Room: 303
Purpose: The potential of quantitative magnetization transfer (qMT) indices as potential biomarkers in disease is being increasingly recognized. qMT can quantify the fraction of protons bound to macromolecules in tissue. Collagen is the primary macromolecule in muscle tissue, and collagen content increases with aging, sarcopenia, and in muscular dystrophies. Further, there are histological studies showing gender differences in muscle collagen content. A non-invasive marker of collagen fraction in muscle tissue may have the potential to identify gender differences. We implement a semi-quantitative magnetization transfer method (MTsat) and qMT to evaluate gender and age based differences.
Methods: MTsat (based on three 3D FLASH sequences) was implemented in a cohort of 7 male and 7 female subjects. A 3D FLASH sequence with variable offsets (1- 100kHz) magnetization transfer saturation pulses at flip angle 3000 and 5000 was optimized for qMT (14 datasets in all). qMT requires an estimate of T1 which was generated using a variable flip angle (VFA) method with a B1+ correction of flip angles for T1 and qMT derived from a saturation prepared turboFLASH sequence. Water excitation was used in all sequences to ensure that fat was suppressed.
Results: Efficient fat suppression was achieved with water excitation. Robust qMT maps were generated in a cohort of young subjects with macromolecular fractions (f) agreeing with previously reported vales. Gender and muscle differences in MTsat were statistically significant and may potentially reflect muscle fiber type and/or muscle microarchitecture.
Conclusion: Semi-quantitative index based on MTsat and quantitative magnetization transfer (qMT) of muscle reveal gender and inter- muscle based differences. As MT indices reflect the macromolecular fraction, MTsat and qMT may have the potential to document differences arising from gender, age and disease in collagen content.
Not Applicable / None Entered.
Not Applicable / None Entered.