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PubMed1998

The DICOM image formatting standard: its role in echocardiography and angiography.

Both echocardiography and angiography have traditionally used analog media for long-term storage, but increasingly there is the desire to develop digital storage and exchange methodology. Before digital storage can become a reality, though, standards must be agreed to by the vendor and user community to ensure global intra operability of medical instrumentation. To this end, the National Electrical Manufacturers' Association and various professional organizations from around the world have collaborated to develop the DICOM (Digital Imaging and Communications in Medicine) image formatting standard. This standard specifies the exact way in which digital images are exchanged between instruments, either using a network or storage medium, and distinct standards have been developed for angiography and echocardiography. In angiography, only gray scale images are considered, whereas in echocardiography several different types of image formats are allowed to account for color Doppler echocardiography. Distinct standards have also evolved for disk-based storage. For angiography, only storage on the writable CD-ROM is allowed, whereas echocardiograms may be stored on re-writable magneto-optical disks, floppy disks, and CD-ROMs. Only lossless compression is allowed in the angiographic standard, whereas echocardiography allows the use of the JPEG (Joint Photographic Expert Group) lossy compression algorithm. Currently, all major angiographic and echocardiographic vendors have agreed to support the DICOM standard, and products are beginning to appear, first with disk-based storage but increasingly with network-based exchange of image data.

Coronary Angiography↗

PubMed2002

Tele-endoscopy: influence of data compression, bandwidth and simulated impairments on the usability of real-time digital video endoscopy transmissions for medical diagnoses.

BACKGROUND AND STUDY AIMS: Real-time digital video transmission (rtDVT) at an acceptable quality through networks has been possible for several years. This technique can be used for telemedical applications, such as tele-endoscopy. The hypotheses of the present study were that the quality of real-time DVT depends on the technical equipment used, and that the resulting image quality influences the usability of the system for diagnostic purposes. MATERIALS AND METHODS: An experimental network was established between two German referral endoscopy centers, using the Asynchronous Transfer Mode (ATM) protocol. At first, rtDVTs of routine gastrointestinal video endoscopies were transferred through the network for prospective evaluation of the feasibility of the technical equipment and its usability for diagnostic tele-endoscopy, based on the video image quality. Secondly, the image quality and usability for correct telemedical diagnosis were evaluated prospectively in a double-blind experimental setting in relation to variations in the methods of data compression used, transmission bandwidths, and simulated transmission errors. Fourteen endoscopists evaluated 27 variations of an endoscopic video sequence. RESULTS: Compression with the Moving Picture Expert Group 2 (MPEG2 [4 : 2 : 2]) standard, the ATM protocol, and a bandwidth of 40 megabits per second (Mb/s) were used successfully in 40 routine tele-endoscopies for practical evaluation. Doctors were able to handle the system with ease, and its availability was 100%. There were no detectable differences between the original video image and the transferred image, and the images were usable for diagnosis in all cases. The set-up used clinically was therefore considered to provide the optimal conditions for comparisons in the experimental part of the study. Experimentally, any technical variation was found to cause a reduction in the overall image quality and hence a reduction in diagnostic usability: compression algorithm (MPEG2 [4 : 2 : 2] vs. others: P = 0.001), bandwidth (> or = 8 vs. < 8 Mb/s: P = 0.001), and error rate (10 (-8) vs. 10 (-7): P = 0.001). CONCLUSIONS: rtDVT using MPEG2 [4 : 2 : 2] compression and a bandwidth of 40 Mb/s did not effectively differ from the original video images in routine tele-endoscopy. The qualitative requirements in diagnostic video endoscopy, however, are obviously much higher than previously assumed, since experienced endoscopists detected a loss of image quality and a reduction in diagnostic usability with any reduction in the technical specification. Modern methods of data compression, broadband networks and a network protocol with good quality-of-service guarantees are therefore prerequisites for diagnostic rtDVT.

Algorithms↗

PubMedDate not supplied

Burn-induced alterations in vasoactive function of the peripheral cutaneous microcirculation.

