Andre J. Duerinckx

Evaluation of Renal Transplant Dysfunction by Duplex Doppler Sonography: A Prospective Study and Review of the Literature

A disconcertingly wide variation exists in the literature as to the accuracy of duplex Doppler sonography in the detection of acute renal transplant rejection. Sensitivities range from 9% to 76%. In an attempt to explain the disparity of results, we undertook a double-blind prospective study of the accuracy of duplex Doppler ultrasound in the detection of acute rejection in renal transplants. We scanned 49 consecutive patients with a total of 65 biopsies; 46 biopsies in 33 consecutive patients were included in our study. In our population, the prevalence of acute rejection was 61% (28/46). Using a resistive index (RI) cutoff of greater than 0.90 based on the main renal artery flow pattern, the sensitivity of our test was 43%, with a 67% specificity. The positive predictive value was 67%. Our results are contrasted and compared with the published data from other groups in a critical survey of the literature. We conclude that duplex Doppler sonography alone is inadequate to evaluate acute rejection in renal transplants.

Postoperative evaluation of pulmonary arteries in congenital heart surgery by magnetic resonance imaging: Comparison with echocardiography

Palliative and corrective operations for the treatment of cyanotic congenital heart disease frequently involve or potentially influence the size of the pulmonary arteries. Echocardiography and magnetic resonance imaging (MRI) are two noninvasive imaging techniques currently used to assess morphologic abnormalities of the pulmonary arteries. The purpose of this study was to evaluate the role of MRI in comparison with echocardiography for defining morphologic changes of the pulmonary arteries after congenital heart surgery. The MRI scans and echocardiograms of 33 patients with surgery involving or affecting the pulmonary arteries were compared. The pulmonary outflow tract, pulmonary confluence, right and left pulmonary arteries, and surgical shunts were separately evaluated. Cineangiography and surgical reports were used to confirm findings. MRI and echocardiography were equivalent for demonstrating abnormalities of the right ventricular outflow tract, main pulmonary artery, and a variety of pulmonary shunts. MRI was superior to echocardiography in demonstrating abnormalities of the right and left pulmonary arterial branches (p < 0.001). MRI is effective for monitoring pulmonary arterial status after surgery and is superior to echocardiography for the evaluation of the right and left pulmonary arteries.

CORONARY MR ANGIOGRAPHY

MR angiography of the coronary arteries became possible in 1991 with the development of a new group of fast MR imaging sequences. Although the role of coronary MR angiography in screening for coronary artery lesions has not yet been established, coronary MR angiography already has been very successful in the detection of coronary artery variants and the imaging of coronary stents and bypass grafts. Variants of these new MR imaging techniques also can quantitate velocity in native coronary arteries. Several generations of coronary MR angiographic techniques exist; all techniques use EKG-triggering. The use of MR contrast agents appears to further improve all techniques. Technical progress and changes in this subfield of cardiac MR imaging have been so fast that large-scale preclinical trials have not been conducted with the majority of the first and second generation coronary MR angiographic pulse sequences as known today. This article reviews the development of these new cardiac MR imaging techniques and the initial successes with clinical application using commercial MR scanners.

MR imaging of surgical complications of systemic-to-pulmonary artery shunts.

Patients with a systemic-to-pulmonary artery shunt and positive findings on traditional imaging modalities such as chest X-ray, echocardiography, or cardiac angiography often can benefit from additional noninvasive imaging with magnetic resonance imaging (MRI). Diagnostic dilemmas encountered include: pseudoaneurysms, contained fluid collection (seroma) surrounding a shunt, and stenosis of the shunt anastomoses. MRI studies using traditional cardiac-triggered spin-echo (SE) imaging and the newer breathhold MRI studies with k-space segmented gradient-recalled echo (GRE) imaging can greatly help resolve diagnostic dilemmas. By combining different MR imaging techniques it becomes possible to clearly distinguish between pseudoaneurysms and seroma, to exclude an active leak and to sometimes visualize the distal anastomosis with more precision than conventional angiography. MRI is often able to add information needed for clinical decision making prior to surgical repair.

A Curriculum in Cardiothoracic Radiology for Medical Students, with Goals and Objectives

