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PubMedDate not supplied

ImNet: a fibre optic LAN for digital image communication.

Data communication requirements in computer networks for medical diagnostics cannot be satisfied by existing LANs if digital images are involved because of the volumes of image data and the heterogeneity of data communication tasks. A user-oriented network behaviour requires a data transport rate which is beyond the physical bit rate of currently used LAN data channels. The key to an increased data transport efficiency is the separation of management data communication and image data communication. For the latter ImNet, a novel type of fibre optic network has been developed. Its hyperstar topology, its asynchronous data transport mechanism and its distributed network control make it particularly suited for PACS applications.

Computer Systems↗
PubMed2006

Evaluation of digital dermoscopy in a pigmented lesion clinic: clinician versus computer assessment of malignancy risk.

Digital dermoscopy systems employ computer-based algorithms to quantitate features of pigmented skin lesions (PSLs) and provide an assessment of malignancy risk. We evaluated interobserver concordance of PSL malignancy risk between a pigmented lesion specialist and an artificial neural network (ANN)-based automated digital dermoscopy system. While digital dermoscopy provides a reliable means of image capture, storage, and comparison of PSLs over time, the ANN algorithm requires further training and validation before the malignancy risk assessment feature can be widely used in clinical practice.

Adult↗
PubMed2001

Digital mammography: wavelet transform and Kalman-filtering neural network in mass segmentation and detection.

RATIONALE AND OBJECTIVES: The authors developed a new adaptive module to improve their computer-assisted diagnostic (CAD) method for mass segmentation and classification. The goal was an adaptive module that used a novel four-channel wavelet transform with neural network rather than a two-channel wavelet transform with manual subimage selection. The four-channel wavelet transform is used for image decomposition and reconstruction, and a novel Kalman-filtering neural network is used for adaptive subimage selection. MATERIALS AND METHODS: The adaptive CAD module was compared with the nonadaptive module by comparing receiver operating characteristic curves for the whole CAD system. An image database containing 800 regions of interest enclosing all mass types and normal tissues was used for the relative comparison of system performance, with electronic ground truth established in advance. RESULTS: The receiver operating characteristic curves yield Az values of 0.93 and 0.86 with and without the adaptive module respectively, suggesting that overall CAD performance is improved with the adaptive module. CONCLUSION: The results of this study confirm the importance of using a new class of adaptive CAD methods that allow a more generalized application for larger image databases or images generated from different sensors or by means of direct x-ray detection, as required for clinical trials.

Humans↗
PubMed1996

Automatic detection of diabetic retinopathy using an artificial neural network: a screening tool.

AIMS: To determine if neural networks can detect diabetic features in fundus images and compare the network against an ophthalmologist screening a set of fundus images. METHODS: 147 diabetic and 32 normal images were captured from a fundus camera, stored on computer, and analysed using a back propagation neural network. The network was trained to recognise features in the retinal image. The effects of digital filtering techniques and different network variables were assessed. 200 diabetic and 101 normal images were then randomised and used to evaluate the network's performance for the detection of diabetic retinopathy against an ophthalmologist. RESULTS: Detection rates for the recognition of vessels, exudates, and haemorrhages were 91.7%, 93.1%, and 73.8% respectively. When compared with the results of the ophthalmologist, the network achieved a sensitivity of 88.4% and a specificity of 83.5% for the detection of diabetic retinopathy. CONCLUSIONS: Detection of vessels, exudates, and haemorrhages was possible, with success rates dependent upon preprocessing and the number of images used in training. When compared with the ophthalmologist, the network achieved good accuracy for the detection of diabetic retinopathy. The system could be used as an aid to the screening of diabetic patients for retinopathy.

Diabetic Retinopathy↗
PubMed2002

[Fundus photography for the screening for diabetic retinopathy].

Despite the efficacy of laser photocoagulation to prevent complications of diabetic retinopathy, diabetic retinopathy remains a major cause of visual impairment and blindness in France. This is mainly due to a too late diagnosis of diabetic retinopathy. In an effort to detect diabetic retinopathy at an early stage before visual loss, international and national guidelines for the screening for diabetic retinopathy have been developed, which recommend annual fundus examination for all diabetic patients. In France, a recent survey showed that less than 50% of diabetic patients had had an eye examination during the previous year. With the increasing number of diabetic patients and the decreasing number of ophthalmologists, this situation should not improve by the next 15 years. Fundus photography is a method at least as sensitive as ophthalmoscopy in the screening for diabetic retinopathy. New nonmydriatic cameras and digital photography may allow a network organization of several screening centers around a central ophthalmological reading center where digital images could be transmitted. This organization should improve the screening for diabetic retinopathy, while saving medical time.

