[Brain computed tomography angiography in case of subarachnoid hemorrhage]

Objective was to evaluate sensitivity, specificity and diagnostic accuracy of brain computed tomography (CTA) in patients with subarachnoid hemorrhage (SAH).

In the period of January-September, 2001 CTA was performed in 46 patients (with SAH on initial CT) of Clinic of Neurosurgery and Clinic of Neurology clinics, Kaunas University Hospital.

CTA was performed at different time from the onset (from several hours to one year). Each patient underwent care bolus procedure (slice thickness 5 mm, rotation time 1.0 s, voltage 140 kV, delay time 11 s, scan plane suspected aneurysm or cavernous sinus, number of scans 15 (each 2 s), volume 20 ml, flow rate 2.8 ml/s) and CTA (slice thickness 1 mm, rotation 2.0, rotation time 1.0 s, voltage 120 kV, increment 1.0, delay time individual, volume 80 ml, flow rate 2.8 ml/s). Axial and 3D (maximum intensity projection (MIP), volume rendering technique (VRT) and surface shaded display (SSD) images were evaluated. Before or after CTA procedure, digital subarachnoid angiography (DSA) was performed in 44 patients.

Twenty-three aneurysms of various localization and size were found. There were no findings in 21 patients. One false negative and one false positive result was present. Specificity and sensitivity was 95.8% (23/24), and diagnostic accuracy--95.6% (44/46). Two patients were operated according to CTA results. Two patients had repeat-DSA (according to CTA results), and the aneurysms were finally found.

CTA is a quick, noninvasive method to be performed in outpatient and inpatient basis. It gives information about vessels and surrounding tissues. In some cases it can replace DSA. CTA must not be considered as replacement of DSA, instead, it should be considered as method providing more additional information.