Cardiovascular MRI: Using Delayed Gadolinium Enhancement for the Best Cardiac Images

The primary reasons people have studies of their heart with MRI currently fall into one of three categories:

1. Patients who have coronary artery disease, and usually they have already had some sort of cardiac event, for example, a heart attack.
2. Patients with cardiac arrhythmias coming for evaluation if they have scars in their heart from some type of non-coronary artery disease.
3. About one in five patients come in for evaluation of arrhythmogenic right ventricular dysplasia.

Most of the exams are done while the patient is holding their breath for eight to 10 seconds. To get the best cine images of the heart, each slice of the heart is usually about an eight second breath-hold. Doing that in a really reproducible manner is critical for good cardiac image quality.

Certainly, very sick patients may not breathe reproducibly, and in those cases, we need to image a lot faster than their breathing motion. In MRI, there is a tradeoff between how fast you can image, and the spatial resolution of the cardiac images.

It does not matter if it is in angiography or in cine imaging. The faster you go, the more you have to compromise somewhere, and we usually compromise in spatial resolution of the cardiac images.

Patients who already have a pacemaker or ICD are cause for concern in terms of the effect of the MR and even the CT scan in reference to device failure.

Other safety concerns are in reference to the contrast agents used in cardiac imaging.

Delayed gadolinium enhancement imaging is the single most important exam we do because it is a very high spatial resolution examination. We administer the gadolinium, wait at least 10 minutes, and the area that contains scar tissue retains the gadolinium and is brighter than the rest of the myocardium.

Bright means dead. So, if there is bright enhancing myocardium, it is nonviable because the scar retains the gadolinium.

Gadolinium is used to distinguish cardiomyopathy from coronary artery disease and also to detect arrhythmogenic right ventricular dysplasia. More unusual conditions, like sarcoidosis, also have gadolinium uptake on the delayed images.

The use of gadolinium poses some safety concerns, which have been addressed in detail by the FDA in their most recent FDA Public Health Advisory on Gadolinium-containing Contrast Agents.

ProHance has been used safely in the main, even in renal patients.

Overall health and risks versus rewards need to be weighed for each cardiac patient, but it is clear that using delayed gadolinium enhancement is currently our most effective method for producing the best cardiac images for accurate diagnosis of heart disease.

Reference: FDA Public Health Notice: Possible Malfunction of Electronic Medical Devices Caused by Computed Tomography (CT) Scanning

—–

CME: Body Imaging: Abdominal, Thoracic and Vascular
University of California, San Francisco, Department of Radiology
This CME program carries 18.5 AMA PRA Category 1 Credits and is designed for the radiologist in clinical practice.

Hot topics include cardiac imaging, multidetector CT, CT/MR angiography, virtual colonoscopy, and tumor ablation.

Read more or order: Body Imaging: Abdominal, Thoracic and Vascular