What is the most sensitive non-invasive imaging strategy for the diagnosis of intracranial aneurysms?
- aUniversity Department of Neurosurgery and Department of Neuroradiology, Institute of Neurological Sciences, Southern General Hospital, Glasgow G52 4TF, UK, bUniversity of Edinburgh Department of Clinical Neurosciences2, Bramwell Dott Building, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK, cUniversity of Edinburgh Department of Medical Statistics, Medical School, Teviot Place, Edinburgh, UK
- Dr PM Whitepmw{at}skull.dcn.ed.ac.uk
- Received 10 October 2000
- Revised 26 February 2001
- Accepted 7 March 2001
Abstract
OBJECTIVES To determine whether combining non-invasive tests for intracranial aneurysms together would significantly improve aneurysm detection over individual tests.
METHODS 114 patients undergoing intra-arterial digital subtraction angiography to confirm or exclude an intracranial aneurysm were also examined by CT angiography, MR angiography, and transcranial power Doppler ultrasound. The reviewers and ultrasonographers were blinded to the angiogram result, other imaging results and all clinical information.
RESULTS The combination of non-invasive tests did improve diagnostic performance on a per patient basis. The combination of power Doppler and CT angiography had the greatest sensitivity for aneurysm detection (0.83; 05% confidence interval (95% CI) 0.66-0.93) and the level of agreement for this strategy with the reference angiographic standard was excellent (κ 0.84; 95% CI 0.72-0.95). The improvement in sensitivity of adding power Doppler to CT angiography was not significant (p=0.55) but the improvement in the level of agreement with the reference standard was substantial. However, even the most sensitive combination strategy performed poorly in the detection of small (3-5 mm) and very small (<3 mm) aneurysms with a sensitivity of 0.43 (95% CI 0.23-0.66) and 0.00 (95% CI 0.00-0.31) respectively.
CONCLUSIONS The addition of transcranial power Doppler ultrasound to either CT angiography or MR angiography does improve diagnostic performance on a per patient basis but aneurysms of 5 mm or smaller can still not be reliably identified by current standard clinical non-invasive imaging modalities.
