Intravascular palpography for vulnerable plaque assessment

For the detection of vulnerable plaque, it is not only important to measure the composition and geometry of the plaques but also the response of the tissue on the pulsating force applied by the blood pressure. The plaque is supposed to be rupture-prone, if the cap is unable to withstand the stress applied on it. All the stress that is applied on the plaque by the blood pressure is concentrated in the cap, since the lipid pool is unable to withstand forces on it.1,2 This leads to a higher stress in a thin cap compared with a thicker cap. Furthermore, the strength of the cap is affected by inflammation: fibrous caps with inflammation by macrophages were locally weakened.3 Therefore, the strength of a cap seems to be a more important parameter than the thickness of the cap.