Background and purpose: Diagnosis and successful therapy before rupture of cerebral aneurysms would be most desirable in view of the high mortality and morbidity rates of aneurysmal subarachnoid hemorrhage. Using transcranial color-coded duplex sonography, we studied radiologically proven cerebral aneurysms to define ultrasonographic criteria and sensitivity for their diagnosis and detection.
Methods: Twenty-nine consecutive patients with 30 radiologically proven cerebral aneurysms were prospectively examined using transcranial color-coded duplex sonography. The sonographer was aware of cerebral computed tomographic and magnetic resonance imaging findings but was blinded to the results of cerebral angiography.
Results: Ultrasonographic findings for aneurysms studied were as follows: (1) Scanning planes that transsected approximately mid-aneurysm showed a round or oval mass that was divided by a "separation zone" into red and blue areas. (2) The "separation zone" was characterized by dark or no colors. (3) Peripheral scanning planes showed monochromatic images. (4) No turbulence was found. (5) No spontaneous fluctuations were detected. Twenty-three of 27 (85%) nonthrombosed aneurysms with a diameter of 6 to 25 mm were identified. The walls and three thrombosed and four nonthrombosed aneurysms (mean diameter, 5 mm) were missed.
Conclusions: Transcranial color-coded duplex sonography can provide the diagnosis of nonthrombosed aneurysm using the above-cited criteria because of its capacity to reveal flow phenomena. It is not the method of choice in the search for aneurysms because small and thrombosed aneurysms are missed. Careful visual inspection of the intracranial arteries to permit incidental detection of cerebral aneurysms should be part of every transcranial color-coded duplex examination.