Blind spots on CT imaging of the head: Insights from 5 years of report addenda at a single institution

Abstract

Background: Errors of detection ("misses") are the major source of error in radiology. There is sparse prior literature describing patterns of detection error on CT head imaging.

Purpose: The objective of this study was to gain insight to areas on CT head imaging where radiologists are most likely to miss clinically relevant findings.

Methods: We performed a cross-sectional study of consecutive reports of CT imaging of the head at a single institution spanning 5/1/2013-5/1/2018 (5 years). Detection errors described in addenda were categorized according to anatomic location, type of pathology, and potential impact on management. Blind spots were defined by the most common sites of missed findings.

Results: A total of 165,943 reports for CT head imaging were obtained. Addenda were found in 1658 (~1%) of reports, of which 359 (21.7%) described errors of detection. Within the extracranial soft tissues (n = 73) the most common "misses" were at incidentally imaged parotid glands and the frontal scalp. Within osseous structures (n = 149), blind spots included the nasal and occipital bones. Vascular lesions (n = 47) which passed detection were most common at the distal MCA, carotid terminus and sigmoid sinus/jugular bulb. No predisposition was seen for anatomic subsites within the CSF space (n = 60) and brain parenchyma (n = 65).

Conclusions: Consistent patterns of blind spots are revealed. Radiologic teaching and search patterns to account for these sites of error may accelerate trainee competence and improve accuracy in the practice of radiology.

Keywords: Blind spots; Brain; CT; Error; Head; Misses.