Accuracy of real-time MR temperature mapping in the brain: A comparison of fast sequences
Received 12 February 2009; received in revised form 29 October 2009; accepted 29 November 2009. published online 25 January 2010. Corrected Proof
Abstract
Purpose
To compare magnetic resonance (MR) thermometry based on the proton resonance frequency (PRF) method using a single shot echoplanar imaging (ss EPI) sequence to both of the standard sequences, gradient echo (GRE) and segmented echoplanar imaging (seg EPI) in the in vivo human brain, at 1.5T and 3T.
Material and methods
Repetitive MR thermometry was performed on the brain of six volunteers using GRE, seg EPI, and ss EPI sequences on whole-body 1.5T and 3T clinical systems using comparable acquisition parameters. Phase stability and temperature data precision in the human head were determined over 12 min for the three sequences at both field strengths. An ex-vivo swine skeletal muscle model was used to evaluate temperature accuracy of the ss EPI sequence during heating by high intensity focused ultrasound (HIFU).
Results
In-vivo examinations of brain revealed an average temperature precision of 0.37 °C/0.39 °C/0.16 °C at 3T for the GRE/seg EPI/ss EPI sequences. At 1.5T, a precision of 0.58 °C/0.63 °C/0.21 °C was achieved. In the ex-vivo swine model, a strong correlation of temperature data derived using ss EPI and GRE sequences was found with a temperature deviation <1 °C.
Conclusion
The ss EPI sequence was the fastest and the most precise sequence for MR thermometry, with significantly higher accuracy compared to GRE.
aSiemens Healthcare, H IM MR PLM AW Oncology, FH5/2008, Allee am Röthelheimpark 2, 91052 Erlangen, Germany
bSection on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Straße 3, 72076 Tübingen, Germany
ABSTRACT