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Biomedical subjects

David S Channin

Publications and source records attributed to David S Channin.

8 recordsLinked to original sources
PubMed2005

Validating DICOM content in a remote storage model.

Verifying the integrity of DICOM files transmitted between separate archives (eg, storage service providers, network attached storage, or storage area networks) is of critical importance. The software application described in this article retrieves a specified number of DICOM studies from two different DICOM storage applications; the primary picture archiving and communication system (PACS) and an off-site long-term archive. The system includes a query/retrieve (Q/R) module, storage service class provider (SCP), a DICOM comparison module, and a graphical user interface. The system checks the two studies for DICOM 3.0 compliance and then verifies that the DICOM data elements and pixel data are identical. Discrepancies in the two data sets are recorded with the data elements (tag number, value representation, value length, and value field) and pixel data (pixel value and pixel location) in question. The system can be operated automatically, in batch mode, and manually to meet a wide variety of use cases. We ran this program on a 15% statistical sample of 50,000 studies (7500 studies examined). We found 2 pixel data mismatches (resolved on retransmission) and 831 header element mismatches. We subsequently ran the program against a smaller batch of 1000 studies, identifying no pixel data mismatches and 958 header element mismatches. Although we did not find significant issues in our limited study, given other incidents that we have experienced when moving images between systems, we conclude that it is vital to maintain an ongoing, automatic, systematic validation of DICOM transfers so as to be proactive in preventing possibly catastrophic data loss.

Computer Communication Networks↗
PubMed2005

Comparison of human observer performance of contrast-detail detection across multiple liquid crystal displays.

Appropriate selection of a display subsystem requires balancing the optimization of its physical parameters with clinical setting and cost. Recent advances in Liquid Crystal Display (LCD) technology warrant a rigorous evaluation of both the specialized and the mass market displays for clinical radiology. This article outlines step two in the evaluation of a novel 9.2 million pixel IBM AMLCD panel. Prior to these experiments, the panel was calibrated according to the DICOM Part 14 standard, using both a gray-scale and a pseudo-gray scale lookup table. The specific aim of this study is to compare human, contrast-detail perception on different computer display subsystems. The subsystems that we looked at included 3- and 5-million pixel "medical-grade" monochrome LCDs and a 9.2-million pixel color LCD. We found that the observer response was similar for these three display configurations.

Artifacts↗
PubMed2004

Effect of viewing angle on luminance and contrast for a five-million-pixel monochrome display and a nine-million-pixel color liquid crystal display.

Digital imaging systems used in radiology rely on electronic display devices to present images to human observers. Active-matrix liquid crystal displays (AMLCDs) continue to improve and are beginning to be considered for diagnostic image display. In spite of recent progress, AMLCDs are characterized by a change in luminance and contrast response with changes in viewing direction. In this article, we characterize high pixel density AMLCDs (a five-million-pixel monochrome display and a nine-million-pixel color display) in terms of the effect of viewing angle on their luminance and contrast response. We measured angular luminance profiles using a custom-made computer-controlled goniometric instrument and a conoscopic Fourier-optics instrument. We show the angular luminance response as a function of viewing angle, as well as the departure of the measured contrast from the desired response. Our findings indicate small differences between the five-million-pixel (5 MP) and the nine-million-pixel (9 MP) AMLCDs. The 9 MP shows lower variance in contrast with changes in viewing angle, whereas the 5 MP provides a slightly better GSDF compliance for off-normal viewing.

Contrast Sensitivity↗
PubMed2004

Reviews in radiology informatics: establishing a core informatics curriculum.

The advent of digital imaging and information management within the radiology department has prompted the growth of a new radiology subspecialty: Radiology Informatics. With appropriate training, radiologists can become leaders in Medical Informatics and guide the growth of this technology throughout the medical enterprise. Radiology Informatics fellowships, as well as radiology residency programs, provide inconsistent exposure to all the elements of this subspecialty, in part because of the lack of a common curriculum. The Society for Computer Applications in Radiology (SCAR) has developed a curriculum intended to guide training in Radiology Informatics. This article is the first in a series presented by SCAR and the Journal of Digital Imaging, titled "Reviews in Radiology Informatics." The series is designed to sample from each of the major components in the Radiology Informatics Curriculum, to spark further interest in the field and provide content for informatics education.