Blindness↗
PubMed1997

A Neural Approach to the Underdetermined-Order Recursive Least-Squares Adaptive Filtering.

The incorporation of the neural architectures in adaptive filtering applications has been addressed in detail. In particular, the Underdetermined-Order Recursive Least-Squares (URLS) algorithm, which lies between the well-known Normalized Least Mean Square and Recursive Least Squares algorithms, is reformulated via a neural architecture. The response of the neural network is seen to be identical to that of the algorithmic approach. Together with the advantage of simple circuit realization, this neural network avoids the drawbacks of digital computation such as error propagation and matrix inversion, which is ill-conditioned in most cases. It is numerically attractive because the quadratic optimization problem performs an implicit matrix inversion. Also, the neural network offers the flexibility of easy alteration of the prediction order of the URLS algorithm which may be crucial in some applications. It is rather difficult to achieve in the digital implementation, as one would have to use Levinson recursions. The neural network can easily be integrated into a digital system through appropriate digital-to-analog and analog-to-digital converters.

Journal Article↗
PubMed1992

An image management and communications (IMAC) system for radiology.

Managing x-ray films is a difficult problem in a hospital. Advances in digital imaging, high speed networks and high fidelity displays make it possible to develop an image management and communication system for a hospital. As many of the technical problems are solved, many operational problems remain. Experience with a prototype installation became the basis for a much more comprehensive implementation of a fully digital filmless imaging support system in a number of hospitals. The use of IMAC technology will bring about profound changes in the radiology community; physicians, administrators, manufactures of imaging systems and the users of radiology service, the patients.

Academic Medical Centers↗
PubMed1994

A high-speed network for cardiac image review.

A high-speed fiber-based network for the transmission and display of digitized full-motion cardiac images has been developed. Based on Asynchronous Transfer Mode (ATM), the network is scaleable, meaning that the same software and hardware is used for a small local area network or for a large multi-institutional network. The system can handle uncompressed digital angiographic images, considered to be at the "high-end" of the bandwidth requirements. Along with the networking, a general-purpose multi-modality review station has been implemented without specialized hardware. This station can store a full injection sequence in "loop RAM" in a 512 x 512 format, then interpolate to 1024 x 1024 while displaying at 30 frames per second. The network and review stations connect to a central file server that uses a virtual file system to make a large high-speed RAID storage disk and associated off-line storage tapes and cartridges all appear as a single large file system to the software. In addition to supporting archival storage and review, the system can also digitize live video using high-speed Direct Memory Access (DMA) from the frame grabber to present uncompressed data to the network. Fully functional prototypes have provided the proof of concept, with full deployment in the institution planned as the next stage.

Cardiology↗
PubMed2026

Listening forward: emerging roles of bioacoustics in ecology, evolution, and conservation.

Bioacoustics is increasingly shifting from a mostly descriptive pursuit to one that can anticipate ecological change. Recent innovations-from autonomous recording units and edge-computing sensors to speech-inspired feature extraction and machine-learning techniques like transfer learning, unsupervised discovery, and explainable AI-are transforming the study of animal communication. These advances let us work at scales previously difficult to imagine. Automated species recognition, individual identification, and even tracking cultural evolution over decades are now within reach. Entire ecosystem soundscapes can be mapped with unprecedented resolution. Looking ahead, global listening networks, adaptive acoustic indices, and live biodiversity dashboards seem increasingly realistic. We may soon build digital models that simulate communication networks under future scenarios. Closer integration with genomics, physiology, and robotics could link vocal traits to their genetic, physiological, and ecological drivers. Challenges remain, including data governance, acoustic privacy, and equitable access to the planet's sonic heritage. Bioacoustics may be on the way to becoming a predictive, integrative science - one particularly well suited to monitoring, interpreting, and helping safeguard life's communication systems in a rapidly changing world.

Animals↗
PubMed1992

Computerized digital image analysis of retinal vessel density: application to normoxic and hyperoxic rearing of the newborn rat.

Because of the inherent nature of existing techniques for vascular assessment of the retina, quantitative rigor has been difficult to attain. Computer imaging has now made possible measurement of oxygen-induced alterations in retinal blood vessels that is precise, accurate and repeatable. Newborn rats were exposed to 80% oxygen for 14 days as an animal model for retinopathy of prematurity (ROP). Ink perfusion, followed by retinal dissection, yielded silhouettes of the retinal vascular network. These images were digitized and enhanced by the MegaVision 1024XM imaging system in order to facilitate measuring extent of vasculature and capillary density. Mean grey levels, or 'mu', were 33.1 +/- 3.4 and 20.1 +/- 3.5 for room air- and oxygen-reared rats, respectively. These values are directly proportional to the fraction of the overall image that is vascular material, and, therefore, describe the extent of vaso-obliteration resulting from the oxygen exposure. The values were subsequently converted to square millimeters of vessel area to facilitate comparison to past and future studies. Oxygen rearing does not effect retinal area, but decreases retinal artery and vein diameter and decreases the linear extent of vessels toward the retinal periphery.