Alterations in the cutaneous vasomotion function caused by scald burns to a large area on the flank were observed and quantified in a dorsal skin flap window with a hamster model. Subsequent to chronic implantation of the window chamber to provide direct microscopic observation of blood flow for an entire thickness of skin, control measurements of vasoactivity in a defined network of arterioles were taken by means of a digital video image splitter over a period of several days. A 100 degrees C, 5-second water scald was then effected over 17% to 55% of the total body surface area, and the vasoactivity was remeasured in the targeted set of sites at serial time intervals for 2 to 4 days. Data were acquired directly into a computer and analyzed for both the magnitude and time pattern of diameter fluctuations during 3-minute observation periods. Average and standard deviations of diameters were computed, and the Prony power spectral analysis method was applied to identify the presence and strength of fluctuation frequencies. In general, vasomotion was suppressed for several hours subsequent to the burn, and the activity was dominated by much slower contractions than control. No direction of vessel diameter changes prevailed uniformly throughout the peripheral microcirculation. Large alternate constrictions and dilations were also observed for some arteriolar and venular components, but others exhibited no significant change at all. The incidence and magnitude of peripheral microvascular response was proportional to the size of the injured area.

Anesthesia, Inhalation↗

PubMed2005

Extracting data from a DICOM file.

DICOM v3.0 is a vendor-independent standard for digital medical images that describes a file format and network protocol for the exchange of images between computer systems. When simply viewing a DICOM file, it is not necessary for the user to understand the details of the entire DICOM standard. However, understanding parts of the standard is essential when DICOM files are read and processed by a user-generated program. This paper offers an overview of information a user needs to write a program for extracting the image and acquisition parameters from a DICOM file.

Computer Communication Networks↗

PubMed1979

Computer aided analysis of chromatin network and basophil color for differentiation of mononuclear peripheral blood cells.

Computer aided differentiation of plasmoblasts, Pfeiffer cells, immunoblasts, lymphocytes and centrocytes is achieved with the parameters of chromatin network arrangement and structure, and multispectral cytoplasm color. The digital methods involve: (a) segmenting the nuclear image into topographic sections and analyzing the optical density distribution from the chromatin in these sections; (b) determining the nuclear structure with a 7 x 7 median filter, gradient filter and contour following algorithms; and (c) clustering two-dimensional chromatic data from panoptically stained cellular components. The parameters reported here are a subset of those needed for the automated diagnosis of many hematologic diseases especially the leukemias.

Blood Cells↗

PubMed1999

Viewing DICOM-compliant CT images on a desktop personal computer: use of an inexpensive DICOM receive agent and freeware image display applications.

OBJECTIVE: Our objective was to determine the ease of installation and use of relatively inexpensive and free software applications that allow Macintosh users to receive and view CT images from a Digital Imaging and COmmunication in Medicine-compliant imaging network. CONCLUSION: Simple-to-use Macintosh-based options to transfer and view images are readily available and easily installed by users with minimal computer expertise.

Humans↗

PubMed2003

Consumer attitudes and use of antibiotics.

Recent antibiotic use is a risk factor for infection or colonization with resistant bacterial pathogens. Demand for antibiotics can be affected by consumers' knowledge, attitudes, and practices. In 1998-1999, the Foodborne Diseases Active Surveillance Network (FoodNet( conducted a population-based, random-digit dialing telephone survey, including questions regarding respondents' knowledge, attitudes, and practices of antibiotic use. Twelve percent had recently taken antibiotics; 27% believed that taking antibiotics when they had a cold made them better more quickly, 32% believed that taking antibiotics when they had a cold prevented more serious illness, and 48% expected a prescription for antibiotics when they were ill enough from a cold to seek medical attention. These misguided beliefs and expectations were associated with a lack of awareness of the dangers of antibiotic use; 58% of patients were not aware of the possible health dangers. National educational efforts are needed to address these issues if patient demand for antibiotics is to be reduced.

