Best test to determine etiology of SAH
C i.e. Intra aerial digital Substraction Once dx is done by CT Scan; digital substraction angiography (DSA) is done to determine etiology. DSA is most sensitive & best inv. for determining etiologyQ. Now DSA is being replaced by noninvasive methods as MRA (MRI - angiography) & CTA (CT - Angiography).
Enhanced CT
Unenhanced CT
Intra aerial digital Substraction Angiography
MRI