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PubMedDate not supplied

Automated system for measurement of mechanics of breathing.

We describe a complete automated system for measurement of total respiratory resistance and compliance, and of pulmonary resistance and compliance in humans and anesthetized animals. The device for testing the chest-lung system consists of a sinusoidal pump with a stroke adjustable from 20 ml to 600 ml over a cycling frequency of 0.3 to 30 Hz. Pressure and flow or volume are inputted into an analog network for wave shaping, then to an arithmetic unit composed of sample-and-hold amplifiers, peak, minimum and zero detecting circuits, an analog division circuit, and a digital logic processor. The computer takes the peak-to-peak amplitude of one of two sinusoidal inputs at 0.3 to 10 Hz and the corresponding amplitude of the other input in the presence of a.c. noise and d.c. shifts, divides one into the other, and displays an answer on a digital voltmeter. In addition, the analog output is displayed on the cathode-ray tube of a storage oscilloscope. Plots of total resistance and pulmonary resistance are recorded as a function of lung volume in both humans inspiring voluntarily as well as anesthetized dogs inflated by positive pressure from the test apparatus. Total and pulmonary dynamic compliance, as a function of breathing frequency, can only be measured by the computer if a symmetrical waveform is presented to it. This cannot be achieved in spontaneously breathing subjects but is accomplished in apneic animals by producing sinusoidal oscillations from the test apparatus. Our on-line method for measurement of total respiratory resistance is now used in the Clinical Pulmonary Laboratory for experimental work, and we are in the process of obtaining values in normal subjects.

Adult↗
PubMed1989

[Fluorescence diagnosis of porphyrin-marked urothelial tumors. Status of experimental development].

On the basis of selective storage of fluorescing hematoporphyrin derivative (HpD) in tumors, a method has been developed that enables the endoscopic detection of early-stage cancer by monitoring fluorescent images. The contrast-reducing portion of the superposed tissue autofluorescence is suppressed by the use of two-wavelength excitation and subsequent image processing in realtime. The amount of photosensitizing HpD necessary for diagnostic purposes is considerably reduced by means of sensitive detection devices. A clear distinction between benign and malignant bladder tissue seems possible according to the results of animal studies.

Animals↗
PubMed1991

Development of an integrated filing system for endoscopic images.

A new integrated filing system for endoscopic images has been developed, comprising a main image filing system and subsystems located at different stations. A hybrid filing system made up of both digital and analog filing devices was introduced to construct this system that combines the merits of the two filing methods. Each subsystem provided with a video processor, is equipped with a digital filing device, and routine images were recorded in the analog image filing device of the main system. The use of a multi-input adapter enabled simultaneous input of analog images from up to 8 video processors. Recorded magneto-optical disks make it possible to recall the digital images at any station in the hospital; the disks are copied without image degradation and also utilised for image processing. This system promises reliable storage and integrated, efficient management of endoscopic information. It also costs less to install than the so-called PACS (picture archiving and communication system), which connects all the stations of the hospital using optical fiber cables.

Analog-Digital Conversion↗
PubMed1987

Analysis of single channel currents with a microprocessor based device.

Data evaluation of single channel currents obtained from artificial black lipid membranes and with the patch clamp method is an important part of every single channel study, but it is a time consuming part often exceeding the time for experimentation and recording by far. We describe here a microprocessor based device, which allows the experimentator to analyse in a simple way the distribution of current levels in a single channel trace (amplitude-histogram analysis of single channel currents) either online, or offline. Current levels are sampled at a constant frequency of 6 kHz and the relative frequencies of occurrence of these current levels are displayed as a histogram on the screen of an analog or digital storage oscilloscope. The data reducing algorithm of this analyser eliminates the requirement of large amounts of mass storage that normally is needed for digital amplitude-histogram analysis of single channel recordings. Examples of evaluation for both a voltage operated cation-channel and a blockage of a potassium channel by tetraethylammoniumchloride (TEA) are given.

Animals↗
PubMed1991

[Digital luminescence radiography. Part 1: Basic principle, technical execution and clinical use].

Digital luminescence radiography (DLR) is a new technique in projection radiography, which enables the production of plain X-ray images and motion tomographies with high quality, and is suitable for digital image management. With this procedure the X-ray image produced by conventional roentgen devices is temporarily stored on a reusable photostimulable storage phosphor screen which is characterized by a wide dynamic range. A laser beam scans the exposed phosphor screen and recovers the stored X-ray information as photostimulated luminescence radiation. A photomultiplier converts the emitted light into electrical signals. After normalization and digitization the signals are transmitted to an image processor. The stored digital image can be individually processed and displayed, digitally archived or transferred to any location. The technique is described in two following papers. Part 1 covers the basic principle of the system and the technical implementation of the data acquisition with its advantages and disadvantages as compared with conventional film/screen radiography.

