What is a common contraindication for the use of MRI?

The presence of metal implants or devices is a common contraindication for the use of MRI due to the strong magnetic fields generated during the procedure. These magnetic fields can cause metal objects to move or heat up, potentially leading to injury or interference with the function of medical devices. Certain implants, such as pacemakers, cochlear implants, and other metallic devices, can pose significant risks during an MRI, including malfunctioning of the device or harm to the patient.

In contrast, while obesity can complicate the MRI process due to equipment size limitations, it is not an absolute contraindication. Pregnancy can also raise concerns regarding MRI, but it is not categorically contraindicated; rather, it is assessed on a case-by-case basis to weigh the risks and benefits. Previous allergic reactions are relevant mainly to contrast agents used in MRI, but do not generally contraindicate the MRI itself unless a specific allergy necessitates avoiding a certain contrast agent.