In vivo validation of a theory-based single-point T1 mapping pulse sequence for quantitative first-pass cardiac perfusion MRI
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KeywordsSaturation Pulse Leave Ventricular Cavity Saturation Recovery Trigger Delay TurboFLASH Sequence
In quantitative analysis of first-pass contrast-enhanced cardiac perfusion MRI, the signal-time curves must be converted to contrast agent (gadolinium-DTPA) concentration-time curves. A theory-based single-point T1 measurement method has been proposed and validated in phantoms at 1.5 T [1, 2] and 3 T (unpublished).
To validate in vivo the accuracy of the proposed single-point T1 mapping pulse sequence against a reference pulse sequence.
Reference T1 measurements were performed with a multi-point saturation recovery TurboFLASH sequence with variable TD and a centric k-space trajectory. A varying trigger delay was introduced to acquire in mid-to-late-diastole, 550 ms after QRS detection. A least square linear regression was used to fit the experimental 6-point-curve (no saturation pulse - TD = 200-300-400-500-550 ms). The single-point and reference T1 measurement pulse sequences were performed during separate breathholds of 8 s and 6 s respectively. Measured T1s were converted to Gd-concentrations ([Gd]) assuming fast water exchange condition  and T1 relaxivity of 3.8 L/mmol/s [5, 6].
The study shows that our theory-based single-point T1 measurement method and the multi-point T1 measurement method produce quantitatively equivalent [Gd] values. Future studies include in vivo validation in patients.
This article is published under license to BioMed Central Ltd.