Fluctuations of Emax of the left ventricle: effect of atrial natriuretic polypeptide.

Recently the circadian rhythm of fluctuations in heart rate variability (HRV) has gained increasing attention, and the use of appropriate treatment corresponding to the circadian rhythm has become an important issue. However, the question has been raised as to whether the rhythm of fluctuation is only limited to HRV, and if a rhythm is also present in the contraction of the heart. The mathematical technique of electrical circuit simulation of the cardiovascular system was used to observe the Emax rhythm. In this study, the therapeutic effect of various drugs, including atrial natriuretic polypeptide (ANP), was confirmed. The effect of inotropic drugs including ANP on Emax was observed, and the results based on an old and a new method of determining Emax . were examined. Furthermore, the chaos analysis of Emax was also made. The time series of Emax showed an increased complexity due to the administration of ANP. In conclusion, it might be important to consider not only the fluctuation of HRV, but also an analysis of the fluctuation in the contraction of the heart.

Improving the quality of care through routine teleradiology consultation.

RATIONALE AND OBJECTIVES: The hypotheses of this study were as follows: (a) University subspecialty radiologists can provide consultations effectively to general radiologists as part of routine clinical operations; (b) these consultations will improve the quality of the final radiologic report; and (c) the consultations will improve the care process and may save money, as well. MATERIALS AND METHODS: For 2,012 consecutive computed tomographic or magnetic resonance (MR) imaging studies, the initial interpretations provided by radiology generalists were subsequently reviewed by specialists, with a final consensus report available. "Truth" was established by final consensus reports. To control for potential bias, 150 adult MR imaging and 250 pediatric radiologic studies were interpreted initially by specialists and then by generalists. Again, truth was established by final consensus reports. RESULTS: There was disagreement between generalist and specialist radiologist interpretations in 427 (21.2%) of the cases reviewed. These disagreements were stratified further by independent specialists, who graded them as important, very important, or unimportant. Differences were considered important or very important in 99% of the cases reviewed. CONCLUSION: Consultations by subspecialty radiologists improved the quality of the radiology reports studied and, at least in some cases, improved the process of care by eliminating unnecessary procedures or suggesting more specific follow-up examinations. The consultation services can be provided cost-effectively from the payer's perspective and may save additional costs when unnecessary procedures can be eliminated.

Systems integration for PACS.

A successful PACS (Picture Archiving and Communications System) implementation requires an eclectic integration of a number of key technologies. Among these are equipment interfaces, communications, storage, and display. Coincident with this, the software architecture must support a distributed system of heterogeneous structures, provide for protocol and format conversions to a unified system standard, be scalable to accommodate expansion, and provide a measure of fault tolerance. In this paper we survey the current state of the UCLA PACS components and architecture.

PACS database architecture and design.

PACS (Picture Archiving and Communication Systems) database design requires careful understanding of the data and processing needs of radiologists, referring physicians, radiology staff, administrators, and researchers. Due to access requirements, the physical implementation for the management of small text data sets differs from the implementation strategy for large image data sets (centralized vs. distributed storage strategies). In this paper we discuss the database structure, storage architecture, file placement strategies, and administration considerations of the UCLA PACS.

Radiological laser film scanner sampling artifact.

Artifacts seen on laser digitized radiographs are analyzed and mathematically explained based on the concept of image contrast. Our investigation considered the following determinants: (a) laser spot size, (b) signal processing components, (c) image characteristics, and (d) observer performance. A functional relationship between the sampling interval, laser spot size, and the contrast of the artifact seen on the digitized image is derived. This relationship is verified experimentally using a variable spot size laser source and sampling at interval of 175.0 microns. The problem of digitizing artifact seen on film images obtained with anti-scatter grids is discussed.

Integration of a voice processor machine in a PACS.

The final stage of development of a clinical picture archiving and communication system (PACS) at the University of California at Los Angeles (UCLA) department of radiological sciences consists of building a documentation package of a complete radiological consultation. In this paper, we present the technological aspect of the integration of a digital voice server in our PACS environment. This component improves the timely delivery of the diagnostic report with the images. The interface of this voice system is integrated into the PACS display station. It offers the user the capability to easily dictate and/or listen to radiological reports, while viewing and/or performing image processing operations at the display station.

