Which scenario poses a high risk for patient burns during MRI?

The scenario involving a temporary epicardial pacing wire in the RF field poses a high risk for patient burns during MRI due to the nature of the device and its interaction with the radiofrequency (RF) energy used in MRI. Epicardial pacing wires are typically made of conductive materials and can heat up significantly when subjected to the RF fields during an MRI scan. This heating effect can lead to thermal injuries or burns on the patient's skin or internal tissues at the site where the wire is in contact with the body.

In contrast, while a tattoo using yellow ink may contain metals that could theoretically heat up, the effect is generally much less significant compared to conductive materials used in medical devices such as pacemaker wires. A bullet within the RF field presents risks related to magnetic forces and potential displacement or movement, but it is less likely to cause burns compared to the heating effects of conductive pacing wires. Lastly, a hip replacement outside the RF field is unlikely to pose any burn risk as it is not directly within the area of RF exposure where heating effects can occur.

Therefore, the critical factor in this scenario is the presence of the temporary epicardial pacing wire within the RF field, leading to significant risks for burns during the MRI procedure.