Use of 4D Computer Tomographic Angiography to Accurately Identify Distal Internal Carotid Artery Occlusions and Pseudo-Occlusions: Technical Note.

Background and purpose: Traditional methods of computed tomographic angiography (CTA) can be unreliable in detecting carotid artery pseudo-occlusions or in accurately locating the site of carotid artery occlusion. With these methods, lack of adequate distal runoff due to pseudo-occlusion or intracranial occlusion can result in the inaccurate diagnoses of complete occlusion or cervical carotid occlusion, respectively. The site of carotid occlusion has important therapeutic and interventional considerations. We present several cases in which 4D CTA was utilized to accurately and noninvasively diagnose carotid pseudo-occlusion and intracranial internal carotid artery (ICA) occlusion.

Methods: We identified five patients who presented to our institute with ischemic stroke symptoms and evaluated images from traditional CTA protocols and 4D CTA protocols in each of these patients, comparing diagnoses rendered by each imaging technique.

Results: In two patients, traditional CTA suggested the presence of complete ICA occlusion. However, 4D CTA demonstrated pseudo-occlusion. Similarly, in three patients, traditional CTA demonstrated cervical ICA occlusion, whereas the 4D CTA demonstrated intracranial ICA occlusion.

Conclusion: 4D CTA may be a more effective noninvasive imaging technique than traditional CTA to detect intracranial carotid artery occlusions and carotid artery pseudo-occlusions. Accurate, rapid, and noninvasive diagnosis of carotid artery lesions may help tailor and expedite endovascular intervention.