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Flip angle optimazation for dynamic contrast-enhanced MRI-studies with spoiled gradient echo pulse sequences

Dieter De Naeyer (UGent) , Johanna Verhulst, Wim Ceelen (UGent) , Patrick Segers (UGent) , Yves De Deene (UGent) and Pascal Verdonck (UGent)
(2011) PHYSICS IN MEDICINE AND BIOLOGY. 56(16). p.5373-5395
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Abstract
Spoiled gradient echo pulse (SPGRE) sequences are commonly used in dynamic contrast-enhanced MRI (DCE-MRI) studies to measure the contrast agent concentration in a tissue of interest over time. However, due to improper tuning of the SPGRE parameters, concentration uncertainty can be very high, even at high signal-to-noise ratio in the MR measurement. In this work, an optimization procedure is proposed for selecting the optimal value of the SPGRE-flip angle FA(opt), given the expected concentration range. The optimization condition ensures that every concentration in the assumed range has the lowest possible uncertainty. By decoupling the R(1)- and R*(2)-effects caused by the presence of the contrast agent, a contour plot has been generated from which FA(opt) can be read off for any study design. Investigation of ten recent DCE-MRI studies showed that improper flip angle selection unnecessarily increases the concentration uncertainty, up to 742% and 72% on average for the typical physiological concentration ranges of 0-2 mM in tumour tissue and 0-10 mM in blood, respectively. Simulations show that the reduced noise levels on the concentration curves, observed at the optimal flip angle, effectively increase the precision of the kinetic parameters estimates (up to 82% for K(trans), 82% for nu(e) and 92% for nu(p) in the case of an individually measured arterial input function (AIF), up to 53% for K(trans), 59% for nu(e) and 67% for nu(p) in the case of a standard AIF). In vivo experiments confirm the potential of flip angle optimization to increase the reproducibility of the kinetic parameter estimates.
Keywords
ARTERIAL INPUT FUNCTION, DCE-MRI, PHARMACOKINETIC PARAMETERS, RHEUMATOID-ARTHRITIS, BREAST-CANCER, TUMOR-MODEL, REPRODUCIBILITY, PERMEABILITY, UNCERTAINTY, ACQUISITION

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Chicago
De Naeyer, Dieter, Johanna Verhulst, Wim Ceelen, Patrick Segers, Yves De Deene, and Pascal Verdonck. 2011. “Flip Angle Optimazation for Dynamic Contrast-enhanced MRI-studies with Spoiled Gradient Echo Pulse Sequences.” Physics in Medicine and Biology 56 (16): 5373–5395.
APA
De Naeyer, D., Verhulst, J., Ceelen, W., Segers, P., De Deene, Y., & Verdonck, P. (2011). Flip angle optimazation for dynamic contrast-enhanced MRI-studies with spoiled gradient echo pulse sequences. PHYSICS IN MEDICINE AND BIOLOGY, 56(16), 5373–5395.
Vancouver
1.
De Naeyer D, Verhulst J, Ceelen W, Segers P, De Deene Y, Verdonck P. Flip angle optimazation for dynamic contrast-enhanced MRI-studies with spoiled gradient echo pulse sequences. PHYSICS IN MEDICINE AND BIOLOGY. 2011;56(16):5373–95.
MLA
De Naeyer, Dieter, Johanna Verhulst, Wim Ceelen, et al. “Flip Angle Optimazation for Dynamic Contrast-enhanced MRI-studies with Spoiled Gradient Echo Pulse Sequences.” PHYSICS IN MEDICINE AND BIOLOGY 56.16 (2011): 5373–5395. Print.
@article{1984473,
  abstract     = {Spoiled gradient echo pulse (SPGRE) sequences are commonly used in dynamic contrast-enhanced MRI (DCE-MRI) studies to measure the contrast agent concentration in a tissue of interest over time. However, due to improper tuning of the SPGRE parameters, concentration uncertainty can be very high, even at high signal-to-noise ratio in the MR measurement. In this work, an optimization procedure is proposed for selecting the optimal value of the SPGRE-flip angle FA(opt), given the expected concentration range. The optimization condition ensures that every concentration in the assumed range has the lowest possible uncertainty. By decoupling the R(1)- and R*(2)-effects caused by the presence of the contrast agent, a contour plot has been generated from which FA(opt) can be read off for any study design. Investigation of ten recent DCE-MRI studies showed that improper flip angle selection unnecessarily increases the concentration uncertainty, up to 742\% and 72\% on average for the typical physiological concentration ranges of 0-2 mM in tumour tissue and 0-10 mM in blood, respectively. Simulations show that the reduced noise levels on the concentration curves, observed at the optimal flip angle, effectively increase the precision of the kinetic parameters estimates (up to 82\% for K(trans), 82\% for nu(e) and 92\% for nu(p) in the case of an individually measured arterial input function (AIF), up to 53\% for K(trans), 59\% for nu(e) and 67\% for nu(p) in the case of a standard AIF). In vivo experiments confirm the potential of flip angle optimization to increase the reproducibility of the kinetic parameter estimates.},
  author       = {De Naeyer, Dieter and Verhulst, Johanna and Ceelen, Wim and Segers, Patrick and De Deene, Yves and Verdonck, Pascal},
  issn         = {0031-9155},
  journal      = {PHYSICS IN MEDICINE AND BIOLOGY},
  keyword      = {ARTERIAL INPUT FUNCTION,DCE-MRI,PHARMACOKINETIC PARAMETERS,RHEUMATOID-ARTHRITIS,BREAST-CANCER,TUMOR-MODEL,REPRODUCIBILITY,PERMEABILITY,UNCERTAINTY,ACQUISITION},
  language     = {eng},
  number       = {16},
  pages        = {5373--5395},
  title        = {Flip angle optimazation for dynamic contrast-enhanced MRI-studies with spoiled gradient echo pulse sequences},
  url          = {http://dx.doi.org/10.1088/0031-9155/56/16/019},
  volume       = {56},
  year         = {2011},
}

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