Nonvisualization of the Internal Carotid Artery on Computed Tomography Angiography: Discussion of Two Cases with Review of Literature

Figure 3

(a) Computed tomographic angiography axial image of the patient shows nonvisualization of the right internal carotid artery. (b) Computed tomographic angiography axial image of the patient shows nonvisualization of the right internal carotid artery with normal right carotid canal. (c) Computed tomographic angiography axial image of the patient at caudal level shows nonvisualization of the right internal carotid artery. Normal internal and external carotid arteries are seen on contralateral side. (d) Digital subtraction angiographic image reconstructed by the volumetric rendering techniques shows absent right internal carotid artery with right middle cerebral artery being supplied by the collateral circulation through the anterior cerebral artery and anterior communicating arteries. (e) Three-dimensional reconstruction by the volumetric rendering techniques shows absent right internal carotid artery with right middle cerebral artery being supplied by the collateral circulation through the anterior cerebral artery and anterior communicating arteries.

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