Single-, bi- and multi-exponential fitting of quantitative T2 MR images

Wednesday, October 26, 2011 — Poster Session III
10:00 a.m. – Noon	Natcher Conference Center	CIT	IMAG-31

Authors

• J Senseney
• A Gilbert
• I Evangelou
• M McAuliffe

Abstract

T2, the transverse relaxation time, is the rate of decay of transverse magnetization in the absence of magnetic field gradients. To quantify T2 relaxation times, a spin echo Carr-Purcell-Meiboom-Gill (CPMG) sequence is typically used and the number of echoes is determined by the imaging time. A minimum of two echoes are needed to determine T2 relaxation, but often 8, 16 or 32 echoes are acquired. If a gradient echo sequence is used T2* may be quantified in a similar fashion. The fitting and visualization has been implemented as a plugin to the Medical Image Processing, Analysis and Visualization (MIPAV) program. In the case of two echoes a single exponential fit of the T2 decay is performed whereas in multiple echoes a multi-exponential fit is performed using nonlinear least squares. The plugin allows for generation of T2 maps derived from the fit and can display the curve fit at defined points in the image. Visualization of these points in 4D datasets is also possible. The plugin is expandable and can handle multi-exponential fitting of T2* images using nonlinear least squares.

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