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CT head interpretation by staff in the Emergency Department

Three Part Question

In [interpretation of CT head for trauma and non-trauma] are [staff in the Emergency Department] able to [interpret results accurately and safely]?

Clinical Scenario

A 21-year old man attends the emergency department after a night out. He is intoxicated and has an occipital head injury. He apparently lost consciousness for 10 minutes and has vomited 4 times since arriving in the department. You decide to request a CT scan of his head. Local guidelines allow you to interpret this yourself. You wonder how robust this is compared to the old system of requesting the scan through the radiologist on call

Search Strategy

Medline 1966-2008 using the OVID interface.
[cranial computed tomography or CT head] AND [emergency]
LIMIT to human and English
Search repeated in EMBASE, CINAHL and Google Scholar

Search Outcome

191 papers were found of which 5 were relevant. Search of references revealed another 3 papers

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Mucci, Brett, Huntley, Greene
100 consecutive CT head scans requested by Emergency Department and reviewed by senior Emergency Department staffRetrospective case series. Single centreConcordance between ED report and consensus opinion of 2 radiologists86.6% agreement. No findings missed that would change the overnight management of patientSmall study. Scans not anonymised
Peron, Huff, Ullrich
83 Emergency Medicine residents at 5 institutionsProspective multi-centre studyParticipants underwent exam of 12 CT scans. Then 2 hour course. Re-examined 3 months later. Comparison of pre and post test scoresMean score in initial test was 60%. Retest 3 months later had mean score of 78% (p<.001 paired t test)Only 63 residents completed post test so may be selection bias
Mehta, Mills, Jones
212 emergency cranial CTs over 5 months reported by senior ED doctorsProspective single centre cohort studyConcordance between reports by senior ED staff and consultant neuroradiologist and between radiology residents and consultant neuroradiologistConcordance between radiology residents and neuroradiologist was significantly higher (93.9%) than between ED staff and neuroradiologist (78.3%). 6.6% of discordant ED reports could have had adverse clinical outcomeAbstract only
Alfaro, Levitt, English
555 patients undergoing CT scanning in ED for trauma and non-trauma. Scans reported by 14 ED staff and result compared with radiology reportProspective single centre cohort studyConcordance between ED report and radiology reportNon-concordance rate 38.7% between radiology and emergency physician reports. Clinically significant misinterpretations found in 24.1% of scansNot blinded. Some of the scans reviewed retrospectively by ED
Arendts, Manovel, Chai
1282 patients undergoing non-contrast CT head for trauma and non-trauma. Reported by senior ED staffProspecive blinded cohort studyConcordance between ED and consultant radiology report190 scans (14.8%) were misinterpreted. 78 (6%) of these had potential or actual consequences. No significant difference with varying level of experience or qualification of ED doctor reporting scanSample selection bias - 43.3% of scans could not be included as reported by radiology before ED, these included a high proportion of abnormal scans
Khoo, Duffy
315 consecutive out of hours scans reported by 7 Emergency Physicians and 14 registrarsRetrospective single centre studyConcordance between ED and consultant radiology report67% agreement. 63 false positives24 films excluded as lost
Levitt, Dawkins, Williams, Bullock
324 scans reported by 14 Emergency medicine residents. Phase I (217 scans) then 1 hour educational session then phase II (89 scans) 10 days laterProspective single centre interventional studyAccuracy rate of reporting compared pre and post testConcordance rate between ED and radiology report improved significantly from 61.3% pre-test to 88.6% post-test. Major missed findings decreased from 11.4% to 2.8% (p<.0001). No clinically significant mismanagementSingle radiology opinion
Perron, Kline, Carolinas
30 Emergency Medicine residents tested on interpretation of 10 CT scans. Then 2-hour educational session. Retested after 3 monthsProspective cohort studyComparison of pre and post test scoresPre test mean score 7, post test score 8. Scores significantly improved between pre and post testsVery small numbers. Only 18 completed post test - selection bias?


The non-concordance rate between emergency physician and radiologist reporting varies between 14 and 33% in these studies. 3 studies showed a significant number of misinterpretations which could have had adverse clinical consequences. It is unclear from the above studies what level of accuracy is needed for safe clinical practice and whether this is different between scans for trauma and non-trauma. 3 studies have shown that a single intervention with a teaching session on CT interpretation leads to a significant improvement in recognition of scans. Currently, in the South West region, Emergency Medicine trainees receive an educational session on CT head in trauma with a senior Consultant Neuro-radiologist as part of their training. There was no significant correlation between level of experience and qualifications of the reporting emergency doctor and misinterpretation rates. One study showed a significantly higher rate of discordance for abnormal scans (27% compared to 5.7% for normal scans) and postulates that the higher the number of normal scans included in a study, the better the ED reporting performance is likely to appear.

Clinical Bottom Line

Reporting performance for CT heads by Emergency Physicians is varied but is shown to improve significantly with a short educational intervention.


  1. Mucci B, Brett C, Huntly LS, Greene MK Cranial computed tomography in trauma: The accuracy of interpretation by staff in the Emergency Department Emergency Medicine Journal 2005; 538-540
  2. Peron AD, Huff JS, Ullrich CG et al A multi-centre study to improve emergency medicine residents' recognition of intracranial emergencies on computed tomography Annals of Emergency Medicine 1998; 32 (5) 554-562
  3. Mehta A, Mills TD, Jones JO et al Accuracy of interpretation of emergency cranial computed tomography scans by radiology residents and the senior attending member of the requesting clinical team Radiology 2005; 221 (RSNA abstract supplement); 440
  4. Alfaro D, Levitt MA, English DK et al Accuracy of interpretation of cranial computed tomography scans in an emergency training programme Annals of Emergency Medicine 1995; 25: 167-174
  5. Arendts, Glenn; Manovel, Alvaro; Chai, Alan Cranial CT interpretation by senior emergency department staff Australasian Radiology 2003; 47, 368-374
  6. Khoo NC, Duffy M Out of hours non-contrast CT head scan interpretation by Senior Emergency Department Medical Staff Emergency Medicine Australia 2007; 19(2) 122-128
  7. Levitt MA, Dawkins R, Williams V et al Abbreviated educational sessions improve computed tomography scan interpretations by emergency physicians Annals of Emergency Medicine 1997; 30: 616-621
  8. Perron AD, Kline JA Blood Can Be Very Bad: A simple mnemonic to improve the accuracy of cranial CT interpretation by the emergency physician (abstract) Annals of Emergency Medicine 1997; 30:385