Objectives-To determine whether combining non-invasive tests for intracrani
al aneurysms together would significantly improve aneurysm detection over i
Methods-114 patients undergoing intraarterial digital subtraction angiograp
hy to confirm or exclude an intracranial aneurysm were also examined by CT
angiography, AIR angiography, and transcranial power Doppler ultrasound. Th
e reviewers and ultrasonographers were blinded to the angiogram. result, ot
her imaging results and all clinical information.
Results-The combination of noninvasive tests did improve diagnostic perform
ance on a per patient basis. The combination of power Doppler and CT angiog
raphy had the greatest sensitivity for aneurysm detection (0.83; 05% confid
ence interval (95% CI) 0.66-0.93) and the level of agreement for this strat
egy with the reference angiographic standard was excellent (kappa 0.84; 95%
CI 0.72-0.95). The improvement in sensitivity of adding power Doppler to C
T angiography was not significant (p = 0.55) but the improvement in the lev
el of agreement with the reference standard was substantial. However, even
the most sensitive combination strategy performed poorly in the detection o
f 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 NM angiography does improve diagnostic performance on a
per patient basis but aneurysms of 5 mm or smaller can still not be reliabl
y identified by current standard clinical non-invasive imaging modalities.