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PubMed1995

Digital optical archiving of medical records in hospital information systems--a practical approach towards the computer-based patient record?

The large number of inpatients and outpatients in university hospitals leads to high costs of medical documentation and to an increasing number of medical documents. Due to legal regulations, these medical records have to be stored for 30 years. This implies spatial, organizational, and economical problems. At present, conventional archiving in hospitals often does not satisfy the need to make medical records available for health-care professionals in a systematic and timely manner. From 1989 to 1993 a pilot study on "digital optical archiving of medical records" was carried out at Heidelberg University Hospital. The study has shown the feasibility of digital optical archiving in hospital s if done under certain conditions. In 1995, Heidelberg University Hospital adopted a procedure for "digital optical archiving of medical records". The digital optical archive will first be filled with the medical records of the department of neurosurgery and the endoscopic and echographic images and reports of the department of internal medicine. It is to be expected that this procedure will gradually lead to an integrated functionality on health-care professional workstations, to a hospital-wide use of an electronic patient record, and to media-independent document management systems. The paper focuses on the potentials of digital optical archiving as an integral part of hospital information systems, and on the requirements for the systematic managements of hospital information systems with respect to digital optical archives.

Archives↗

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↗

PubMed2002

Efficacy of antitachycardia pacing confirmed by stored electrograms. A retrospective analysis of 613 stored electrograms in implantable defibrillators.

The implantable defibrillator (ICD) is an established therapy in the prevention of sudden cardiac death by defibrillation of ventricular fibrillation. Another specific feature of the ICDs is antitachycardia pacing (ATP) of ventricular tachycardia. Several studies report success rates of ATP in 83 to 98% of cases. In clinical practice the success of terminating ventricular tachycardia is estimated only by automatic device analysis. Therefore the objective of this study was to confirm the efficacy of ATP based on the evaluation of stored electrograms. From the German Ventritex MD-register stored electrograms of 613 monomorphic ventricular tachycardias in 44 patients were analyzed retrospectively. The cycle length of the ventricular tachycardias was between 265 and 560 ms. The success rate of ATP-induced termination of the episodes reached 89.3%; another 2.3% of the ventricular tachycardias were accelerated by antitachycardia pacing into ventricular fibrillation. Left ventricular function did not influence the success rate, but the success rate was lower for fast ventricular tachycardias > 200/min (63.9%). For ventricular tachycardias < 150 bpm there was no restriction of ATP effectiveness. Of the episodes 72.9% were terminated by the first ATP burst. In these cases the duration of tachycardia was very short (11.9 +/- 2.8 s). Fifty-eight ventricular tachycardias (9.5%) had to be terminated by means of a shock, and only one case required 2 shocks. In patients with more than 10 episodes an individual therapy success > 90% was recorded for 80% of them. The very high success rate of the first ATP attempt in ICD therapy can be achieved with uniform programming, and is confirmed for ventricular tachycardias analyzed on the basis of stored electrograms.

Aged↗

PubMed2005

New adaptive color quantization method based on self-organizing maps.

Color quantization (CQ) is an image processing task popularly used to convert true color images to palletized images for limited color display devices. To minimize the contouring artifacts introduced by the reduction of colors, a new competitive learning (CL) based scheme called the frequency sensitive self-organizing maps (FS-SOMs) is proposed to optimize the color palette design for CQ. FS-SOM harmonically blends the neighborhood adaptation of the well-known self-organizing maps (SOMs) with the neuron dependent frequency sensitive learning model, the global butterfly permutation sequence for input randomization, and the reinitialization of dead neurons to harness effective utilization of neurons. The net effect is an improvement in adaptation, a well-ordered color palette, and the alleviation of underutilization problem, which is the main cause of visually perceivable artifacts of CQ. Extensive simulations have been performed to analyze and compare the learning behavior and performance of FS-SOM against other vector quantization (VQ) algorithms. The results show that the proposed FS-SOM outperforms classical CL, Linde, Buzo, and Gray (LBG), and SOM algorithms. More importantly, FS-SOM achieves its superiority in reconstruction quality and topological ordering with a much greater robustness against variations in network parameters than the current art SOM algorithm for CQ. A most significant bit (MSB) biased encoding scheme is also introduced to reduce the number of parallel processing units. By mapping the pixel values as sign-magnitude numbers and biasing the magnitudes according to their sign bits, eight lattice points in the color space are condensed into one common point density function. Consequently, the same processing element can be used to map several color clusters and the entire FS-SOM network can be substantially scaled down without severely scarifying the quality of the displayed image. The drawback of this encoding scheme is the additional storage overhead, which can be cut down by leveraging on existing encoder in an overall lossy compression scheme.

