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Biomedical subjects

E A Krupinski

Publications and source records attributed to E A Krupinski.

At least 19 recordsLinked to original sources
PubMed2000

Emergency department coverage by academic departments of radiology.

RATIONALE AND OBJECTIVES: The purpose of this study was to survey academic radiology departments to determine how emergency radiology coverage is handled and whether there are any prerequisites for those individuals providing this coverage. MATERIALS AND METHODS: The authors developed a simple two-page survey and sent it to a total of 608 program directors, chiefs of diagnostic radiology, chairpersons, and chief residents at academic departments of radiology. RESULTS: Of the 608 surveys sent, 278 (46%) were returned. More than half of the departments have an emergency radiology section that provides "wet read" coverage during the day, and most academic departments cover the emergency department during the night and on weekends. Nighttime and weekend coverage is handled mostly by residents. Most departments give time off for lunch, with few other prerequisites for faculty who provide emergency coverage. Sixty percent of the departments have teleradiology capability, and many use it for emergency department coverage. CONCLUSION: These results can serve as the basis for discussion and comparison with other institutions regarding a variety of aspects of emergency department coverage.

Data Collection↗
PubMed2000

The influence of a perceptually linearized display on observer performance and visual search.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine whether perceptual linearization of the tone scale affects the detection and visual search behaviors of radiologists searching mammograms for masses and microcalcifications. A perceptually linearized display is designed to match the capabilities of the human visual system more closely than a nonlinearized display. MATERIALS AND METHODS: Six radiologists viewed 50 pairs of mammograms, once on a perceptually linearized cathode-ray tube (CRT) monitor and once on a non-linearized CRT monitor. Eye position also was recorded as the observers searched the images for masses and microcalcifications. RESULTS: Observer performance was significantly (P = .003) better with the perceptually linearized display. Dwell times associated with true-negative decisions were significantly longer with use of the nonlinearized display. The number of fixation clusters generated during search was also greater with use of the nonlinearized display for the lesion-free images. CONCLUSION: A perceptually linearized display yields better detection performance and a more efficient visual search. Perceptually linearized displays should be used for reading radiographs displayed on CRT monitors.

Breast Neoplasms↗
PubMed1999

Patterns of use and satisfaction with a university-based teleradiology system.

The Radiology Department at the University of Arizona has been operating a teleradiology program for almost 2 years. The goal of this project was to characterize the types of cases reviewed, to assess radiologists' satisfaction with the program, and to examine case turnaround times. On average, about 50 teleradiology cases are interpreted each month. Computed tomography (CT) cases are the most common type of case, constituting 65% of the total case volume. Average turnaround time (to generate a "wet read" once a case is received) is about 1.3 hours. Image quality was rated as generally good to excellent, and the user interface as generally good. Radiologists' confidence in their diagnostic decisions is about the same as reading films in the clinical environment. The most common reason for not being able to read teleradiology images is poor image quality, followed by lack of clinical history and not enough images.

Arizona↗
PubMed1998

Influence of image processing on chest radiograph interpretation and decision changes.

RATIONALE AND OBJECTIVES: The authors investigate the effect of image processing on diagnostic performance in the reading of computed chest radiographs. MATERIALS AND METHODS: Six radiologists read 168 chest images with and without the use of image processing. Diagnostic performance was measured by means of receiver operating characteristic analysis, and changes made in diagnostic decisions with the use of image processing were evaluated. RESULTS: There were no statistically significant differences between reader performance with image processing and reader performance without image processing (P < .05). Readers' decisions were just as likely to change from false-negative to true-positive as from true-positive to false-negative with the use of image processing. More decisions changed from true-negative to false-positive than from false-positive to true-negative with processing, CONCLUSION: The effect of image processing does not greatly influence diagnostic performance in chest radiography.

Attitude of Health Personnel↗
PubMed1998

Perceptual skill, radiology expertise, and visual test performance with NINA and WALDO.

