Fig. 6

Under-reading (type 4) error with inattentional bias (Gorilla effect). A female patient was admitted to the emergency department with bilateral hip pain after falling down stairs. X-ray and pelvic CT were interpreted as “normal” by the on-call radiologist. However, shortening of the right femoral neck (red arrow, a) and a hyperdense line due to impacted fracture (red arrows, b, c) were missed. After retrospective detection of fracture, the radiologist was asked about the cause of missing these findings. He stated that he did not expect to see a hyperdense impaction fracture at all while evaluating that particular case. The prejudice of “fractures are seen as hypodense lines” caused inattentional blindness. A hyperdense fracture line is an uncommon finding, and due to its unexpected nature, may result in an under-reading error