Adult↗

PubMed2004

[Reorganization of microtubule system in pulmonary endothelial cells in response to thrombin treatment].

Thrombin induces rapid and reversible increase of endothelial (EC) barrier permeability associated with actin cytoskeleton remodeling and contraction. The role of microtubules (Mts) in EC barrier regulation compared with actin systems is poorly understood. In this work we studied pathways of Mt and actin regulation in response to thrombin treatment in cultured EC, and the involvement of trimeric G-proteins and in this process. Cells were treated with thrombin, and further analysed using immunofluorescent staining of actin and Mts, digital microscopy and morphometric analysis. In normal cells actin network consists of thin bundles basically located in the cell periphery, Mt density decreases from the cell center to the cell edge. Thrombin (25 nM) induced endothelial dysfunction associated with a rapid (within 5 min) decrease of peripheral Mt network and a slower actin stress fiber formation in the cytoplasm. Pretreatment with Pertussis toxin, which is Gi protein inhibitor, attenuated thrombin-induced stress fiber formation and Mt disassembly. Overexpression of activated G12, G13, Gi and Gq proteins, which are involved in thrombin receptor-mediated signaling, resulted in increasing stress fibers thickness and density and complete Mt disassembly. From the results obtained we suggest that thrombin regulates actin cytoskeleton of EC using local Mt depolymerization at the cell edge.

Actins↗

PubMed2005

Computed Quality Assessment of MPEG4-compressed DICOM Video Data.

Digital Imaging and Communication in Medicine (DICOM) has become one of the most popular standards in medicine. This standard specifies the exact procedures in which digital images are exchanged between devices, either using a network or storage medium. Sources for images vary; therefore there exist definitions for the exchange for CR, CT, NMR, angiography, sonography and so on. With its spreading, with the increasing amount of sources included, data volume is increasing, too. This affects storage and traffic. While for long-time storage data compression is generally not accepted at the moment, there are many situations where data compression is possible: Telemedicine for educational purposes (e.g. students at home using low speed internet connections), presentations with standard-resolution video projectors, or even the supply on wards combined receiving written findings. DICOM comprises compression: for still image there is JPEG, for video MPEG-2 is adopted. Within the last years MPEG-2 has been evolved to MPEG-4, which squeezes data even better, but the risk of significant errors increases, too. Within the last years effects of compression have been analyzed for entertainment movies, but these are not comparable to videos of physical examinations (e.g. echocardiography). In medical videos an individual image plays a more important role. Erroneous single images affect total quality even more. Additionally, the effect of compression can not be generalized from one test series to all videos. The result depends strongly on the source. Some investigations have been presented, where different MPEG-4 algorithms compressed videos have been compared and rated manually. But they describe only the results in an elected testbed. In this paper some methods derived from video rating are presented and discussed for an automatically created quality control for the compression of medical videos, primary stored in DICOM containers.

Algorithms↗

PubMed1992

Automated interictal EEG spike detection using artificial neural networks.

Feed-forward, error-back-propagation artificial neural networks were applied to recognition of epileptiform patterns in the EEG. The inherent network properties of generalization and variability tolerance were effective in identifying wave forms that differed from the training patterns but still maintained 'epileptiform' spatio-temporal characteristics. The certainty of recognition was measured as a continuous function with a range of 0-1. Two levels of certainty (0.825 and 0.900) were used to indicate recognition of spikes and sharp waves (SSW). An average 94.2% (+/- 7.3) of the SSW were recognized; 20.9% (+/- 22.9) of all recognized SSW were false-positive recognitions. The time required for pattern recognition was well within the time required for digitizing the analogue data. This study provides evidence that neural network technology is, in principle, an effective pattern recognition strategy for identification of epileptiform transients in the EEG. The analysis is sufficiently rapid to be of potential value as a strategy for data reduction of long recordings stored on bulk media.

Electroencephalography↗

PubMed2002

Storage and distribution of pathology digital images using integrated web-based viewing systems.

