Which pulse sequences are known to create the most tissue heating?

The correct answer is that both Fast Spin Echo (FSE) and Turbo Spin Echo (TSE) pulse sequences are known to create the most tissue heating. These sequences are similar in that they utilize several refocusing pulses, which, while they enhance image quality and reduce scan times, can also lead to increased energy deposition in the tissues.

These techniques operate with multiple radiofrequency (RF) pulses in a shorter time frame, which can significantly raise the specific absorption rate (SAR) in the tissues being imaged. When the SAR is elevated, there is a higher potential for tissue heating, as the RF energy is absorbed by the body's tissues.

Gradient Echo (GRE), while also capable of producing images quickly, generally induces less tissue heating compared to FSE and TSE sequences. This is due to GRE's use of a single RF pulse and variable flip angles, which results in lower energy deposition.

Understanding the thermal implications of these sequences is crucial for ensuring patient safety during MRI procedures, especially for those with conditions that make them more susceptible to heat.