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Biomedical subjects

R L Arenson

Publications and source records attributed to R L Arenson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Comparison of diagnostic studies in the pretreatment evaluation of stage Ib carcinoma of the cervix.

The results of our study highlight the need for change in the pretreatment workup of clinical stage Ib cervical cancer. The routine use of excretory urography, barium enema, cystoscopy,and sigmoidoscopy is not justified. MR evaluation is recommended in patients with lesions larger than 2 cm (the group with the greatest increase in predictive value). Although CT scanning is not recommended for the evaluation of parametrial invasion, both CT scanning and MR imaging provide similar positive and negative posttest probabilities for the evaluation of nodal disease.

Bayes Theorem↗
PubMed1996

Invasive cervical carcinoma: role of MR imaging in pretreatment work-up--cost minimization and diagnostic efficacy analysis.

PURPOSE: To examine the cost and efficacy of diagnostic work-up in patients with invasive cervical cancer. MATERIALS AND METHODS: In 246 patients with invasive cervical cancer, all diagnostic tests performed before treatment were recorded. Patients were divided into two groups: those who underwent magnetic resonance (MR) imaging as the initial study (n = 105) and those who did not (n = 141). A list of 1995 Medicare global payments was used to measure cost. Bayesian analysis (likelihood ratios derived from a literature search) was performed for bladder, rectal, parameterial, and nodal involvement in stage Ib disease. RESULTS: Significantly fewer procedures and fewer invasive studies were performed in the MR imaging group. Net cost savings for the MR imaging group was $401 for all patients and $449 for patients with stage Ib disease. For stage Ib disease, the 0% pretest probability of bladder or rectal invasion does not justify the routine use of barium enema examination, cystoscopy, or proctoscopy. The increase in predictive values for parameterial and nodal disease was highest for MR imaging when tumor size was at least 2 cm. CONCLUSION: Guidelines for the pretreatment work-up of clinical stage Ib cervical cancer need revision. MR imaging should be used as an adjunct to clinical evaluation.

Adenocarcinoma↗
PubMed1996

Workstation design. Image manipulation, image set handling, and display issues.

The importance of this article is fourfold. First, the introduction of workstation technology and the types of image workstations provides readers with a better understanding of the state-of-the-art and availability of digital image-display workstations in the market-place. Second, this article identifies primary processes related to image viewing in radiology daily operations. This is crucial because it illustrates the important concepts of the Folder Manger with image preprocessing, patient folder organization, and automatic image display sequencing. With these features incorporated in the workstation design, the number of steps required for a radiologist to interact with a workstation is minimized. Third, the discussions on how to present and manipulate images on the workstations suggest methods concerning the issue of displaying large volumes of image sets on a limited number of monitor screens. Lastly, examples of automatic image sequencing, high-resolution color monitors, and voice-based user interface illustrate current research topics in the future of digital workstation design.

Computer Systems↗
PubMed1995

Asynchronous transfer mode technology for radiologic image communication.

Image communication is an important component in picture archiving and communication systems (PACS) and teleradiology applications. Currently, local area networks (LANs) and wide area networks (WANs) use different technologies for image communication. Asynchronous transfer mode (ATM) is an emerging technology that can be used for both LANs and WANs. This article describes experimental results using an ATM network to transmit CT scans and digitized radiographs between the University of California, San Francisco (UCSF) and Mount Zion Hospital, an affiliated community hospital in the San Francisco Bay area. The WAN connection between the two hospitals is via an ATM main switch at Pacific Bell, a local communication carrier located in Oakland, CA, which uses single-mode optical fibers. Preliminary results show that, using the ATM Optical Carrier Level 3 (OC3) (155 Mbits/sec) specification, it takes 1.3 sec and 2.7 sec to transmit a 10-Mbyte digitized radiograph and a 20-Mbyte CT scan, respectively, between the two locations. Encouraged by these results, we have designed and implemented an ATM WAN and LAN between UCSF and Mount Zion Hospital. This is the first of a three-phase project of installing a WAN serving four hospitals and one clinic in the San Francisco Bay area.

Computer Communication Networks↗
PubMed1994

High-resolution image workstation for intensive care units.