RATIONALE AND OBJECTIVES: The goal of this study was to determine if radiologists possess superior visual search and analysis skills compared with those of laypeople. MATERIALS AND METHODS: In two experiments, radiologists and laypeople searched one of two complex pictorial scenes for hidden targets. Eye position was recorded during the search. Two measures of performance were obtained: accuracy of detecting targets as measured by using alternative free response receiver operating characteristic analysis and visual search efficiency as measured by using eye position analysis. RESULTS: There were no statistically significant differences in detection performance between radiologists and laypeople for either of the search tasks. Radiologists took longer on average to search the images and to first fixate on the targets than did the laypeople. For both groups, true-positive and false-positive decisions were associated with longer dwell times than true-negative decisions. As with radiology search tasks, false-negative decisions were also associated with longer dwell times than true-negative decisions. CONCLUSION: Performance on two visual search and detection tasks indicate that radiologists do not possess superior visual skills compared with laypeople. Radiology expertise is more likely to be a combination of specific visual and cognitive skills derived from medical training and experience in detecting and determining the diagnostic importance of radiographic findings.

Clinical Competence↗
PubMed1997

Dynamic-robotic telepathology: Department of Veterans Affairs feasibility study.

In this retrospective study, we assess the accuracy, confidence levels, and viewing times of two generalist pathologists using both dynamic-robotic telepathology and conventional light microscopy (LM) to render diagnoses on a test set of 100 consecutive routine surgical pathology cases. The objective is to determine whether telepathology will allow a pathology group practice at a diagnostic hub to provide routine diagnostic services to a remote hospital without an on-site pathologist. For TP, glass slides were placed on the motorized stage of the robotic microscope of a telepathology system by a senior laboratory technologist in Iron Mountain, MI. Real-time control of the motorized microscope was then transferred to a pathologist in Milwaukee, WI, who viewed images of the glass slides on a video monitor. The telepathologists deferred rendering a diagnosis in 1.5% of cases. Clinically important concordance between the individual diagnoses rendered by telepathology and the "truth" diagnoses established by rereview of glass slides was 98.5%. In the telepathology mode, there were five incorrect diagnoses out of a total of 197 diagnoses. In four cases in which the telepathology diagnosis was incorrect, the pathologist's diagnosis by LM was identical to that rendered by telepathology. These represent errors of interpretation and cannot be ascribed to telepathology. The certainty of the pathologists with respect to their diagnoses was evaluated over time. Results for the first 50 cases served as baseline data. For the second 50 cases, confidence in rendering a diagnosis in the telepathology mode was essentially identical to that of making a diagnosis in the LM viewing mode. Viewing times in the telepathology mode also improved with more experience using the telepathology system. These results support the concept that an off-site pathologist using dynamic-robotic telepathology can substitute for an on-site pathologist as a service provider.

Feasibility Studies↗
PubMed1997

Diagnostic accuracy of an international static-imaging telepathology consultation service.

Static-image and dynamic- (real-time) image telepathology are competing technologies. Although some studies suggest that the diagnostic accuracy of the dynamic-image telepathology approaches the accuracy of light microscopy, few reports have documented the diagnostic accuracy of static-image telepathology as used in the setting of an actual surgical pathology consultation practice. We report the results of an analysis of 171 telepathology consultation cases submitted to the Arizona-International Telemedicine Network (AITN). Digital images were submitted by pathologists from six participating institutions in Arizona, Mexico, and China. Telepathologists could render a telepathology diagnosis (TP) or defer rendering a diagnosis to obtain additional video images, glass slides for detailed analysis, or to obtain tissue blocks for special studies such as immunohistochemistry. The telepathologists rendered diagnoses for 144 cases and deferred 27 cases. Two pathologists retrospectively evaluated-glass slides from each case and rendered a consensus glass slide (GS) "truth" diagnosis. There was 88.2% concordance between TP and GS diagnoses (127 of 144 diagnoses). Concordance of 96.5% was achieved for clinically important diagnoses (139 of 144 diagnoses). Telepathologists deferred making a diagnosis to obtain glass slides for conventional light microscopy in 14 cases (8.1%) and for results of immunohistochemistry studies in 13 cases (7.6%). Thus, correct diagnoses were rendered by static-image telepathology in 127 of 171 cases (74.3%) at the time of telepathology diagnostic sessions. Inappropriate field selection and sampling biases of referring pathologists, as well as a tendency of static-image telepathologists to underestimate the complexity of some cases, may reduce the value of consultations based on the viewing of static images.

