Cardiac Application Tips

Patient Set-up

Before the Study

1. Ensure that the patient has no contraindications for MR pacemaker, implanted defibrillator, Swan-Ganz catheter, recent coronary stenting (<6 wks), and other conventional contraindications. Prosthetic valves and IVC filters are not contraindicated.
2. Identify the specific clinical question. It is vital that the referring physician provide clinical information and define the specific question at hand. For example, anatomic questions will require predominantly fast spin echo imaging and selected cine gradient echo images, while functional questions may require flow quantification and comprehensive cine images.
3. Assess for a history of cardiac arrhythmias since they can significantly impair cardiac imaging.
4. MR hardware and software demands. To perform cardiac MR routinely, a high-performance system is required that will enable cine gradient echo imaging and 3D contrast-enhanced MR angiography each to be performed within a breath-hold (acquisition times < 25 sec). Phase-contrast flow quantification should also be available. Post-processing software (for calculations of LV volumes and EF) can be very useful.

Patient Set-Up

1. A dedicated cardiac or torso phased-array coil is typically used for cardiac and thoracic aorta imaging. The body coil can be used for whole body aortic imaging if high spatial resolution is not essential. Use smaller coils for smaller patients (head coil for infants).
2. ECG leads are needed for all cardiac cases and for aortic studies for dissection and where evaluation of the aortic valve and root is needed. Leads can be positioned on either the anterior or posterior chest wall. Posterior positioning may cause less motion artifact. MR-compatible ECG leads with adhesive and conductive gel should be used and wires braided or twisted (without looping). Ensure good contact by shaving the skin if necessary. Check tracing before scanning (reposition leads to maximize R waves). Consider peripheral gating if all else fails.
3. Consider mild sedation to ensure minimal motion. Pediatric cases typically require sedation.
4. For patients who are unable to breath hold adequately, 2 liters by nasal cannula can be helpful.
5. Intravenous and gadolinium contrast only needed for MR angiography of the aorta or pulmonary arteries (or coronary arteries).
6. MR compatible monitoring devices that include blood pressure, pulse, and end-tidal CO2 are commercially available and are important for pharmacologic studies or in potentially unstable patients.