{'fraction_non_alphanumeric': 0.02626892252894034, 'fraction_numerical': 0.014692787177203919, 'mean_word_length': 5.056603773584905, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Common sites and etiologies of residents' misinterpretation of head CT scans in the emergency department of a level I trauma center.

BACKGROUND
Misinterpretation of head computerized tomographic (CT) scans by radiology residents in the emergency department (ED) can result in delayed and even erroneous radiology diagnoses. Better knowledge of pitfalls and environmental factors may decrease the occurrence of these errors.


OBJECTIVES
To evaluate common misinterpretations of head CT scans by radiology residents in a level I trauma center ED.


METHODS
We studied 955 head CT scans of patients admitted to our ED from January 2010 to May 2011. They were reviewed separately by two senior neuroradiologists and graded as being unimportant (score of 1), important but not requiring emergent treatment (score of 2), and important requiring urgent treatment (score of 3). We recorded the time of day the examination was performed, the year of residency, the site, subsite and side of the lesion, the pathology, the anatomical mistake, false-positive findings, and the attending neuroradiologists' score.


RESULTS
A total of 955 examinations were interpreted of which 398 had misinterpreted findings that were entered into the database, with the possibility of multiple errors per examination. The overall misinterpretation rate was 41%. The most commonly missed pathologies were chronic infarcts, hypodense lesions, and mucosal thickening in the paranasal sinuses. The most common sites for misdiagnosis were brain lobes, sinuses and deep brain structures. The highest percentage of misinterpretation occurred between 2.30 p.m. and 8 p.m. and the lowest between midnight and 8 a.m. (P < 0.05). The overall percentage of errors involving pathologies with a score of 3 by at least one of the neuroradiologists was 4.7%. Third-year residents had an overall higher error rate and first-year residents had significantly more false-positive misinterpretations compared to the other residents.


CONCLUSIONS
The percentage of errors made by our residents in cases that required urgent treatment was comparable to the published data. We believe that the intense workload of radiology residents contributes to their misinterpretation of head CT findings.