Type I lesions consist of the first microscopically and chemically detectable lipid deposits in the intima and the cell reactions associated with such deposits.The initial histological changes in the human intima are minimal. Small, isolated groups of macrophages containing lipid droplets (macrophage foam cells) form. In coronary arteries these cells pref- erentially accumulate in regions of the intima that have an adaptive intimal thickening of the eccentric type.