CT Scan of the Skull Base in Internal Carotid Artery Hypoplasia

Abstract

Internal carotid artery (ICA) hypoplasia is a rare congenital anomaly that is sometimes difficult to distinguish from acquired diseases associated with narrowing of the ICA. As the carotid canal develops in association with the ICA, a hypoplastic carotid artery should result in a hypoplastic carotid canal. We used skull base CT scans to measure the size of carotid canals in 4 patients with ICA hypoplasia (bilateral in 1) and in 30 consecutive controls. The diameter of the carotid canal was significantly smaller in the patients with carotid hypoplasia (2.4–3.0 mm, on the involved side) than in the controls (mean = 6.4 ± 0.8 mm, range = 5.2–9.8 mm) with no overlapping value (p < 0.001). The ratio of the largest to the smallest carotid diameter was greater than 2 in patients with unilateral hypoplasia, while it never exceeded 1.2 in controls. CT scan of the skull base is a simple and reliable tool for confirming the diagnosis of ICA hypoplasia.

Hypoplasia of the internal carotid artery: a noninvasive diagnosis

“…1 e, 2 d). In a CT study comparing a dysgenetic group of patients to a control group, the ratio of the greater to the lesser diameter was greater than 2 in cases of unilateral hypoplasia, whereas it never exceeded 1.2 in the second group [16]. Based on the anatomic study of ten petrosae, Leonetti et al considered the upper and lower limits of the carotid canal to be 4±7.5 mm for the vertical portion and 4.5±7 mm for the horizontal portion [17].…”

MDCT angiography of the major congenital anomalies of the extracranial arteries: Pictorial review

“…Hypoplasia of the ICA has been characterised as being unilateral, primal and bilateral . Hypoplasia of the ICA is determined by the diameter of the carotid canal, which is significantly smaller in these patients (Fig. ).…”

Differenzialdiagnostik seltener Schlaganfallursachen

“…Da es sich hierbei meist um asymptomatische Zufallsbefunde handelt, ist die genaue Häufigkeit nicht sicher bekannt. Bei Unterschieden in der Weite des knöchernen Kanals der A. carotis an der Schädelbasis gibt die dünnschichtige Computertomografie (CT) einen Hinweis auf die angeborene Hypoplasie [6]. Als pathologisch gilt hierbei ein Unterschied der Durchmesser um den Faktor > 2.…”