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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↗

A comparison of video and digital data in the assessment of myocardial perfusion abnormalities by myocardial contrast echocardiography.

OBJECTIVE: The objective of the present study was to compare the digital and video data of myocardial contrast echocardiography (MCE) to assess altered myocardial blood flow produced by graded coronary stenoses. METHODS: Three grades of left anterior descending (LAD) coronary artery stenosis and occlusion were created in eight open-chest canine models. MCE was performed with BR1 infusion by harmonic power Doppler with ECG gated intermittent triggered imaging at pulsing intervals ranging from 1:1 to 1:10. For images that were recorded simultaneously on both a videotape (video data) and an optical disk (digital data), myocardial signal intensity in the LAD region was plotted vs. pulsing intervals and was fitted to an exponential function: y = A(1 - e(-bt)), where A is the peak plateau signal intensity, and b is the rate of signal intensity rise for quantification of myocardial blood flow. RESULTS: Both values for A and b progressively decreased with a greater level of stenosis. The correlation of A with myocardial blood flow (determined by use of fluorescent microspheres) was weak with digital data (r = 0.38, p = 0.037), and was insignificant with video data (r = 0.16, p = 0.38). The correlation of b with microsphere-derived myocardial blood flow was better than that of A with both video and digital data, and was similar between the two kinds of data (video: r = 0.69, p < 0.0001; digital: r = 0.68, p < 0.0001). CONCLUSIONS: Video and digital MCE data are equivalent in their ability to quantify altered myocardial blood flow produced by graded coronary stenoses.

Analysis of Variance↗

Integration of a picture archiving and communication system with videocapture and computed radiography in a dental hospital.

A method for the integration of a picture archiving and communication system (PACS) at Kyushu University Dental Hospital with radiological information (RIS) and hospital information (HIS) systems is described. CT, US and DSA from different manufacturers were integrated by videocapture and then subsequently integrated with computed radiography (CR) by means of DICOM. The approximate amount of data stored each month on optical discs is 2 GB. The system does not incorporate intra-oral radiography.

Angiography, Digital Subtraction↗

Simulation of radiation effects on three-dimensional computer optical memories.

A model was developed to simulate the effects of heavy charged-particle (HCP) radiation on the information stored in three-dimensional computer optical memories. The model is based on (i) the HCP track radial dose distribution, (ii) the spatial and temporal distribution of temperature in the track, (iii) the matrix-specific radiation-induced changes that will affect the response, and (iv) the kinetics of transition of photochromic molecules from the colored to the colorless isomeric form (bit flip). It is shown that information stored in a volume of several nanometers radius around the particle's track axis may be lost. The magnitude of the effect is dependent on the particle's track structure.

Biophysical Phenomena↗

Nonvolatile read-out molecular memory.

A versatile molecule is described that performs as a nondestructible read-out optical-storage molecular memory. This molecular memory is composed of two distinct molecules that are chemically bonded to each other to form a single molecule with unique properties. One component is a photochromic fulgimide, and the other is a strongly fluorescing oxazine dye. This composite molecule was specifically designed and synthesized to display, under specific conditions, both the photochromic functions of the first component and the fluorescence properties of the dye. To store information, the polar, closed form of the photochromic component is illuminated with 530-nm light, which converts it to the open, nonpolar form. The information is accessed by excitation at the 650-nm band of the oxazine dye component, causing the dye to fluoresce. However, the dye emits intense fluorescence under a nonpolar environment, which is attained only when the fulgimide component is in its open, nonpolar structure. The ultrafast kinetics, spectroscopy, and mechanism of the photoreaction of this molecule and its photoinduced intermediates have been measured, and fluorescence quantum yields and cross sections were determined.

Coloring Agents↗

From papyrus to compact disc: the microbial deterioration of documentary heritage.

Highly significant evidence of the intellectual and cultural efforts of the human race is contained in documents. They take many forms, from papyri through paper to modern magnetic media and optical records. These items are mainly made of organic materials many of which contain polymers, which span from cellulose and its derivatives to synthetic resins. As with other manmade objects, however, documentary heritage is susceptible to chemical, physical, and biological damage. For the colonization and establishment of any biological community, the composition of materials used, their status of conservation, and environmental and climatic factors, such as temperature and humidity, are important elements to take into account. This article covers the scientific investigation of microbial degradation of documents, which is one of the most serious and underappreciated sources of damage to library and archival materials. In particular, although less known, modern records, including compact discs, are also subjected to biodeterioration. Archival and library material preservation broadly encompasses those activities and functions designed to produce a suitable and safe environment that extends the life of collections in useable condition for as long as is feasible. In the literature quoted, key information is also provided to avoid or limit microbial growth and some conservation treatments are also reported.

Animals↗

Teleophthalmology link between a primary health care centre and a reference hospital.

