Two-dimensional transcranial color Doppler: its role in subarachnoid hemorrhage

Objectives

The M-mode transcranial color Doppler technique became an important tool for neurointensivists in the follow-up of patients with subarachnoid hemorrhage and after its corrective surgery. Through the two-dimensional color Doppler (TDCD) technique we could obtain the same sort of information obtained with M-mode, but additionally it would be possible to visualize anatomically intracranial vessels. Therefore our purpose was to acquire color images from the intracranial vessels, the identification of arterial segments under vasospasm, and the recognition of aneurysms using the color Doppler technique.

Methods

We used a two-dimensional color Doppler ultrasound with a 2 MHz transducer. We obtained two-dimensional color images from the Circle of Willis, recording vessel velocities and analyzing the flow, resistance index and pulsatility index of patients admitted to the intensive care unit with subarachnoid hemorrhage. We used transtemporal, occipital and ocular windows in order to register the arterial flow. We defined vasospasm when mean velocities were higher than 120 cm/s. Images of vasospasm and probable aneurysms were recorded, and afterwards compared with cerebral angiography.

Results

From May 2000 to August 2001, 16 patients were admitted to our surgical intensive care unit, where 13 were considered Fisher stage IV on head computed tomography scan. We diagnosed three aneurysms that were later confirmed by cerebral angiography. One was on the top of the basilar artery and the two others were in the middle cerebral artery. Arteries under vasospasm were also identified. Sixty-one percent of patients in Fisher stage IV had vasospasm initially diagnosed by TDCD and confirmed in the angiogram afterwards. Flow and velocities were recorded; these data helped us to understand and to use appropriate therapeutic intervention.

Conclusions

There was technical feasibility on obtaining two-dimensional color Doppler images of intracranial vessels. There was no need to use contrast in the identification of the vessels. Immediate better management of cerebral vasospasm, including percutaneous angioplasty in selected cases, were possible thanks to color Doppler. Finally, good anatomical correlation between images from TDCD and angiography were also noted.