Disadvantages of cardiac MR

• cardiac magnetic resonance (CMR) cannot be used in patients with large implanted metallic devices, such as cardiac defibrillators or pacemakers (although there are some MRI compatible pacing devices now available). However, patients with modern mechanical heart valves or coronary artery stents can be imaged safely
• CMR requires patients to lie inside a narrow tube for a considerable amount of time. Consequently, some patients experience anxiety and claustrophobia - this can sometimes be overcome by using sedation
• image quality may be suboptimal in patients who are unable to hold their breath or in those with an irregular heart rate, such as atrial fibrillation
• in patients with severe renal impairment gadolinium contrast (used to image myocardial scarring) can lead to the rare complication of nephrogenic systemic fibrosis
• CMR requires a highly trained multidisciplinary team, including cardiologists, radiologists, radiographers and physicists

Reference:

• 1) British Heart Foundation Factfile (January 2010). Cardiac imaging with MRI, CT and Nuclear techniques.