Curriculum↗
PubMed2003

Assessment of a novel, high-resolution, color, AMLCD for diagnostic medical image display: luminance performance and DICOM calibration.

This article documents the results of the first in a series of experiments designed to evaluate the suitability of a novel, high resolution, color, digital, liquid crystal display (LCD) panel for diagnostic quality, gray scale image display. The goal of this experiment was to measure the performance of the display, especially with respect to luminance. The panel evaluated was the IBM T221 22.2" backlit active matrix liquid crystal display (AMLCD) with native resolution of 3840 x 2400 pixels. Taking advantage of the color capabilities of the workstation, we were able to create a 256-entry grayscale calibration look-up table derived from a palette of 1786 nearly gray luminance values. We also constructed a 256-entry grayscale calibration look-up table derived from a palette of 256 true gray values for which the red, green, and blue values were equal. These calibrations will now be used in our evaluation of human contrast-detail perception on this LCD panel.

Contrast Sensitivity↗
PubMedDate not supplied

Integrating the healthcare enterprise: a primer. Part 6: the fellowship of IHE: year 4 additions and extensions.

Recently, one of my friends, a computer wizard, paid me a visit. As we were talking, I mentioned that I had recently installed a picture archiving and communication system and a radiology information system. I told him how happy I was with the system and showed him a compact disk (CD) from it. To my surprise, he threw it into my microwave oven and turned it on. Instantly I got very upset, because the System had become precious to me, but he said, "Do not worry, it is unharmed." After a few minutes, he took the CD out, gave it to me and said, "Take a close look at it." To my surprise, the CD was quite cold to hold and it seemed to be heavier than before. At first, I could not see anything, but on the inner edge of the central hole, I saw an inscription, an inscription finer than anything I had ever seen before. The inscription shone piercingly bright, and yet remote, as if out of a great depth: 12413AEB2ED4FA5E6F7D78E78BEDE8209450920F923A40Eel0E50CC98D444AA08E324. "I cannot understand the fiery letters," I said in a timid voice. "No, but I can," he said. "The letters are Hex, of an ancient mode, but the language is that of DICOM, which I shall not utter here. But in common English, this is what it says: Two integration profiles to schedule work flow. Five for radiology with room to grow. One for the bacon to bring it home. One for HIPAA all alone. And one for results for those who would know. One technical framework in which to find them. One technical framework to guide them. One technical framework to bring them all. And in the Connect-a-thon bind them. In the Land of Lincoln where no shadows are. We continue the saga of the fellowship of the IHE: clinicians, radiologists, informaticians, administrators, technologists, imaging system vendors, and non-imaging system vendors, as they begin their year 4 transactions.

Computer Communication Networks↗
PubMedDate not supplied

Informatics in radiology (infoRAD): integrating MIRC-compliant semiautomated teaching files into PACS work flow.

A Medical Image Resource Center (MIRC)-compliant teaching file system was created that can be integrated into a picture archiving and communication system (PACS) environment. This system models the three-step process necessary for efficient teaching file creation in a PACS environment: (a) identifying and transferring a case quickly and easily during primary interpretation, (b) editing and authoring the case outside of primary interpretation time, and (c) publishing the case locally and via MIRC standard-based mechanisms. Images from interesting cases are e-mailed to the teaching file system from either the PACS workstation or the radiologist's personal computer. Notes and clinical information may be included in the e-mail text to prompt the recollection of case details. Images are automatically extracted from the e-mail and sent to an image repository, and text fields are captured in a database. The World Wide Web-based authoring component provides tools for final authoring of cases and for the manipulation of existing cases. Authors designate access levels for each case, which is then made available locally and, potentially, to the entire MIRC-compliant community. Although this application has not yet been implemented as a departmental solution, it promises to improve and streamline medical education and promote better patient care.

Radiology↗