[CT angiography in dissections of the internal carotid artery. Value of a new examination technique in comparison with DSA and Doppler ultrasound].

PURPOSE: To evaluate the role of CT angiography (CTA) in the diagnosis of dissection of the internal carotid artery (ICA).

METHODS

In 21 patients who were clinically or sonographically suspected of having a dissection 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 130 kV, amperage 125 mA, i.v. bolus injection of 100 ml nonionic contrast medium, injection rate 4 ml/s and scan delay 15 s. Spiral data were processed using a workstation (Picker Voxel Q) to calculate 3D "angiographic" reconstructions, maximal intensity projections and multiplanar reconstructions. In 20 of the 21 patients transfemoral angiography was performed, and in all patients cw-Doppler ultrasonography of the carotid arteries was performed.

RESULTS

Sensitivity of CTA in acute extracranial 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 in all cases. One intracranial ICA dissection, not covered by the scan field, was missed by CTA. CTA source images demonstrated mural thickening and eccentric luminal narrowing in cases of dissection. 3D reconstructions showed tapering of the ICA.

CONCLUSION

CTA is a reliable tool in the diagnosis of ICA dissection. Further studies comparing CTA, MRI and duplex ultrasound are necessary.