Transcranial Doppler grading criteria for basilar artery vasospasm

Area of Science:

• Neuroscience
• Medical Imaging
• Vascular Neurology

Background:

• Transcranial Doppler (TCD) criteria for basilar artery (BA) vasospasm lack definition.
• Existing grading criteria for vertebrobasilar vasospasm are unavailable.

Purpose of the Study:

• To establish TCD grading criteria for BA vasospasm using absolute flow velocities and intracranial to extracranial flow velocity ratios.
• To enhance the sensitivity and specificity of TCD for diagnosing BA vasospasm.

Main Methods:

• 123 patients with aneurysmal subarachnoid hemorrhage underwent cerebral arteriography during vasospasm (Days 3-14).
• Basilar artery (BA) diameters were measured and compared to baseline.
• BA and extracranial vertebral artery (VA) flow velocities were measured by TCD within 4 hours pre-arteriography.

Main Results:

• The BA/VA velocity ratio strongly correlated with BA narrowing (r² = 0.648; P < 0.0001).
• A BA/VA ratio > 2.0 showed 73% sensitivity and 80% specificity for vasospasm.
• A BA/VA ratio > 3.0 with BA velocity > 85 cm/s achieved 92% sensitivity and 97% specificity for >50% BA narrowing.

Conclusions:

• The BA/VA ratio significantly improves TCD sensitivity and specificity for detecting BA vasospasm.
• New TCD grading criteria for BA vasospasm are proposed based on the BA/VA ratio and mean BA velocities.