Ultrafast compartmentalized relaxation time mapping with linear algebraic modeling

Yi Zhang, Xiaoyang Liu, Jinyuan Zhou, Paul A Bottomley

Research output: Contribution to journalArticle

Abstract

Purpose: To dramatically accelerate compartmental-average longitudinal (T1) and transverse (T2) relaxation measurements using the minimal-acquisition linear algebraic modeling (SLAM) method, and to validate it in phantoms and humans. Methods: Relaxation times were imaged at 3 Tesla in phantoms, in the abdomens of six volunteers, and in six brain tumor patients using standard inversion recovery and multi-spin-echo sequences. k-space was fully sampled to provide reference T1 and T2 measurements, and SLAM was performed using a limited set of phase encodes from central k-space. Anatomical compartments were segmented on scout images post-acquisition, and SLAM reconstruction was implemented using two algorithms. Compartment-average T1 and T2 measurements were determined retroactively from fully sampled data sets, and proactively from SLAM data sets at acceleration factors of up to 16. Values were compared with reference measurements. The compartment's localization properties were analyzed using the discrete spatial response function. Results: At 16-fold acceleration, compartment-average SLAM T1 measurements agreed with the full k-space compartment-average results to within 0.0%±0.7%, 1.4%±3.4%, and 0.5%±2.9% for phantom, abdominal, and brain T1 measurements, respectively. The corresponding T2 measurements agreed within 0.2%±1.9%, 0.9%±7.9%, and 0.4%±5.8%, respectively. Conclusion: SLAM can dramatically accelerate relaxation time measurements when compartmental or lesion-average values can suffice, or when standard relaxometry is precluded by scan-time limitations.

Original languageEnglish (US)
JournalMagnetic Resonance in Medicine
DOIs
StateAccepted/In press - 2017

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Brain Neoplasms
Abdomen
Volunteers
Brain
Datasets

Keywords

  • Abdomen, brain tumors
  • Discrete spatial response function (dSRF)
  • Fast imaging
  • Relaxation times (T and T)
  • Spectroscopy with linear algebraic modeling (SLAM)

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

Cite this

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title = "Ultrafast compartmentalized relaxation time mapping with linear algebraic modeling",
abstract = "Purpose: To dramatically accelerate compartmental-average longitudinal (T1) and transverse (T2) relaxation measurements using the minimal-acquisition linear algebraic modeling (SLAM) method, and to validate it in phantoms and humans. Methods: Relaxation times were imaged at 3 Tesla in phantoms, in the abdomens of six volunteers, and in six brain tumor patients using standard inversion recovery and multi-spin-echo sequences. k-space was fully sampled to provide reference T1 and T2 measurements, and SLAM was performed using a limited set of phase encodes from central k-space. Anatomical compartments were segmented on scout images post-acquisition, and SLAM reconstruction was implemented using two algorithms. Compartment-average T1 and T2 measurements were determined retroactively from fully sampled data sets, and proactively from SLAM data sets at acceleration factors of up to 16. Values were compared with reference measurements. The compartment's localization properties were analyzed using the discrete spatial response function. Results: At 16-fold acceleration, compartment-average SLAM T1 measurements agreed with the full k-space compartment-average results to within 0.0{\%}±0.7{\%}, 1.4{\%}±3.4{\%}, and 0.5{\%}±2.9{\%} for phantom, abdominal, and brain T1 measurements, respectively. The corresponding T2 measurements agreed within 0.2{\%}±1.9{\%}, 0.9{\%}±7.9{\%}, and 0.4{\%}±5.8{\%}, respectively. Conclusion: SLAM can dramatically accelerate relaxation time measurements when compartmental or lesion-average values can suffice, or when standard relaxometry is precluded by scan-time limitations.",
keywords = "Abdomen, brain tumors, Discrete spatial response function (dSRF), Fast imaging, Relaxation times (T and T), Spectroscopy with linear algebraic modeling (SLAM)",
author = "Yi Zhang and Xiaoyang Liu and Jinyuan Zhou and Bottomley, {Paul A}",
year = "2017",
doi = "10.1002/mrm.26675",
language = "English (US)",
journal = "Magnetic Resonance in Medicine",
issn = "0740-3194",
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T1 - Ultrafast compartmentalized relaxation time mapping with linear algebraic modeling

AU - Zhang, Yi

AU - Liu, Xiaoyang

AU - Zhou, Jinyuan

AU - Bottomley, Paul A

PY - 2017

Y1 - 2017

N2 - Purpose: To dramatically accelerate compartmental-average longitudinal (T1) and transverse (T2) relaxation measurements using the minimal-acquisition linear algebraic modeling (SLAM) method, and to validate it in phantoms and humans. Methods: Relaxation times were imaged at 3 Tesla in phantoms, in the abdomens of six volunteers, and in six brain tumor patients using standard inversion recovery and multi-spin-echo sequences. k-space was fully sampled to provide reference T1 and T2 measurements, and SLAM was performed using a limited set of phase encodes from central k-space. Anatomical compartments were segmented on scout images post-acquisition, and SLAM reconstruction was implemented using two algorithms. Compartment-average T1 and T2 measurements were determined retroactively from fully sampled data sets, and proactively from SLAM data sets at acceleration factors of up to 16. Values were compared with reference measurements. The compartment's localization properties were analyzed using the discrete spatial response function. Results: At 16-fold acceleration, compartment-average SLAM T1 measurements agreed with the full k-space compartment-average results to within 0.0%±0.7%, 1.4%±3.4%, and 0.5%±2.9% for phantom, abdominal, and brain T1 measurements, respectively. The corresponding T2 measurements agreed within 0.2%±1.9%, 0.9%±7.9%, and 0.4%±5.8%, respectively. Conclusion: SLAM can dramatically accelerate relaxation time measurements when compartmental or lesion-average values can suffice, or when standard relaxometry is precluded by scan-time limitations.

AB - Purpose: To dramatically accelerate compartmental-average longitudinal (T1) and transverse (T2) relaxation measurements using the minimal-acquisition linear algebraic modeling (SLAM) method, and to validate it in phantoms and humans. Methods: Relaxation times were imaged at 3 Tesla in phantoms, in the abdomens of six volunteers, and in six brain tumor patients using standard inversion recovery and multi-spin-echo sequences. k-space was fully sampled to provide reference T1 and T2 measurements, and SLAM was performed using a limited set of phase encodes from central k-space. Anatomical compartments were segmented on scout images post-acquisition, and SLAM reconstruction was implemented using two algorithms. Compartment-average T1 and T2 measurements were determined retroactively from fully sampled data sets, and proactively from SLAM data sets at acceleration factors of up to 16. Values were compared with reference measurements. The compartment's localization properties were analyzed using the discrete spatial response function. Results: At 16-fold acceleration, compartment-average SLAM T1 measurements agreed with the full k-space compartment-average results to within 0.0%±0.7%, 1.4%±3.4%, and 0.5%±2.9% for phantom, abdominal, and brain T1 measurements, respectively. The corresponding T2 measurements agreed within 0.2%±1.9%, 0.9%±7.9%, and 0.4%±5.8%, respectively. Conclusion: SLAM can dramatically accelerate relaxation time measurements when compartmental or lesion-average values can suffice, or when standard relaxometry is precluded by scan-time limitations.

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