Equipment Design↗
PubMed1989

[Field localization and verification system for proton beam radiotherapy in deep-seated tumors].

It has been recognized that, for precise localization and verification of radiation fields, a marking drawn on the skin surface is not entirely reliable because its position relative to bony structures or internal organs is not stationary. This is especially true when treating deep-seated tumors located below the clavicle. In proton beam radiotherapy at the University of Tsukuba, we ristrict the margins around the target volume. Therefore, special care in field localization and verification is needed, and we make it a rule to take X-ray pictures on each treatment day. To accomplish this, we have developed a localize-and-verify system by using fluoroscopic techniques and combining it with a real-time digital image processing device. This allows for the formation of a digital image of the proton field and storage it in the optic disc. By using this system as well as verification films, filed placement errors were measured in 10 patients with deep-seated tumors. Out of a total of 190 localizations, 22% exhibited a field placement error of more than 5 mm, where patient positioning and field localization were done by using skin drawings aligned with laser beams. This result strongly suggests the necessity for daily localization and verification of radiation fields, as is being done by us, for precision in the execution of proton beam radiation therapy.

Adult↗
PubMed1990

Design of the diagnostic encyclopedia workstation (DEW).

The Diagnostic Encyclopedia Workstation (DEW) contains reference knowledge for diagnostic support in pathology. Illustrations are accessible via a video disc device. DEW can hold more knowledge, pictures and case histories than books, and its information is accessible via several entries. Software for data entry has been written in MUMPS with use of the relational database toolkit AIDA, which is particularly suited for manipulation of free text. The graphical mouse-driven user interface is written in C using MetaWindows. The DEW contains 85 diagnoses in ovarian pathology, covering all frequent cases and many rarities, illustrated by approximately 3000 pictures, divided among 158 cases.

Computer Systems↗
PubMed1991

Surface and volume rendering in three-dimensional imaging: a comparison.

Many surface rendering techniques are currently available for the three-dimensional display of structure data captured by imaging devices. Comparatively fewer volume rendering techniques are also available for the same purpose. The relative performance of these two methodologies in visualization tasks has been a subject of much discussion recently. Although it is very desirable to establish, based on observer studies, objective guidelines stating the relative merits of the two methodologies even for specific situations, it is impossible to conduct meaningful observer studies that take into account the numerousness of the techniques in each methodology, and within each technique, the numerousness of the parameters and their values that control the outcome of the technique. Our aim in this article is to compare the two methodologies purely on a technical basis in an attempt to understand their common weaknesses and disparate strengths. The purpose of this article is twofold--to report a new surface rendering technique and to compare it with two volume rendering techniques reported recently in the literature. The bases of comparison are: ability to portray thin bones; clarity of portrayal of sutures, fractures, fine textures, and gyrations; smoothness of natural ridges and silhouettes; and computational time and storage requirements. We analyze the underlying algorithms to study how they behave under each of these comparative criteria. Our conclusion is that, at the current state of development, the surface method has a slight edge over the volume methods for portrayal of information of the type described above and a significant advantage considering time and storage requirements, for implementations in identical environments.

Algorithms↗
PubMed1991

Network system: the integrated picture archiving and communication system with the hospital information system.

We describe the outline of Hokkaido University picture archiving and communication system (HU-PACS) and its network functions. HU-PACS processes 0.5 Gbytes of images daily through 10 acquisition devices. Functional integration of hospital information system (HIS) and PACS has been implemented. The HU-PACS can access common data base with HIS. Multi-image data-base systems provide fast throughput of image retrieval. The system is composed of 4 modules: (1) 2 image data-base systems (IDS), (2) 1 image management system (IMS), (3) image display terminals (IDT), and (4) 8 image acquisition nodes interfaced to 10 modalities and 1 film scanner. These 4 modules are connected by branch and loop type local area networks (LAN). HU-PACS has functions other than basic PACS functions. Images in optical disk library (ODL) are loaded onto magnetic disks (MD) in advance according to patient booking information, the images expected to be viewed are transferred to the local storage automatically, and the desired images can be pre-downloaded into local storage by instruction through HIS terminals.

Computer Communication Networks↗
PubMed1985

Data acquisition and analysis of hemodynamic signals using a standard microcomputer.

Hemodynamic drug-effect studies require repetitive measurements and time-consuming calculations, particularly for the indices of left ventricular (LV) contractility and relaxation. To save time, we have created a system of acquisition, calculation, storage, and report of hemodynamic data processing E.K.G, peripheral arterial pressure, and LV pressure signals using a standard microcomputer (Apple II+) and simple accessory devices. The master program is written in BASIC Applesoft, with Mem/Dos as the disk operating system. A suite of utility routines, written in machine language, are used to program the A/D converter and to perform the vectorial calculations on the data. The software, written to process single-dose drug-effect studies, performs 1) data acquisition and storage as vectorial arrays accessible using BASIC, 2) monitor display, 3) calculations of the peripheral pressure and of the LV contractility and relaxation indices, 4) storage of the calculated indices, and 5) print-out of a report (curves and tables) at the end of each experiment and cumulated results of all the animals included in a protocol. The drawback of such a low-cost system is essentially the lack of available memory and the relatively slow speed of the microprocessor, which hinders simultaneous processing of indices needing nonlinear curve fitting and adequate print-out of protocols that are not single dose.

