 3 patients with plasmocytoma were included in the study. All dynamic 18F-FDG PET data sets were iteratively
A virtual patient record (VPR) is an ideal electronic healthcare record (EHR) that is decentraliz... more A virtual patient record (VPR) is an ideal electronic healthcare record (EHR) that is decentralized and contains heterogeneous and distributed medical and clinical data. Extensible markup language (XML) is a web standard that was introduced by the world wide web consortium (W3C) and today has become the major driver towards heterogeneous system integration for any industry solution. This work is based on our efforts to create an XML schema that operates as an interface between different heterogeneous patient record structures. The XML Schema structure is based on standards such as HL7, DICOM, VITAL, GEHR and prENV 13606-4 and was modeled with UML metadata techniques. We are describing our efforts and technological platform used to test this XML schema by implementing various healthcare scenarios and using state of the art java components and XML based technologies. The developed pilot is initially being tested for two homecare scenarios (anticoagulation treatment and ventilation and...
Proceedings of 17th International Conference of the Engineering in Medicine and Biology Society, 1995
The introduction of information and telecommunication technologies into medicine and health care ... more The introduction of information and telecommunication technologies into medicine and health care has improved the communication and exchange of data between different health care institutions. Along that direction, we are developing a strategic plan for a countrywide infrastructure for exchanging medical imaging information in digital form, as well as providing for telemedicine and teleconsulting capabilities in rural areas. Two pilot
Proceedings of 18th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 1997
In this study, the authors attempt to determine the efficacy of computer assisted ultrasonic live... more In this study, the authors attempt to determine the efficacy of computer assisted ultrasonic liver tissue characterization using texture analysis techniques. Two different algorithms were used in this study; the gray level difference statistics (GLDS) and the fractal dimension texture analysis (FDTA). Both techniques were applied on three sets of ultrasonic liver images, normal-hepatoma-cirrhosis, all histologically proven. In all images,
The objective of this study is to investigate the usefulness of texture analysis in the endometri... more The objective of this study is to investigate the usefulness of texture analysis in the endometrium during hysteroscopy in endoscopic imaging of the uterine cavity. Endoscopy images from the endometrium from three subjects, at optimum illumination and focus, were frozen and digitized at 720x576 pixels using 24bits color. Regions of Interest (ROI) of normal (N=61) and abnormal (N=69) regions were manually selected by the physician. ROI images were converted into gray scale and Statistical Features (SF) and Spatial Gray Level Dependence Matrix features (SGLDM) were computed. The non-parametric Wilcoxon rank sum test at a = 0.05 was carried out for comparing the differences between normal and abnormal tissue. There was significant difference between normal and abnormal endometrium for the SF features variance, energy and entropy and for the SGLDM feature of angular second moment. There was no significant difference for the SF features mean, median, and SGLDM features of contrast, correlation and homogeneity.
Although VEP (visual evoked potential) is an electrophysiological test commonly used in investiga... more Although VEP (visual evoked potential) is an electrophysiological test commonly used in investigating different neurophysiological disorders, there are not many objective criteria for distinguishing a normal from an abnormal VEP. The authors used the phase characteristics of the power spectrum for the distinction of VEPs. The phase spectrum of a VEP was proved to have a certain periodicity in the 0-40-Hz region. By studying the phase characteristics of VEP waveforms, the authors were able to determine the range of the period that characterizes normal and abnormal VEPs and to establish an experimental method for distinguishing the different populations.>
A model was developed to simulate the function of a positron emission tomography (PET) scanner. I... more A model was developed to simulate the function of a positron emission tomography (PET) scanner. It can be used both to determine the effects of different design parameters on the performance of a PET scanner and to aid in the design and performance evaluation of a specific scanner design. The model incorporates the characteristics of the source, collimators, γ-ray detectors,
IEEE Transactions on Nuclear Science, 1990
A Monte Carlo study of the timing resolution of small BaF2 crystals for time-of-flight (TOF) posi... more A Monte Carlo study of the timing resolution of small BaF2 crystals for time-of-flight (TOF) positron emission tomography (PET) is presented. The interaction of 511-keV gammas, the emission and transport of ultraviolet light in the crystal, and the pulse formation in the photomultiplier are simulated. The individual contributions to the timing resolution and the overall effect are calculated and compared
We liavt, tlt7vt.loped a Monte-Carlo program that simulates the f1ulct,ion of a PET scauner to be... more We liavt, tlt7vt.loped a Monte-Carlo program that simulates the f1ulct,ion of a PET scauner to be used as a design t,ool for PET. Several design parameters were studied an their efftxt on the prrformance of the scanner was determinctl .
