[Dissection of epiaortic vessels: clinical appearance and potentiality of imaging techniques].

PURPOSE To analyse the major radiological and clinical features of dissections of the epiaortic vessels and evaluate the potential of imaging techniques on the basis of the findings reported in the literature over the last few years. MATERIALS AND METHODS We evaluated 9 dissections (7 carotid lesions and 2 vertebral lesions) in 9 patients (5 women and 4 men; age range: 30-56 years) who came to our attention between September 1999 and June 2002. These were all stenoses and obstructions located in the cervical region and, in two patients, extended intracranially. The morphologic features were assessed in each case by colour-Doppler US, CT, MR or conventional angiography and correlated with clinical, therapeutic and distant progression patterns. Colour-Doppler US of the neck vessels was performed in 4 patients; CT angiography of neck and intracranial vessels was performed in 4 patients using a single-slice spiral scanner and a single contrast medium bolus injection, following unenhanced examination of the brain; MR angiography was performed in 6 patients after baseline examination using flow-dependent and/or angiographic sequences; conventional angiography was performed in 7 patients. Clinical manifestations at onset were peripheral neurological lesions in 5 cases and central ischaemic lesions in the remaining 4 cases. All patients underwent medical therapy (anticoagulants or antiaggregants). The follow-up was done by colour-Doppler US, MR and/or MR angiography; follow-up conventional angiography at 6-9 months was also performed in 6 patients. Distant progression was assessed on the basis of the degree of vascular re-canalization and the residual signs and symptoms. RESULTS MR- and CT-angiography were diagnostic in all cases. In particular, diagnosis was obtained by MR-angiography in 4 patients and by CT-angiography in 3 patients. Conventional angiography yielded a diagnosis in 2 cases which had previously undergone non-contrast brain CT or MR without examination of neck vessels alone. Colour-Doppler US revealed non-specific wall and flow alterations in 2 cases, thus requiring further diagnostic studies. In patients with central neurological symptoms at onset the diagnosis was obtained within 48-72 hours, whereas in patients with initial peripheral neurological symptoms the time to diagnosis was significantly longer (up to 10 days) due to the poor specificity of the clinical picture and/or failed detection of the warning symptoms. Medical treatment gave rise to no major complications. Overall, distant progression was good: 6 patients recovered completely and 3 had mild to moderate residual neurological deficits. DISCUSSION AND CONCLUSIONS Dissection of epiaortic vessels should always be considered as a probable cause of cerebral ischaemia in adults aged 20-50 years, particularly in the absence of vascular risk factors. Clinical assessment is fundamental for the diagnosis and treatment. Currently, CT and MR imaging techniques providing similar information are reliable diagnostic tools that can rapidly and non-invasively clarify suspicious clinical cases. Nevertheless, angiography continues to have an important role in the overall evaluation of disease severity in view of the possible endovascular or surgical treatment of complications.