Animals↗
PubMed1996

Picture archiving and communication system bandwidth and storage requirements.

The purpose of this work was to determine the requirements for image storage and network bandwidth for a total digital department in a moderate sized academic radiology department. Data from the radiology information system was combined with image production information to produce a model of image acquisition. Destinations of images to reading rooms were studied to determine the final distributions of film. All findings were used to model the flow of data that would be expected if the images in the department were completely digital. Using today's standards, the department would produce approximately 15.7 Gbytes of data per day or 3.5 Tbytes of data per year if all acquisitions were digital. The peak acquisition rate would be 1.8 Gbytes per hour with a sustained rate greater than 1 Gbyte per hour for most of the working day. The anticipated bandwidth for the total digital department exceeded the capabilities of the existing picture archiving and communication system equipment. A distributed networked archive solution was shown to optimize access to images by radiologists and referring clinicians.

Computer Storage Devices↗
PubMed2004

Potential for Personal Digital Assistant interference with implantable cardiac devices.

OBJECTIVE: To determine whether the wireless local area network (WLAN) technology, specifically the Personal Digital Assistant (PDA), interferes with implantable cardiac pacemakers and defibrillators. MATERIAL AND METHODS: Various pacemakers and defibrillators were tested in vitro at the Mayo Clinic in Rochester, Minn, between March 6 and July 30, 2003. These cardiac devices were exposed to an HP Compaq IPAQ PDA fitted with a Cisco Aironet WLAN card. Initial testing was designed to show whether the Aironet card radiated energy in a consistent pattern from the antenna of the PDA to ensure that subsequent cardiac device testing would not be affected by the orientation of the PDA to the cardiac device. Testing involved placing individual cardiac devices in a simulator and uniformly exposing each device at its most sensitive programmable value to the WLAN card set to maximum power. RESULTS: During testing with the Cisco WLAN Aironet card, all devices programmed to the unipolar or bipolar configuration single- or dual-chamber mode had normal pacing and sensing functions and exhibited no effects of electromagnetic interference except for 1 implantable cardioverter-defibrillator (ICD). This aberration was determined to relate to the design of the investigators' testing apparatus and not to the output of the PDA. The ICD device appropriately identified and labeled the electromagnetic aberration as "noise." CONCLUSIONS: We documented no electromagnetic interference caused by the WLAN technology by using in vitro testing of pacemakers and ICDs; however, testing ideally should be completed in vivo to confirm the lack of any clinically important interactions.

Artifacts↗
PubMed1996

[Test of a teleradiology network based on ATM (asynchronous transfer mode)].

The retain project (Radiological Examination Transfer on ATM Integrated Network) consisted in teleradiology trials focused on pediatric imaging between two university hospitals. Rennes (France) and Barcelona (Spain) using an integrated broadband communication network based on ATM (asynchronous transfer mode), as part of a European research program. The network used was a full 10 Mbits/s ATM network directly connected to local PACSs (medical imaging hospital networks). One important reason to explicitly consider ATM for medical imaging is that multimedia applications on such networks allow integration of digital data and person-to-person communication. The utility of broadband communication for teleradiology has been confirmed. High quality video and sound are important for both human communication and medical video transfer. The project led to guidelines regarding technical options still open to improvement.

Computer Communication Networks↗
PubMed1994

Neurolink: a neurosurgical wide-area computer network.

A computerized system capable of transmitting digitally formatted images of the central nervous system has been used to develop a neurosurgical wide-area network in western Pennsylvania. This system links remote or primary care hospitals with a large, tertiary-care, Level 1 trauma center for the constant availability of neurosurgical evaluation by receiving and interpreting computed tomography and magnetic resonance images sent via ordinary public telephone lines. This network has been used in over 20 cases to receive and interpret transmitted cranial computed tomographic images consisting of subarachnoid hemorrhage, intracerebral hematoma, cerebral neoplasm, cerebral abscess, cerebrovascular accident, and normal studies. There has been no known instance of false-positive or false-negative interpretation or of a patient being adversely managed by this method. On the contrary, it appears that patient management has been positively affected through the ability of the neurosurgical evaluation to include a review of the radiological studies. The initial experience has led to the conclusion that this network is an effective, accurate, and cost-effective means of delivering neurosurgical care to underserved areas.