A unified timeline model and user interface for multimedia medical databases.

A multimedia medical database model and prototype is described for supporting a timeline-based presentation of information. The database links image and text data in a way that permits users to look at medical information in a single unified view. Various visualization programs permit the user to view data in various ways, including full image views, graphs, and tables. Our technology is applied for proof-of-concept to two areas: thoracic oncology and thermal tumor ablation therapy of the brain. This effort is part of the multidisciplinary KMeD project in collaboration with medical research and clinical treatment projects at UCLA.

Implementation of a large-scale picture archiving and communication system.

This paper describes the implementation of a large-scale picture archiving and communication system (PACS) in a clinical environment. The system consists of a PACS infrastructure, composed of a PACS controller, a database management system, communication networks, and optical disk archive. It connects to three MR units, four CT scanners, three computed radiography systems, and two laser film digitizers. Seven display stations are on line 24 h/day, 7 days/wk in genitourinary radiology (2K), pediatric radiology in-patient (1K and 2K) and outpatient (2K), neuroradiology (2K), pediatric ICU (1K), coronary care unit (1K), and one laser film printing station. The PACS is integrated with the hospital information system and the radiology information system. The system has been in operation since February 1992. We have integrated this PACS as a clinical component in daily radiology practice. It archives an average of 2.0-gigabyte image data per workday. A 3-mo system performance of various components are tabulated. The deployment of this large-scale PACS signifies a milestone in our PACS research and development effort. Radiologists, fellows, residents, and clinicians use it for case review, conferences, and occasionally for primary diagnosis. With this large-scale PACS in place, it will allow us to investigate the two critical issues raised when PACS research first started 10 yrs ago: system performance and cost effectiveness between a digital-based and a film-based system.

A picture archiving and communication system module for radiology.

This paper presents the design and implementation of a clinical picture archiving and communication system (PACS) module within the radiology department of a 700-bed teaching hospital. The system is composed of an integrated network of digital devices used to electronically acquire, store, manage, and display radiological text and image information. Operationally the system behaves as a large queueing network allowing processes to operate concurrently in a coordinated and prioritized fashion. Secondary reviews (radiology conferences and fast case reviews by clinicians) are being conducted from a 512 X 512 CRT viewing station. Preliminary evaluation based on formal survey and usage statistics shows that the system is rapidly being accepted by radiologists and clinicians for the review and processing of digital radiographic images.

[Laboratory-based evaluation of DainaScreen TPAb to detect specific antibodies against Treponema pallidum].

A newly developed immunochromatography assay, DainaScreen TPAb (Dainabot, Tokyo), to detect antibodies specific to Treponema pallidum was evaluated. When we tested serum and plasma samples of Syphilis Mixed Titer Performance Panel PSS201 (Boston Biomedica, Inc. , Bridgewater, MA, U.S.A.), all the test results obtained by DainaScreen TPAb were comparable to those determined by fluorescent treponemal antibody absorption test (FTA-ABS). Both within-run and day-to-day variation tests were highly precise, and no discrepant interpretation was obtained by the different medical technicians performed. Also, the testings of whole blood and plasma for individual samples gave same interpretations. The minimum detectable antibody titer was equal to that of Mediace TPLA (Sekisui Chemicals, Osaka) determined by Behring Nephelometer Analyzer (Dade Behring, Marburg, Germany). All the test results by DainaScreen TPAb for clinical serum samples were comparable to those by Mediace TPLA. With these results, we can conclude that DainaScreen TPAb is a rapid, practical and easy-to-perform alternative to detect antibodies specific to Treponema pallidum, in particular as being a point-of-care testing.

Effect of neurotrophic factor, MDP, on rats' nerve regeneration.

