SPIRAL CT ANGIOGRAPHY AND SURGICAL CORRELATIONS IN THE EVALUATION OF INTRACRANIAL ANEURYSMS

We investigated the accuracy of spiral computed tomography angiography (CTA) in the detectiOn and study of intracranial aneurysms by compari ng CTA with selective angiograms and surgical findings. Twenty-six pat ients (9 men and 17 women; ; mean age 53.1 +/- 1.8 pears) with suspect ed intracranial aneurysms were submitted to CTA (1- to 2-mm slices, pi tch 1:1, 24 s RI = 1) after a conventional CT examination showing suba rachnoid hemorrhage (SAH) in 19 cases and during neuroradiological inv estigations performed for other reasons in 7 cases. One hundred twenty to 150 mi iodate contrast agent (0.3-0.4 gl/ml) were injected intrave nously at 5 ml/s rate and with 12- to 25-s delay calculated with a pre liminary test bolus, Three-dimensional shaded surface display (3D SSD) and maximum intensity projection (MIP) reconstructions were obtained from axial images, Then, within 48 h, all patients were submitted to d igital subtraction angiographpy (DSA), :with separate assessment of CT A and DSA findings. Twenty-two aneurysms shown by CTA were con firmed at DSA and surgery (true positives), whereas the vascular lesion was n ot confirmed at DSA in 2, cases (false positives). The presence of int racranial :aneurysms was excluded at both CTA and subsequent DSA in 7 cases (true negatives) and there were no false negatives; sensitivity was 100%, specificity 77.8 %, and diagnostic accuracy 93.5 %. Computed tomography angiography aneurysm location ,Nas confirmed at surgery in all cases, with very high accuracy in assessing the presence of an an eurysm ;neck (100%). Computed tomography angiography accurately depict ed the aneurysm shape in 20 of 22 cases, but failed to depict its mult ilobed nature in 2 cases. The mean aneurysm diameter calculated at CTA was 0.99 +/- 0.12 cm vs 1.09 +/- 0.11 cm at surgery (p < 0.01), The p resent results suggest that the high sensitivity of CTA, if confirmed by further studies, might help in avoiding having to resort to arterio graphy after negative CTA in SAH patients.