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At least 307 records · Page 17Linked to original sources
PubMedDate not supplied

The effect of scatter reduction on the signal-to-noise ratio in computed radiography.

Signal-to-noise ratio (SNR) in computed radiography (CR) was assessed by using the computerized image data from storage phosphor radiographs in a modification of the Rose model. A multiple pencil-beam (MPB) imaging device, a conventional 1:12 grid, and an air gap of 90 cm were compared in terms of improvement of the signal-to-noise ratio caused by the reduction of scatter. The MPB device showed better SNRs by a factor of 1.25 compared to the grid and air gap which were approximately equal to each other. This is related to its superiority in scatter control, which has also been shown previously. Air gap screening has not been very popular because of geometrical problems, but in scatter reduction it is still comparable to today's grid technology. The optimization of image information content in CR is briefly discussed.

Radiographic Image Enhancement↗
PubMedDate not supplied

Clinical application of a magneto-optical disk image filing system/image save and carry (ISAC) system.

We propose the utilization of portable magneto optical disks for image filing. The main problems in PACS are the need for a high-speed local area network (LAN) and a large mass storage device. An image filing system--image save and carry (ISAC)--is one solution for these problems in present PACS and requires minimal additional hardware and cost for the installation. Whenever a patient is examined, the clerk carries the medical record and the ISAC magneto-optical disk for recording image data, and after inspection records the image data into the magneto-optical disk. We investigated the number of image retrievals done for inpatients and outpatients in 1988 at our radiation therapy department. The data storage requirements were on the average 18.5 MB for outpatients and 173.9 MB for inpatients. An ISAC display console needs also an easy-to-use man/machine interface for specifying images and image display characteristics in order to realize the ISAC system.

Computer Systems↗
PubMedDate not supplied

Combination of multiple pencil-beam imaging to computed storage phosphor radiography: a new method.

Computed radiography (CR) with storage phosphors offers a wide dynamic range and improved sensitivity compared to film-screen technology. CR was combined in this study with a prototype multiple pencil-beam (MPB) imaging device which has been shown to be very effective in scatter reduction. The combination was analyzed and compared to the standard technique of grid screening in two ways: a free-response ROC (FROC) analysis was first performed followed by a blinded test arrangement for visual analysis of image quality in a series of computed radiography of the lumbar spine by both the MPB and grid modalities. The results of the FROC study showed a statistically significant (P less than or equal to 0.01) improvement in signal detection. The MPB-CR images of the lumbar spine had more contrast but also a slightly mottled or grainy appearance. Image quality was found good but contrast processing was criticized because it seemed to result in a too steep display of contrast in MPB imaging. This should be avoidable by changing the image processing parameters.

Adult↗
PubMed2001

A new system for digital image acquisition, storage and presentation in an accident and emergency department.

OBJECTIVES: To develop a computer based storage system for clinical images-radiographs, photographs, ECGs, text-for use in teaching, training, reference and research within an accident and emergency (A&E) department. Exploration of methods to access and utilise the data stored in the archive. METHODS: Implementation of a digital image archive using flatbed scanner and digital camera as capture devices. A sophisticated coding system based on ICD 10. Storage via an "intelligent" custom interface. RESULTS: A practical solution to the problems of clinical image storage for teaching purposes. CONCLUSIONS: We have successfully developed a digital image capture and storage system, which provides an excellent teaching facility for a busy A&E department. We have revolutionised the practice of the "hand-over meeting".

Computer Security↗
PubMed1985

The microcomputer in the dental office: a new diagnostic aid.

The first computer applications in the dental office were based upon standard accountancy procedures. Recently, more and more computer applications have become available to meet the specific requirements of dental practice. This implies not only business procedures, but also facilities to store patient records in the system and retrieve them easily. Another development concerns the automatic calculation of diagnostic data such as those provided in cephalometric analysis. Furthermore, growth and surgical results in the craniofacial area can be predicted by computerized extrapolation. Computers have been useful in obtaining the patient's anamnestic data objectively and for the making of decisions based on such data. Computer-aided instruction systems have been developed for undergraduate students to bridge the gap between textbook and patient interaction without the risks inherent in the latter. Radiology will undergo substantial changes as a result of the application of electronic imaging devices instead of the conventional radiographic films. Computer-assisted electronic imaging will enable image processing, image enhancement, pattern recognition and data transmission for consultation and storage purposes. Image processing techniques will increase image quality whilst still allowing low-dose systems. Standardization of software and system configuration and the development of 'user friendly' programs is the major concern for the near future.

Computer-Assisted Instruction↗
PubMed1981

Computer processing of visual field data. I. Recording, storage, and retrieval.

