Dataset Information

Associations of edge-detected and manual-traced common carotid intima-media thickness measurements with Framingham risk factors: the multi-ethnic study of atherosclerosis.

ABSTRACT: Carotid intima-media thickness (IMT) is a marker of cardiovascular disease derived from ultrasound images of the carotid artery. In most outcome studies, human readers identify and trace the key IMT interfaces. We evaluate an alternate approach using automated edge detection.We studied a subset of 5640 participants with an average age 61.7 years (48% men) of the Multi-Ethnic Study of Atherosclerosis composed of whites, Chinese, Hispanic, and blacks that are part of the Multi-Ethnic Study of Atherosclerosis IMT progression study. Manual tracing IMT (mt-IMT) and edge-detected IMT (ed-IMT) measurements of the far wall of the common carotid artery served as outcome variables for multivariable linear regression models using Framingham cardiovascular risk factors and ethnicity as independent predictors.Measurements of mt-IMT were obtainable in 99.9% (5633/5640) and measurements of ed-IMT were obtainable in 98.9% (5579/5640) of individuals. Average ed-IMT was 0.19 mm larger than mt-IMT. Inter-reader systematic differences (bias) in IMT measurements were apparent for mt-IMT but not ed-IMT. Based on complete data for 5538 individuals, associations of IMT with risk factors were stronger (P<0.0001) for mt-IMT (model r2, 19.5%) than for ed-IMT (model r2, 18.5%).We conclude that this edge-detection process generates IMT values equivalent to manually traced ones because it preserves key associations with cardiovascular risk factors. It also decreases inter-reader bias, potentially making it applicable for use in cardiovascular risk assessment.

SUBMITTER: Polak JF

PROVIDER: S-EPMC3169166 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Associations of edge-detected and manual-traced common carotid intima-media thickness measurements with Framingham risk factors: the multi-ethnic study of atherosclerosis.

Polak Joseph F JF Pencina Michael J MJ Herrington David D O'Leary Daniel H DH

Stroke 20110505 7

<h4>Background and purpose</h4>Carotid intima-media thickness (IMT) is a marker of cardiovascular disease derived from ultrasound images of the carotid artery. In most outcome studies, human readers identify and trace the key IMT interfaces. We evaluate an alternate approach using automated edge detection.<h4>Methods</h4>We studied a subset of 5640 participants with an average age 61.7 years (48% men) of the Multi-Ethnic Study of Atherosclerosis composed of whites, Chinese, Hispanic, and blacks ...[more]

PMID: 21546477

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Project description:BackgroundIntima-media thickness of the walls of the common carotid artery and internal carotid artery may add to the Framingham risk score for predicting cardiovascular events.MethodsWe measured the mean intima-media thickness of the common carotid artery and the maximum intima-media thickness of the internal carotid artery in 2965 members of the Framingham Offspring Study cohort. Cardiovascular-disease outcomes were evaluated for an average follow-up of 7.2 years. Multivariable Cox proportional-hazards models were generated for intima-media thickness and risk factors. We evaluated the reclassification of cardiovascular disease on the basis of the 8-year Framingham risk score category (low, intermediate, or high) after adding intima-media thickness values.ResultsA total of 296 participants had a cardiovascular event. The risk factors of the Framingham risk score predicted these events, with a C statistic of 0.748 (95% confidence interval [CI], 0.719 to 0.776). The adjusted hazard ratio for cardiovascular disease with a 1-SD increase in the mean intima-media thickness of the common carotid artery was 1.13 (95% CI, 1.02 to 1.24), with a nonsignificant change in the C statistic of 0.003 (95% CI, 0.000 to 0.007); the corresponding hazard ratio for the maximum intima-media thickness of the internal carotid artery was 1.21 (95% CI, 1.13 to 1.29), with a modest increase in the C statistic of 0.009 (95% CI, 0.003 to 0.016). The net reclassification index increased significantly after addition of intima-media thickness of the internal carotid artery (7.6%, P<0.001) but not intima-media thickness of the common carotid artery (0.0%, P=0.99). With the presence of plaque, defined as intima-media thickness of the internal carotid artery of more than 1.5 mm, the net reclassification index was 7.3% (P=0.01), with an increase in the C statistic of 0.014 (95% CI, 0.003 to 0.025).ConclusionsThe maximum internal and mean common carotid-artery intima-media thicknesses both predict cardiovascular outcomes, but only the maximum intima-media thickness of (and presence of plaque in) the internal carotid artery significantly (albeit modestly) improves the classification of risk of cardiovascular disease in the Framingham Offspring Study cohort. (Funded by the National Heart, Lung, and Blood Institute.).

Dataset Information

Associations of edge-detected and manual-traced common carotid intima-media thickness measurements with Framingham risk factors: the multi-ethnic study of atherosclerosis.

Publications

Associations of edge-detected and manual-traced common carotid intima-media thickness measurements with Framingham risk factors: the multi-ethnic study of atherosclerosis.

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