Despite their potential for improving patient management and decreasing costs, picture archiving and communication systems (PACS) are not being absorbed rapidly into clinical practice because of their technical immaturity and because the cost-effectiveness of the technology has not been established. Workstations and archives need to be significantly improved before they can be useful. This report describes the authors' experiences with a high-resolution image workstation for a medical intensive care unit. The workstation has been designed around a standard computer platform and is equipped with two high-resolution image displays. The user interface stresses speed and simplicity. Image manipulation is simplified by providing empirical preset window and level values. Images are displayed in less than 2 seconds. The workstation also displays radiologic reports as soon as they become available. Future work will focus on using the workstation to improve communication between the physician and the radiologist.

Humans↗
PubMed1994

Digital archive system for radiologic images.

Use of a picture archiving and communication system (PACS) for clinical review requires rapid access to patient images. The authors have developed a second-generation archive system for a departmental PACS that optimizes access time for both current and historical images. The system is based on a composite staging mechanism that uses multiple storage media: magnetic disks, erasable magneto-optical disks, and write-once-read-many (WORM) disks. A two-tiered communication network composed of a standard Ethernet network and a gigabit bandwidth fiberoptic UltraNet network is used for distributing images to remote display stations. The system currently archives 1.5 Gbytes of radiologic images daily from three magnetic resonance imagers, two computed tomographic scanners, one computed radiographic system, and one laser film digitizer. The system features (a) multiple optical drives and robotic arms, which support concurrent archival and retrieval operations; (b) a stacking mechanism, which provides fast retrieval of current images; (c) a pre-fetch mechanism, which minimizes on-line image retrieval, hence relieving peak-hour workload of the optical disk library and the networks; (d) studies grouping and platter management, which optimize retrieval of a patient's images from multiple examinations; and (e) a job-prioritizing control, which minimizes waiting time for radiologists and referring physicians to review images at the display stations. This system is suitable for a large-scale PACS to serve the clinical and research staff.

Radiology Information Systems↗
PubMed1992

The impact of PACS on research and education.

Picture Archiving and Communication Systems (PACS) are rapidly evolving and the total digital radiology department may be a reality within the next decade. PACS can have a major impact on the educational and research responsibilities of a medical institution. The possibility of correlating real patient data with existing radiological teaching files opens up numerous possibilities. Multi-institutional research can be strengthened by employing the PACS as the means to the end. This paper discusses the representative examples of how teaching and research can be enhanced with PACS and the technical requirements to achieve the inter-connectivity.

Education, Medical↗
PubMed1992

Software suite for image archiving and retrieval.

The efficient operation of a clinical picture archiving and communication system (PACS) requires a fully functional image archive. The archive should not only be able to store and retrieve images reliably but should also work in concert with software that optimizes the flow of image-related information throughout the PACS. The authors devised a software suite that serves to improve the flow and content of information and the integrity of the data. The software was developed by translating the functions performed by a conventional film library. Types of transactions possible with this system include scheduling, canceling, rescheduling, and prestaging examinations; changing demographic information; merging patient information; and generating reports. The authors believe such a software suite is essential for a clinically useful PACS.

Data Display↗
PubMed1992

Picture archiving and communication systems in the United States.

Picture archiving and communication systems (PACS) are expected to replace film in the years to come. PACS acquire, store, transmit, and display medical images. Although there are several clinical PACS in operation today, there are significant problems slowing their introduction. PACS are limited in spatial and contrast resolution and the workstation's displays present difficulties due to low light levels, slow image presentation, and poorly designed software. Standard interfaces are still lacking for most of the imaging equipment currently in use, making connections to these devices nearly impossible. Cost is a major issue as well. Yet limited implementations, often called mini-PACS, offer advantages such as faster image presentation to radiologists and referring physicians, reduced portable retake rates, the capability for viewing images at home off-hours, and transmission from remote sites. More development is needed for interfaces with the radiology information system and for sophisticated network and image management.

Radiology Information Systems↗
PubMed1990

The digital imaging workstation.

Picture archiving and communication systems (PACS) are expected to convert film-based radiology into a computer-based digital environment, with associated cost savings and improved physician communication. The digital workstation will be used by physicians to display these "soft-copy" images; however, difficult technical challenges must be met for the workstation to compete successfully with the familiar viewbox. Issues relating to image perception and the impact on physicians' practice must be carefully considered. The spatial and contrast resolutions required vary according to imaging modality, type of procedure, and class of user. Rule-based software allows simple physician interaction and speeds image display. A consensus appears to be emerging concerning the requirements for the PACS workstation. Standards such as the American College of Radiology/National Electrical Manufacturers' Association Digital Imaging and Communication Standard are facilitating commercial applications. Yet much careful study is needed before PACS workstations will be fully integrated into radiology departments.

