T1 Mapping for DCE-MRI / Nurun Najwa Kamaluzaman
The main purpose of this study is to develop a T1 mapping technique by using variable flip angle (VFA) technique based on fast spoiled gradient echo (FSPGR) pulse sequence and to implement the technique in in vivo imaging. FSPGR imaging was performed on a set of T1 gel phantoms with different con...
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Format: | Thesis |
Published: |
2013
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Online Access: | http://studentsrepo.um.edu.my/7285/1/fullreport2.pdf http://studentsrepo.um.edu.my/7285/ |
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Summary: | The main purpose of this study is to develop a T1 mapping technique by using
variable flip angle (VFA) technique based on fast spoiled gradient echo (FSPGR) pulse
sequence and to implement the technique in in vivo imaging. FSPGR imaging was
performed on a set of T1 gel phantoms with different concentrations of Gd3Cl by using 1.5
Tesla MRI. To determine the T1 values of the gel phantoms, signal intensities from three
sets of images produced by using three different flip angles were fitted pixel-by-pixel by
using spoiled gradient echo equation. The T1 values calculated were displayed as a T1 map.
The T1 values of the gel phantoms estimated with selected ROI were compared with the
values determined by a standard T1 measurement technique i.e. inversion recovery [TR =
6500 ms, TE = 7.51 ms, inversion time (TI) = 50, 300, 550, 800, 1050 ms]. The VFA
mapping was then performed on four healthy volunteers to assess its effectiveness in
clinical imaging. The mapping was performed on the right thigh of the volunteer for two
different anatomical orientations, axial and coronal. The T1 values of the fat and muscle
estimated with selected ROI were compared with different orientations, scanning
dimensions and pulse sequences. The comparison of T1 value for different orientation was
performed for three pulse sequences i.e., Multislice Two Dimensional (M2D) FSPGR, three
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dimensional (3D) FSPGR and Liver acceleration volume acquisition (3D LAVA) at axial
and coronal orientations. The comparison of T1 value for scanning technique was
performed using M2D FSPGR and 3D FSPGR pulse sequences. The comparison of T1
value for different pulse sequence was performed using 3D FSPGR and 3D LAVA pulse
sequences. The curve fitting and image analysis were performed by using Matlab
software.The T1 values of the gel phantoms produced by using VFA technique of 3D
FSPGR and 3D LAVA were close to the values determined by the IR method. The T1
values estimated by 2D FSPGR showed different values respect to IR method. The T1
values produced on volunteer at axial orientation was higher than values at coronal
orientation. The T1 values estimated using 3D FSPGR and 2D FSPGR showed in large
difference. The T1 values estimated using 3D FSPGR and 3D LAVA pulse sequence
showed a smaller difference. We have developed a technique to map the T1 values by using
VFA spoiled gradient echo technique. The technique has been successfully implemented on
T1 gel phantoms and healthy volunteers. Further works will include more volunteers for
improve the validity of this study. |
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