TY - JOUR
T1 - Simultaneous T1, T2, and T1ρ relaxation mapping of the lower leg muscle with MR fingerprinting
AU - Sharafi, Azadeh
AU - Medina, Katherine
AU - Zibetti, Marcelo W.V.
AU - Rao, Smita
AU - Cloos, Martijn A.
AU - Brown, Ryan
AU - Regatte, Ravinder R.
N1 - Funding Information:
National Institutes of Health (R01 DK114428, R01 DK106292, R01 AR076328-01A1, and R01 AR068966), Center of Advanced Imaging Innovation and Research (CAI2R), and NIBIB Biomedical Technology Resource Center (NIH P41 EB017183) The authors thank Ding Xia, M.Sc., for the assistance in data analysis.
Publisher Copyright:
© 2021 International Society for Magnetic Resonance in Medicine
PY - 2021/7
Y1 - 2021/7
N2 - PURPOSE: To develop a novel MR-fingerprinting (MRF) pulse sequence that is insensitive to
B
1
+
and B
0 imperfections for simultaneous T
1 , T
2 , and T
1ρ relaxation mapping.
METHODS: We implemented a totally balanced spin-lock (TB-SL) module to encode T
1ρ relaxation into an existing MRF framework that encoded T
1 and T
2 . The spin-lock module used two 180° pulses with compensatory phases to reduce T
1ρ sensitivity to B
1 and B
0 inhomogeneities. We compared T
1ρ measured using TB-SL MRF in Bloch simulations, model agar phantoms, and in vivo experiments to those with a self-compensated spin-lock preparation module (SC-SL). The TB-SL MRF repeatability was evaluated in maps acquired in the lower leg skeletal muscle of 12 diabetic peripheral neuropathy patients, scanned two times each during visits separated by about 30 days.
RESULTS: The phantom relaxation times measured with TB-SL and SC-SL MRF were in good agreement with reference values in regions with low B
1 inhomogeneities. Compared with SC-SL, TB-SL MRF showed in experiments greater robustness against severe B
1 inhomogeneities and in Bloch simulations greater robustness against B
1 and B
0 . We measured with TB-SL MRF an average T
1 = 950.1 ± 28.7 ms, T
2 = 26.0 ± 1.2 ms, and T
1ρ = 31.7 ± 3.2 ms in skeletal muscle across patients. Bland-Altman analysis demonstrated low bias between TB-SL and SC-SL MRF and between TB-SL MRF maps acquired in two visits. The coefficient of variation was less than 3% for all measurements.
CONCLUSION: The proposed TB-SL MRF sequence is fast and insensitive to
B
1
+
and B
0 imperfections. It can simultaneously map T
1 , T
2 , T
1ρ , and
B
1
+
in a single scan and can potentially be used to study muscle composition.
AB - PURPOSE: To develop a novel MR-fingerprinting (MRF) pulse sequence that is insensitive to
B
1
+
and B
0 imperfections for simultaneous T
1 , T
2 , and T
1ρ relaxation mapping.
METHODS: We implemented a totally balanced spin-lock (TB-SL) module to encode T
1ρ relaxation into an existing MRF framework that encoded T
1 and T
2 . The spin-lock module used two 180° pulses with compensatory phases to reduce T
1ρ sensitivity to B
1 and B
0 inhomogeneities. We compared T
1ρ measured using TB-SL MRF in Bloch simulations, model agar phantoms, and in vivo experiments to those with a self-compensated spin-lock preparation module (SC-SL). The TB-SL MRF repeatability was evaluated in maps acquired in the lower leg skeletal muscle of 12 diabetic peripheral neuropathy patients, scanned two times each during visits separated by about 30 days.
RESULTS: The phantom relaxation times measured with TB-SL and SC-SL MRF were in good agreement with reference values in regions with low B
1 inhomogeneities. Compared with SC-SL, TB-SL MRF showed in experiments greater robustness against severe B
1 inhomogeneities and in Bloch simulations greater robustness against B
1 and B
0 . We measured with TB-SL MRF an average T
1 = 950.1 ± 28.7 ms, T
2 = 26.0 ± 1.2 ms, and T
1ρ = 31.7 ± 3.2 ms in skeletal muscle across patients. Bland-Altman analysis demonstrated low bias between TB-SL and SC-SL MRF and between TB-SL MRF maps acquired in two visits. The coefficient of variation was less than 3% for all measurements.
CONCLUSION: The proposed TB-SL MRF sequence is fast and insensitive to
B
1
+
and B
0 imperfections. It can simultaneously map T
1 , T
2 , T
1ρ , and
B
1
+
in a single scan and can potentially be used to study muscle composition.
KW - T
KW - diabetic neuropathy
KW - lower leg muscle
KW - magnetic resonance fingerprinting
KW - multiparametric mapping
KW - Magnetic Resonance Imaging
KW - Image Processing, Computer-Assisted
KW - Humans
KW - Muscle, Skeletal/diagnostic imaging
KW - Phantoms, Imaging
KW - Leg
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U2 - 10.1002/mrm.28704
DO - 10.1002/mrm.28704
M3 - Article
C2 - 33554369
AN - SCOPUS:85100576976
SN - 0740-3194
VL - 86
SP - 372
EP - 381
JO - Magnetic resonance in medicine
JF - Magnetic resonance in medicine
IS - 1
ER -