Multiecho reconstruction for simultaneous water-fat decomposition and T2* estimation.
OBJECTIVE
To describe and demonstrate the feasibility of a novel multiecho reconstruction technique that achieves simultaneous water-fat decomposition and T2* estimation. The method removes interference of water-fat separation with iron-induced T2* effects and therefore has potential for the simultaneous characterization of hepatic steatosis (fatty infiltration) and iron overload.


METHODS
The algorithm called "T2*-IDEAL" is based on the IDEAL water-fat decomposition method. A novel "complex field map" construct is used to estimate both R2* (1/T2*) and local B(0) field inhomogeneities using an iterative least-squares estimation method. Water and fat are then decomposed from source images that are corrected for both T2* and B(0) field inhomogeneity.


RESULTS
It was found that a six-echo multiecho acquisition using the shortest possible echo times achieves an excellent balance of short scan and reliable R2* measurement. Phantom experiments demonstrate the feasibility with high accuracy in R2* measurement. Promising preliminary in vivo results are also shown.


CONCLUSIONS
The T2*-IDEAL technique has potential applications in imaging of diffuse liver disease for evaluation of both hepatic steatosis and iron overload in a single breath-hold.
Yu
Huanzhou
H
Global Applied Science Lab, GE Healthcare, Menlo Park, California, USA. Huanzhou.Yu@ge.com
McKenzie
Charles A
CA
Shimakawa
Ann
A
Vu
Anthony T
AT
Brau
Anja C S
AC
Beatty
Philip J
PJ
Pineda
Angel R
AR
Brittain
Jean H
JH
Reeder
Scott B
SB
D000273:Adipose Tissue / Q000378:metabolism*; D000465:Algorithms; D017352:Echo-Planar Imaging / Q000379:methods*; D005234:Fatty Liver / Q000473:pathology*; D006432:Hemochromatosis / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007501:Iron / Q000378:metabolism*; D016018:Least-Squares Analysis; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry*
D014867:Water; D007501:Iron