Animals↗
PubMedDate not supplied

Design and implementation of a biomedical image database (BDIM).

We developed a biomedical image database (BDIM) which proposes a standardized representation of value arrays such as images and curves, and of their associated parameters, independently of their acquisition mode to make their transmission and processing easier. It includes three kinds of interactions, oriented to the users. The network concept was kept as a constraint to incorporate the BDIM in a distributed structure and we maintained compatibility with the ACR/NEMA communication protocol. The management of arrays and their associated parameters includes two distinct bases of objects, linked together via a gateway. The first one manages arrays according to their storage mode: long term storage on optionally on-line mass storage devices, and, for consultations, partial copies of long term stored arrays on hard disk. The second one manages the associated parameters and the gateway by means of the relational DBMS ORACLE. Parameters are grouped into relations. Some of them are in agreement with groups defined by the ACR/NEMA. The other relations describe objects resulting from processed initial objects. These new objects are not described by the ACR/NEMA but they can be inserted as shadow groups of ACR/NEMA description. The relations describing the storage and their pathname constitute the gateway. ORACLE distributed tools and the two-level storage technique will allow the integration of the BDIM into a distributed structure, Queries and array (alone or in sequences) retrieval module has access to the relations via a level in which a dictionary managed by ORACLE is included. This dictionary translates ACR/NEMA objects into objects that can be handled by the DBMS.(ABSTRACT TRUNCATED AT 250 WORDS)

Database Management Systems↗
PubMed1991

Wearable system for acquisition, processing and storage of the signal from amperometric glucose sensors.

A wearable device for the acquisition, processing and storage of the signal from needle-type glucose sensors has been designed and developed as part of a project aimed at developing a portable artificial pancreas. The device is essential to assess the operational characteristics of miniaturized sensors in vivo. It can be connected to sensors operating at a constant potential of 0.65 Volts, and generating currents in the order of 10(-9) Amp. It is screened and equipped with filters that permit data recording and processing even in the presence of electrical noise. It can operate with sensors with different characteristics (1-200 nA full scale). The device has been designed to be worn by patients, so its weight and size have been kept to a minimum (250 g; 8.5 x 14.5 x 3.5 cm). It is powered by rechargeable Ni/Cd batteries allowing continuous operation for 72 h. The electronics consists of an analog card with operational amplifiers, and a digital one with a microprocessor (Intel 80C196, MCS-96 class, with internal 16-bit CPU supporting programs written in either C or Assembler language), a 32 Kb EPROM, and an 8 Kb RAM where the data are stored. The microprocessor can run either at 5 or 10 Mhz and features on-chip peripherals: an analog/digital (A/D) converter, a serial port (used to transfer data to a Personal Computer at the end of the 72 h), input-output (I/O) units at high-speed, and two timers. The device is programmed and prepared to operate by means of a second hand-held unit equipped with an LCD display and a 16-key numeric pad.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose Self-Monitoring↗
PubMed1986

High-speed transient-recording microprocessor system for the analysis of asymmetrical diffraction spectra from striated muscle.

A microprocessor based digital recording system has been developed to study the fine structure and asymmetry of diffraction spectra from striated muscle during contraction. Two linear 256-element photodiode arrays provide analog videosignals of the diffraction lines imaged onto these charged coupled devices. The photodiode arrays are alternately read and the videosignals can be digitized and stored within 1.36 ms (two images of 256 points) with a spatial resolution of 5 nm. (In this paper the spatial resolution is considered to be the standard deviation of the first-order maximum of a monochromatic wave of the He/Ne laser measured from the diode-arrays, using ideal gratings with a spacing between 1.6 and 3.6 microns.) The system's memory with a capacity of 192 pairs of images of 256 points can be optimized by means of a threshold to contain about 2000 images without any loss of information. A transient recording approach makes the system capable of recording long term slow phenomena of up to 5 s as well as fast events and the combination of fast events within slow processes. The system presented here has a significantly improved time resolution and storage capacity when compared to other systems and is more versatile. This is the first system which enables the simultaneous examination of the fine structure and asymmetry of diffraction spectra.

Animals↗
PubMed1992

Was the Dalkon Shield a safe and effective intrauterine device? The conflict between case-control and clinical trial study findings.

