Abstract: The present invention provides in vivo methods for detection of vulnerable plaque in a subject in need thereof. In the invention method the subject is administered a diagnostic amount of a biologically compatible detectable lipid-avid agent, the detectable lipid-avid agent is allowed to penetrate arterial walls and attach to any lipid accumulations of oxidized LDL-cholesterol in arterial walls in the wall of an artery; unbound detectable lipid-avid agent is allowed to clear from the body by natural processes, and the presence of the detectable lipid-avid agent attached to the lipid accumulation in the wall of the artery is detected. Detection of bound lipid-avid agent indicates the presence of a vulnerable plaque and predicts a heightened risk of lethal heart attack or thrombus. The detectable lipid-avid agent is selected for its ability to penetrate arterial walls and bind with oxidized LDL-cholesterol in the lipid accumulation in a vulnerable plaque.