Digital watermarking is a recently emerged research area, which has the potential of providing al... more Digital watermarking is a recently emerged research area, which has the potential of providing alternative/complementary solutions for a number of issues relating to medical data management and distribution. The present paper aims to reveal the perspectives of digital watermarking in health information systems, and proposes a wavelet-based multiple watermarking scheme that addresses the issues of medical data protection, archiving, and retrieval, as well as of origin and data authentication. The scheme applies multiple watermarking in medical images, and embeds in them the physician's digital signature, patient's personal and examination data, keywords for image retrieval, and a reference watermark for the purpose of data integrity control. The experimental results demonstrate the efficiency and transparency of the watermarking scheme, which conforms to the strict limitations that apply to regions of diagnostic significance.
Beyond its already established wide range of applications, digital watermarking has recently star... more Beyond its already established wide range of applications, digital watermarking has recently started to gain a foothold in the healthcare sector. The paper discusses the potential of multiple watermarking to address a number of health information management issues, such as protection of sensitive data, origin and data authentication, image archiving and retrieval. A wavelet-based multiple watermarking scheme focusing on these medical-oriented applications is presented; the scheme allows the physician to define a Region of Interest, whose diagnostic value is explicitly protected throughout the embedding process, since the only additional information inserted therein is for the purpose of integrity control. The rest part of the image casts multiple watermarks conveying the physician's digital signature, patient's sensitive data, and keywords allowing image retrieval. In order to increase data robustness, a form of hybrid coding is applied, which includes repetitive embedding of BCH encoded watermarks.
In this study we present a multipurpose health care telemedicine system, which can be used for em... more In this study we present a multipurpose health care telemedicine system, which can be used for emergency or patient monitoring cases. Ambulances, Rural Health Centers (RHC) or other remote health location, Ships navigating in wide seas and Airplanes in flight are common examples of possible emergency sites, while critical care telemetry and telemedicine home followups are important issues of patient monitoring. The telemedicine system is a combined real-time and store and forward facility that consists of a base unit and a telemedicine (mobile) unit. The telemedicine unit (patient site) allows the transmission of vital biosignals (3-12 lead ECG, SPO2, NIBP, IBP, Temp) and still images of the patient from the incident place to the base unit (consultation site). The transmission is performed through GSM, Satellite links or POTS. Using this device a specialist doctor can telematically "move" to the patient site and instruct medical personnel when handling a patient. The consultation site is equipped with a multimedia database able to store and manage the data collected by the system. The system was validated in four different countries using a standardized medical protocol.
A Virtual patient record (VPR) is an ideal Electronic healthcare record (EHR) that is decentraliz... more A Virtual patient record (VPR) is an ideal Electronic healthcare record (EHR) that is decentralized and contains heterogeneous and distributed medical and clinical data Extensible Markup Language (XML) is a Web standard that was introduced by the World Wide Web Consortium (W3C) and today has become the major driver towards heterogeneous system integration for any industry solution. This work is based on our efforts to create an XML Schema that operates as an interface between different heterogeneous patient record structures. The XML Schema structure is based on standards such as HL7, DICOM, VITAL, CEHR and prENV 1 3 6 M and was modeled with UML metadata techniques. We are describing our efforts and technological platform used to test this XML schema by implementing various healthcare scenarios and using state of the art java components and XML based technologies. The developed pilot is initially being tested for two homecare scenarios (anticoagulation treatment and ventilation and oxygen therapy mpport) in conjunction with a standard primary healthcare patient record software package.
In this study, the authors attempt to determine the efficacy of computer assisted ultrasonic live... more In this study, the authors attempt to determine the efficacy of computer assisted ultrasonic liver tissue characterization using texture analysis techniques. Two different algorithms were used in this study; the gray level difference statistics (GLDS) and the fractal dimension texture analysis (FDTA). Both techniques were applied on three sets of ultrasonic liver images, normal-hepatoma-cirrhosis, all histologically proven. In all images, 32×32 pixel rectangular regions-of-interest were selected by specialized physicians and used in the analysis. FDTA was able to differentiate hepatoma from cirrhosis and normal liver with an accuracy of 90% and the GLDS was able to differentiate cirrhosis from normal with an accuracy of 75%. The combination of the two techniques proved to differentiate the three types with an overall accuracy of 81.7%
A wavelet-based multiple watermarking scheme is proposed, which addresses the problems of medical... more A wavelet-based multiple watermarking scheme is proposed, which addresses the problems of medical confidentiality protection and both origin and data authentication. The scheme embeds multiple watermarks serving different purposes: a robust watermark containing the doctor's digital signature for authentication, a caption watermark with patient's personal and examination related data, and a fragile watermark for the purpose of data integrity control. Thus, the proposed added-value tool offers alternatives for different issues associated with medical data management and distribution. The experimental results demonstrate the efficiency of the watermarking scheme, which fulfills the strict requirements concerning the acceptable alterations of medical images.
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Papers by Sotiri Pavlopoulos