Robust cardiac T1p mapping at 3T using adiabatic spin-lock preparations
Chiara Coletti, Anastasia Fotaki, Joao Tourais, Yidong Zhao, Christal van de Steeg-Henzen, Mehmet Akçakaya, Qian Tao, Claudia Prieto, Sebastian Weingärtner
Abstract
Purpose
The aim of this study is to develop and optimize an adiabatic T1ρ (T1ρ,adiab) mapping method for robust quantification of spin-lock (SL) relaxation in the myocardium at 3T.
Methods
Adiabatic SL (aSL) preparations were optimized for resilience against B0 and B1+ inhomogeneities using Bloch simulations. Optimized B0-aSL, Bal-aSL and B1-aSL modules, each compensating for different inhomogeneities, were first validated in phantom and human calf. Myocardial T1ρ mapping was performed using a single breath-hold cardiac-triggered bSSFP-based sequence. Then, optimized T1ρ,adiab preparations were compared to each other and to conventional SL-prepared T1ρ maps (RefSL) in phantoms to assess repeatability, and in thirteen healthy subjects to investigate image quality, precision, reproducibility and inter-subject variability. aSL and RefSL sequences were tested on six patients with known or suspected cardiovascular disease and compared with LGE, T1 and ECV mapping.
Results
The highest T1ρ,adiab preparation efficiency was obtained in simulations for modules comprising 2 HS pulses of 30 ms each. In vivo T1ρ,adiab maps yielded significantly higher quality than RefSL maps. Average myocardial T1ρ,adiab values were 183.28 ± 25.53 ms, compared with 38.21 ± 14.37 ms RefSL-prepared T1ρ. T1ρ,adiab maps showed a significant improvement in precision (avg. 14.47 ± 3.71% aSL, 37.61 ± 19.42% RefSL, p < 0.01) and reproducibility (avg. 4.64 ± 2.18% aSL, 47.39 ± 12.06% RefSL, p < 0.0001), with decreased inter-subject variability (avg. 8.76 ± 3.65% aSL, 51.90 ± 15.27% RefSL, p < 0.0001). Among aSL preparations, B0-aSL achieved the better inter-subject variability. In patients, B1-aSL preparations showed the best artifact resilience among the adiabatic preparations. T1ρ,adiab times show focal alteration colocalized with areas of hyper-enhancement in the LGE images.
Conclusion
Adiabatic preparations enable robust in vivo quantification of myocardial SL relaxation times at 3T.