Techniques for temperature measurement and corrections in long-term magnetic resonance thermometry

摘要

Techniques for temperature measurement and correction in long-term MR thermometry utilize a known temperature distribution in an MR imaging area as a baseline for absolute temperature measurement. Phase shifts that arise from magnetic field drifts are detected in one or more portions of the MR imaging area, facilitating correction of temperature measurements in an area of interest.

主权项

1. A method of performing proton resonance frequency (PRF) based magnetic resonance (MR) temperature measurement, the method comprising the steps of:
using an MRI unit, acquiring a first phase image of an MR imaging area having a known temperature distribution, the MR imaging area comprising an area of interest; using the MRI unit, acquiring a second phase image of the MR imaging area subsequent to the acquisition of the first phase image; without modifying the first image, determining, from differences between the second phase image and the first phase image, one or more first corrections in one or more portions of the MR imaging area that have experienced a known or clinically insignificant change in temperature since the acquisition of the first phase image; determining one or more second corrections in at least the area of interest by extrapolating the one or more first corrections; assigning a first set of one or more absolute temperatures to the area of interest based at least in part on (i) the known temperature distribution and (ii) the one or more second corrections, detecting a movement and/or deformation of the area of interest; determining a new temperature distribution of at least the area of interest by registering the known temperature distribution to the new temperature distribution based at least in part on the detected movement and/or deformation; acquiring a third phase image of the MR imaging area subsequent to the detected movement and/or deformation; acquiring a fourth phase image of the MR imaging area subsequent to the acquisition of the third phase image; and assigning a second set of one or more absolute temperatures to the area of interest based at least in part on (i) the new temperature distribution and (ii) a difference between the fourth phase image and the third phase image.