Sensitivity and specificity are both >98% for catheter cerebral angiography when compared with surgical findings, including small aneurysms <3 mm [10]. Catheter cerebral angiography also identified vascular abnormalities in up to 13% of patients with SAH and negative CTA imaging [11]. Although catheter cerebral angiography has been reported to be negative in 2% to 24% of patients with aneurysmal SAH, 3-D rotational angiography has been shown to identify an aneurysm on 25% of previously angiogram, both 2-D and 3-D, negative patients [12]. Angiography is an invasive procedure with a small complication risk related to intravascular instrumentation. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the evaluation of known acute SAH. CTA Head CTA head is a fast, noninvasive study to evaluate patients with acute SAH. CTA head has been shown to have >90% sensitivity and specificity in the evaluation for aneurysms [4,10,13-18] responsible for SAHs. However, CTA head sensitivity for detecting aneurysm decreases for aneurysms <3 mm in size [4,10,13,15,17,19], in the setting of diffuse SAH [20], and for aneurysms occurring adjacent to an osseous structure [19]. CTA head may be sufficient to rule out a vascular cause of SAH when the location of hemorrhage is isolated to the perimesencephalic region with follow-up catheter-directed angiography indicated in CTA negative diffuse or peripheral SAHs [20]. CTA Neck There is no relevant literature to support the use of CTA neck in the initial imaging evaluation of known acute SAH. CTA neck may be useful for potential treatment planning, but preference will be individual or site specific. CTV Head There is no relevant literature to support the use of CT venography (CTV) head in the evaluation of known acute SAH.
Cerebrovascular Diseases Aneurysm Vascular Malformation and Subarachnoid Hemorrhage PCAs. Sensitivity and specificity are both >98% for catheter cerebral angiography when compared with surgical findings, including small aneurysms <3 mm [10]. Catheter cerebral angiography also identified vascular abnormalities in up to 13% of patients with SAH and negative CTA imaging [11]. Although catheter cerebral angiography has been reported to be negative in 2% to 24% of patients with aneurysmal SAH, 3-D rotational angiography has been shown to identify an aneurysm on 25% of previously angiogram, both 2-D and 3-D, negative patients [12]. Angiography is an invasive procedure with a small complication risk related to intravascular instrumentation. CT Head Perfusion There is no relevant literature to support the use of CT head perfusion in the evaluation of known acute SAH. CTA Head CTA head is a fast, noninvasive study to evaluate patients with acute SAH. CTA head has been shown to have >90% sensitivity and specificity in the evaluation for aneurysms [4,10,13-18] responsible for SAHs. However, CTA head sensitivity for detecting aneurysm decreases for aneurysms <3 mm in size [4,10,13,15,17,19], in the setting of diffuse SAH [20], and for aneurysms occurring adjacent to an osseous structure [19]. CTA head may be sufficient to rule out a vascular cause of SAH when the location of hemorrhage is isolated to the perimesencephalic region with follow-up catheter-directed angiography indicated in CTA negative diffuse or peripheral SAHs [20]. CTA Neck There is no relevant literature to support the use of CTA neck in the initial imaging evaluation of known acute SAH. CTA neck may be useful for potential treatment planning, but preference will be individual or site specific. CTV Head There is no relevant literature to support the use of CT venography (CTV) head in the evaluation of known acute SAH.