Nonenhanced Chemical Exchange Saturation Transfer Cardiac Magnetic Resonance Imaging in Patients With Amyloid Light-Chain Amyloidosis

Background Chemical exchange saturation transfer (CEST) is an emerging metabolic MRI technique to map creatine distribution in the myocardium. Purpose To investigate the feasibility of using a contrast-free CEST technique to evaluate cardiac involvement in amyloid light-chain (AL) amyloidosis. Study type Prospective. Population Forty patients with biopsy-proven AL amyloidosis (age 57.6 +/- 9.1 years, 31 males) and 20 healthy controls (age 42.8 +/- 13.8 years, 13 males). Field strength/Sequence A 3.0 T, CEST imaging using a single-shot FLASH sequence, T1 mapping with a modified Look-Locker inversion recovery sequence and late gadolinium enhancement (LGE) imaging with a phase-sensitive inversion recovery gradient echo sequence. Assessment The average CEST was calculated in the basal short-axis slice of the entire left ventricle and septum. LGE was assessed subjectively (none/patchy/global) and extracellular volume (ECV), CEST and T1 maps generated. Statistical Tests Comparison between patient groups and healthy controls was performed by one-way analysis of variance with post hoc Bonferroni correction. Correlation was assessed using the Pearson's r correlation or Spearman rho correlation. Statistical significance was defined as P < 0.05. Results Global (0.09 +/- 0.03 vs. 0.11 +/- 0.02) and septal (0.09 +/- 0.03 vs. 0.11 +/- 0.03) basal short-axis CEST was significantly decreased in patients with AL amyloidosis compared to the controls. Global CEST correlated significantly with Mayo stage (rho = -0.508), NYHA Class (rho = -0.430), LVEF (r = 0.511), mass index (r = -0.373), LGE (rho = -0.537), ECV (r = -0.544), and T2 (r = -0.396). Septal CEST correlated significantly with LVEF (r = 0.395), LGE (rho = -0.330), and ECV (r = -0.391). Data Conclusions This study highlights the potential of CEST MRI to identify cardiac involvement and evaluate disease burden and to give insight into cellular changes intermediary between function and structure in AL amyloidosis patients. Evidence Level 2 Technical Efficacy Stage 2