Why is MRI necessary when my cath showed normal coronaries and valves? 

Why would an MRI be needed if a cath didn’t show blocked arteries or a damaged valve? I have a subaortic membrane that needs to be taken out and I just don’t feel I need a MRI after the cath showed no other problems.

Submitted by Pam from Gainesville, Florida on 10/02/2013

by Benjamin Y. Cheong, MD

Coronary angiography (cath) and cardiac magnetic resonance imaging (CMR) provide different information.

As a pre-operative evaluation, it is often very common, if not mandatory, to show the status of the coronary arteries, so that during open heart surgery, coronary bypass surgery could be performed simultaneously (in your case with surgery of the subaortic membrane).

CMR is a very good modality for visualizing and locating the subaortic membrane, showing its relationship with the aortic valve (an important factor to know as part of the surgical planning) as well as to assess the function of the aortic valve to confirm it is not leaking. CMR can also assess the degree of “obstruction” of the subaortic membrane and can help clinicians decide if surgery is needed, or can be deferred for a time. Finally, CMR also provides a comprehensive assessment of the heart itself, to see if there are any other aspects of heart disease (such as hypertrophy or wall thickening of the heart).

From the information provided, it appears that you already have the diagnosis of subaortic membrane and are planning for surgery. As you discuss this with your Cardiologist / Cardiac Surgeon, I am sure they can explain the reason(s) for a CMR in your individual case. Best wishes. I hope the above helps.