Final answer:
FFR and IVUS are techniques used for CAD quantification. FFR measures pressure difference while IVUS uses ultrasound imaging.
Step-by-step explanation:
The comparison between FFR (Fractional Flow Reserve) and IVUS (Intravascular Ultrasound) for CAD (Coronary Artery Disease) quantification involves understanding the purpose and functionality of each diagnostic tool in assessing the severity of stenoses.
FFR is a pressure-guided index used during coronary angiography to measure the pressure difference across a coronary stenosis. It provides an assessment of the functional significance of the narrowing in the coronary arteries by indicating how much the lesion is impairing blood flow. A value of 0.80 or less suggests that the stenosis is hemodynamically significant and likely causing myocardial ischemia, which may necessitate intervention, such as stenting or bypass surgery.
IVUS, on the other hand, gives a cross-sectional image of the coronary artery. It's an imaging modality that uses ultrasound to visualize the arterial wall and provides detailed anatomical information regarding plaque characteristics, vessel size, and the extent of atherosclerosis. Unlike FFR, IVUS does not provide functional information on blood flow but is excellent for guiding stent placement and ensuring optimal expansion and apposition to the vessel wall.
In clinical practice, FFR and IVUS can be complementary when treating patients with CAD. The choice between or combination of these tools often depends on individual patient factors and the complexity of coronary lesions.