Frequently Asked Questions

Section A 
CMR: Clinical Indications and CMR Applications

Diastolic function can be studied with MR making use of the flow profile across the mitral valve to calculate E and A velocities and their ratio; although this has not been validated very much, several publications have used this approach (e.g. A. De Roos from Leiden).
Using volume measurements over time, filling rates and times to peak filling rate and to half filling have been used in MR much as has been done in nuclear cardiology.
Furthermore myocardial velocities can be measured much as with MVI in echo and diastolic parameters can be extracted but this is more experimental today. Similarly some groups have measured torsion and untwisting as a parameter for recoil and diastolic function.

So, MR can measure diastolic function using some techniques and parameters from echo and nuclear. Untwisting has been the most “original” MR parameter but is now also being measured with echo speckle tracking.

CMR can be used to detect coronary artery disease (CAD) by either looking at infarcted tissue and/or ischemia. Infarcted tissue can be visualised by function CMR in long and short axis orientations and by using viability imaging based on the late enhancement CMR technique, which demonstrates scar and scar distribution within the wall (extent and transmurality of scar tissue) (R. Kim et al, NEJM, 2001, A. Wagner, Lancet, 2003). Ischemia is even more important in the setting of CAD and can be detected by assessing wall motion abnormalities during dobutamine stress CMR or be looking for hypoperfused myocardium during adenosine- (or dipyridamole)-induced hyperemia by first-pass perfusion-CMR. Dobutamine stress-CMR has been shown to yield better sensitivity and specificity for CAD detection in comparison with stress-echocardiography, particularly in those patients with suboptimal echo-windows (Nagel et al. Circulation, 1999). First-Pass perfusion-CMR has been successfully used for detection of CAD defined by quantitative coronary angiography in single center (Schwitter et al, Circulation 2001, Paetsch et al, Circulation 2004) and multicenter trials (Giang et al, Eur. Heart J., 2004). Recently, several multicenter trials compared perfusion-CMR vs SPECT and demonstrated superiority for perfusion-CMR (MR-IMPACT programme: MR-IMPACT: Schwitter et al. ESC Annual Scientific Meeting, Clinical Trial Update II, Stockholm, 2005. MR-IMPACT II: Schwitter et al. AHA Annual Scientific Meeting, Chicago, 2006).

Summary: CMR has been shown to be superior to dobutamine stress echo and SPECT imaging for the diagnosis of significant coronary artery stenoses. It is usually combined with infarct imaging. The prognostic value of CMR imaging for the diagnosis of ischemia and scar has been proven (W.P. Ingkanisorn et al, JACC, 2006; Jahnke et al Circulation 2007; Kwong, Circulation 2006). In addition, one should keep in mind, that MR is free of radiation.

Fat suppression in CMR describes a pulse sequence feature (=imaging acquisition mode), which allows to selectively suppress the signal from fat (unfortunately it does not burn fat). This CMR technique yields additional information e.g. in the evaluation of arrhtythmogenic right ventricular cardiomyopathy (ARVC), where fat can infiltrate the right ventricular myocardium. CMR pulse sequences with and without fat suppression applied to the right ventricular myocardium can objectivate this pathological process in ARVC.
So, fat suppression in CMR does not reduce fat mass in patients. Of course in obesity, the success of a diet e.g. can be accurately quantified by MR (in units of gram). MR allows to selectively image the fat and thus, to quantify subcutaneous as well as intra-abdominal fat, and its reduction caused e.g. by a lifestyle change.

Section B 
CMR: Technical Aspects – Pulse Sequences – Physics

Section C 
CMR: safety

Pacemakers (PM) and ICDs are a contraindication for MR imaging, since leads may heat during rf pulsing in the scanner and the magnetic field and gradient switching can cause malfunctioning of the device (see overview by Shinbane et al, J. Cardiovasc. Magn. Reson., 2007:9;5-13). Reports on incidental imaging of PM and ICD patients with severe and even deadly complications are published. However, in smaller studies patients with PM and ICDs have been imaged without major adverse effects. Since sufficient evidence on safety is missing, PM and ICDs are regarded as contraindicated for MR imaging. In individual cases and with adequate patient preparation (e.g. device programming), corresponding monitoring and expert knowledge available, and follow-up control visits, MR imaging in selected cases may be justified weighting the need for MR information against risk.
During the past 10 years, MR-compatible PMs were under development. The first specifically designed MR-compatible PM underwent successful MR imaging as a world-premiere on April 10, 2007 (University Hospital Zurich, Switzerland, in cooperation with the Federal Institute of Technology, and Medtronic, EnRhythm MRI Study).

The answers to the frequently asked questions (FAQ) represent the opinion of one or several of our nucleus members. The answers are reviewed internally within the nucleus of the ESC WG EuroCMR before communicating them to you and/or posting them on this FAQ section. The answers are reflecting the best of our knowledge, but in no event will the ESC and the ESC WG EuroCMR be liable to the user or anyone else for any decision made or action taken in reliance upon the information contained in or provided through this FAQ initiative, nor for any incidental, indirect, special or consequential damages.