Calcium at the carotid siphon as an indicator of internal carotid artery stenosis
- 689 Downloads
Carotid siphon calcification is often visible on unenhanced head CT (UCT), but the relation to proximal carotid artery stenosis (CAS) is unclear. We investigated the association of carotid siphon calcification with the presence of CAS.
This IRB-waived retrospective study included 160 consecutive patients suspected of stroke (age 64 ± 14 years, 63 female) who underwent head UCT and CTA of the head and neck. CAS was rated on CTA as not present or present with non-significant (<50 %), moderate (50–69 %) or significant (≥70 %) stenosis. Presence, shape (on UCT) and volume (on CTA) of carotid siphon calcifications were related to CAS.
Carotid siphon calcification was absent in 41 % of patients and bilateral in 94 % of those with calcifications. Presence, shape and volume of calcification resulted in odds ratios for having significant CAS of 10.1, 3.9 and 8.4, with 95 % CIs of 1.3–79.6, 1.1–14.1 and 2.6–26.8, respectively. Corresponding NPVs were 0.98, 0.98 and 0.96, while PPVs were 0.14, 0.07 and 0.29, respectively.
Absence of calcification in the carotid artery siphon on UCT has high negative predictive value for carotid artery stenosis in patients with suspected stroke. However, siphon calcification is not a reliable indicator of significant carotid artery stenosis.
• Many stroke patients do not have calcification in the carotid artery siphon.
• Carotid stenosis ≥50 % is unlikely in stroke patients without siphon calcification.
• Carotid siphon calcium is a poor indicator of significant carotid artery stenosis.
KeywordsAtherosclerosis Intracranial atherosclerosis Internal carotid artery Vascular calcification Carotid stenosis
Proximal internal carotid artery stenosis
95 % confidence interval
Computed tomography angiography
Unenhanced computed tomography
Positive predictive value
Negative predictive value
Transitory ischaemic attack
Some of the patients were presented as EPOS on ECR 2011.
- 2.Furie KL, Kasner SE, Adams RJ et al (2011) American Heart Association Stroke Council, Council on Cardiovascular Nursing, Council on Clinical Cardiology, and Interdisciplinary Council on Quality of Care and Outcomes Research. Guidelines for the prevention of stroke in patients with stroke or transient ischemic attack: a guideline for healthcare professionals from the American heart association/American stroke association. Stroke 42:227–276PubMedCrossRefGoogle Scholar
- 6.Jacobs PC, Prokop M, van der Graaf Y et al (2010) Comparing coronary artery calcium and thoracic aorta calcium for prediction of all-cause mortality and cardiovascular events on low-dose non-gated computed tomography in a high-risk population of heavy smokers. Atherosclerosis 209:455–462PubMedCrossRefGoogle Scholar
- 8.Mak HK, Wong CW, Yau KK, Wong WM, Gu J, Khong PL, Chan BP (2009) Computed tomography evaluation of intracranial atherosclerosis in Chinese patients with transient ischemic attack or minor ischemic stroke—its distribution and association with vascular risk factors. J Stroke Cerebrovasc Dis 18:158–63PubMedCrossRefGoogle Scholar
- 25.Taoka T, Iwasaki S, Nakagawa H et al (2006) Evaluation of arteriosclerotic changes in the intracranial carotid artery using the calcium score obtained on plain cranial computed tomography scan: correlation with angiographic changes and clinical outcome. J Comput Assist Tomogr 30:624–628PubMedCrossRefGoogle Scholar