Intracranial Internal Carotid Artery Calcifications: Association with Vascular Risk Factors and Ischemic Cerebrovascular Disease

) that were significantly associated with ICAC volume. Rs1537372 replicated in an independent sample of 716 stroke patients (P combined =1.38×10 −10 ). Conclusions-ICAC volume is a heritable trait, which is partly explained by common genetic variation. We identified specific genetic variants associated with ICAC, which given the importance of ICAC in stroke risk, needs replication in larger-scale studies to further elucidate its genetic basis.

Section: Assessment Of Icacmentioning

confidence: 99%

Heritability and Genome-Wide Association Analyses of Intracranial Carotid Artery Calcification

Adams

Ikram

Vernooij

et al. 2016

“…Extracranial and intracranial carotid artery calcifications are associated with cardiovascular risk factors and history of stroke. 13,22,23 Furthermore, extracranial carotid artery calcifications are associated with carotid artery stenosis in asymptomatic patients, but in symptomatic patients this association is less clear. [24][25][26] Moreover, calcifications can be assessed easily and quantified at MDCTA, an imaging modality increasingly used in daily clinical work-up of patients with stroke, making them a suitable and robust marker of atherosclerosis.…”

Section: Discussionmentioning

confidence: 99%

“…A detailed description of the measurements is provided elsewhere. [12][13][14][15] An intraclass correlation coefficient and coefficient of variation for the aortic arch, extracranial and intracranial carotid artery scoring method was assessed in 29 MDCTA examinations based on the ratings of 2 observers. The intraclass correlation coefficient was 1.00 and the coefficient of variation 10% to 11% for all 3 vessel beds.…”

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confidence: 99%

Association Between Arterial Calcifications and Nonlacunar and Lacunar Ischemic Strokes

Dijk¹,

Fonville²,

Zadi³

et al. 2014

Background and Purpose-Nonlacunar cerebral infarcts are presumed to be caused by thromboembolism from the heart or extracranial arteries, whereas lacunar infarcts are thought to be caused by small vessel disease. We investigated to what extent arterial calcifications differ between nonlacunar and lacunar ischemic strokes. Methods-We studied 820 consecutive patients with transient ischemic attack or ischemic stroke in the anterior circulation who underwent multidetector computed tomography angiography and had no rare cause of stroke.

“…However, the authors also argue that these methods, especially the method described by de Weert et al, 3 are too time consuming and impractical for larger epidemiological studies. From our experience, there is typically less time pressure in epidemiological studies than in clinical practice, and there is more emphasis on the precision of measurements.…”

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confidence: 99%

“…From our experience, there is typically less time pressure in epidemiological studies than in clinical practice, and there is more emphasis on the precision of measurements. Against this background, we would like to highlight that we quantified ICAC semiautomatedly 3 in a large, prospective population-based sample of >2500 middle-aged and elderly people and found that larger calcification volumes considerably increased the risk of stroke. 4 This quantification strategy was relatively time consuming (≤8 minutes for a 1-mm thin slice protocol) but definitely not insuperable.…”

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confidence: 99%

Letter by Bos et al Regarding Article, “Intracranial Carotid Calcification on Cranial Computed Tomography: Visual Scoring Methods, Semiautomated Scores, and Volume Measurements in Patients With Stroke”

Bos

Bruijne

Lugt

2015

1in which the performance of 2 visual scoring methods for intracranial carotid artery calcification (ICAC; ie, the original Woodcock score 2 and a modified Woodcock score) is compared with volumetric ICAC measurements. The original Woodcock score characterizes calcification in the intracranial carotid artery as absent, mild, moderate, or severe. The modified Woodcock score as proposed by the authors involves the same 4-point classification, but it was applied to each slice of the computerized tomographic examination and then summed into a total calcification score.The authors found a high correlation between the original Woodcock score and volumetric calcification measurements. Not surprisingly, this correlation improved for the modified score, which may be explained by the fact that more inspections reflect a more accurate approximation of the actual calcification volume. This directly underlines that, in contrast to the original score, the modified Woodcock score still involves slice-to-slice investigation of the total trajectory of the intracranial internal carotid artery. Although we expect that this could be less time consuming than slice-to-slice annotation of calcification, which is necessary for quantification, one should carefully balance the amount of information lost because of visual rating against time invested in the quantitative measurements.At this moment, the semiautomated methods for ICAC quantification may be too complicated and time consuming for clinical use. However, the authors also argue that these methods, especially the method described by de Weert et al, 3 are too time consuming and impractical for larger epidemiological studies. From our experience, there is typically less time pressure in epidemiological studies than in clinical practice, and there is more emphasis on the precision of measurements. Against this background, we would like to highlight that we quantified ICAC semiautomatedly 3 in a large, prospective population-based sample of >2500 middle-aged and elderly people and found that larger calcification volumes considerably increased the risk of stroke.4 This quantification strategy was relatively time consuming (≤8 minutes for a 1-mm thin slice protocol) but definitely not insuperable.We think that future research on ICAC could benefit from the development of fully automated quantification tools, given several advantages of quantitative image analysis over qualitative ratings.5 Quantitative analyses are more objective and reproducible and provide continuous measures that are more sensitive to small changes. With respect to interscan reproducibility, an important consideration on the modified Woodcock score is the high dependency on the slice thickness (ie, the sum score is directly depending on the number of slices), whereas for quantitative/volumetric analyses, the slice thickness is taken into account in the calculations. There are numerous biomarkers for which qualitative scales have been replaced by automated quantification algorithms. Examples include the quantificatio...