Negative CT Angiography Findings in Patients with Spontaneous Subarachnoid Hemorrhage: When is Digital Subtraction Angiography Still Needed?
AJNR 31:695-705, Agid,R., et al, 2010
Assessment: Transcranial Doppler Ultrasonography
Neurol 62:1468-1481, Sloan,M.A.,et al, 2004