Purpose: To measure diagnostic accuracy of fracture detection, visual accommodation, reading time, and subjective ratings of fatigue and visual strain before and after a day of clinical reading. Methods:Forty attending radiologists and radiology residents viewed 60 de-identified HIPAA compliant bone examinations, half with fractures, once before any clinical reading (Early) and once after a day of clinical reading (Late). Reading time was recorded. Visual accommodation (ability to maintain focus) was measured before and after each reading session. Subjective ratings of symptoms of fatigue and oculomotor strain were collected. The study was approved by local IRBs.Results: Diagnostic accuracy was reduced significantly after a day of clinical reading, with average receiver operating characteristic (ROC) area under the curve (AUC) of 0.885 for Early reading and 0.852 for Late reading (p < 0.05). After a day of image interpretation, visual accommodation was no more variable, though error in visual accommodation was greater (p < 0.01) and subjective ratings of fatigue were higher. Conclusions:After a day of clinical reading, radiologists have reduced ability to focus, increased symptoms of fatigue and oculomotor strain, and reduced ability to detect fractures. Radiologists need to be aware of the effects of fatigue on diagnostic accuracy and take steps to mitigate these effects.

There are several different statistical methods for analysing multireader ROC studies, with the Dorfman-Berbaum-Metz (DBM) method being the most frequently used. Another method is the corrected F method proposed by Obuchowski and Rockette (OR). The DBM and OR procedures at first appear quite different: DBM is a three-way ANOVA analysis of pseudovalues while OR is a two-way ANOVA analysis of accuracy estimates with correlated errors. We show that the original DBM and OR F statistics for testing the null hypothesis of equal treatments have the same form and will typically have similar values; however, differences in the denominator degrees of freedom will result in differences in p-values even when the F statistics are identical. We show how the methods can be generalized to include variations in the accuracy measure, covariance method, and degrees of freedom. Identical results are obtained when the methods agree with respect to all three of these procedure parameters; hence for a particular choice of procedure parameters the choice of method appears to depend mainly on software preference and availability. The methods are compared using data from a factorial study with two modalities, five readers, and 114 patients.

Purpose A previous study demonstrated decreased diagnostic accuracy for finding fractures and decreased ability to focus on skeletal radiographs after a long working day. Skeletal radiographic examinations commonly have images that are displayed statically. This study investigated whether diagnostic accuracy for detecting pulmonary nodules in computed tomography (CT) of the chest displayed dynamically would be similarly affected by fatigue. Methods Twenty-two radiologists and 22 residents were given two tests searching CT chest sequences for a solitary pulmonary nodule before and after a day of clinical reading. To measure search time, ten lung CT sequences, each containing 20 consecutive sections and a single nodule, were inspected using free search and navigation. To measure diagnostic accuracy, one hundred CT sequences, each with 20 sections and half with nodules, were displayed at preset scrolling speed and duration. Accuracy was measured using ROC analysis. Visual strain was measured via dark vergence, an indicator of the ability to keep the eyes focused on the display. Results Diagnostic accuracy was reduced after a day of clinical reading (p = 0.0246), but search time was not affected (p > 0.05). After a day of reading, dark vergence was significantly larger and more variable (p = 0.0098), reflecting higher levels of visual strain and subjective ratings of fatigue were also higher. Conclusions After their usual workday, radiologists experience increased fatigue and decreased diagnostic accuracy for detecting pulmonary nodules on CT. Effects of fatigue may be mitigated by active interaction with the display.

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Purpose-Satisfaction of search (SOS) occurs when an abnormality is missed because another abnormality has been detected. This research studied whether the severity of a detected fracture determines whether subsequent fractures are overlooked.Materials and Methods-Each of seventy simulated multi-trauma patients presented examinations of three anatomic areas. Readers evaluated each patient under two experimental conditions: when the images of the first anatomic area included a fracture (the SOS condition), and when it did not (the control condition). The SOS effect was measured on detection accuracy for subtle test fractures presented on examinations of the second and third anatomic areas. In an experiment with twelve radiology readers, the initial SOS radiographs showed non-displaced fractures of extremities, fractures associated with low morbidity. In another experiment with twelve different radiology readers, the initial examination, usually a CT, showed cervical and pelvic fractures of the type associated with high morbidity. Because of their more direct role in patient care, the experiment using high morbidity SOS fractures was repeated with seventeen orthopedic readers.Results-Detection of subtle test fractures was substantially reduced when fractures of low morbidity were added (p<0.01). No similar SOS effect was observed in either experiment in which added fractures were associated with high morbidity. Conclusion-The satisfaction of search effect in skeletal radiology was replicated, essentially doubling the evidence for SOS in musculoskeletal radiology, and providing an essential contrast to the absence of SOS from high morbidity fractures.

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Rationale and Objectives We tested whether satisfaction of search (SOS) effects occur in computed tomography (CT) examination of the chest on detection of native abnormalities is produced by the addition of simulated pulmonary nodules. Materials and Methods Two experiments were conducted. In the first experiment, seventy CT examinations, half that demonstrated diverse, subtle abnormalities and half that demonstrated no native lesions, were read by 18 radiology residents and fellows under two experimental conditions: presented with and without pulmonary nodules. In a second experiment, many of the examinations were replaced to include more salient native abnormalities. This set was read by 14 additional radiology residents and fellows. In both experiments, detection of the naturally abnormalities was studied. ROC curve areas for each reader-treatment combination were estimated using empirical and proper ROC models. Additional analyses focused on decision thresholds and visual search time on abnormality-free CT slice ranges. Institutional review board approval and informed consent from 32 participants were obtained. Results Observers more often missed diverse native abnormalities when pulmonary nodules were added but also made fewer false positive responses. There was no change in ROC area, but decision criteria grew more conservative. The SOS effect on decision thresholds was accompanied by a reduction in search time on abnormality-free CT slice ranges. Conclusion The SOS effect in CT examination of the chest is similar to that found in contrast examination of the abdomen, involving induced visual neglect.