Our objective was to determine the immune-modulating effects of the neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration in rats. We used male Wistar rats (120-140 days of age, weighing 250-332 g) and compared the results of three different techniques of nerve repair: 1) epineural neurorrhaphy using sutures alone (group S - 10 rats), 2) epineural neurorrhaphy using sutures plus fibrin tissue adhesive (FTA; group SF - 20 rats), and 3) sutures plus FTA, with MDP added to the FTA (group SFM - 20 rats). Functional assessments using the grasp test were performed weekly for 12 weeks to identify recovery of flexor muscle function in the fingers secondary to median nerve regeneration. Histological analysis was also utilized. The total number and diameter of myelinated fibers were determined in each proximal and distal nerve segment. Two indices, reported as percentage, were calculated from these parameters, namely, the regeneration index and the diameter change index. By the 8th week, superiority of group SFM over group S became apparent in the grasping test (P = 0.005). By the 12th week, rats that had received MDP were superior in the grasping test compared to both group S (P < 0.001) and group SF (P = 0.001). Moreover, group SF was better in the grasping test than group S (P = 0.014). However, no significant differences between groups were identified by histological analysis. In the present study, rats that had received MDP obtained better function, in the absence of any significant histological differences.

Effect of neurotrophic factor, MDP, on rats’ nerve regeneration

Our objective was to determine the immune-modulating effects of the neurotrophic factor N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) on median nerve regeneration in rats. We used male Wistar rats (120-140 days of age, weighing 250-332 g) and compared the results of three different techniques of nerve repair: 1) epineural neurorrhaphy using sutures alone (group S - 10 rats), 2) epineural neurorrhaphy using sutures plus fibrin tissue adhesive (FTA; group SF - 20 rats), and 3) sutures plus FTA, with MDP added to the FTA (group SFM - 20 rats). Functional assessments using the grasp test were performed weekly for 12 weeks to identify recovery of flexor muscle function in the fingers secondary to median nerve regeneration. Histological analysis was also utilized. The total number and diameter of myelinated fibers were determined in each proximal and distal nerve segment. Two indices, reported as percentage, were calculated from these parameters, namely, the regeneration index and the diameter change index. By the 8th week, superiority of group SFM over group S became apparent in the grasping test (P = 0.005). By the 12th week, rats that had received MDP were superior in the grasping test compared to both group S (P < 0.001) and group SF (P = 0.001). Moreover, group SF was better in the grasping test than group S (P = 0.014). However, no significant differences between groups were identified by histological analysis. In the present study, rats that had received MDP obtained better function, in the absence of any significant histological differences.

Structure localization in brain images: application to relevant image selection.

Recent advances in imaging have lead to increases in the number of images/study. Automated methods to select relevant images are critical to effectively convey study results. The proposed method combines natural language processing (NLP) and automatic structure localization to identify relevant images of a MR brain study. NLP extracts relevant locations of findings. Two algorithms were implemented and evaluated for structure localization. The first method involves registration of patient dataset to a labeled atlas. The second method involves an eigenimage search using a training set of images. A prototype was developed and tested on MR brain studies of nine patients. With the registration method, slices containing the relevant structure agreed with expert selection in 98% of cases. Structure localization by eigenimage search was able to locate the lateral ventricles correctly in all the test cases. The proposed method provides an accurate method for identifying relevant slices of an imaging study.

Infrastructure design of a picture archiving and communication system.

A picture archiving and communication system (PACS) infrastructure is the necessary framework to integrate distributed and heterogeneous imaging systems, provide intelligent data-base management of all radiology-related information, arrange an efficient means of viewing, analyzing, and documenting study results, and furnish a mechanism for effectively communicating study results to the referring physician. The PACS infrastructure consists of a basic skeleton of hardware components integrated by standardized, flexible software subsystems. This review describes these concepts and basic building blocks drawn from our original investigation, past experience, and the current clinical system in our radiology department.

A statistical natural language processor for medical reports.

Statistical natural language processors have been the focus of much research during the past decade. The main advantage of such an approach over grammatical rule-based approaches is its scalability to new domains. We present a statistical NLP for the domain of radiology and report on methods of knowledge acquisition, parsing, semantic interpretation, and evaluation. Preliminary performance data are given. A discussion of the perceived benefit, limitations and future work is presented.

Digital archive center: implementation for a radiology department.

