Table 1. Summary of Hemodynamic Parameters and Their Clinical Applications.

Parameter*	Definition	Physiological Implication	Application in Previous Studies	Notes
Flow velocity & flow rate	Amount of blood transported	Abnormal increase or decrease in blood flow indicates possible ischemia or local contraction of vessel	1. Peak velocity at aortic valve (14,68) 2. In- and outflow within intracardiac chamber (30,56,69,70) 3. Flow rate through intracardiac branches (72,73)	Sufficient spatial and temporal resolutions are required
WSS	Frictional shearing force on vessel	Abnormal alteration of flow pattern near vessel wall influences vascular dysfunction	1. WSS increase in patients with BAV (3,4,74) 2. Low & oscillatory WSS in carotid artery (2) 3. WSS increase in intracranial aneurysms (75,76,77)	WSS can be influenced by spatial resolution
Vortex	Rotational structure of blood flow	Abnormal appearance of vortical flow indicates abnormal alteration of flow pattern	1. Development of vortex flow at pulmonary hypertension (57)	Vortex identification can be highly influenced by noise
TKE	Turbulent kinetic energy	Increased TKE indicates more energy loss of blood flow	1. Increased TKE at aortic stenosis (17) 2. Increased TKE at cardiomyopathy (78)	More than two acquisitions are required
Relative pressure	Pressure gradient from arbitrary reference	Increased pressure drop indicates decreased blood flow or increased work load of heart	1. Pressure gradient through stenosis in aorta (23,65,66,79,80) and carotid, iliac (82), and renal (81) arteries 2. Pressure distribution at intracardiac plaque (83)	Influence of turbulence on pressure field cannot be included

^*Note that most of parameters except flow velocity and flow rate are currently unavailable in most commercial software. Therefore, development of in-house software is required to estimate hemodynamic parameters. BAV = bicuspid aortic valve, TKE = turbulent kinetic energy, WSS = wall shear stress