Rationale and objective Variation of visual selective attention through the day has been demonstrated in several arenas of human performance, including radiology. It is uncertain whether this variation translates to an identifiable diurnal pattern of error rates for radiology interpretation. The purpose of this study was to attempt to identify particular days of the week and times of the day when radiologists might be most prone to error. Materials and methods Abdomen/pelvis CT studies containing at least one major error were collected from a 10-year period from the quality assurance (QA) database at our institution. A major error was defined as a missed finding that had altered management in a way potentially detrimental to the patient. The identified studies were categorized by the day of the week and hour of the day that the study was interpreted. Study volume data over this same period was also obtained by day of the week and time of day, so to normalize the data based on case volume. Standard errors of the volume-adjusted error rates were obtained based on the binomial distribution. The null hypothesis of constant error rates over time was tested using a weighted logistic regression model with linear time as predictor. Results A total of 252 major errors were identified. More errors were made on Monday than on any other day of the week (n = 58). Major error rates increased through the mid to late morning (9 am to 12 pm), and then decreased progressively through the afternoon until 4 pm, when a rise in the error rate was seen. This pattern persisted when error rates were normalized by study volume within each hour. Overall tests of time-constancy of error rates by day and hour were statistically significant (both p-values < 0.001). ConclusionOur study shows that error rates in abdominal CT do seem to vary with time of day and day of the week. During the workweek, error rates were highest in the late morning and at the close of the workday, and greater on Mondays than other days.

Objectives: Radiologists reading multiplanar abdominal/pelvic computed tomography (CT) are vulnerable to oversight of specific anatomic areas, leading to perceptual errors (misses). The aims of this study are to identify common sites of major perceptual error at our institution and then to put these in context with earlier studies to produce a comprehensive overview. Material and Methods: We reviewed our quality assurance database over an 8-year period for cases of major perceptual error on CT examinations of the abdomen and pelvis. A major perceptual error was defined as a missed finding that had altered management in a way potentially detrimental to the patient. Record was made of patient age, gender, study indication, study priority (stat/routine), and use of IV and/or oral contrast. Anatomic locations were subdivided as lung bases, liver, pancreas, kidneys, spleen, mesentery, peritoneum, retroperitoneum, small bowel, colon, appendix, vasculature, body wall, and bones. Results: A total of 216 missed findings were identified in 201 patients. The most common indication for the study was cancer follow-up (71%) followed by infection (11%) and abdominal pain (6%). The most common anatomic regions of error were the liver (15%), peritoneum (10%), body wall (9%), retroperitoneum (8%), and mesentery (6%). Data from other studies were reorganized into congruent categories for comparison. Conclusion: This study demonstrates that the most common sites of significant missed findings on multiplanar abdominal/pelvic CT included the mesentery, peritoneum, body wall, bowel, vasculature, and the liver in the arterial phase. Data from other similar studies were reorganized into congruent categories to provide a comprehensive overview.