Measurement · not graded
Carotid Ultrasound (Intima-Media Thickness and Plaque)
What the evidence looks at: added value over standard risk factors for predicting heart attack and stroke.
At a glance
A carotid scan uses ultrasound to look at the wall of the main neck artery and at any plaque. This page asks whether the scan improves a heart attack or stroke risk estimate. Adding wall thickness to the usual risk factors helped very little. Plaque helped a bit more. A scan gives information, and what is done about the risk is a separate question.
What the studies looked at: Added value over standard risk factors for predicting heart attack and stroke
Why this letter
Ungraded: a carotid ultrasound measures the artery wall, it does not treat anything. The letters on this site belong to interventions. A scan that finds plaque or a thick wall is information for a risk estimate; what is then done about that risk is graded on its own record.
In 14 cohorts and 45,828 people, adding intima-media thickness to the Framingham risk factors improved 10-year prediction of heart attack or stroke by an amount the authors judged unlikely to matter clinically (net reclassification 0.8 percent; Den Ruijter 2012, PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 22910757). Change in thickness between two scans did not predict events, and did not even repeat between scans (PROG-IMT, PMID 22541275). Plaque predicted heart attack slightly better than thickness (PMID 21764060), and in the MESA cohort coronary artery calcium added more to prediction than either (PMID 25596139).
Evidence notes: Risk-prediction studies (measurement value)
Last reviewed: October 2026
Dose, form and timing
A single scan feeds a one-time risk estimate. In the PROG-IMT cohorts, the change in thickness between two scans did not predict events and did not repeat from one pair of scans to the next (PMID 22541275).
Grade history
How this letter has changedLatest: No. 340 · October 2026 · Corrected.
Carotid scans were sold direct to consumers at a longevity conference, so they now have a record. Like DEXA, the scan is a measurement and carries no letter. Den Ruijter et al. (JAMA, 2012; PMID 22910757) found intima-media thickness added little to standard risk factors across 45,828 people, and Lorenz et al. (Lancet, 2012; PMID 22541275) found change between two scans did not predict events.PMID 22910757 PMID 22541275
Every change to a letter on this site is dated and published. The full evidence log →
Sources
Primary evidenceFour papers, each linked to its PubMed record.
Den Ruijter et al. (JAMA, 2012; PMID 22910757): individual-participant meta-analysis A study that pools the numbers from several trials into one combined estimate. of 14 population cohorts, 45,828 people without cardiovascular disease, median 11 years; adding common carotid intima-media thickness to the Framingham risk factors gave a net reclassification improvement of 0.8 percent (3.6 percent at intermediate risk), judged unlikely to be clinically important. Lorenz et al. (Lancet, 2012; PMID 22541275), the PROG-IMT project: 16 cohorts, 36,984 people; yearly progression of thickness between two scans was not associated with events (hazard ratio How often an event happened in the treated group compared with the control group over the same period. A ratio of 0.80 means 20 percent fewer events. 0.98), and in people with four scans progression did not correlate between occasions. Inaba et al. (Atherosclerosis, 2012; PMID 21764060): meta-analysis of 11 cohorts, 54,336 people; plaque predicted myocardial infarction slightly better than thickness (area under the curve 0.64 against 0.61). Gepner et al. (Circ Cardiovasc Imaging, 2015; PMID 25596139), MESA: 6,779 adults over 9.5 years; coronary artery calcium improved prediction of cardiovascular disease more than carotid plaque or thickness, and thickness above the 75th percentile alone did not predict events. Ungraded: measurement value, not a treatment claim.
Disclosure
Educational use only · Not medical advice · EBL grades published human evidence and does not recommend treatment.
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