CONTEXT: Health care providers have expressed increasing interest in incorporating digital images of gross pathology specimens and photomicrographs in routine pathology reports. OBJECTIVE: To describe the multiple technical and logistical challenges involved in the integration of the various components needed for the development of a system for integrated Web-based viewing, storage, and distribution of digital images in a large health system. DESIGN: An Oracle version 8.1.6 database was developed to store, index, and deploy pathology digital photographs via our Intranet. The database allows for retrieval of images by patient demographics or by SNOMED code information. SETTING: The Intranet of a large health system accessible from multiple computers located within the medical center and at distant private physician offices. RESULTS: The images can be viewed using any of the workstations of the health system that have authorized access to our Intranet, using a standard browser or a browser configured with an external viewer or inexpensive plug-in software, such as Prizm 2.0. The images can be printed on paper or transferred to film using a digital film recorder. Digital images can also be displayed at pathology conferences by using wireless local area network (LAN) and secure remote technologies. CONCLUSIONS: The standardization of technologies and the adoption of a Web interface for all our computer systems allows us to distribute digital images from a pathology database to a potentially large group of users distributed in multiple locations throughout a large medical center.

Computer Storage Devices↗

PubMed1997

Digital radiographs: will the future ever arrive?

The benefits of introducing digital technologies and specifically digital radiographs should be compelling and yet the widespread acceptance has been slow. A brief anecdotal look at two other industries suggests possible insight into the factors leading to the acceptance of digital radiography in the dental industry. Rather than to argue for a single digital radiography product, it is suggested that irrespective of the means of digital radiograph capture, there are pervasive benefits for the dental practitioner in using digital radiograph technology.

Computer Communication Networks↗

PubMed2006

Twenty-first century learning in school systems: the case of the Metropolitan School District of Lawrence Township, Indianapolis, Indiana.

To empower students with skills such as information and technological literacy, global awareness and cultural competence, self-direction, and sound reasoning, teachers must master these skills themselves. This chapter examines how the Digital Age Literacy Initiative of the Metropolitan School District of Lawrence Township in Indianapolis, Indiana, which is funded by the Lilly Endowment, incorporated twenty-first century learning through a systemic approach involving teacher training and the use of data. The authors explain the district's content, process, and context goals toward accomplishing its mission of empowering students with the necessary twenty-first century skills to succeed in the digital age. The district places a strong emphasis on professional development for teachers. To support the necessary teacher learning and therefore sustain the work of the initiative, the district has adopted action research, self-assessment, and an online professional development network. To support teachers in implementing new strategies, master teachers serve as digital age literacy coaches. The chapter discusses the initiative's focus on evidence of progress. Through a partnership with the Metiri Group of California, the district has built a range of assessments including online inventories and twenty-first century skill rubrics. For example, the Mankato Survey collected teacher and student data around access, ability, and use of technology in the classroom in 2001 and then in 2004. This research showed significant gains in some technologies across all grade levels and consistent gains in nearly all technologies for middle and high school students. As it moves into the next phase of implementing the Digital Age Literacy Initiative, the district embraces the systemic shifts in school culture necessary to institutionalize twenty-first century learning.

Adolescent↗

PubMed1992

Chromosome analysis by image processing in a computerized environment. Clinical applications.

Dealing with a routine regional cytogenetic activity, we have developed and adapted to clinical work a semi automatic karyotyping machine. Attempts for an accurate automated chromosome classification using a neural network have led to partial results. A specific adaptation to cancer cytogenetics is under development (determination of the modal number, translocations analysis with densitometric curves, automatic identification of markers). A specific program allows quantification of chromosome labelling with radioactive probes. Exchanges of digitized karyotypes are feasible with labs using automated karyotyping machines. A local network connects several karyotyping and metaphase finding stations. Guidelines for an international data bank concerning abnormal chromosome images have been elaborated. On the other hand the ISH techniques have been applied to the following topics: identification of human chromosome aberrations in amniotic and chorionic cells, chromosome studies of human gametes and embryos (including sex determination), identification of markers in cancer cells.

