An order parameter without magic angle effect (OPTIMA) derived from R1ρ dispersion in ordered tissue.

ABSTRACT:

Purpose

MR R₂ imaging of ordered tissue exhibits the magic angle effect, potentially masking subtle pathological changes in cartilage. This work aimed to develop an orientation-independent order parameter (S) exclusively sensitive to collagen degeneration.

Methods

A theory was developed based on R1ρ dispersion coupled with a simplified molecular motion model in which anisotropic R2a(θ) became directly proportional to correlation time τbθ and S could be derived. This new parameter was validated with ex vivo R1ρ dispersion reported on orientated (n = 4), enzymatically depleted bovine cartilage (n = 6), and osteoarthritic human knee specimens (n = 14) at 9.4 Tesla, which was further demonstrated on 1 healthy human knee in vivo at 3 Tesla.

Results

τbθ from orie

SUBMITTER: Pang Y 

PROVIDER: S-EPMC6982556 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature