Fast measurement of blood T1 in the human carotid artery at 3T: Accuracy, precision, and reproducibility

Authors

  • Wenbo Li,

    1. Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    2. F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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  • Peiying Liu,

    1. Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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  • Hanzhang Lu,

    1. Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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  • John J. Strouse,

    1. Division of Pediatric Hematology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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  • Peter C.M. van Zijl,

    1. Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    2. F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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  • Qin Qin

    Corresponding author
    1. Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
    2. F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
    • Correspondence to: Qin Qin, Ph.D., Department of Radiology, Johns Hopkins University School of Medicine, F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD, 21205. E-mail: qin@mri.jhu.edu

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Abstract

Purpose

To develop a fast protocol for measuring T1 values in the internal carotid artery (ICA), to validate this technique with in vitro measurements, and to evaluate its reproducibility.

Methods

A modified Look–Locker sequence was optimized to enable rapid determination of T1 in the ICA at 3T. T1 values from the ICA were compared with in vitro measurements on individually sampled venous blood oxygenated to arterial levels. A test–retest reproducibility study was also conducted.

Results

The group-averaged arterial blood T1 value was 1908 ± 77 ms for six women (hematocrit = 0.39 ± 0.03) and 1785 ± 55 ms for seven men (hematocrit = 0.45 ± 0.02), which is 100–200 ms longer than the widely adopted value obtained from bovine blood experiments. The arterial T1 value per subject correlated significantly with individual hematocrit values. The intrasession and intersession coefficients of variation were 1.1% and 2.1%, respectively, indicating good precision and reproducibility of our method. Reasonable agreement was observed between the in vivo and in vitro results with a correlation coefficient of 0.78.

Conclusion

The proposed method can provide fast arterial T1 measurement on individual subjects. When not performing such a subject-specific measurement, we recommend the use of 1908 ms and 1785 ms for healthy women and men, respectively, or 1841 ms for adults in general. Magn Reson Med, 2016. © 2016 Wiley Periodicals, Inc.

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