COMPUTED-TOMOGRAPHY ATTENUATION VALUES IN ACUTE BASILAR ARTERY-OCCLUSION

The purpose of this study was to determine the value of the so-called dense basilar artery sign in computed tomography as a sign of its occl usion. One hundred and eleven patients (105 control patients; 6 patien ts with basilar artery occlusion) were examined by computed tomography of the head, and attenuation values were measured in the basilar arte ry before and after intravenous contrast administration. In controls t he values in the basilar artery before contrast (b.c.) were 38.9, afte r contrast (a.c.) 89.9; in patients with basilar artery occlusion, the values were 43.4 b.c. and 62.5 a.c. In patients with basilar artery o cclusion the attenuation ratio, corresponding to (a.c. - b.c.)/b.c., w as lower than in controls (p < 0.0007). We found no significant differ ence in attenuation values with age. These results stress the importan ce of measuring attenuation values in selected regions of interest in patients with suspected occlusion of cerebral arteries.