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Biomedical subjects

R G Jost

Publications and source records attributed to R G Jost.

At least 19 recordsLinked to original sources
PubMed1992

Chest imaging within the radiology department by means of photostimulable phosphor computed radiography: a review.

Photostimulable phosphor computed radiography has been clinically used outside of Japan for more than 8 years. Results of at least 35 quantitative or semiquantitative studies have been published so far in which the clinical utility of computed radiography (CR) is compared with that of conventional screen/film radiography (FR) for the study of the adult chest within the radiology department. The results can be summarized as follows: CR is superior to FR in the mediastinum, retrocardiac region, and subdiaphragmatic recesses, as well as in the evaluation of coronary artery calcifications. CR is reported to be generally superior or equivalent in the detection and evaluation of pulmonary nodules and larger pulmonary opacities. Equivocal results have been reported for pathologies requiring the inspection of fine details, such as interstitial infiltrates or pneumothorax. The studies indicate that image processing algorithms dedicated to the delineation of specific anatomies or pathologies improve clinical performance.

Coronary Angiography↗
PubMed1991

A distributed approach to integrated inquiry and display for radiology.

Picture archive and communications (PACS) systems should be flexible and modular in design so that new advances in storage, computation, and display technology can be introduced into the system without a significant redesign of existing software. The acquisition, storage, and management of radiologic images must be carefully integrated with a radiology information system. Our architecture is based on a four-level data model: (1) patient information, (2) examination information and reports, (3) image information, and (4) instances of images. The PACS being developed at the Mallinckrodt Institute of Radiology within the Electronic Radiology Laboratory consists of three primary components: application clients, database servers and image servers. One type of application client is an image-capable workstation that supports a radiology image viewing application. The application client queries the database server for information regarding patient and examination data in response to user-level requests. The database server responds to the request by retrieving the appropriate patient demographics and examination information, along with a pointer to the image/instance data from a central database. The client then uses the image data pointer to query the image server for the actual pixel data. The image server responds by transmitting the pixel data to the requesting application client or a designated auxiliary display device. Other clients act as image data acquisition nodes. Queries to the database servers are made via a library of callable subroutines. Software integrity is maintained throughout the system by dynamically loading software from a code-control database. Inquiry and display transactions, supported on a local-area network (Ethernet), have been measured and analyzed. Results and observations are presented.

Computer Communication Networks↗
PubMed1991

A prototype of a high-resolution computerized radiology teaching file.

Computers provide an excellent tool for handling the task of organizing a radiology teaching file. Currently available computerized teaching files are either film-based, slide-based, or use laser-disc video technology for image display. There are obvious advantages to having the management of radiologic images under the control of a computer, and the need for a higher resolution alternative to video laser-disc technology becomes apparent when one tries to computerize a chest radiology teaching file. We describe the prototype of such a system, named MIRTLE, (the Mallinckrodt Institute of Radiology Teaching and Learning Environment) which was designed to integrate text under the control of a custom data base with high-resolution digital images from a Picture Archiving and Communications System. This system with its easy-to-use windows environment should allow a significant increase in the use of the radiology teaching file.

Computer Systems↗
PubMed1991

Artifacts in computed radiography.

Storage-phosphor digital radiographic systems are becoming widely used in a variety of diagnostic procedures. The equipment is reliable and produces images of consistently high quality. However, the images may contain artifacts directly related to the digital techniques used, to the phosphor imaging plate, or to radiography in general. This article illustrates many of the artifacts encountered that are specific to computed radiography, some of which can simulate pathologic lesions. Their causes and remedies are discussed briefly.

Algorithms↗
PubMed1991

MR examination of the knee: interpretation with multiscreen digital workstation vs hardcopy format.

