Patient warming or thermal loading in MRI is quantified using Specific Absorption Rate (SAR). SAR measures the rate at which energy is absorbed by the body when exposed to the radiofrequency (RF) fields generated during an MRI scan. It is expressed in watts per kilogram (W/kg) and provides a critical metric for assessing the safety and thermal effects of MRI on patients.
Monitoring SAR is essential for ensuring that the temperature rise in the patient's body remains within safe limits during an MRI procedure. High SAR values can increase the risk of burns or other heat-related injuries, which is why understanding and managing SAR is crucial in MRI safety protocols.
Other factors like RF Power, Magnetic Field Strength, and Pulse Sequence Time can influence the imaging process and patient experience, but they do not specifically quantify the thermal load on the patient. RF Power contributes to the overall energy output but does not address how much of that energy is absorbed by the body. Magnetic Field Strength is relevant for imaging capabilities but does not pertain to thermal loading. Pulse Sequence Time primarily reflects the timing and duration of different phases of the imaging process rather than the patient's thermal response to RF energy.