Carotid Intima-Media Thickness (CIMT)

•Observational— Cohort-validated; supplanted by CAC for risk stratification in many centres

What it shows

CIMT measures the combined thickness of the intima and media of the common carotid artery. It rises with age, smoking, hypertension, dyslipidaemia, diabetes. Discrete carotid plaques are even more predictive than mean CIMT.

CIMT vs CAC

For risk stratification in middle-aged adults, CAC has largely supplanted CIMT in many centres because:

• CAC is more reproducible.
• CAC has stronger event prediction in head-to-head studies.
• CAC of zero is a very strong negative prediction.

CIMT retains advantages: no radiation, can detect early non-calcified disease, useful in younger adults where CAC may still be zero with real plaque present.

When CIMT is most useful

• Pre-CAC age (under 40–45) where calcification has yet to develop.
• Family-history-positive adults wanting non-radiation alternative.
• Tracking response to lipid-lowering therapy over years.

Limitations

• Operator-dependent.
• Standardisation across labs imperfect.
• Less event-prediction than CAC in head-to-head trials.

Related entries

CAC score, ApoB, Cardiovascular disease.