A patient is scheduled for a magnetic resonance imaging (MRI) scan for suspected lung cancer. Which of the following is a contraindication to the study for this patient?
A. The patient is allergic to shellfish.
B. The patient has a pacemaker.
C. The patient suffers from claustrophobia.
D. The patient takes antipsychotic medication.
Correct Answer: B. The patient has a pacemaker
The implanted pacemaker will interfere with the magnetic fields of the MRI scanner and may be deactivated by them. Patients with cardiac implantable electronic devices or CIED are at risk for inappropriate device therapy, device heating/movement, and arrhythmia during MRI. These patients must be scheduled in a CIED blocked slot or scheduled with electrophysiology nurse or technician support. But nowadays MRI conditional cardiac implantable electronic devices are widely available.
Option A: Shellfish/iodine allergy is not a contraindication because the contrast used in MRI scanning is not iodine-based. MRI contrast agents are gadolinium chelates with different stability, viscosity, and osmolality. Gadolinium is a relatively very safe contrast; however, it rarely might cause allergic reactions in patients.
Options C: Open MRI scanners and anti-anxiety medications are available for patients with claustrophobia. Claustrophobic patients might refuse to complete the MRI scan and need sedation. These patients need to be well informed about the MRI scan procedure. The recommendation is that a physician has a discussion with them about the details in advance. Using Larger and opener MRI systems might be helpful in claustrophobic patients.
Option D: Psychiatric medication is not a contraindication to MRI scanning. MRI helps in high-resolution investigations of soft tissues without the use of ionizing radiation. This safe modality currently becomes the imaging technique of choice for diagnosing musculoskeletal, neurologic, and cardiovascular disease. However, there are restrictions and contraindications caused by MRI magnetic fields, machine structure, and gadolinium contrast agents.