A minicomputer system has been developed to provide real-time management of visual field data. Records of a large population of patients with glaucoma in a university ophthalmic practice are stored on magnetic disks. Data storage has been semiautomated by means of a microprocessor-controlled recording device for standard perimeters. Existing visual field records may also be digitized by means of a magnetic graphics tablet. Records are retrievable in real time and are graphically displayed at video terminals.

Diagnosis, Computer-Assisted↗
PubMed1988

A model for capacity planning of a comprehensive integrated information system for hospitals and clinics.

Appropriate system sizing is essential to ensuring a reasonable computer response time for end users. A model is discussed that describes the type and number of interactions between user terminals and printers and the central processor for a comprehensive, integrated medical information system. The system modeled includes support to inpatient and outpatient order entry and results reporting for clinical services; registration; admission, disposition, and transfer; patient appointing; pharmacy, clinical laboratory, and radiology; medical record management; and electronic messages. Originally developed for use in benchmark testing of comprehensive systems designed for military hospitals and clinics, the model has been generalized to be applicable to other systems and settings. Results are presented for a routine busy day in a 200-bed teaching hospital providing extensive outpatient services, and a large free-standing clinic. The model results can be applied to several facets of system planning, including sizing of the central processor and communications network, determining the optimal number of storage devices and user devices, and fine tuning the user interface.

Ambulatory Care Information Systems↗
PubMedDate not supplied

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↗
PubMed1994

Data compression for medical report archiving.

In a hospital environment, where large numbers of reports are compiled, data compression offers a method for substantially reducing the required disk space whilst protecting the confidentiality of patient data. An analysis is given of the most important parameters that influence compression of free-text data, to realize an efficient implementation of an archiving system for medical reports. An overall reduction of the required disk space by more than 50% can be attained, as well as supplementary level of protection. A slight increase in access time is thereby inevitable, but almost insignificant. Such an archiving system constitutes a necessary component for an intelligent information retrieval system. The access to information contained in medical documents (by means of natural language processing and artificial intelligence techniques) is considered to be one of the key issues in the field of medical informatics for the coming decades.

Archives↗
PubMed1995

An interactive histology image-barcode manual for a videodisc image library.

UNLABELLED: Cell Biology and HISTOLOGY (alias Microanatomy, alias Microscopic Anatomy) is a required course for first-year medical and dental students in most health science centers. The traditional approach used in teaching this discipline is to present photomicrographic images of structures to students in lecture using 35 mm slides of fields seen through the microscope. The students then spend many hours viewing and studying specimens of tissues using a light microscope in a laboratory setting. Students in traditional courses of histology spend an inordinate amount of time learning the component structures by attempting to find and identify them in tissue sections using a microscope, where the structure being sought is surrounded by a multitude of other structures with which they are also not familiar. With the recent availability of videodisc stored image libraries of histological samples, it is now possible to study histological principles without the use of the microscope as the primary learning tool. A videodisc entitled " HISTOLOGY: A Photographic Atlas" by S. Downing (published by Image Premastering Services Limited, Minneapolis, MN, 1991) has been incorporated into our histology course. Fifteen videodisc player stations are provided for 150 students. Images are retrieved by students using a bar code scanner attached to a videodisc player (Pioneer CLD-2400). Using this kind of image library, students can now learn basic histological structure, such as cell and tissue types, without the use of a microscope or as a tool for facilitating microscopy. The use of a videodisc library of randomly accessible images simplifies learning the basic components which all organs are composed of by presenting the learner with clear-cut examples to avoid confusion with other structures. However, videodisc players and TV monitors are still not appropriately priced for every student to own. This presents a problem in that the same images studied in class are not available to study and review outside of class. There is a need for resources for additional study outside of the institutional setting, for students to have and interact with to reinforce the learning experience in the teaching laboratory. A hard copy manual was created and is being used in our course; it incorporates photos captured from the videodisc. The images displayed in the manual are chosen to give the student one example of each histological component. Additional labeling is added to the images, and each image is accompanied by a bar code that may be used at a videodisc player with a bar code reader to retrieve the same color image from the disc displayed in larger format on a TV monitor. Each topic in the manual is accompanied by learning objectives and a statement of clinical relevance. Following the presentation of the images in each section of the manual, the students are encouraged to practice by viewing multiple examples of each structural component presented in the lesson. They can do this by using the bar-coded catalog supplied with each disc. The presentation of each topic concludes with a quiz composed of questions about images that the student can retrieve from the videodisc using barcodes in the text of the manual. Some of the images on the quiz are printed in miniature in the manual to provide the student with an opportunity for personal review at home when hardware to obtain and display images from a video disc is not available. This manual provides an answer to the dilemma faced by the learner when access to hardware is not available; reinforcement is therefore facilitated outside the teaching laboratory. This allows learning to continue outside of the classroom, using the same materials. (abstract truncated)

Computer-Assisted Instruction↗
PubMed1999

Belt worn control system and battery for the percutaneous model of the Jarvik 2000 heart.