Algorithms↗

PubMed1998

Devices for structured data entry in electronic patient record.

Electronic patient record is expected to have edit, data analysis, and decision supporting functions. To realize these functions, the entered data should be structured. We made a template based data entry system with some devices. We defined a template for each describing unit, i.e., symptom, physical finding and examination report. Template is composed of several describing elements (a pair of property and value), which form tree structure in general. When a template is selected, the top layers of the elements are displayed at once allowing data entry. When the data qualified by other elements is entered then system presents the second layer about this data at once. This enables users to skip entering some unnecessary items. Users can constitute a form by combining some templates frequently used in a situation. Furthermore, at the second patient visit, the system can present the templates used in the former patient visit to check the different point. These templates and forms can be made easily by editing the master data using template master maintenance program. The entered patient data are presented in progress note and flow sheet. In progress note, the entered data are translated into natural language. In the flow sheet, representative data of each template are present in the cell of the matrix whose line indicates the describing unit and column indicates date. If the cell is clicked, then the details are presented. Using this system, we made templates and forms for cardiovascular field and entered the data about an actual patient with angina pectoris. The time taken by inputting data is shorter than that by handwriting and the content is enough for a patient record. This system is practical for structured data entry in electrical patient record.

Cardiovascular Diseases↗

PubMed2003

In vivo measurement of D2 receptor density and affinity for 18F-(3-N-methyl)benperidol in the rat striatum with a PET system for small laboratory animals.

UNLABELLED: A recent investigation showed that intracerebral radioactivity concentrations can reliably be quantified in vivo with a small-animal PET device. The purpose of the current study was to investigate the binding characteristics of the D(2) receptor radioligand (18)F-(3-N-methyl)benperidol ((18)FMB) in rat striatum by determining receptor density (B(max)) and affinity (K(d)) in vivo. For validation, K(d) and B(max) additionally were determined in vitro using storage phosphor autoradiography. METHODS: Striatal radioactivity was measured with PET in 8 Sprague-Dawley rats after injection of (18)FMB in increasing specific activities. Free radioligand concentrations were estimated from cortical radioactivity concentrations and were subtracted from striatal radioactivity concentrations to obtain specific binding. In vitro saturation experiments were performed on 7 further rats according to the isotopic dilution method. Specific binding was determined by both subtraction of (18)FMB binding in the presence of raclopride and subtraction of cortical radioactivity concentrations from total radioligand binding. Saturation binding curves were obtained by plotting specifically bound radioligand concentrations against free radioligand concentrations and were evaluated with regression analysis. RESULTS: PET yielded a K(d) of 6.2 nmol/L and a B(max) of 16 fmol/mg for the striatal D(2) receptor. In vitro, K(d) and B(max) amounted to 4.4 nmol/L and 84.1 fmol/mg (subtraction of (18)FMB binding in the presence of raclopride), respectively, and 7.9 nmol/L and 70.1 fmol/mg (subtraction of cortical radioactivity concentrations), respectively. CONCLUSION: K(d) values measured with PET and autoradiography agreed and corresponded to inhibition constants obtained in previous in vitro studies. B(max) values lay within the same order of magnitude. The results of in vitro saturation binding analyses also agreed, irrespective of the mode of determination of free radioligand concentrations. Thus, B(max) and K(d) may be determined with PET in analogy to the evaluation of in vitro binding data by regression analysis of bound-versus-free ligand concentrations. Our results show that small-animal tomographs are valuable tools for the in vivo characterization of receptor radioligands as an alternative to autoradiography.

Animals↗

PubMed2006

Analog signal acquisition from computer optical disk drives for quantitative chemical sensing.

