Stress cardiac MRI

What is a cardiac stress MRI?

A cardiac stress MRI is a specialized radiological examination of the heart. It involves performing an MRI scan of the heart while inducing stress using medication. This allows for an assessment of blood flow and heart function under stress conditions.

Magnetic Resonance Imaging (MRI) is a common radiological technique used for various medical examinations. It works by generating a strong magnetic field, causing the atoms in the human body to align in a specific way. A computer then processes this data to create cross-sectional images of the body. MRI has the advantage of being completely free from radiation exposure.

To examine the heart under stress conditions, a cardiac stress MRI involves administering medication that increases heart activity and oxygen consumption. This resembles physical exertion and allows doctors to evaluate how the heart functions under stress.

When is a stress cardiac MRI used?

A stress cardiac MRI is mostly used to assess blood flow to the heart muscle under stress conditions when there is a suspicion of narrowing in a coronary artery. Furthermore, it is used to detect any functional impairments of the heart muscle during stress.

The heart pumps blood through the systemic and pulmonary circulation by rhythmically contracting and relaxing. This mechanism is essential for maintaining circulation. The heart muscle requires a good blood supply to function optimally. For this reason, it has its own blood vessels, known as coronary arteries. These supply the heart muscle during the relaxation phase of the cardiac cycle.

Coronary arteries can become narrowed due to plaque buildup, leading to reduced blood flow to the heart muscle depending on the severity. This condition is known as coronary artery disease (CAD).

Under stress conditions, the heart rate increases, and the relaxation phase of the cardiac cycle is shortened. As a result, there is less time for the heart muscle cells to receive blood. Coronary artery disease therefore often becomes more obvious during stress conditions, which makes a stress cardiac MRIa valuable diagnostic tool.

Moreover, stress cardiac MRI can be used to assess the heart after a previous heart attack (myocardial infarction). Scar tissue forms in the heart muscle following a heart attack, potentially impairing blood flow. Stress cardiac MRI can provide insights into the location and extent of these impairments.

Procedure: how does a specialist perform a cardiac stress MRI?

Before a stress cardiac MRI scan is done, a detailed explanation of the procedure is provided by the attending specialist. The procedure is discussed, and patients are able to ask questions.

Patients are not allowed to consume foods containing caffeine or similar substances for around 24 hours before the examination. This includes coffee, cocoa, cola and energy drinks. In addition, certain medications must not be taken. These will be discussed during the consultation.

MRI machines contain a very strong magnet, which means that all metal objects such as jewelry, watches or piercings must be removed before the examination. Patients are also given venous access so that medication can be administered. A monitor is connected so that blood pressure and heart rate can be monitored.

There are two types of stress cardiac MRIs: stress perfusion MRI and dobutamine stress MRI.

Stress perfusion MRI

In this procedure, patients are given a drug that causes the blood vessels to dilate. This causes the blood pressure to drop and the heart rate to increase. A contrast agent is also administered. Stress perfusion MRI primarily provides information on the blood flow to the heart muscle. The coronary vessels are examined before and after administration of the drug to assess and compare blood flow at rest and under stress.

Dobutamine stress MRI

During this examination, patients receive a continuous infusion of medication that increases heart activity via a syringe pump. The medication is usually dobutamine, which is similar to adrenaline. It is administered until a predetermined maximum heart rate has been reached.

The MRI images now provide information on possible wall movement disorders of the heart muscles. The additional administration of a contrast agent also allows scarring to be identified.

The entire examination takes about an hour. During this time, patients lie on an examination table inside the MRI machine. The medical staff monitor the patient and their vital signs from the neighboring room using a camera. The examination is painless, although the loud noises of the MRI machine can be uncomfortable.

What results does a stress cardiac MRI provide?  

A stress cardiac MRI provides important insights into blood flow in the heart muscle under stress conditions. It is used to identify and assess significant narrowings of the coronary arteries. Additionally, in cases of suspected blood flow disturbances, the scan can help differentiate between a stenosis and a scar from a previous heart attack as the underlying cause. Studies also suggest that stress cardiac MRIs can help estimate the risk of a future heart attack.

Costs: does health insurance cover the costs of a stress cardiac MRI?

The cost of a stress cardiac MRI is around 900 to 1200 euros per examination. There is currently no standardized regulation for cost coverage by health insurance companies. Nevertheless, in some cases the costs are refunded by private health insurance companies.

It is advisable to obtain information on possible cost coverage from the clinic carrying out the examination and from the respective health insurance company beforehand.

Risks: is a cardiac stress MRI dangerous?

As a stress cardiac MRI simulates heart stress, there are certain risks associated with the procedure. To prevent complications, the examination is not performed in patients with certain risk factors. These include having very low or very high blood pressure, acute heart failure, unstable angina pectoris (chest pain), or a recent heart attack (within the last 48 hours).

Due to the medication used to stress the heart, patients may experience palpitations, headaches, or chest tightness. However, continuous monitoring is in place throughout the entire procedure to ensure patient safety.

If any complications such as arrhythmias, severe blood pressure fluctuations, or significant ECG changes occur, the examination is immediately stopped.

Which doctors & clinics specialize in stress cardiac MRI?

The performance and interpretation of  stress cardiac MRI requires close collaboration between radiologists and cardiologists. Therefore, a specialist from each field is present throughout the entire examination.

Stress cardiac MRI is available in the radiology departments of most hospitals and in some specialized radiology clinics.

Heart conditions should always undergo comprehensive diagnostic evaluation. As a patient, it is important to rely on experienced specialists for diagnosis and treatment. Our goal is to connect patients with leading experts to ensure the highest level of medical care based on the latest scientific standards.

All radiologists and cardiologists listed here specialize in stress cardiac  MRIs and have extensive experience in the field. See for yourself and schedule an initial consultation quickly and easily with one of our experts.

Sources:

• Klinikleitfaden Kardiologie. Ulrich Stierle, Franz Hartmann. Urban&Fischer. 2013.
• Basiswissen Radiologie – Nuklearmedizin und Strahlentherapie. Martina Kahl-Scholz, Christel Vockelmann. Springer-Verlag 2017.
• Deutsche Gesellschaft für Kardiologie – Herz- und Kreislaufforschung e.V.
• dgk.org/pressemitteilungen/2014-jahrestagung/2014-ft-aktuelle-pm/2014-ft-pm/pm-tag3/deutsche-studie-stress-mrt-sagt-herzinfarktrisiko-verlaesslich-voraus/
• leitlinien.dgk.org/files/2021_stellungnahme_kompetenz_und_innovation_mrt.pdf