Using intravascular ultrasound (IVUS), stenosis formation and restenosis (or late lumen loss following coronary angioplasty procedures) can be subdivided into two distinct underlying components: tissue accumulation and arterial remodeling. Arterial remodeling is defined as a change in total arterial cross-sectional area over time; it can be adaptive (an increase in arterial cross-sectional area as a compensatory response to plaque accumulation) or pathologic (a decrease in arterial cross-sectional area or chronic arterial shrinkage). Adaptive arterial remodeling can delay the development of coronary artery stenoses and prevent restenosis; pathologic remodeling can contribute to de novo lesion formation and has been shown to be the dominant mechanism of restenosis following coronary intervention. Serial IVUS studies have also been used to study the natural history of the restenosis process; adaptive remodeling occurs early (within 1 month) and pathologic remodeling occurs late (between 1 and 6 months) after intervention. The residual plaque burden postintervention acts as an amplifier in this process.