Precision of T1-relaxation time measurements in the hepatic portal vein: influence of measurement technique and sequence parameters
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To investigate the effects of a range of parameter settings on T1 measurement stability in the portal vein using the T1-mapping sequences Look-Locker (LL) and Modified Look-Locker inversion recovery (MOLLI).
Materials and methods
Ten different versions of LL and MOLLI sequences were tested and compared to a reference sequence provided by the MR manufacturer. Ten healthy volunteers were imaged multiple times on two separate scan days at 3T. The mean T1 values and coefficient of variation (CoV) were calculated for each of the ten sequences and compared to the reference sequence.
Six of the tested sequences had T1 values close to the reference sequence; among those, three sequences achieved lower CoV than the reference sequence. Lowest CoV was achieved using a non-triggered LL sequence with 5 beat readout and a 45o flip angle (mean T1 1733 ms ± 89 ms, CoV 1.3% ± 0.58%).
T1-measurements in the hepatic portal vein can be performed with high precision using either MOLLI or LL sequences provided that LL sampling duration is sufficiently long and flip angle sufficiently high. The advantage of constant timing outweighed the advantage of ECG-triggering.
KeywordsRelaxometry T1 measurements Blood
Grant support: this project is funded by the Research Council of Norway.
SASV design and planning of the study, acquisition of data, analysis and interpretation of data, drafting of manuscript, and critical revision. PKH design and planning of the study, drafting of manuscript, and critical revision. AB design and planning of the study, drafting of manuscript, and critical revision. MA-M design and planning of the study, drafting of manuscript, and critical revision. CH design and planning of the study, drafting of manuscript, and critical revision. THS design and planning of the study, drafting of manuscript, and critical revision.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institution and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
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