A belt worn controller and lithium-ion battery pack have been developed for use with the initial clinical trials of the Jarvik 2000 heart. Patient interface considerations, safety, and simplicity were major design inputs for the system. The controller was developed using all analog technology to avoid difficulties with electromagnetic interference (EMI), to minimize susceptibility to electrostatic discharge, and to avoid the need for software validation. Manual control of pump speed is accomplished by a patient operated knob, according to physician instructions for rest and exercise for each individual patient. The system includes alarms and indicators which show the following: the amount of remaining battery charge, if the battery is low and needs replacement, the power in watts being consumed, if the power consumed is above 15 W, if the pump is running below the selected speed setting, and if the pump stops. The control box, curved to be worn on the belt, is only 2.5 inches high for comfort when sitting. The battery pack, also form fitted for patient comfort, weighs just over 1 1/2 pounds and supplies 65 W-h of energy storage, sufficient to run the device for over 8 h at nominal load.

Computers, Analog↗
PubMed2001

Digital imaging modalities for dental practice.

The introduction of the computed tomograph in the 1970s revolutionized medical diagnosis by initiating the transition from analogue to digital imaging. During this period, more specialized equipment for image processing was developed, such as cathode-ray tubes for image display, special sensors for image acquisition, and storage devices for image archiving. Digital imaging systems designed exclusively for use in dentistry were developed in the latter half of the 1980s. Some are now being clinically applied under conditions of close scrutiny to determine diagnostic accuracy, image quality, and radiation exposure to patients. This article reviews the enabling technologies of digital systems used in dentistry, and focuses upon intraoral digital imaging systems, concepts for digital image acquisition, and variations in radiation dose and their effects on diagnostic accuracy of caries detection.

Data Display↗
PubMed2005

On the building of binary spelling interfaces for augmentative communication.

A criterion for design of optimal binary spelling interfaces (SI)--the average expectation of number of writing steps (trials) required to write one letter--is presented and discussed. This criterion is relevant for practical usage of any menu-oriented alternative communication system, mechanical device or brain-computer-interface, when a user (typically, a patient with devastating neuromuscular handicap) can not create an intended single binary response with an absolute reliability. An algorithm for building of a corresponding binary tree is developed and evaluated. This algorithm is efficient, when selection probabilities have essentially different values (the worst case).

Algorithms↗
PubMed1998

What's new in mammography.

Early diagnosis of breast cancer plays the leading role in reducing mortality rates and improving the patients' prognosis: mammography is the most sensitive technique currently available for the detection of nonpalpable lesions and therefore the method of choice. However, mammography has some limitations and the technique must be improved with technological devices without affecting image quality. This could be the target to increase diagnostic accuracy. Mammography sensitivity and specificity are now improved with the digital computer assisted technique, teleradiology, digital tomosynthesis or digital angiography--used to study microvascularization--3D imaging or synchrotron light, and laser mammography. Such other technological devices as Mammospot reduce breast thickness and provide better breast compression. Digital mammography can be carried out with film or direct digitization. The advantages of the digital technique are a shorter examination time, less storage space, electronic image recording, with image 'adjustments' made by the radiologist, and especially computerized analysis. The computer aided diagnosis can be defined as the diagnosis made by the radiologist who considers the results of computerized analysis as a 'second opinion'. In this way incidental mistakes made by radiologists, can be corrected by the computer analysis. Computers are a basic element also in teleradiology, which needs immediate and simultaneous admittance to the patient's history and permits radiology optimization in rural areas too. As for tomosynthesis, it permits to study a single slice of the breast without glandular tissue overlapping, which is useful in dense breasts where the diagnosis can be made with a lower X-ray dose. Moreover, this method fits the current mammographic systems easily. 3D imaging is still a work in progress. Synchrotron mammography is used only on surgery specimens, where it exhibits high resolution and contrast, depicting structures and details missed by conventional mammography. Breast DSA allows the study of vessels < 0.20 mm in diameter and of fine microvascular details; it can also demonstrate neoangiogenesis. Laser mammography permits bilateral examinations of the breast in 10-15 mins and is currently used also for breast cancer therapy, although only in animal trials. To conclude, after reviewing new techniques and evaluating the real cost/benefit ratio for each of them, conventional mammography remains the most sensitive tool for breast cancer diagnosis.

Angiography, Digital Subtraction↗