A multiscreen imaging workstation was compared with conventional hardcopy format for diagnostic interpretation of MR images of the knee. MR examinations from 30 patients were interpreted by two observers using film displayed both on a standard film panel alternator and an eight-screen digital workstation. Arthroscopic examination of these patients disclosed 30 meniscal tears and five anterior cruciate ligament tears in 28 patients. Two patients had normal arthroscopic examinations. The MR examinations were evaluated with a five-point confidence rating scale. Results were correlated with arthroscopic findings, and receiver-operating-characteristic curves were generated from these data. No significant difference was found between the areas under the receiver-operating-characteristic curves for film and digital display. The time required for image interpretation was greater when using the digital workstation than when using the film by a factor of approximately 2.7. Our data indicate that a multiscreen digital workstation can be used for interpreting MR examinations of the knee without impairment of diagnostic performance, but with increased time required for image interpretation when compared with radiographic film and a film panel alternator.

Adult↗
PubMed1990

Hospital-wide distribution of nuclear medicine studies through a broadband digital network.

Nuclear medicine provides a good environment for the evaluation of picture archiving and communication systems (PACS) because of the relatively small quantity of digital data that are generated, leading to reduced requirements for storage, display, and transmission compared with those found in radiology. The PACS in nuclear medicine is characterized by use of a single computer as a central storage, display, and analysis node. Images are acquired with use of small, low-cost computers attached to each camera. This network configuration offers advantages of convenience, but with great reliance on a single computer. A campus-wide picture network is under development at Washington University employing broadband cable television technology supplemented by baseband Ethernet (Digital Equipment Corp, Maynard, MA) components. All areas of diagnostic radiology and nuclear medicine are connected via a PACS testbed project. A radiology information system, supporting over 250 terminals, provides digital tracking of patients and report generation and retrieval. A new image workstation is under development in conjunction with Digital Equipment Corp. This system will permit display in multiple windows of report information and images from various modalities. A lung scan demonstration project is now beginning that is designed to test the value of a PACS in nuclear medicine. Digitally acquired chest radiographs will be displayed on an image workstation in nuclear medicine along with digital ventilation and perfusion lung scans. It is hoped that time-consuming logistic bottlenecks now encountered in lung scan interpretation will be reduced.

Computer Communication Networks↗
PubMed1990

Digital mobile radiography.

A storage phosphor digital imaging system has been used to perform virtually all of an increasing number of mobile (portable) projectional roentgenographic examinations in a busy hospital. Approximately 130 such studies are done per day, of which about 110 are chest examinations. The processing unit suffices to keep pace with peak activity in the radiology department. This technique has decreased the repeat rate for portable anteroposterior chest radiographic examinations from 4.5% to less than 1% and has resulted in an even more dramatic reduction in the rate for lateral or decubitus chest examinations as well as for studies of the abdomen and those done in the operating room. The diagnostic accuracy and confidence level achieved in interpreting the complementary pair of digital images has been equivalent to or has exceeded that obtained with conventional mobile analog film-screen radiographs.

Equipment Design↗
PubMed1988

The senior radiology clerkship. Disparate goals of students and faculty.

A survey of medical students taking our radiology elective over the past five years revealed that 51% were chiefly interested in learning "to read x-rays." Other motivations for taking the elective, such as learning "radiographic workups" were relatively low-priority goals. On the other hand, a survey of our staff revealed a low priority placed on teaching medical students to interpret radiographic images and a high value placed on imparting an understanding of the role of radiology in clinical diagnosis and management. This disparity between the goals of the students and teachers delineates one of the major challenges in designing a radiology curriculum for medical schools.

Clinical Clerkship↗
PubMed1988

Student analysis of imaging studies. A radiology clerkship exercise.

Senior radiology clerkships often must cope with medical students whose overly optimistic course goals are quite different from the objectives of the radiology faculty. Conference formats that satisfy both the clerks and the teachers are therefore difficult to design. We use a conference based on student assessments of radiology examinations that attracts student interest while accomplishing staff objectives. This learning session relies on student-prepared analyses of radiologic examinations. The five-year experience with this teaching method has been quite positive from the perspectives of students and the staff.

