Hypoplasia of the internal carotid artery: a noninvasive diagnosis

Abstract

We present the characteristic imaging findings of hypoplasia of the internal carotid artery (ICA) in two cases, one accompanied by an intracranial aneurysm. Finding of a diffuse luminal narrowing of the ICA on MR angiography or digital subtraction angiography (DSA) could wrongly evoke severe acquired diseases such as dissection or atherosclerosis. Absence of associated wall thickening and flow disturbances on color Doppler sonography (CDS) should suggest carotid hypoplasia. Confirmation of the diagnosis is obtained by CT of the skull showing a small carotid canal. Non-invasive procedures are sufficient to differentiate this rare congenital anomaly from acquired string signs.

A Quantitative Comparison of the Vertebral Artery and Transverse Foramen Using CT Angiography

“…A unilaterally small TF is associated with hypoplasia or aplasia of the VA, and internal carotid artery (ICA) hypoplasia is usually accompanied by adjacent bony carotid canal narrowing 4. The prevalence of an anomalous VA in patients with failure of sclerotomal segmentation, such as occipitalization of the atlas or Klippel-Feil syndrome, is higher than that in the general population 5,6.…”

Bilateral Congenital Absence of Internal Carotid Arteries in a Woman with Dementia

“…Acquired causes of occlusion or stenosis of internal carotid artery include atherosclerosis, arteritis, chronic dissection and fibromuscular dysplasia 1 . The distinction between congenital and acquired absence of the internal carotid artery is very important because the latter condition requires treatment such as anticoagulotherapy and endarterectomy 13 .…”

Intracranial Dissection and Extracranial Hypoplasia of the Internal Carotid Artery

“…However, in all of the cases investigated by color duplex sonography (CDS), a uniform narrowing of the luminal and external vessel diameters not associated with wall thickening and flow disturbances should suggest ICA hypoplasia. 2 Although the combined use of CDS and MRA allows a diagnosis of ICA hypoplasia, diagnostic confirmation should be obtained by depiction of a small carotid canal on computed tomography or MRI of the skull base. 2 Spontaneous intracranial ICA dissection, in particular in the terminal segment of the artery, is a rare cause of stroke or TIA.…”

“…2 Although the combined use of CDS and MRA allows a diagnosis of ICA hypoplasia, diagnostic confirmation should be obtained by depiction of a small carotid canal on computed tomography or MRI of the skull base. 2 Spontaneous intracranial ICA dissection, in particular in the terminal segment of the artery, is a rare cause of stroke or TIA. 3 Dissection more often occurs at the level of the carotid knee just beyond the ophthalmic artery and also involves the ipsilateral MCA and ACA.…”