CT ANGIOGRAPHY IN DISSECTION OF THE INTER NAL CAROTID-ARTERY - EVALUATION OF A NEW EXAMINATION TECHNIQUE IN COMPARISON WITH DSA AND DOPPLERSONOGRAPHY

Purpose: To evaluate the role of CT angiography (CTA) in the diagnosis of dissection of the internal carotid artery (ICA). Methods: In 21 pa tients who were clinically or sonographically suspected of having a di ssection of the ICA, we performed CTA covering the extracranial course of the ICA. Our technique included spiral scanning (Picker PQ 2000), slice thickness 3 mm, index 1.5 mm, pitch factor 1.25, tube voltage 13 0 kV, amperage 125 mA, i.v. bolus injection of 100 ml nonionic contras t medium, injection rate 4 ml/s and scan delay 15 s. Spiral data were processed using a workstation (Picker Voxel Q) to calculate 3D ''angio graphic'' reconstructions, maximal intensity projections and multiplan ar reconstructions. In 20 of the 21 patients transfemoral angiography was performed, and in all patients cw-Doppler ultrasonography of the c arotid arteries was performed. Results: Sensitivity of CTA in acute ex tracranial dissection of the ICA was 100 % (14/14). One patient had a pseudoaneurysm of the ICA, two patients had excessive kinking and one patient showed an atheromatous carotid ulcer. DSA could confirm this i n all cases. One intracranial ICA dissection, not covered by the scan field, was missed by CTA. CTA source images demonstrated mural thicken ing and eccentric luminal narrowing in cases of dissection. 3D reconst ructions showed tapering of the ICA. Conclusion: CTA is a reliable too l in the diagnosis of ICA dissection. Further studies comparing CTA, M RI and duplex ultrasound are necessary.