Black-blood T1 mapping at 3T: Reduced partial-voluming using adiabatic MSDE preparation
Journal of Cardiovascular Magnetic Resonance volume 18, Article number: W5 (2016)
Myocardial T1 mapping in pathologies with decreased myocardial wall thickness such as dilated cardiomyopathy (DCM) is strongly impaired by partial-voluming from the neighboring blood pools [Kellman et al., JCMR2014].
Significant differences between the T1 times in myocardium and blood lead to decreased accuracy in the presence of partial-voluming. This causes sensitivity to the region-of-interest (ROI), compromising the inter-observer reproducibility.
The aim of this work is to study the use of blood-signal suppression using a motion-sensitized driven equilibrium (MSDE) [Wang et al., MRM2007] magnetization preparation in order to reduce partial-voluming in myocardial T1 mapping.
An adiabatic MSDE preparation module was added directly before the imaging pulses of a SAPPHIRE sequence [Weingärtner et al., MRM2014] (Fig. 1). The preparation consists of a rectangular tip-down pulse, an adiabatic BIREF1 refocusing pulse, a composite tip-up pulse and motion-sensitizing gradients before and after refocusing. The MSDE parameters were TEMSDE = 11 ms, gradients: amplitude = 16 mT/m, duration = 2 ms.
6 healthy volunteers (25 ± 6 y; 4 M) were scanned using conventional and black-blood T1 mapping on a 3T MR Scanner (Siemens Skyra). T1 mapping was performed using a bSSFP imaging readout with the following parameters: TE/TR/α = 1.0 ms/2.9 ms/35°, FOV/res = 440 × 375 mm²@1.7 × 1.7 mm², sl.th. = 8 mm, GRAPPA = 2, Partial-Fourier = 6/8, bw = 1085 Hz/px.
A three parameter model was used for T1 fitting, avoiding potential quantification inaccuracies caused by the recovery curve modulation through the MSDE preparation. T1 times, the average thickness and the apparent in-plane area of the myocardium were quantified in the T1 maps using manually drawn ROIs. Furthermore, cross myocardial T1 times were analyzed from the endo- to the epicardial border.
Visually strong blood suppression was achieved using the adiabatic MSDE preparation (Fig. 2a). Quantitative analysis reveals increased T1 times towards the myocardial borders in conventional T1 mapping (Figure 2c), while consistent T1 times through the entire myocardial thickness were measured using black-blood SAPPHIRE. No significant difference was found in the average T1 time of the two methods (Conv.: 1574 ± 52 ms vs BB: 1593 ± 47 ms). A 25%-28% gain in apparent in-slice area of the myocardium and average wall-thickness in the T1 maps was achieved using blood-suppression (BB: 1596 ± 266 mm2, 7.37 ± 1.16 mm vs. Conv.: 1278 ± 213 mm2, 5.72 ± 0.87 mm, p < 0.05).
An adiabatic MSDE preparation enables robust myocardial T1 Mapping at 3T. The apparent myocardial in-slice area and average wall-thickness is significantly increased using a black-blood preparation. Furthermore, elevated T1 times at the myocardial borders were eliminated. This reduces sensitivity to ROI placement and potentially benefits the reproducibility of myocardial T1 mapping, especially in the presence of pathologies with reduced myocardial wall-thickness.
About this article
Cite this article
Weingärtner, S., Messner, N.M., Zoellner, F.G. et al. Black-blood T1 mapping at 3T: Reduced partial-voluming using adiabatic MSDE preparation. J Cardiovasc Magn Reson 18 (Suppl 1), W5 (2016). https://doi.org/10.1186/1532-429X-18-S1-W5