Digital subtraction (DS) angiography is the gold standard for detecting cerebral vasospasm after subarachnoid hemorrhage (SAH). Computed tomography (CT) perfusion is a recently developed modality for the evaluation of cerebral hemodynamics. This study was conducted to evaluate the potential of using CT perfusion to detect vasospasm in patients with SAH.
Fourteen patients between the ages of 41 and 66 years with aneurysmal SAH underwent 23 CT perfusion scans for suspected vasospasm. All patients underwent DS angiography within 12 hours of the CT perfusion scans. The presence of vasospasm on CT perfusion images was determined based on qualitative reading using color maps of mean transit time, cerebral blood flow, and cerebral blood volume as criteria. The presence or absence of vasospasm as retrospectively determined using CT perfusion was compared with DS angiography findings.
Of the 23 CT perfusion scans performed, 21 (91%) were concordant with angiography findings in predicting the presence or absence of vasospasm. In 15 of 23 scans, the presence of vasospasm was detected on CT perfusion scans and confirmed on DS angiography studies. In two cases, vasospasm was revealed on DS angiography but was not confirmed on CT perfusion. The degree of agreement between CT perfusion and DS angiography for detection of vasospasm was high (κ = 0.8, p < 0.0001).
Computed tomography perfusion is an accurate, reliable, and noninvasive method to detect the presence or absence of vasospasm. It can be used as a tool to help guide the decision to pursue DS angiography with the intent to treat vasospasm.