Chromosome Aberrations↗

PubMed2003

Prototype of an in vitro model of the microcirculation.

We have used microfabrication technology to construct a network of microchannels, patterned after the dimensions and architecture of the mammalian microcirculation. The network is cast in transparent silicone elastomer and the channels are coated with silanated mPEG to provide lubrication. Flow of red and white blood cells through the network is readily visualized by the use of high-speed digital image acquisition. The acquired sequences of high-quality images are used to calculate hematocrits and rates of red cell movement in the microchannels. Our prototype system has significant advantages over scaled-up room-size experimental systems in that it permits experimentation with actual human blood cells. Experiments can be carried out under well-controlled conditions in a network of microchannels with precisely known dimensions using cell suspensions of defined composition. Moreover, there is no need to counteract or anticipate the host's adaptive responses that may confound live animal experiments. Notwithstanding its limitations, the current prototype demonstrates certain features characteristic of the microcirculation, such as parachute and bullet shapes of red cells deformed in capillary channels, rouleaux formation, plasma skimming, and the utilization of collateral flow pathways due to flow obstruction caused by a white cell blocking a microchannel. We present this device as a prototype scale-to-scale model of the mammalian microcirculation. Limitations of the system as well as a variety of possible applications are described.

Animals↗

PubMed1980

A distributed computer network using microcomputers for on-line data processing in clinical monitoring and medical research.

Microelectronic technology has made possible a rapid expansion in the exploitation of the digital computer in medicine, but software development remains an increasingly significant problem. This paper describes a distributed computer network which combines the low cost computing power of the microcomputer with the highly developed features of a minicomputer. Powerful data processing facilities are provided through centralization of major resources on the minicomputer. Parallel real-time computing is assigned to microcomputers which have access to the minicomputer filestore, and to its comprehensive software development aids.

Animals↗

PubMed1999

3D reconstruction of the cerebral arterial network from stereotactic DSA.

The authors present an automatic algorithm for 3D reconstruction of cerebral blood vessels by digital subtracted angiography. The patient is localized by a stereotactic method. The reconstruction algorithm includes two steps: first vessel extraction then 2D matching and reconstruction. Accurate vessel skeletons are generated by a combination of mathematical morphological algorithms and adaptive filters. The 3D reconstruction algorithm is based on the reconstruction of vessels center lines. For that purpose, three different projections of the vascular network are used. Reconstruction is computed segment by segment (a curved line between two nodes). For each segment point, the algorithm defines all epipolar solutions on the other views. These epipolar solutions are sorted and pooled by 2D continuity and 3D proximity criteria resulting in a 3D graph. Optimal 3D segment is defined by a recursive algorithm that looks up the better path in the 3D graph. The algorithms have been implemented on a Compatible-PC computer in C language. More than 95% of static copper phantom was reconstructed in 5 min and with 1 mm 3D accuracy. 70% of arteries (from carotid to the seventh node) of a true patient arterial network were reconstructed is less than 30 min.

Algorithms↗

PubMed2005

Use of a wireless local area network in an orthodontic clinic.

Radiographic images and other patient records, including medical histories, demographics, and health insurance information, can now be stored digitally and accessed via patient management programs. However, digital image acquisition and diagnosis and treatment planning are independent tasks, and each is time consuming, especially when performed at different computer workstations. Networking or linking the computers in an office enhances access to imaging and treatment planning tools. Access can be further enhanced if the entire network is wireless. Thanks to wireless technology, stand-alone, desk-bound personal computers have been replaced with mobile, hand-held devices that can communicate with each other and the rest of the world via the Internet. As with any emerging technology, some issues should be kept in mind when adapting to the wireless environment. Foremost is network security. Second is the choice of mobile hardware devices that are used by the orthodontist, office staff, and patients. This article details the standards and choices in wireless technology that can be implemented in an orthodontic clinic and suggests how to select suitable mobile hardware for accessing or adding data to a preexisting network. The network security protocols discussed comply with HIPAA regulations and boost the efficiency of a modern orthodontic clinic.

Cell Phone↗