Mannheim carotid intima-media thickness and plaque consensus (2004-2006-2011). An update on behalf of the advisory board of the 3rd, 4th and 5th watching the risk symposia, at the 13th, 15th and 20th European Stroke Conferences, Mannheim, Germany, 2004, Brussels, Belgium, 2006, and Hamburg, Germany, 2011

Abstract

Intima-media thickness (IMT) provides a surrogate end point of cardiovascular outcomes in clinical trials evaluating the efficacy of cardiovascular risk factor modification. Carotid artery plaque further adds to the cardiovascular risk assessment. It is defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value or demonstrates a thickness >1.5 mm as measured from the media-adventitia interface to the intima-lumen interface. The scientific basis for use of IMT in clinical trials and practice includes ultrasound physics, technical and disease-related principles as well as best practice on the performance, interpretation and documentation of study results. Comparison of IMT results obtained from epidemiological and interventional studies around the world relies on harmonization on approaches to carotid image acquisition and analysis. This updated consensus document delineates further criteria to distinguish early atherosclerotic plaque formation from thickening of IMT. Standardized methods will foster homogenous data collection and analysis, improve the power of randomized clinical trials incorporating IMT and plaque measurements and facilitate the merging of large databases for meta-analyses. IMT results are applied to individual patients as an integrated assessment of cardiovascular risk factors. However, this document recommends against serial monitoring in individual patients.

Fig. 1

Longitudinal view of CCA and carotid bifurcation and origin of internal and external carotid arteries. The double arrow line corresponds to the end of the CCA, where near and far walls start diverging.

Fig. 2

Age-related quartiles of risk factors (RF). No patients between 30 and 39 years have >3 risk factors

Fig. 3

Drawn representation of carotid tree, with plaque and IMT measurement according to Mannheim consensus: (1) thickness >1.5 mm; (2) lumen encroaching >0.5 mm; (3, 4) >50% of the surrounding IMT value.

Fig. 4

Automatic selection of the end diastole frame from a CCA video acquisition for an IMT measure.

Fig. 5

IMT measurement in diastole on the selected frame. QI = Quality Index indicates that 94% of 150 measures could be performed. Maximal is the highest value obtained from all the elementary measures. Mean is the average of all the measurements that could be performed.