OBJECTIVE: To compare the findings of the case-control and cohort studies used to indict the Dalkon Shield (A.H. Robins Company, Inc., Richmond, VA) with the findings of the Dalkon Shield clinical trials. DATA IDENTIFICATION: All published reports on the Dalkon Shield were identified through MEDLARS system (United States National Library of Medicine) searches and by cross checking all references in these reports. The same approach was used to identify all case-control and cohort studies of the purported relationship between intrauterine devices (IUDs) and pelvic inflammatory disease (PID). STUDY SELECTION: Only studies of interval patients that included 50 or more women and 6 or more months of follow up that computed standard IUD event rates (rates of pregnancy and expulsion and removal for pain and bleeding) were selected for this study. All case-control and cohort studies identified were included except two case-control studies that included women with sterile chronic salpingitis. RESULTS: The 16 case-control and 2 cohort studies found or suggested that the Dalkon Shield increased the risk of PID. The 71 clinical trials of the Dalkon Shield show that when this device is inserted by an experienced clinician it is a safe and effective contraceptive method, comparable with other IUDs used at the time. There was no evidence of an increased risk of PID found in these clinical trials. CONCLUSIONS: This study offers convincing evidence that the indictment of the Dalkon Shield was a mistake. Additionally, this study shows that physician skill and experience is far more important to successful IUD insertion than previously recognized, a finding with considerable implications for IUD study designs and for marketing strategies.

Case-Control Studies↗
PubMed1990

High-speed digital imaging of cytosolic Ca2+ and contraction in single cardiomyocytes.

A charge-coupled device (CCD) camera, with the capacity for simultaneous spatially resolved photon counting and rapid frame transfer, was utilized for high-speed digital image collection from an inverted epifluorescence microscope. The unique properties of the CCD detector were applied to an analysis of cell shortening and the Ca2+ transient from fluorescence images of fura-2-loaded [corrected] cardiomyocytes. On electrical stimulation of the cell, a series of sequential subimages was collected and used to create images of Ca2+ within the cell during contraction. The high photosensitivity of the camera, combined with a detector-based frame storage technique, permitted collection of fluorescence images 10 ms apart. This rate of image collection was sufficient to resolve the rapid events of contraction, e.g., the upstroke of the Ca2+ transient (less than 40 ms) and the time to peak shortening (less than 80 ms). The technique was used to examine the effects of beta-adrenoceptor activation, fura-2 load, and stimulus frequency on cytosolic Ca2+ transients and contractions of single cardiomyocytes. beta-Adrenoceptor stimulation resulted in pronounced increases in peak Ca2+, maximal rates of rise and decay of Ca2+, extent of shortening, and maximal velocities of shortening and relaxation. Raising the intracellular load of fura-2 had little effect on the rising phase of Ca2+ or the extent of shortening but extended the duration of the Ca2+ transient and contraction. In related experiments utilizing differential-interference contrast microscopy, the same technique was applied to visualize sarcomere dynamics in contracting cells. This newly developed technique is a versatile tool for analyzing the Ca2+ transient and mechanical events in studies of excitation-contraction coupling in cardiomyocytes.

Animals↗
PubMed1989

[Evaluation of CRT images of digitized film angiographs].

X-ray sheet film images of the test chart, the vascular phantom and angiography were digitized at sampling pitch of 0.2 mm and 0.15 mm using film digitizer TFR-01 (Toshiba) and transferred to a device for image storage and display system with 1635-line display monitor (TDF-500AS, Toshiba). Comparison of image qualities between film- and CRT-images was performed in fundamental and clinical studies. Resolution of the test chart image of conventional radiography was worse on CRT than on the original film, although it was improved when film image was digitized at resolution of 0.15 mm/pixel in comparison with that at resolution of 0.2 mm/pixel. Moiré stripes which occurred due to interference were found on CRT images taken using a grid technique. On CRT images of X-ray sheet film using direct magnification technique moiré stripes were not produced because of non grid technique, and the resolution approached that of the original film. In the study using vascular phantom, the optimal image on CRT could be obtained by various image processing procedures, and image quality on CRT with resolution of 0.15 mm approached that of original film. In case of direct magnification CRT images were superior to film images. Subtraction image of the vascular phantom at resolution of 0.2 mm/pixel was obtained on CRT and compared with film subtraction image. On conventional subtraction CRT image moiré stripes impaired the image quality in comparison with the film subtraction. However, magnification subtraction image of the vascular phantom on CRT was superior to the film subtraction. The results obtained in the test chart studies and phantom studies were also confirmed in clinical studies using various kind of angiograms. In addition, ROC study using clinical angiograms showed no significant statistical differences between the original film and CRT image even with 0.2 mm matrix size. Angiographic image on CRT at resolution of 0.15 mm/pixel or less is available for clinical use in place of conventional film image.

Angiography, Digital Subtraction↗