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T1 mapping has also been developed to quantify diffuse myocardial fibrosis. [20] T2-weighted imaging is mainly used to detect myocardial edema which may develop in acute myocarditis or infarction. Phase-contrast imaging uses bipolar gradients to encode velocity in a given direction and is used to assess valve disease and quantify shunts.
Cardiac stress testing is used to determine to assess cardiac function and to disclose evidence of exertion-related cardiac hypoxia. Radionuclide testing using thallium or technetium can be used to demonstrate areas of perfusion abnormalities. With a maximal stress test the level of exercise is increased until the person's heart rate will not ...
Apical four chamber ultrasound view of heart. Transthoracic echocardiography (TTE) uses ultrasonic waves for continuous heart chamber and blood movement visualization. It is the most commonly used imaging tool for diagnosing heart problems, as it allows non-invasive visualization of the heart and the blood flow through the heart, using a technique known as Doppler.
In order to further allow for proper velocity quantification, especially in clinical applications where the velocity dynamic range of flow is high (e.g. blood flow velocities in vessels across the thoracoabdominal cavity), a dual-echo PC-MRI (DEPC) method with dual velocity encoding in the same repetition time has been developed. [5]
In PC-MRI, the quantitative analysis of stroke volume, mean peak velocity, and peak systolic velocity is possible only in the plane that is perpendicular to the unidirectional flow. Additionally, it is not possible to calculate multidirectional flow in multiaxial planes in 2D or 3D PC-MRI.
The E/A ratio is a marker of the function of the left ventricle of the heart. It represents the ratio of peak velocity blood flow from left ventricular relaxation in early diastole (the E wave) to peak velocity flow in late diastole caused by atrial contraction (the A wave). [1]
Cardiac magnetic resonance imaging perfusion (cardiac MRI perfusion, CMRI perfusion), also known as stress CMR perfusion, [1] is a clinical magnetic resonance imaging test performed on patients with known or suspected coronary artery disease to determine if there are perfusion defects in the myocardium of the left ventricle that are caused by narrowing of one or more of the coronary arteries.
The instantaneous wave-free ratio (iFR, sometimes referred to as the instant wave-free ratio or instant flow reserve) is a diagnostic tool used to assess whether a stenosis is causing a limitation of blood flow in coronary arteries with subsequent ischemia. iFR is performed during cardiac catheterisation (angiography) using invasive coronary pressure wires which are placed in the coronary ...