Optoelectronic consumer products that are widely employed in the office and home attract attention for optical sensor applications due to (1) their cost advantage over analytical instruments produced only in small quantities, (2) robustness in operation due to the detailed manufacturability improvements, and (3) ease of operation. We demonstrate here a new approach for quantitative chemical/biochemical sensing when analog signals are acquired from conventional optical disk drives, and these signals are used for quantitative detection of optical changes of sensor films deposited on conventional CD and DVD optical disks. Because we do not alter manufacturing process of optical disks, any disk can be employed for deposition and readout of sensor films. The optical disk drives also perform their original function of reading and writing digital content to optical media because no optical modifications are introduced to obtain the analog signal. Such a sensor platform is quite universal and can be applied for chemical and biological quantitative detection, as well as for monitoring of changes of physical properties of regions deposited onto a CD or DVD (e.g., during combinatorial screening of materials). As a model example, we demonstrate the concept using chemical detection of ionic species such as Ca2+ in liquids (e.g., blood, urine, or water). Colorimetric calcium-sensitive sensor films were deposited onto a DVD, exposed to water with different concentrations of Ca2+, and quantified in the optical disk drive. The developed lab-on-DVD system demonstrated a 5 ppm detection limit of Ca2+ determinations, similar or slightly better than that achieved using a conventional fiber-optic portable spectrometer. This detection limit corresponded to a 0.023 absorbance unit resolution, as determined by the measurement of the same colorimetric films with a portable spectrometer. Determinations of Ca2+ unknowns using the lab-on-DVD system demonstrated +/-5 ppm accuracy and 2-5% relative standard deviation precision in predicting 100 ppm Ca2+.

Biosensing Techniques↗

PubMed1999

[Medical tele-imaging: a good chance for the future].

Tele-imaging is an important part of telemedicine: it includes the transmission of medical digital images and plays a role in all fields of telemedicine, such as expertise, consultation, teaching and research. Tele-imaging has been made possible through the digitalization of medical imaging. There are two possibilities: either digitalization of conventional radiological film or direct acquisition of digital images. The transmission of medical imaging requires a high data rate so as to obtain a good quality transmission of the initial images in a reasonable delay. In order to deal with the great amount of information to be stocked and transmitted, a compression of the data, without loss of information, is usually necessary. Interactivity is very important in all these types of transmissions. These tele-transmission techniques are already used world wide, especially in Japan and in the United States, to help in therapeutic or diagnostic decisions. In France, we have been performing real time interactive tele-imaging sessions between radiology and endocrinology departments of Hotel Dieu in Montréal and Hôpital Cochin in Paris. This experimental device includes a visual-conference link between the medical teams and a real time link between two CT scanners. The CT scanner slices appear simultaneously both CT scanner screens; it is even possible to guide a CT scanner examination using remote control from the other hospital. We have successfully repeated the experiment between Cochin and a private hospital in Paris. In the case of the "Prison de la Santé", we have been using telemedicine in order to reduce problematic transfers of prison inmates. Moreover, access to doctors in the prison is sometimes difficult. The system ensures the daily transmission of X-rays, which are immediately read by radiologists at Cochin. In the past, 50 to 70 X-rays had to be read during one weekly visit. Medical tele-imaging raises certain legal, ethical and economic issues, such as problems concerning confidentiality, the right to compensation, patient information. It would be interesting in this context to open a discussion on the possible dangers of telemedicine, its value for the patients and the physicians, its role in emergency care, and the possibility of creating imaging data storage that may help radiologists in making diagnoses, especially for unusual images. Drawbacks not to be ignored: Poor digital images could lead to difficulties in their reading and interpretation. There is still a debate as to whether tele-diagnosis is reliable or not. Further evaluations must be made to as certain the effectiveness of these techniques. A certain dehumanization of medicine due to an increase in the distance between the physician and patient is another difficult issue. The great number of people involved in the process of tele-imaging could confuse the issue of determining individual responsibility. Such consultations of experts may reduce the freedom of patients to choose their doctor. Tele-consultation must not be performed without the patient's consent. If consent was not obtained before tele-transmission, the patient should be informed after the procedure; and the use of tele-consultation should be mentioned in the report. The utilization of public networks could lead to the manipulation of data as well as undermine confidentiality. These pitfalls must be avoided. Lastly, the financial ramifications of these new technologies must not be overlooked.

Confidentiality↗

PubMed2004

Digital photography: a primer for pathologists.

