77 © Turkish Society of Radiology 2005 Spiral CT angiography in diagnosis of cerebral aneurysms of cases with acute subarachnoid hemorrhage Ender Uysal, Barış Yanbuloğlu, Mehmet Ertürk, Bekir M. Kılınç, Muzaffer Başak From the Departments of Radiology (E.U. * enderuysal@ hotmail.com, B.Y., M.E., M.B.), and Neurosurgery (B.M.K.), Şişli Etfal Training and Research Hospital, İstanbul, Turkey. Received 2 January 2004; first revision requested 2 June 2004; first revision received 10 October 2004; second revision requested 17 January 2005; second revision received 25 January 2005; accepted 28 January 2005. M ortality is high in subarachnoid hemorrhages (SAH) due to rupture of aneurysms. Most deaths occur due to the first bleeding or repetitive bleeding (1, 2). For this reason, fast and accurate evaluation of the patients is of great importance in planning the therapeutic interventions. For the time being, selective digital sub- traction angiography (DSA) is used as the standard method in diagnosis and preoperative evaluation of cerebral aneurysms. Although the per- manent neurologic complication risk is low (0.07%-0.5%) in DSA exams performed in cases with suspected cerebral aneurysms, this method is invasive, time consuming and expensive (3). DSA has high sensitivity and specificity values in diagnosis of cerebral aneurysms while false negative results ranging from 5% to 10% have been reported in the literature (4). The main reason for this is, not being able to obtain the optimal projections necessary for diagnosis of some aneurysms due to physical limitations rather than the insufficiency of spatial resolution of the angiography machine (5). When compared to DSA, spiral CT angi- ography (CTA) is a faster and a more easily applied method. In contrast to another non-invasive imaging method, magnetic resonance angiog- raphy (MRA), spiral CTA enables faster acquisition of three dimensional images related to the cerebral vascular anatomy without patient motion artifacts or artifacts due to flow rate. Another advantage of CTA is its applicability following routine non-enhanced cranial computed tom- ography (CT) in patients with suspected SAH in emergency conditions. In this study, we aimed to compare the effectiveness of single detector spiral CTA to DSA in diagnosis and evaluation of intracranial aneurysms in cases with acute SAH. Materials and methods Thirty-two cases who had CTAs and DSAs with suspicion of aneurysm due to SAH detected by non-enhanced cranial CT between September 2002 and May 2004 were included in the study. There were 17 women and 15 men, ages ranging from 32-75 (mean, 45.5) years. All CTA exami- nations were performed with spiral technique by a single row detector CT machine (General Electric Hi-Speed, Milwaukee, WI, USA). After de- tection of the location from lateral scanogram, slices parallel to orbito- meatal line were obtained in caudo-cranial direction starting from 1 cm below the base of sella turcica up to the level of lateral ventricles. Spiral CTA was obtained with 1 mm collimation, 1.5:1 pitch, 120 kV, 150 mAs and 25 cm field-of-view. Slice reconstruction thickness was 0.5 mm. One hundred and twenty ml non-ionic iodinated contrast (Iomeron 400, Bracco Diagnostic, Milan, Italy) was administered through a 20 G needle from the antecubital vein with a rate of 3 ml/second. Acquisition of im- ages started after 15 seconds and examination lasted for about 40-60 sec- onds. No allergic reaction occurred in any cases. Spiral CTA images were PURPOSE To investigate the diagnostic accuracy of spiral CT angi- ography (CTA) in detection of cerebral aneurysms in cases with acute subarachnoid hemorrhage (SAH). MATERIALS AND METHODS Spiral CT angiography and DSA examinations were performed in 32 cases due to non-traumatic SAH. CTA data were obtained by maximum intensity projection (MIP) method. CTA and DSA findings were evaluated and compared in terms of existence of aneurysm, size and location. RESULTS In 32 patients, DSA detected 34 aneurysms with di- ameters ranging from 3 to 13 mm while four cases were free of aneurysms. With CTA, an aneurysm at anterior communicating artery location could not be demonstrated. In all other cases CTA correlated well with DSA in detecting the site, size and orientation of the aneurysms. It was found that CTA sensitivity was 97% and specificity was 100% in diagnosis of intrac- ranial aneurysms. CONCLUSION Spiral CTA is a highly accurate, cheap and non-in- vasive imaging method in diagnosis of intracranial aneurysms in cases with SAH and can be used as a safe alternative method to DSA when emergency surgery is needed. Key words: • intracranial aneurysm • subarachnoid hemorrhage • tomography, spiral computed ORIGINAL ARTICLE Diagn Interv Radiol 2005; 11:77-82 NEURORADIOLOGY