OBJECTIVE: In this article, we describe the implementation of a digital archive center for a radiology department in a 700-bed teaching hospital. MATERIALS AND METHODS: The archive center consists of two identical archive systems, each comprising five components: an archive server, a data-base server, an optical disk library, a stand-alone optical disk drive, and a communication network. An image management system controls the image traffic from acquisition devices to display stations. A fault-tolerant mechanism was built into the archive center to achieve a 100% uptime. RESULTS: The center has been in operation for over 6 months. We have not experienced a single total system failure during this period. It currently archives all digital images from three MR units and four CT scanners and selected images from three computed radiographic systems and two laser film digitizers. The center archives between 1.5 and 2.0 gigabytes of images per workday. CONCLUSION: With its built-in fault-tolerant mechanism, we believe that the implemented archive center is very reliable and is suitable for a radiology department to archive its digital images.

Automatic structuring of radiology free-text reports.

A natural language processor was developed that automatically structures the important medical information (eg, the existence, properties, location, and diagnostic interpretation of findings) contained in a radiology free-text document as a formal information model that can be interpreted by a computer program. The input to the system is a free-text report from a radiologic study. The system requires no reporting style changes on the part of the radiologist. Statistical and machine learning methods are used extensively throughout the system. A graphical user interface has been developed that allows the creation of hand-tagged training examples. Various aspects of the difficult problem of implementing an automated structured reporting system have been addressed, and the relevant technology is progressing well. Extensible Markup Language is emerging as the preferred syntactic standard for representing and distributing these structured reports within a clinical environment. Early successes hold out hope that similar statistically based models of language will allow deep understanding of textual reports. The success of these statistical methods will depend on the availability of large numbers of high-quality training examples for each radiologic subdomain. The acceptability of automated structured reporting systems will ultimately depend on the results of comprehensive evaluations.

Interfacing aspects between the picture archiving communications systems, radiology information systems, and hospital information systems.

Information relevant to radiological applications is commonly managed by several autonomous medical information systems including hospital information systems (HIS), radiological information systems (RIS), and picture archiving and communications systems (PACS). In this report, we explain the need to coordinate these systems and to provide some framework in which they can exchange information. In the first half of this report, we describe the integration of a PACS system into a hospital operation. Next, we present the interfacing methods between the HIS and the RIS, and between the RIS and the PACS. Two methods are further detailed for the communication between the RIS and the PACS (1) the triggered database to database transfer, and (2) the query protocol. The implementation of the first method successfully allows RIS reports, procedure and patient demographic information to be displayed at the request of the user along with the associated images at a PACS workstation. The query protocol allows a PACS to dynamically query RIS information. It will be eventually integrated into the design of a scientific multimedia distributed medical database system built on top of the HIS, the RIS, and the PACS.

Operational radiologic image archive on digital optical disks.

A digital optical disk archive for storage of computed radiographic, computed tomographic, magnetic resonance, ultrasonographic, and digitized film radiographic images was installed. In the system, digital images enter a minicomputer, are temporarily stored on magnetic disks, and are archived onto write-once read-many optical disks at their full resolution. A pictorial index of minified images is maintained for each patient. After 8 months of operation, 49,400 megabytes of images had been retained on 19 optical disks stored, after January 1987, in a mechanical jukebox-style optical disk library. The success rate for archival capture of images during the initial period was 96.6%. The failures were due to overfilling of the magnetic disk, a problem addressed through the addition of a second magnetic disk unit. There were no medium-related image errors during the early period. Problems resulting from the slow speed of optical disk systems were addressed operationally by initiating recall of a patient's archived images from the optical to the faster magnetic disk as soon as the system received a request to acquire a new image. Also, optical disk retrieval times are expected to improve with technologic development.

Requirements of a Web-based experiment management system.

Recent advances in tools for scientific data acquisition, visualization, and analysis have lead to growing information management problems for medical research laboratories. An exponential increase in the volume of data, combined with a proliferation of heterogeneous formats and autonomous systems, has driven the need for flexible and powerful Experiment Management Systems (EMS). This paper provides a detailed analysis of the informatics requirements of an EMS, and proposes a new type of middleware called an EMS-Building Environment (EMSBE), which enables the rapid development of web-based systems for managing laboratory data and workflow. We describe the Web-Interfacing Respository Manager (WIRM), an open-source application server for building customizable experiment management systems. WIRM is being used to manage several ongoing experiments, including a natural language processor of radiological findings, and an interdisciplinary project for studying brain function.