[Dissections of the internal carotid artery--new diagnostic and pathogenetic aspects].

Initial and follow-up investigations were done systematically in 15 cases of internal carotid artery (ICA) dissections by means of angiography, computerized tomography, Magnetic Resonance Imaging, extracranial and transcranial Doppler sonography, as well as B-mode imaging. Cerebral hemodynamic reserve was evaluated by means of both SPECT and CO2-dependent vasomotor reactivity. The findings are focussed on two major issues: Do modern diagnostic tools permit to make the diagnosis of ICA dissection without angiographical proof? What is the pathogenesis of brain infarctions due to ICA dissections? Our findings demonstrate that the diagnosis of carotid artery dissection can reliably be done noninvasively by means of ultrasound techniques and MRI. These methods also allow for frequent follow-up investigations without any inconvenience for the patient. Embolic brain infarctions caused by carotid artery dissections are equally frequent as low flow induced lesions. Acute and follow-up findings suggest that surgical intervention is contraindicated in the acute phase, but may be considered for chronic pseudoaneurysms. Initial anticoagulation with high dose heparin is safe and seems to be efficacious. In certain cases, subsequent cumarine therapy may be indicated for a maximum of six months. Measures improving hemodynamics, e. g. induced hypertension, are reasonable, as long as the vasomotor reserve is exhausted.