Humans↗
PubMed1997

Differences in time to interpretation for evaluation of bone radiographs with monitor and film viewing.

RATIONALE AND OBJECTIVES: The authors evaluated how observers search hard-copy versus soft-copy images to determine why viewing times are longer for images displayed on a monitor. METHODS: Twenty-seven nonconsecutive bone-trauma computed radiographs were collected from the routine emergency practice. Eye positions of three bone radiologists and three orthopedic surgeons were recorded as they searched images on a view box and digital images at a workstation. RESULTS: Overall viewing time was longer for images displayed on a monitor. Time to first fixate a lesion and true-negative dwell times were significantly longer with the monitor than with the film. Absolute numbers of clusters and dwell times were greater for diagnostic image areas on the monitor than on the film. Twenty percent of the clusters for images viewed on the monitor were on the image-processing menu. CONCLUSION: The amount and type of information that is processed during search is different when images are viewed on a monitor rather than on film.

Bone and Bones↗
PubMed1997

Reduction of patient exposure in pediatric radiology.

RATIONALE AND OBJECTIVES: The authors determined whether presently used exposure levels in pediatric imaging can be reduced without loss of information or a decrease in diagnostic accuracy. MATERIALS AND METHODS: Multiple (stacked) image detectors and filters were used to obtain identical compute radiographic images at different exposure levels of neonates with either no active lung disease or hyaline membrane disease. Physical characteristics of the images were measured. A contrast-detail study and a receiver operating characteristic study were conducted to measure observer performance. RESULTS: Physical measurements and results of the contrast-detail study revealed that the dose-reduction images were essentially limited by x-ray quantum noise. Results of the receiver operating characteristic study indicated that diagnostic accuracy did not decrease significantly up to about 75% exposure reduction levels, although image quality rating data decreased with each exposure reduction. CONCLUSION: Decreasing exposure levels to about 75% of current levels may be acceptable in some clinical situations where dose is a concern, such as in pediatric imaging.

Diagnostic Errors↗
PubMed1997

Comparison of conventional and computed radiography: assessment of image quality and reader performance in skeletal extremity trauma.

RATIONALE AND OBJECTIVES: Reader performance and image quality wee assessed for standard film, computed film, and computer monitor radiography viewing formats in the evaluation of skeletal extremity trauma. MATERIALS AND METHODS: Three radiologists and three orthopedic surgeons interpreted 27 skeletal radiographs obtained with equivalent technical parameters. Readers evaluated standard film, computed film, and computer monitor formats randomly for fracture and soft-tissue abnormalities. Sessions were videotaped, and eye motion was recorded. RESULTS: No statistically significant differences were found between image formats for true-positive or false-positive findings of trauma indicators. Findings were classified as false-negative based on eye position fixation times. Search errors (lesion not fixated) accounted for 21.7%, 20.6% and 17.1% of false-negative errors with the computer monitor, computed film, and standard film formats, respectively. Combined recognition errors and decision errors were 78.3%, 79.4%, and 82.9%, respectively. Viewing times were longest for the computer monitor images (P < .001). Image quality, contrast, and sharpness were rated highest for computed radiographs (P = .001). Radiologists had a higher true-positive decision rate than orthopedic surgeons (P = .03). CONCLUSION: No statistically significant differences were seen in reader performance among viewing formats. The computed film format received the highest quality rating, and workstation viewing times were longest.

Adolescent↗
PubMed1997

Comparison of eye position versus computer identified microcalcification clusters on mammograms.

