A multiparametric alternative to short inversion‐time inversion recovery for imaging inflammation: T_2water and fat fraction measurement using chemical shift–encoded turbo spin‐echo MRI

Abstract

Short-inversion-time inversion-recovery MRI is used widely for imaging bone and soft-tissue inflammation in rheumatic inflammatory diseases, but there is no widely available quantitative equivalent of this sequence. This limits our ability to objectively assess inflammation and distinguish it from other processes. To address this, we investigate the use of the widely available Dixon turbo spin echo (TSE Dixon) sequence as a practical approach to simultaneous water-specific T 2 (T 2water ) and fat fraction (FF) measurement. Methods:We use a series of TSE Dixon acquisitions with varying effective TEs (TE eff ) to quantify T 2water and FF. The validity of this approach is assessed in a series of phantom and in vivo experiments, with reference values provided by Carr-Purcell-Meiboom-Gill acquisitions, MRS, and phantoms. The effect of inflammation on parameter values is evaluated in patients with spondyloarthritis.