A system includes an in vivo imaging device for imaging a blood vessel with a resolution level of at least fifty micrometers. The in vivo imaging device is capable of detecting a microcalcification in a fibrous cap of an atheroma. The system also includes a processor for receiving an image of the blood vessel from the in vivo imaging device. The processor uses the image to determine whether the blood vessel contains at least one microcalcification within the fibrous cap. In some embodiments, the processor is configured and arranged to predict a risk of rupture of the fibrous cap based, at least in part, on the presence of the at least one microcalcification. In some embodiments, treatment of a patient is based on the determination from the imaging whether the blood vessel includes at least one microcalcification within the fibrous cap of the atheroma.
