Experimental issues in the measurement of multi-component relaxation times in articular cartilage by microscopic MRI.


Journal Article

A number of experimental issues in the measurement of multi-component T2 and T1ρ relaxations in native and enzymatically digested articular cartilage were investigated by microscopic MRI (μMRI). The issues included the bath solutions (physiological saline and phosphate buffered saline (PBS)), the imaging resolution (35-140 μm), the specimen orientations (0° and 55°), and the strength of spin-lock frequencies (0.5-2 kHz) in the T1ρ experiments. In addition to cartilage, the samples of agar gel and doped water solution were also used in the investigation. Two imaging sequences were used: CPMG-SE and MSME. All raw data were analyzed by the non-negative least square (NNLS) method. The MSME sequence was shown to result in the observation of multi-component T2, even in the gel and liquid samples, demonstrating the artificial uncleanness of this sequence in the multi-component measurements. The soaking of cartilage in PBS reduced the observable T2 components to one at both 0° and 55°, suggesting the effect of phosphate ions on proton exchange between different pools of water molecules. The cartilage orientation with respect to the external magnetic field and the spin-lock strengths in the T1ρ experiment both affected the quantification of the multi-component relaxation. The transitions between a mono-component and multi-components in cartilage under various experimental conditions call for the extra caution in interpreting the relaxation results.

Full Text

Duke Authors

Cited Authors

  • Wang, N; Xia, Y

Published Date

  • October 2013

Published In

Volume / Issue

  • 235 /

Start / End Page

  • 15 - 25

PubMed ID

  • 23916991

Pubmed Central ID

  • 23916991

Electronic International Standard Serial Number (EISSN)

  • 1096-0856

Digital Object Identifier (DOI)

  • 10.1016/j.jmr.2013.07.001


  • eng

Conference Location

  • United States