We have evaluated a teleophthalmology service linking a primary health care centre and an eye clinic at a reference hospital. General practitioners at the primary care centre serving a population of 15,000 and ophthalmologists at the reference hospital participated in this study. Eye fundus digital images were taken from 278 eye fundi of 139 consecutive patients with clinical conditions that could potentially produce fundus alterations. Fundus images were obtained with a non-mydriatic fundus camera (Canon CR6-45M) and were electronically sent reference hospital where ophthalmologist inspected the images and returned the diagnosis. In 18 patients (13%) the images did not have good enough quality to exclude eye fundus lesions. In 24 patients (17%) clear eye fundus alterations were found in at least one eye. In 14 patients (10%) there were image features suggesting retinal alterations that could not be confirmed by image inspection. Media opacity (13 eyes, 5%, seven patients, 5%) was the most common cause of poor image quality. The most difficult assessment was the evaluation of optic nerve head cupping. Retinal oedema was not observable in the digital images. In our experience teleopthalmology services seem to be an effective alternative for eye fundus diagnosis and patient follow-up.

Computer Communication Networks↗

Compressing data volume of left ventricular cineangiograms.

In this paper a method of compressing data volume for left ventricular cineangiograms is proposed. This method enables digital-optical discs to store the cineangiograms with an equivalent recording density to that of HDTV VTR's while preserving the quality of the original image. The data volume of the cineangiograms is compressed by approximating function and storing its coefficients. With this method, each cineangiogram frame is first decomposed into three regions: the inner part, the inner wall, and the background (using a statistical method previously reported by the authors). Each region is then compressed by means of a difference operation and an adaptive approximation with smooth functions. Performance is tested on 20 cases using actual cineangiograms. The specifications were verified for a spatial resolution of 1000 TV lines, a dynamic range of 60 dB, an SNR of 40 dB [pp/rms], volume compression to 7% of the original volume, and 0.19 [second/frame] for decoding on a 1.7 MFLOPS computer.

Algorithms↗

Optical imaging systems--the future of medical record storage.

This paper explains the processes which were undertaken to solve the problem of lack of storage for medical records at Logan Hospital. The paper contains analysis of why optical disk proved to be the most appropriate storage medium, and the system components of an Optical Disk System. A detailed description of how the Optical Imaging System has been structured and the processes which make the Optical Disk System a major part of the hospital's Health Information System is provided. The paper also discusses the much talked about legal side of optical imaging. Lastly the paper explains the future plans of Logan Hospital's Medical Record Storage System.

Hospital Bed Capacity, under 100↗

[Development of a universal interface for the exchange of medical image data using magneto-optical media].

Digital images generated by medical imaging form the basis for radiological diagnosis and surgical planning. Despite the advent of the DICOM 3.0 standard for medical image communication, widespread application of the existing information is often limited by incompatibility of the data formatting used by different equipment generations, and the manufacturer-specific standards employed. An exchange interface based on magneto optical discs has been developed to retrieve and present medical image data regardless of the technological hardware and the specific formats used. Specially adapted routines to retrieve the data first had to be developed. A modular program structure was used to allow flexibility in the implementation of further routines and other exchange media. Over 20,000 CT and MRI images including header information obtained from different General Electric and Siemens scanners were extracted successfully from MO discs. The image data were used for follow up and surgical planning and were transferred to a PAC-server. The interface proved reliable and easy to use. Support for further proprietary formats is currently being developed. The present exchange interface permits reliable retrieval of digital images for diagnostic and surgical planning purposes, regardless of the hardware generation and manufacturer-specific formats.

Computers↗

Digital image storage.

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Analog-Digital Conversion↗

Hybrid data capture for monitoring patients on highly active antiretroviral therapy (HAART) in urban Botswana.

Individual patient care and programme evaluation are pivotal for the success of antiretroviral treatment programmes in resource-limited countries. While computer-aided documentation and data storage are indispensable for any large programme, several important issues need to be addressed including which data are to be collected, who collects it and how it is entered into an electronic database. We describe a patient-monitoring approach, which uses patient encounter forms (in hybrid paper + electronic format) based on optical character recognition, piloted at Princess Marina Hospital in Gaborone, Botswana's first public highly active antiretroviral therapy (HAART) outpatient clinic. Our novel data capture approach collects "key" data for tracking patient and programme outcomes. It saves physician time and does not detract from clinical care.

Antiretroviral Therapy, Highly Active↗

Storage and utilization of images in otorhinolaryngology.

The amount of data in the field of otorhinolaryngology has rapidly increased, in proportion to the growing number of patients. Medical imaging has especially expanded and the percentage of image data in all information is also large. Because the space to preserve image films is increasing, it is very important to preserve them and make them easily available. Therefore, we have established a graphic filling system for storing endoscopic and radiographic images on VHS video tape and magnet-optical disk (MOD), using a personal computer. The MOD filing system is useful for storing a large amount of medical records. The user can simultaneously see the text data and the picture image on a display, and thus this system can be utilized as a database for both decision making and medical research.

Barium Sulfate↗