Thermal imaging of fat and muscle using a simultaneous phase and magnitude double echo sequence

A method for thermal magnetic resonance imaging, comprising:

• generating a first two echo sequence before heating a tissue region within a patient, the first two echo sequence having a first echo optimized for temperature contrast from fat tissue and a second echo optimized for temperature contrast from water-based tissue;
• directing thermal energy towards the tissue region;
• generating a second two echo sequence after directing the thermal energy towards the tissue region, the second two echo sequence having a third echo optimized for temperature contrast from fat tissue and a fourth echo optimized for temperature contrast from water-based tissue;
• comparing the third echo and the first echo to obtain a first difference;
• comparing the fourth echo and the second echo to obtain a second difference;
• and
• combining a complex difference between the first difference and the second difference to identify a location of the thermal energy.

A method for thermal magnetic resonance imaging, comprising:

• applying a first two echo gradient echo sequence to a tissue region of a patient, the first two echo sequence generating a first echo and a subsequent second echo within the tissue region;
• directing thermal energy towards the tissue region;
• applying a second two echo gradient echo sequence after directing the thermal energy towards the tissue region, the second two echo sequence generating a third echo and a subsequent fourth echo within the tissue region;
• comparing the first echo to the third echo to obtain temperature shift data attributable substantially to fat tissue within the tissue region;
• and
• comparing the second echo to the fourth echo to obtain temperature shift data attributable substantially to water-based tissue within the tissue region.