Robust cardiac T1ρ$$ {\mathrm{T}}_{1_{\boldsymbol{\rho}}} $$ mapping at 3T using adiabatic spin‐lockpreparations

PurposeThe aim of this study is to develop and optimize an adiabatic T1ρ$$ {\mathrm{T}}_{1\uprho} $$ (T1ρ,adiab$$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$) mapping method for robust quantification of spin‐lock (SL) relaxation in the myocardium at 3T.MethodsAdiabatic SL (aSL) preparations were optimized for resilience against B0$$ {\mathrm{B}}_0 $$ and B1+$$ {\mathrm{B}}_1^{+} $$ inhomogeneities using Bloch simulations. Optimized B0$$ {\mathrm{B}}_0 $$‐aSL, Bal‐aSL and B1$$ {\mathrm{B}}_1 $$‐aSL modules, each compensating for different inhomogeneities, were first validated in phantom and human calf. Myocardial T1ρ$$ {\mathrm{T}}_{1\uprho} $$ mapping was performed using a single breath‐hold cardiac‐triggered bSSFP‐based sequence. Then, optimized T1ρ,adiab$$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ preparations were compared to each other and to conventional SL‐prepared T1ρ$$ {\mathrm{T}}_{1\uprho} $$ maps (RefSL) in phantoms to assess repeatability, and in 13 healthy subjects to investigate image quality, precision, reproducibility and intersubject variability. Finally, aSL and RefSL sequences were tested on six patients with known or suspected cardiovascular disease and compared with LGE, T1$$ {\mathrm{T}}_1 $$, and ECV mapping.ResultsThe highest T1ρ,adiab$$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ preparation efficiency was obtained in simulations for modules comprising 2 HS pulses of 30 ms each. In vivo T1ρ,adiab$$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ maps yielded significantly higher quality than RefSL maps. Average myocardial T1ρ,adiab$$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ values were 183.28 ±$$ \pm $$ 25.53 ms, compared with 38.21 ±$$ \pm $$ 14.37 ms RefSL‐prepared T1ρ$$ {\mathrm{T}}_{1\uprho} $$. T1ρ,adiab$$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ maps showed a significant improvement in precision (avg. 14.47 ±$$ \pm $$ 3.71% aSL, 37.61 ±$$ \pm $$ 19.42% RefSL, p < 0.01) and reproducibility (avg. 4.64 ±$$ \pm $$ 2.18% aSL, 47.39 ±$$ \pm $$ 12.06% RefSL, p < 0.0001), with decreased inter‐subject variability (avg. 8.76 ±$$ \pm $$ 3.65% aSL, 51.90 ±$$ \pm $$ 15.27% RefSL, p < 0.0001). Among aSL preparations, B0$$ {\mathrm{B}}_0 $$‐aSL achieved the better inter‐subject variability. In patients, B1$$ {\mathrm{B}}_1 $$‐aSL preparations showed the best artifact resilience among the adiabatic preparations. T1ρ,adiab$$ {\mathrm{T}}_{1\uprho, \mathrm{adiab}} $$ times show focal alteration colocalized with areas of hyper‐enhancement in the LGE im