Introduction: Novel postprocessing techniques have enabled accurate quantification of intracranial carotid atherosclerotic disease on CT Angiography (CTA). Our purpose was to estimate the prevalence of intracranial carotid artery disease, i.e., stenosis and calcium, on CTA in patients with recent neurological symptoms.
Methods: The degree of stenosis and calcium volume of 162 extracranial and intracranial internal carotid arteries (ICAs) was quantitatively measured on CTA images of 88 consecutive patients with recent neurological symptoms and extracranial ICA stenosis as screened by ultrasound. The prevalence of intracranial ICA stenosis and presence of calcium was estimated and correlated with extracranial ICA stenosis.
Results: Intracranial ICA stenosis was observed in 83 % (95 %CI: 77-89 %) and 39 % (95 %CI: 31-47 %) for a stenosis of ≥30 % and ≥50 %, respectively. Only on the symptomatic side, a statistical significant correlation between intracranial and extracranial stenoses was observed (Pearson's r 0.32, P = 0.006). In the 37 arteries with an extracranial ICA stenosis of ≥70 %, 89 % (95 %CI: 79-99 %) and 46 % (95 %CI: 30-62 %) of the intracranial ICA showed a stenosis of ≥30 % and ≥50 %, respectively.
Conclusion: In our population of patients with recent neurological symptoms and extracranial stenosis as screened by ultrasound, CTA imaging resulted in a substantially higher prevalence of intracranial ICA disease than previously reported. This remarkably high prevalence of intracranial ICA disease on CTA may have important future implications for acute and preventive treatment strategies.