Computer Systems↗
PubMed1989

The impact of sonography on the management of extratesticular abnormalities of the scrotum.

The results of scrotal sonography performed in a recent one-year period (1987) were retrospectively reviewed to assess the role of sonography in the management of patients with extratesticular abnormalities. The study included 226 examinations performed in 204 men. In extratesticular abnormalities, scrotal sonography confirms the clinical impression of the referring physicians, monitors the progress of conservative treatment, and guides the surgical approach. Patients with sonographically classic cystic extratesticular abnormalities rarely come to surgery. Those with complicated cystic abnormalities are usually followed clinically but have a higher incidence of surgery. Those with solid-appearing echogenic abnormalities usually have surgical removal.

Adolescent↗
PubMed1989

The diagnosis of pulmonary nodules: comparison between standard and inverse digitized images and conventional chest radiographs.

We compared plain chest radiographs, standard (bones white) digitized images, and inverse-intensity (bones black) images to determine their ability to identify pathologically confirmed malignant pulmonary nodules. The images were digitized by using a photo-optical laser scanner and were displayed on a 1024 x 1024 x 8 bit system capable of operator-controlled magnification (2x or 4x) and nonlinear (logarithmic/exponential) contrast transformation in both standard and inverse-intensity modes. Receiver-operator curve analysis was used to study the detection performance of six observers who viewed 40 images obtained in 15 normal subjects and 25 abnormal subjects. There was no statistically significant difference in the area under the ROC curve between the standard digital images and the plain chest radiographs. However, ROC areas were significantly greater (p less than or equal to .05) for inverse-intensity digital images when compared with either standard-intensity digital images or plain chest radiographs. These results suggest that inverse-intensity images may have some advantages in the detection of pulmonary nodules.

Humans↗
PubMed1989

A prospective trial of ionic vs nonionic contrast agents in routine clinical practice: comparison of adverse effects.

A multicenter study of adverse effects of ionic and nonionic contrast agents was conducted in three similar time periods. In 1985, before approval of the nonionic contrast agents by the Food and Drug Administration, 6006 consecutive patients received iv ionic agents for urography or CT. After approval of the nonionic agents, 7170 consecutive patients referred for the same examinations were studied. The two groups of patients were significantly different, but the differences were small and did not uniformly favor either group. The incidence of adverse effects in the patients given ionic contrast material was significantly higher than that of the nonionic group (4.17% vs 0.69%, p less than .001). The reactions were also more severe in the ionic group than in the nonionic group (p less than .005). A patient questionnaire disclosed that many patients did not feel well for hours to days after the procedure and also did not immediately resume normal activities of daily living. The nonionic agent was significantly less distressful than the ionic agent. We conclude that nonionic agents cause fewer and less severe adverse effects. Reducing adverse effects can save the patient or the examining site either time or money. However, this study does not show that nonionic agents are more cost-effective than ionic agents.

Contrast Media↗
PubMed1989

Hepatic and biliary tract abnormalities in patients with AIDS. Sonographic-pathologic correlation.

A retrospective evaluation of hepatobiliary sonograms in 22 patients with AIDS was performed and the sonographic abnormalities were correlated with pathologic findings in 10 patients. Hepatic parenchymal abnormalities noted on ultrasound include a hyperechoic parenchymal echo pattern in 45.5%, hepatomegaly in 41%, and focal masses in 9% of patients. Etiologies for the diffuse hyperechoic pattern based on pathologic correlation in eight cases were hepatic steatosis and granulomatous hepatitis. Biliary tract abnormalities identified included gallbladder wall thickening in 55% of patients, dilated gallbladder in 18%, biliary sludge in 23%, and gallstones in 5% of patients. Extrahepatic ductal dilation was seen in 23% of patients, but the intrahepatic ducts were dilated in only 5% of patients. Possible etiologies for biliary tract abnormalities suggested by pathologic correlation in five patients and literature review were cytomegalovirus and cryptosporidial infection, although constitutional factors may have played a role. Hepatobiliary ultrasound is, therefore, an effective screening tool for directing further diagnostic and therapeutic procedures in AIDS patients presenting with clinical evidence of hepatobiliary dysfunction.

Acquired Immunodeficiency Syndrome↗