Cardiovascular MRI is a versatile tool which can provide comprehensive information about heart structure, heart muscle tissue composition, heart function, blood flow to the heart muscle, blood flow to and from various chambers of the heart (valvular function), and viability of the heart muscle. When used judiciously, cardiac MRI can often provide a more complete picture of the heart health than individual tests like echocardiography, coronary angiography, or nuclear cardiology.
Cardiac MRI can visualize the soft tissue structures within the thoraco-abdominal cavity with exquisite contrast. The ability of the MRI to acquire cross sectional images of the heart in arbitrary orientations – unconstrained by acoustic windows, and the ability to manipulate the underlying image contrast with various magnetization preparation methods are unique advantages compared to other cardiac imaging modalities.
Modern cardiac MR images can be acquired with temporal resolutions on the order of few tens of milliseconds and from these images global function of the heart muscle such as cardiac chamber volumes in diastole and systole can be measured with high accuracy and reproducibility. The ability to evaluate both systolic (contracting phase of the heart muscle) and diastolic (relaxing phase of the heart muscle) can provide insight into the health of the heart muscle. With tagging methods, cardiac MRI can also reveal information about regional dysfunction of the heart muscle.
Flow to and between the cardiac chambers is regulated by valves. Cardiac MRI provides quantitative methods to evaluate valvular dysfunction by quantifying the volume of blood transported across a slice which can shed information about the extent of reverse flow due to leaky valves (regurgitation), and the velocity of blood flow which can help evaluate any narrowing (stenosis) across the valve. While Doppler echocardiography can also be used to evaluate valvular function, the ability of MRI to provide direct information about both the quantity of blood flow across a slice as well as the velocity of blood flow renders it a powerful tool in the evaluation of valvular dysfunction.
Infiltrative processes inherent in various cardiomyopathies, e.g., fatty infiltration in the ventricles in patients with arrhythmogenic right ventricular dysplasia, or deposition of amyloid fibrils in the heart muscle as in the case of cardiac amyloidosis, or iron deposition in patients with hemochromatosis, etc. alter MR signal characteristics to sufficient degree that they are routinely used as non-invasive imaging-based biomarkers for the evaluation of these conditions.
Under stress conditions (physiologic or pharmacologically induced) the differential microvascular blood flow between regions of myocardium fed by patent coronary arteries and those fed by coronary arteries with varying degrees of blockage can be evaluated by concurrent administration of MR contrast agents. This measurement of myocardial ischemia does not require the use of radiopharmaceuticals and the associated radiation dose.
Live Healthy Imaging is one of the few select imaging centers that offers cardiovascular MRI in a convenient outpatient setting in the Greater Houston area.