The computer and the digital camera provide a unique means for improving hematology education, research, and patient service. High quality photographic images of gross specimens can be rapidly and conveniently acquired with a high-resolution digital camera, and specialized digital cameras have been developed for photomicroscopy. Digital cameras utilize charge-coupled devices (CCD) or Complementary Metal Oxide Semiconductor (CMOS) image sensors to measure light energy and additional circuitry to convert the measured information into a digital signal. Since digital cameras do not utilize photographic film, images are immediately available for incorporation into web sites or digital publications, printing, transfer to other individuals by email, or other applications. Several excellent digital still cameras are now available for less than 2,500 dollars that capture high quality images comprised of more than 6 megapixels. These images are essentially indistinguishable from conventional film images when viewed on a quality color monitor or printed on a quality color or black and white printer at sizes up to 11x14 inches. Several recent dedicated digital photomicroscopy cameras provide an ultrahigh quality image output of more than 12 megapixels and have low noise circuit designs permitting the direct capture of darkfield and fluorescence images. There are many applications of digital images of pathologic specimens. Since pathology is a visual science, the inclusion of quality digital images into lectures, teaching handouts, and electronic documents is essential. A few institutions have gone beyond the basic application of digital images to developing large electronic hematology atlases, animated, audio-enhanced learning experiences, multidisciplinary Internet conferences, and other innovative applications. Digital images of single microscopic fields (single frame images) are the most widely utilized in hematology education at this time, but single images of many adjacent microscopic fields can be stitched together to prepare "zoomable" panoramas that encompass a large part of a microscope slide and closely simulate observation through a real microscope. With further advances in computer speed and Internet streaming technology, the virtual microscope could easily replace the real microscope in pathology education. Later in this decade, interactive immersive computer experiences may completely revolutionize hematology education and make the conventional lecture and laboratory format obsolete. Patient care is enhanced by the transmission of digital images to other individuals for consultation and education, and by the inclusion of these images in patient care documents. In research laboratories, digital cameras are widely used to document experimental results and to obtain experimental data.

Computers↗

PubMed1996

Validation testing of the SEER real-time digital holter monitor.

OBJECTIVES: Perioperative myocardial ischemia, detected by off-line Holter ST-segment monitoring, has been associated with adverse cardiac outcome. Technical advances in digital signal processing have facilitated development of digital Holter recorders that allow 24- to 48-hour recording, full disclosure storage, and "real-time" quantitative analysis of ST-segment levels. These recorders may be useful for "on-line" clinical detection of perioperative ischemia. However, little data are available, independent of manufacturers' claims, to validate their accuracy. Using a previously validated digital electrocardiogram (ECG) simulator, a commercially available device was evaluated. DESIGN: Laboratory bench study. SETTING: Not applicable. PARTICIPANTS: Not applicable. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: Custom digital ECG waveform templates were programmed for use with a commercially available ECG simulator (M311 ECG simulator; Fogg Systems, Inc, Aurora, CO). For each template, ST-segment morphology (horizontal elevation or depression, downsloping depression), QRS duration (80 v 120 msec) and the presence or absence of a P wave were manipulated, yielding six unique QRS shapes. For each shape, the degree of ST-segment deviation was altered over a wide range. ST-segment values from the simulator (measured at 60 msec after the J point) ranged from +10 to -18 mm. The SEER digital Holter recorder (Marquette Electronics, Milwaukee, WI) was tested. One hundred twenty-six measurements of ST-segment deviation were input to the SEER at each of two testing sessions. The ST-segment value from the recorder in the "noninteractive" analysis mode was obtained, and the two results averaged for comparison with the expected simulator value. Variability of ST-segment measurement over a continuous 1-hour period of simulator input was also assessed. Sixty-seven percent of measurements were within 95% to 100% of expected, whereas 90% were within 90% to 110%. The regression equation for the complete dataset was SEER output (mm) = -0.47 + 1.015 * simulator input, R2 = 0.99. The mean observed-to-expected value ratio was 100% +/- 6% (+/-SD), range 80% to 114%. The mean deviation in millimeters from expected for all measurements was 0.10 +/- 0.20 mm, median 0.05 mm, range -0.25 to +0.60 mm. For the 72 measurements obtained by 5-minute sampling over 1 hour of continuous simulator input for each of the six QRS shapes, the mean percent difference between observed and expected values was 0.5% +/- 4.5%, median 0.0%, with a mean coefficient of variation of 2.7% (median 1.9%). CONCLUSIONS: Using a digital ECG simulator, it was found that the SEER recorder analyzed ST-segment deviation with a high degree of accuracy. These findings, along with its full disclosure reporting capabilities, suggest it may be useful in perioperative risk stratification. However, accuracy in the clinical setting remains to be validated.

Electrocardiography, Ambulatory↗