Patient Preparation of the CARDIAC MRI

• Contraindications include the presence of a cardiac pacemaker, cardiac defibrillator, and Swan-Ganz catheter. MR study is also recommended to be delayed for 6 to 8 weeks after an implant or coronary stent placement.
• The cardiac MRI for functional evaluation alone does not require Gd injection. If the patient has a mass, ischemic heart disease or congenital heart disease, then he/she will require Gd injection. If necessary for the further evaluation of cardiopulmonary structures, start an iv line (20 or 22 gauge).
• ECG gating is essential for cardiac imaging. First, prepare the skin for lead placement. If necessary, shave the body hairs for maximum lead-skin contact and scrub the skin with an abrasive to create edema to improve electrical conductivity. Position the ECG electrodes (RA, LA, RL and LL) on the chest of the patient (in supine position, the most motionless area is the posterior chest). It is best to use MRI electrodes which have no metal (only carbon snaps) and a large surface area with abundant lubrication to minimize burns. Do not place leads over bony areas and avoid looping ECG leads which may result in superficial burns and can increase electrical interference from gradient activity. Leads should not be too far away from each other. Click ‘Gating control’ from the Rx manager area, turn on the advanced ECG gating. View R waves for at least 16 heart cycles while patient is lying down still. If there is a difficulty in detecting the R waves, or the R wave amplitude is low (<1mV) reposition the ECG leads. The detected vectors will be I, II, or III leads. Choose the one which has a clean trace. Whenever you change the lead, do not forget to update the R-peak amplitude. If some of the R waves are missing trigger marks, reduce ‘Cardiac Trigger Level’ to 50%.
• Both fast breath-held and respiratory triggered sequences are used in cardiac studies. For respiratory gating and triggering, place the respiratory monitoring bellows around the patient’s abdomen or chest, so the operator will know if the patient is cooperating with breathing instructions.
• Valium (5-10mg po) or Xanax (1-2 mg po) if patient is claustrophobic.
• Provide ear plugs or music headphones. 

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