The Liaison Committee on Medical Education is the accrediting body for medical education programs leading to the MD degree in the United States and Canada. According to the Committee’s accreditation standards (1), “The curriculum must provide grounding in the body of knowledge represented in the disciplines that support the fundamental clinical subjects, for example, diagnostic imaging and clinical pathology.” In a survey of 119 directors of medical student education in radiology, 46 (39%) responded to questions regarding the teaching of radiology to medical students at their institution (2). A core radiology clerkship was required at 13 (29%) of 46 schools responding and was an elective at 33 (72%) (2). The number of schools with a required radiology clerkship has not changed since 1994 (3). The clerkship is given in the 3rd year at 12 (26%) of 46 schools, in the 4th year at 20 (44%), and in either the 3rd or 4th year at 14 (30%) (2). Twenty-six (57%) of 46 programs have computers in the department that students use during the course, usually shared with residents. Reported simultaneously with these survey results were results from a second survey of directors of medical student education, in which 69 (50%) of 139 responded (2). Six (9%) of 69 responding programs directed the medical school’s gross anatomy course, and 14 (20%) taught some portion of the course. A telephone survey (4) showed that a formal dedicated radiology clerkship was a graduation requirement in only five of the 16 top-ranked medical schools in a U.S. News & World Report ranking (Cornell, Duke, Harvard, University of California at San Francisco, and University of California at Los Angeles) (5). In contrast, a survey of 322 nonradiologist physicians showed that 87% believed formal radiology instruction should be mandatory (6). Radiology can be taught to medical students through an integrated curriculum, an independent curriculum, or a combination of the two. In an integrated curriculum, radiology faculty provide radiology instruction to medical students rotating through a nonradiology course or a course that is jointly sponsored by radiology and nonradiology departments. For example, radiologists teach projectional and cross-sectional imaging to medical students enrolled in a gross anatomy course. Radiologists may give a series of imaging lectures related to topics covered in a required medicine clerkship. Collaboration can occur when radiology faculty participate in required introductory courses that expose students early in medical school to physical examination techniques, history taking, and writing patient notes. These courses have various titles, such as “Introduction to Clinical Medicine” or “Patient, Doctor, and Society.” Radiology faculty can provide correlative imaging instruction in most required courses. The Alliance of Medical Student Educators in Radiology is a group associated with the Association of University Radiologists whose purpose is to promote radiology as an essential component of the medical student curricuAcad Radiol 2001; 8:1247–1251

Assessment of asynchronous transfer mode (ATM) networks for regional teleradiology

The purpose of this study was to assess the effect of ATM network capabilities on the clinical practice of regional teleradiology, by providing immediate interactive radiology consultations between subspecialists and general radiologists at affiliated academic institutions. PACS installed at three affiliated hospitals (UCLA Medical Center, West LA VAMC and UCLA Olive-View Medical Centers) were connected via an ATM network. Two commercial PACS (Agfa) systems, one at the VAMC and one in an ultrasound outpatient clinic at UCLA were connected via ATM switches (Newbridge, Inc.) and a Santa Monica GTE central office switch. We evaluated this initial system configuration and measured image transfer performance, including memory-to-memory, disk-to-disk, disk-to-archive with and without DICOM protocols. Although the memory-to-memory data rate was 25 Mbps, the average remote disk-to-disk image transfer performance, using DICOM 3.0 communications protocols on SUN SPARCstation 10 servers, was 3 to 5 Mbps. Using these capabilities, timely interactive subspecialty consultations between radiologists was successfully performed while both were at different physical locations. We present the use of ATM technology in a realistic clinical environment and evaluate its impact on patient care and clinical teaching within the radiology departments of 2 institutions. Image communications over a regional PACS using an ATM network can allow interactive consultations between different subspecialist and general radiologists or other specialized radiologist spread over three different medical centers.

Estimation of acoustic attentuation in liver using one megabyte of data and the zero-crossings technique☆

Statistical fluctuations due to scatter-induced frequency variations in reflected acoustic pulses are a major problem when estimating acoustic attenuation. Disagreement exists in the ultrasound community as to how much data is sufficient to overcome these statistical fluctuations. The range of attenuation values for normal livers and a tissue equivalent phantom, using 1 megabyte of data per liver and the zero-crossings technique, was investigated. The significance of statistical fluctuations and their effects on attenuation are discussed.

Introduction to two PACS ‘82 Panel Discussions edited by André J. Duerinckx, M.D., Ph.D.: “Equipment Manufacturers’ View on PACS” and “The Medical Community’s View on PACS”

