Computed tomography and magnetic resonance angiography in the evaluation of aberrant origin of the external carotid artery branches.

Aim of our study was to evaluate the prevalence of aberrant origin of the branches of the external carotid artery (ECA) in 97 patients by computed tomography (CTA) and magnetic resonance angiography (MRA) and to compare the accuracy of these two techniques in the visualization of the ECA system. All patients underwent CTA and MRA examination of the head and neck. Multiplanar and volumetric reformations were obtained in all cases. For each set of images, the presence of aberrant origin of the branches of the external carotid artery was investigated. MRA and CTA images of each patient were compared to define their information content. Anatomical anomalies were found in 88 heminecks, with a prevalence of 53.3%. In the 61 patients in whom the CTA was performed before the MRA, the latter method showed only 92% of abnormalities detected at the first examination; in the 36 patients in whom MRA was performed first, CTA identified all of the anomalies highlighted by the former, adding 12 new. Knowledge of the anomalies of origin of the ECA branches is essential for the head and neck surgeon; the high prevalence of anomalies found in our series as in the previous studies indicates the opportunity to perform a CTA or a MRA of the head and neck before any surgical or interventional procedure. CTA is the method of choice in the evaluation of anomalies of origin of the branches of the ECA and in the definition of their course.