Brain Diseases↗
PubMed1996

Auditory cortical neurons in vitro: initial pharmacological studies.

Dissociated embryonic tissue from murine auditory cortex formed spontaneously active monolayer networks in culture that were maintained for up to 113 days in vitro (div). As a first step in determining whether neurons retain histiotypic properties, we subjected a set of 10 cultures to a sequence of 4 synaptically active substances. The test sequence consisted of 50 microM bicuculline, 10 microM strychnine, 5 microM NMDA, and 20 microM GABA. Recordings were made for 5-30 min under each condition followed by complete medium changes. Six to 14 channels with the best signal-to-noise ratios were selected for analysis that consisted of continual chart recordings of integrated burst data and further analysis of short data segments after digitizing and processing. All networks showed spontaneous activity, but had greatly varying native activity ranging from organized, quasi-periodic bursting on all channels to more complex spatio-temporal patterns with less coordination among channels. Bicuculline triggered oscillatory activity, simplified bursting, increased burst amplitude, and enhanced burst regularity among electrodes. Strychnine also changed the burst activity to a simpler pattern and enhanced the burst amplitude, indicating presence of glycine receptors in cortical tissue. Application of NMDA increased burst frequencies, but reduced burst regularity and coordination among channels. 20 microM of GABA inhibited all bursting activity in the networks. These results suggest that monolayer networks cultured on multi-electrode arrays retain some basic histiotypic pharmacological responses and may provide useful platforms for the study of network dynamics in the auditory cortex.

Animals↗
PubMed1999

Clinical decision making using teleradiology in urology.

OBJECTIVE: Using a personal computer-based teleradiology system, we compared accuracy, confidence, and diagnostic ability in the interpretation of digitized radiographs to determine if teleradiology-imported studies convey sufficient information to make relevant clinical decisions involving urology. Variables of diagnostic accuracy, confidence, image quality, interpretation, and the impact of clinical decisions made after viewing digitized radiographs were compared with those of original radiographs. MATERIALS AND METHODS: We evaluated 956 radiographs that included 94 IV pyelograms, four voiding cystourethrograms, and two nephrostograms. The radiographs were digitized and transferred over an Ethernet network to a remote personal computer-based viewing station. The digitized images were viewed by urologists and graded according to confidence in making a diagnosis, image quality, diagnostic difficulty, clinical management based on the image itself, and brief patient history. The hard-copy radiographs were then interpreted immediately afterward, and diagnostic decisions were reassessed. All analog radiographs were reviewed by an attending radiologist. RESULTS: Ninety-seven percent of the decisions made from the digitized radiographs did not change after reviewing conventional radiographs of the same case. When comparing the variables of clinical confidence, quality of the film on the teleradiology system versus analog films, and diagnostic difficulty, we found no statistical difference (p > .05) between the two techniques. Overall accuracy in interpreting the digitized images on the teleradiology system was 88% by urologists compared with that of the attending radiologist's interpretation of the analog radiographs. However, urologists detected findings on five (5%) analog radiographs that had been previously unreported by the radiologist. CONCLUSION: Viewing radiographs transmitted to a personal computer-based viewing station is an appropriate means of reviewing films with sufficient quality on which to base clinical decisions. Our focus was whether decisions made after viewing the transmitted radiographs would change after viewing the hard-copy images of the same case. In 97% of the cases, the decision did not change. In those cases in which management was altered, recommendation of further imaging studies was the most common factor.

Decision Making↗
PubMed2005

[Clinical efficacy of image processing of grid detection and suppression (GDS) in computed radiography].

In projection radiography, stationary grids are indispensable accessories to the improvement of diagnostic imaging. On the other hand, they are becoming one of the issues facing digital image processing. The lead foil that composes the grid can produce moiré on printed films and monitors according to the sampling interval at which the image is read by computed radiography (CR), creating a major obstacle to diagnosing images. The subject of this study on Grid Detection and Suppression (GDS) was the development of comprehensive image-processing software to detect and suppress grid lines automatically. Our results showed that applying GDS parameters 3 approximately 5 could provide a sufficient effect on suppression with little impact on images through the use of a multi-purpose grid (grid ratio 8:1, density 34 lp/cm) for general purposes. In projection radiography, it is expected that soft copy diagnosis will increase because the digital transition is proceeding, and the establishment of high-speed networks is becoming easier. Therefore, the digital environment is expected to improve and the choice of grids and monitors to expand, by using software such as GDS that does not require special skills.

Data Display↗