THE FIRST INTERNATIONAL CONFERENCE AND WORKSHOP on Picture Archiving and Communications System (PACS) for Medical Applications in 1982 was the creation of Andre Duerinckx during his early years as a researcher at Philips Ultrasound Inc., in Santa Ana, California.1 At that time Dr. Duerinckx and Jim Pisa, the head of research and development at Philips Ultrasound, were exploring the concept of an Ultrasound Mini-PACS.1,2 To help design this early PACS concept Dr. Duerinckx called together experts from many fields for a meeting in beautiful Southern California in January 1982. Obviously the word “PACS” in radiology as we understand it today did not yet exist. The term was created by Dr Duerinckx prior to this first meeting in 1982 after many discussions with Sam Dwyer and others, and after rejecting many alternate names.3 Dr. Duerinckx has since moved on from being a medical physicist and engineer to become a diagnostic radiologist with residency training at the University of California at Los Angeles (UCLA) and fellowship training in cardiovascular magnetic resonance imaging at the University of California, San Francisco (UCSF). His first encounter with a clinical PACS was as a radiology resident. Later, as a faculty member at UCLA, he worked with the early PACS developed by H. K. Huang at UCLA. He went on to work through the very early stages of a commercial PACS development by a major vendor (AGFA) and witnessed firsthand the clinical impact and growing pains of commercial PACS technology while working at the West Los Angeles Veterans Affairs Medical Center (West LA VA), a UCLA-affiliated institution, from 1992 to 2000.4 With Dr. Edward Grant, Chief of Radiology at the West LA VA, and many other collaborators, an ambitious project was started to implement and link the PACS of all VA Medical Centers in Southern California via a fast network, including asynchronous transfer mode (ATM) links to selected sites.5,6,7,8 The impact on educational programs has been described.6,7 Extensive planning and cost analyses were needed to justify the PACS-based digital radiography services for a network of hospitals (like the Southern California Veterans Integrated Service Network).9,10 These new services were successfully implemented in the Southern California VA network in 2001. In June 2000 Dr. Duerinckx moved to Dallas, Texas, to become the Chief of Radiology at the VA Medical Center. There he uses a commercial PACS from a small vendor that does not have all of the refinements and updates available in the latest PACS from larger vendors. Communication between PACS at several VA hospitals in Texas is a key element in the delivery of patient care. Many of the concerns expressed by both the equipment manufacturers and the medical community during the panel discussions of the 1982 PACS workshop are still true today and were visionary, even though the technology has changed dramatically since. Access to fast computers, fast networks, and fast data transmission has improved, but the fundamental issues of how to integrate and standardize these technologies, and how to improve the workflow once the equipment is in place remain partially unresolved and not widely implemented, as shown in some of the more recent papers in this special issue of the Journal of Digital Imaging. One of the recurring topics during the equipment manufacturer discussion was the importance of standardization. Obviously 1982 was pre-DICOM (digital imaging and communications in medicine) standards. The standardization issues that were discussed in January 1982 were a reflection of the state of technology and the nonexistence of large clinical PACS. Many concepts proposed and discussed were linked to 1982 technology but have since resurfaced with 2002-2003 technology. One idea proposed in 1982 was the patient “image credit card” which would contain the full medical record including images and would be portable from location to location.2 It is interesting to look at the newest concept of image data portability offered 20 years later by many large PACS vendors in 2002-2003. The idea of the image credit card has basically resurfaced as the capability of burning a CD with image data embedded in such a way that it can be read on any computer system using any type of image format. Concerns in 1982 about the possibility that standards could be a deterrent to innovation in the PACS world have proved not to be true. In fact, DICOM standards have helped PACS development by demonstrating the importance of integrating all the pieces needed to make PACS into an integral, cost-effective, and universal patient care component. The medical community’s views on PACS expressed in 1982 reflect the fact that “filmless” PACS was a big unknown. The clinicians on the panel described how film-based radiology systems worked, why it would be important to get information on the workflow in radiology departments, and how that would help design PACS. Shortcomings of film-based radiology departments were described (misplaced films, film handling, film file room inadequacies, etc.). However, nobody at that time could yet consider futuristic concepts like redesigning workflow as a key to success when using a non-film-based PACS. People at that time also discussed the differences between film-based PACS versus a non-film-based PACS. Overall the 1982 workshop was a great stimulus to bring bright minds (industry, vendors, scientists, and clinicians) together to discuss this very important concept for today’s practice of clinical imaging. The ideas presented in 1982 are part of the foundation of the expansion of PACS worldwide in 2003 and beyond.

Cost analysis of PACS: fact or fiction?

The purpose of this paper is to analyze the incremental costs of PACS and computed Radiography and to evaluate the key factors affecting a cost-analysis for PACS.

Teleradiology for Veterans Integrated Service Networks

Veterans Affairs Health Care has become more decentralized with the creation of local Veteran Integrated Service Networks (VISN). The purpose of this study was to analyze the design and cost of a wide-area-network (WAN) for teleradiology in a local VISN. The Southern California VISN includes 4 large and 3 small medical centers. Only one of the 7 medical centers has an operational PACS. Data were collected on the radiologist workloads and patient and image flow within and between the 7 medical centers. This was used to estimate the size and cost of local PACS at each medical center and the need for teleradiology services. A simplified cost-analysis model was used to estimate potential cost- savings by gong filmless. Asynchronous transfer mode (ATM) technology was selected for the WAN between the medical centers. A realistic cost-savings model was developed. Cost- effectiveness of a PACS/Teleradiology system was established. Based on this model, a PACS/Teleradiology configuration for the VISN was successfully designed and partially implemented. The ATM-based WAN provides instantaneous access to PACS at each centers. Cost-analysis of the design and implementation of a PACS/teleradiology network in a VISN is possible and important when planning such system. The experience gained will serve a model for future similar projects nationwide.