Power transcranial Doppler ultrasound in the detection of intracranial aneurysms

Background and Purpose - We sought to perform a large, prospective, multice nter, blinded study comparing power transcranial color duplex sonography (p ower TCDS) with intra-arterial digital subtraction angiography (IADSA) in t he detection of intracranial aneurysms, Methods-Contemporaneous TCDS and IADSA examinations were performed in 171 s ubjects with suspected intracranial aneurysm. Via the temporal bone window, a 2-dimensional hand-held noncontrast transcranial duplex ultrasound imagi ng system was used operating in power and spectral modes. Sonographers were blinded to clinical history and results of brain CT and IADSA. Results - We found that 157 subjects (92%) had an adequate bone window. Sen sitivity per patient was 0.78 (95% CI, 0.66 to 0.87) and 0.46 (95% CI, 0.36 to 0.56) for any anterior circulation aneurysms. Sensitivity was 0.35 (95% CT, 0.24 to 0.46) for aneurysms less than or equal to5 mm and 0.81 (95% CI , 0.62 to 0.94) for aneurysms >5 mm, Accuracy was lower for aneurysms on th e cavernous and terminal internal carotid arteries, including posterior com municating artery origin (0.71; 95% CI, 0.63 to 0.79), than for those on th e anterior (0.82; 95% CI, 0.74 to 0.89) or the middle cerebral arteries (0. 79; 95% CI, 0.71 to 0.86). Conclusions-power TCDS is a promising, inexpensive, noninvasive test for an terior circulation intracranial aneurysms but is less sensitive per aneurys m than alternatives such as CT angiography or MR angiography. Sensitivity i s poor for aneurysms less than or equal to5 mm in diameter. The internal ca rotid artery is the most difficult segment to interpret.