The purpose of this study was to compare identifications of microcalcification clusters on mammograms by a computerized detection scheme and by human observers having their eye position recorded. Eighty digitized mammograms (half with a subtle microcalcification cluster) were analyzed by a computerized detection scheme and then were read from laser-printed films by six mammographers while eye position was recorded. The computer had 83% true positives with a false-positive rate of 0.5 per image. The true positives of the radiologists ranged from 78% to 90%, with false-positive rates ranging from 0.03 to 0.20. Locations of true and false positives identified by computer and by the human were compared. All but 5% of the true clusters were identified by either the computer, human, or by both. Here 10% of the clusters were detected by only the computer, and 11% were missed by the computer but detected by at least one radiologist. False positives were of three types: identified by computer only, by the human reader only, or by both. Eye-position data indicated significant differences in dwell time between both true-positive and false-positive locations reported by the radiologist versus the computer detections. A follow-up analysis indicated that microcalcification clusters and false positives were judged to have more identifiable characteristics of true calcifications and were associated with longer gaze durations than those with fewer microcalcification characteristics. In general, the computer was able to detect clusters judged to have few or no features that the radiologists were not able to detect. Comparison of computer versus human identification of microcalcification clusters may be useful for improving computerized detection schemes to serve as clinical aids to mammographers, and for understanding what image features lead to false-positive decisions for both the computer and the human reader.

Breast Diseases↗
PubMed1997

Ultrasonographic detection of testicular ischemia in a canine model using phospholipid coated microbubbles (MRX-115).

The purpose of this study was to determine if the sonographic contrast agent MRX-115 could improve the accuracy of Doppler ultrasonographic diagnosis of testicular ischemia. Testicular duplex ultrasonography was performed on six dogs before and after surgical ligation of the testicular artery, and before and after intravenous injection of MRX-115. Six radiologists blinded to experimental conditions rated the testicular blood flow. Receiver operating characteristics curves for conditions with and without administration of contrast agent were compared using Student's t-test for paired observations. Statistically significant differences were found both for the tests viewed individually (P = 0.003) and for the testes in comparison to the contralateral side (P = 0.0001). MRX-115 therefore is found to improve duplex sonographic evaluation of testicular ischemia.

Analysis of Variance↗
PubMed1996

Visual scanning patterns of radiologists searching mammograms.

RATIONALE AND OBJECTIVES: I examined whether the principles of search, detection, and decision making described for pulmonary nodule detection can be applied to lesion detection in mammographic images. METHODS: The eye position of six radiologists (three staff mammographers and three radiology residents) was recorded as they searched mammograms for masses and microcalcifications. RESULTS: True- and false-positive decisions were associated with prolonged gaze durations; false-negative decisions were associated with longer gaze durations than true-negatives. Readers with more experience tended to detect lesions earlier in the search than did readers with less experience, but those with less experience tended to spend more time overall searching the images and cover more image area than did those with more experience. CONCLUSION: Gaze duration is a useful predictor of missed lesions in mammography, making gaze duration a potential tool for perceptual feedback. Mammographic search for readers with different degrees of experience can be characterized by gaze durations, scan paths, and detection times.

Breast Neoplasms↗
PubMed1996

Cause of satisfaction of search effects in contrast studies of the abdomen.

RATIONALE AND OBJECTIVES: Extraintestinal abnormalities visible without contrast material on abdominal radiographs are reported less frequently when contrast examinations are performed. Gaze dwell time was used to determine whether this difference is due to failure by observers to scan plain-film regions of contrast studies or discounting of plain-film abnormalities that were actually scanned. METHODS: Patients were included whose contrast studies had elicited the largest reductions in positive responses compared with their plain-film studies in a previous detection experiment. Gaze of 10 radiologists was studied. RESULTS: Significantly less time was spent gazing at non-contrast regions of contrast examinations than at the corresponding regions of radiographs. Errors with radiographs were based primarily on failures of recognition and decision making, whereas errors with contrast studies were based primarily on faulty scanning. CONCLUSION: Satisfaction of search errors on contrast examinations are caused by reduction in scanning of noncontrast regions.

Contrast Media↗