CT head interpretation by staff in the Emergency Department
Date First Published:
February 21, 2008
Last Updated:
February 21, 2008
Report by:
Helen Blackhurst, SPR Emergency Medicine (Cheltenham General Hospital)
Search checked by:
Phil Cowburn, Cheltenham General Hospital
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.
Search Details:
[cranial computed tomography or CT head] AND [emergency]
LIMIT to human and English
Search repeated in EMBASE, CINAHL and Google Scholar
LIMIT to human and English
Search repeated in EMBASE, CINAHL and Google Scholar
Outcome:
191 papers were found of which 5 were relevant. Search of references revealed another 3 papers
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Cranial computed tomography in trauma: The accuracy of interpretation by staff in the Emergency Department Mucci B, Brett C, Huntly LS, Greene MK 2005 UK | 100 consecutive CT head scans requested by Emergency Department and reviewed by senior Emergency Department staff | Retrospective case series. Single centre | Concordance between ED report and consensus opinion of 2 radiologists | 86.6% agreement. No findings missed that would change the overnight management of patient | Small study. Scans not anonymised |
| A multi-centre study to improve emergency medicine residents' recognition of intracranial emergencies on computed tomography Peron AD, Huff JS, Ullrich CG et al 1998 USA | 83 Emergency Medicine residents at 5 institutions | Prospective multi-centre study | Participants underwent exam of 12 CT scans. Then 2 hour course. Re-examined 3 months later. Comparison of pre and post test scores | Mean 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 |
| Accuracy of interpretation of emergency cranial computed tomography scans by radiology residents and the senior attending member of the requesting clinical team Mehta A, Mills TD, Jones JO et al 2005 UK | 212 emergency cranial CTs over 5 months reported by senior ED doctors | Prospective single centre cohort study | Concordance between reports by senior ED staff and consultant neuroradiologist and between radiology residents and consultant neuroradiologist | Concordance 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 outcome | Abstract only |
| Accuracy of interpretation of cranial computed tomography scans in an emergency training programme Alfaro D, Levitt MA, English DK et al 1994 USA | 555 patients undergoing CT scanning in ED for trauma and non-trauma. Scans reported by 14 ED staff and result compared with radiology report | Prospective single centre cohort study | Concordance between ED report and radiology report | Non-concordance rate 38.7% between radiology and emergency physician reports. Clinically significant misinterpretations found in 24.1% of scans | Not blinded. Some of the scans reviewed retrospectively by ED |
| Cranial CT interpretation by senior emergency department staff Arendts, Glenn; Manovel, Alvaro; Chai, Alan 2003 Australia | 1282 patients undergoing non-contrast CT head for trauma and non-trauma. Reported by senior ED staff | Prospecive blinded cohort study | Concordance between ED and consultant radiology report | 190 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 scan | Sample selection bias - 43.3% of scans could not be included as reported by radiology before ED, these included a high proportion of abnormal scans |
| Out of hours non-contrast CT head scan interpretation by Senior Emergency Department Medical Staff Khoo NC, Duffy M 2007 Australia | 315 consecutive out of hours scans reported by 7 Emergency Physicians and 14 registrars | Retrospective single centre study | Concordance between ED and consultant radiology report | 67% agreement. 63 false positives | 24 films excluded as lost |
| Abbreviated educational sessions improve computed tomography scan interpretations by emergency physicians Levitt MA, Dawkins R, Williams V et al 1997 USA | 324 scans reported by 14 Emergency medicine residents. Phase I (217 scans) then 1 hour educational session then phase II (89 scans) 10 days later | Prospective single centre interventional study | Accuracy rate of reporting compared pre and post test | Concordance 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 mismanagement | Single radiology opinion |
| Blood Can Be Very Bad: A simple mnemonic to improve the accuracy of cranial CT interpretation by the emergency physician (abstract) Perron AD, Kline JA 1997 USA | 30 Emergency Medicine residents tested on interpretation of 10 CT scans. Then 2-hour educational session. Retested after 3 months | Prospective cohort study | Comparison of pre and post test scores | Pre test mean score 7, post test score 8. Scores significantly improved between pre and post tests | Very small numbers. Only 18 completed post test - selection bias? |
Author Commentary:
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.
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.
Bottom Line:
Reporting performance for CT heads by Emergency Physicians is varied but is shown to improve significantly with a short educational intervention.
References:
- Mucci B, Brett C, Huntly LS, Greene MK. Cranial computed tomography in trauma: The accuracy of interpretation by staff in the Emergency Department
- Peron AD, Huff JS, Ullrich CG et al. A multi-centre study to improve emergency medicine residents' recognition of intracranial emergencies on computed tomography
- 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
- Alfaro D, Levitt MA, English DK et al. Accuracy of interpretation of cranial computed tomography scans in an emergency training programme
- Arendts, Glenn; Manovel, Alvaro; Chai, Alan. Cranial CT interpretation by senior emergency department staff
- Khoo NC, Duffy M. Out of hours non-contrast CT head scan interpretation by Senior Emergency Department Medical Staff
- Levitt MA, Dawkins R, Williams V et al. Abbreviated educational sessions improve computed tomography scan interpretations by emergency physicians
- 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)