Clinical Clerkship↗
PubMed1979

Are excretory urograms necessary in evaluating women with urinary tract infection?

Of 164 excretory urograms obtained from women with a history of recurrent urinary tract infections 88 per cent were perfectly normal. Eleven (6.7 per cent) had minor, normal, anatomic variations. Nine (5.5 per cent) were considered to have positive findings but in no case a significant finding present that required surgical intervention or altered the therapeutic approach. The total cost of the studies to the patients involved was $17,930. Thus, an extremely negative cost-benefit ratio emerged. The routine use of excretory urograms as part of the evaluation of a woman with a urinary tract infection is expensive, unrewarding and has little justification.

Cost-Benefit Analysis↗
PubMed1979

Utilization of head computed tomography units: in installations with greater than two-and-a-half years' experience.

Utilization and economic data from head computed tomography (HCT) units providing more than 2 1/2 years' experience are compared with data from installations in 1976. The average unit operates 60 hr/wk, examining 63 patients. Nearly half the examinations are "double" studies, requiring about 53 minutes. The annual total technical cost is approximately $383,000. Charges have been reduced since 1976. While technical charges are lower in high-volume institutions, professional charges are higher. Usual charges and expected net revenues are above Medicare maximum allowable charges. Most units meet the national guidelines. There is considerable variation in data from individual facilities; a "typical" HCT unit cannot be defined.

Cost-Benefit Analysis↗
PubMed1979

Utilization of body computed tomography units: in installations with greater than one-and-a-half years' experience.

Utilization and economic data from body computed tomography (BCT) units with more than 1 1/2 years' experience are compared to data in 1977. The average unit operates 52 hr./wk., examining 34 patients. Head studies constitute 55% of examinations, abdominal and pelvic 38%. The total technical cost of examining 35 patients/wk. is approximately $384,000. Charges have been reduced since 1977 by approximately 5%; the average annual loss is about $77,000. Technical and professional charges are lower in high-volume institutions. Current Medicare maximum allowable charges are below BCT costs and charges. Only 17% of installations meet the National Guidelines of 2,500 patient examinations per year.

Cost-Benefit Analysis↗
PubMed1979

Oat cell carcinoma manifesting as a bronchocele.

Three cases of oat cell carcinoma appearing as a bronchocele on the chest radiograph are described. A bronchocele as the major radiologic manifestation of oat cell carcinoma has not been emphasized previously. Such a bronchocele may be filled with neoplastic cells rather than only inspissated mucus. Needle aspiration biopsy was definitive in two of the cases when conventional diagnostic methods failed.

Aged↗
PubMed1978

Computed tomography of the thorax.

Computed tomography (CT) provides a valuable new perspective in assessing abnormalities of the thorax. In the patient with a mediastinal mass or widening detected by plain chest radiography, a definitive diagnosis is sometimes possible which would not be obtainable by conventional noninvasive radiological techniques. In certain clinical situations, CT is a highly sensitive modality for examining the lungs. The proved and potential clinical uses of CT in solving diagnostic problems of the thorax are discussed.

Adult↗
PubMed1978

Complementary use of ultrasound and computed tomography in studies of the pancreas and kidney.

113 cases of pancreatic and renal disease studied by both ultrasound and computed tomography (CT) were analyzed retrospectively. CT provided a diagnosis when pancreatic ultrasound was unsuccessful due to overlying bowel gas or obesity and when renal ultrasound was unsuccessful due to obesity, reverberations from ribs, small lesions, or multiple lesions. Conversely, ultrasound provided a diagnosis when CT was unsuccessful due to lack of fat planes or respiratory motion. CT usualy distinguished carcinoma from pancreatitis when ultrasound showed a focal echogenic mass. CT resolved renal cyst from neoplasm when ultrasound showed a mixed echo pattern mass.

Diagnosis, Differential↗