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Biomedical subjects

Jill L King

Publications and source records attributed to Jill L King.

6 recordsLinked to original sources
PubMed2007

The prevalence effect in a laboratory environment: Changing the confidence ratings.

RATIONALE AND OBJECTIVES: We sought to assess whether or not prevalence levels affected the confidence ratings of readers during the interpretation of cases in a laboratory receiver operating characteristic-type observer performance study. MATERIALS AND METHODS: We reanalyzed a previously conducted observer performance study that included 14 readers and 5 different levels of prevalence. The previous study yielded the observation that in the laboratory we could not detect a "prevalence effect" in terms of differences in areas under the receiver operating characteristic curves. The detection ratings (for presence or absence) of lung nodules, interstitial disease, and pneumothorax for the five prevalence levels were compared, and a test for trend in averaged ratings as a function of abnormality prevalence was performed within a mixed-model setting that accounts for different sources of variability and correlations induced by the study design. RESULTS: The ratings of the cases in terms of confidence that the specific abnormality in question is present tend, on average, to be larger when actual disease prevalence is lower. The rate of the increase of the average confidence ratings with the decreasing prevalence of a specific abnormality is very similar for actually positive and actually negative cases for every considered abnormality. The observed trend in the changes of the average confidence ratings as a function of prevalence levels was statistically significant (p < 0.01). CONCLUSION: Expectations of disease prevalence in the case mix during a laboratory observer performance study may systematically affect the behavior of observers in terms of their actual confidence ratings.

Humans↗
PubMed2006

The effect of image display size on observer performance an assessment of variance components.

RATIONALE AND OBJECTIVE: Our goal was to investigate the effect of the displayed image size on variance components during the performance of an observer performance study to detect masses on abdominal computed tomography (CT) examinations. MATERIALS AND METHODS: A previously performed receiver operating characteristic (ROC) study with eight observers to detect abdominal masses on 166 CT examinations was reanalyzed to assess variance components when comparing two similar modes with displayed image sizes varying by a factor of 2. Case, mode, and reader-related variance components were estimated for the group of eight observers and subsets of readers after excluding each of the participants. RESULTS: There was no significant difference in the average area under the ROC curves between the two modes using the two image sizes (P > .05). Reader and reader-by-case variability were substantially larger for the mode displaying enlarged images for the group and all subsets formed by excluding a single reader. Reader variability was affected by one observer who actually performed better with the enlarged images. CONCLUSION: Sequential viewing of enlarged CT images for the detection of abdominal masses did not improve performance and increased reader variability.

Abdominal Neoplasms↗
PubMed2006

Screening mammography: do women prefer a higher recall rate given the possibility of earlier detection of cancer?

PURPOSE: To prospectively survey women undergoing screening mammography to assess their attitudes toward and preference for the level of recall rates given the possibility that an increase in recall rates may result in earlier detection of cancer. MATERIALS AND METHODS: This HIPAA-compliant survey was performed with an institutional review board-approved protocol. Women who arrived for their routine screening mammographic examination from November 2004 to March 2005 were informed before they consented to participate. The distribution of responses for each survey question was summarized, and proportions for the entire group and different subgroups were computed. The z score statistic was used to assess significant differences between subgroups. RESULTS: Fifteen hundred seventy anonymized questionnaires were collected; 1171 (75%) were from women between 40 and 59 years of age. Of 1528 respondents, 1486 (97%) believed that a false-positive result would not deter them from continuing with regular screening, and most would have been willing to be recalled more often for either a noninvasive (86% [1308 of 1519 respondents]) or an invasive (82% [1248 of 1515 respondents]) procedure if it might increase the chance of detecting a cancer (if present) earlier. Compared with respondents undergoing their initial screening mammographic examination, women who had undergone at least one prior screening examination reported that they were more likely to continue with screening if they had received a previous false-positive result (P = .02). Women younger than 60 years and those previously recalled were more willing to be called back more often for a noninvasive or, when indicated, an invasive procedure (P < .05). CONCLUSION: A substantial fraction of women in this study would have preferred the inconvenience of and anxiety associated with a higher recall rate if it resulted in the possibility of detecting breast cancer earlier.

Adult↗
PubMed2005

Variability in observer performance studies experimental observations.

RATIONALE AND OBJECTIVES: The aim of the study is to assess variance components in observer performance studies and the possible impact on study results and conclusions. MATERIALS AND METHODS: Two previously performed retrospective receiver operating characteristic-type observer performance studies to evaluate the performance of seven radiologists in detecting interstitial disease on conventional posteroanterior chest films and nine radiologists in detecting interstitial disease on a high-resolution workstation were reanalyzed by using the Beiden, Wagner, and Campbell nine-component model to estimate the different variance components. We estimated case-, reader-, and mode-related components of the variance for the group as a whole and after excluding (round robin) each reader. Overall variance was evaluated, and the effect of individual readers on overall study conclusions was assessed. RESULTS: Overall results and conclusions of the reanalysis agreed with the original one in that, as a group, radiologists performed significantly better when using conventional films (P < .05) in both studies. Reader variability was large compared with all other components, and in one study, it was substantially larger for the workstation reading mode. Reader variability was affected substantially by one observer in each study, and in one study, reader-by-mode variability was affected by another reader who performed better on the workstation. CONCLUSION: Estimates of variance components can shed light on the appropriateness of study design, as well as the sensitivity of results to the inclusion (or exclusion) of individual observers.

Humans↗
PubMed2003

Prescreening mammography by technologists: a preliminary assessment.

OBJECTIVE: We assessed the ability of technologists to accurately classify screening mammograms as either showing negative findings or requiring follow-up. SUBJECTS AND METHODS: In a prospective study, 33 technologists at a central facility and five satellite breast imaging facilities recorded whether mammograms obtained during 3019 examinations showed negative findings or findings that indicated that additional procedures were required. The technologists were not specifically trained for the experiment. The technologists' interpretations were compared with radiologists' interpretations. RESULTS: Technologists and radiologists agreed in 82% of the cases (77% negative findings and 5% requiring follow-up). Of the 175 cases recommended for follow-up by only the radiologists, 17 were ultimately biopsied and two were found to be malignant. CONCLUSION: Even without undergoing additional training, technologists can perform at reasonable levels of accuracy in classifying screening mammograms. The possibility of using technologists to group cases after the technologists have undergone training is an interesting concept that should be explored further.

Allied Health Personnel↗