In examining patients with cardiomyopathy, various imaging techniques are used to determine the form of the disease, the severity of heart damage. This is magnetic resonance imaging or conventional computed tomography, the study of coronary arteries with contrast, as well as a specific stress test using thallium, a labeled isotope. A sleep study in the lab with polysomnography is also shown. Why is all this necessary?
Thallium Stress Tests: A Heart Exam
Many patients with dilated or restrictive cardiomyopathy can undergo a cardiac stress test with thallium to assess how well the heart is supplied with blood, how effective the ventricles or atria are. This information is used to decide the best way to treat patients.
Magnetic resonance imaging (MRI) for cardiomyopathy
MRI uses strong magnetic fields and radio waves instead of radiation to create three-dimensional images and two-dimensional cross-sections of the heart. Images created with magnetic resonance imaging, similar to x-rays, but show more detailed information about the soft tissues of the body.
Magnetic resonance imaging is performed in a large tube by MRI Scan Centres in Noida that is wide enough to accommodate a patient lying on a couch. Radio waves and strong magnetic fields are generated inside the shell of the tube and directed towards the body during magnetic resonance imaging. The body reacts by emitting weak energy signals that are detected by a scanner. A computer converts these signals into three-dimensional images of the heart that can be moved to obtain any two-dimensional cross-section.
Magnetic resonance imaging involves the removal from the body of all accessories and clothing containing metal, including jewelry, metal fasteners, prostheses, wigs and hearing aids. Metallic objects can interfere with the magnetic field, affecting image quality. Magnetic resonance imaging is painless; it usually lasts from 30 to 60 minutes.
The procedure involves lying on a table that slides into the tube. The motion may blur images, so it is important to lie still. The space inside the tube is rather narrow, and some patients may feel uncomfortable. Patients are often offered headphones or earplugs that help block out loud squeaking and percussion sounds generated by an MRI machine.
MRI examination of the coronary arteries Magnetic resonance angiography (MRA) of the coronary arteries is one of the new applications of MRI. For this test, a contrast agent is injected into the vein on the arm. Contrast medication facilitates visualization of the heart and reveals the coronary arteries. One of the advantages of an MRA is that contrast agents tend to cause fewer allergic reactions than those used during computed tomography.
There are no known risks from magnetic fields, and radio waves generated when the coronary arteries are visualized. However, people who have pacemakers, cardioverter defibrillators, or other metal-containing objects inside the body cannot be examined with MRI. Also, the effect of magnetic fields on the fetus is not well understood, so an MRI scan is not recommended for pregnant women.
Computed tomography in the diagnosis
If there is evidence, computed tomography is also performed, but it may not provide the full amount of information, especially if it is performed without contrasting. However, for patients with implanted electronic devices, tomography is the only choice.