In vivo biochemical assessment of cartilage with gagCEST MRI: Correlation with cartilage properties

Abstract

To assess articular cartilage in vivo, a noninvasive measurement is proposed to evaluate damage of the cartilage. It is hypothesized that glycosaminoglycan chemical exchange saturation transfer (gagCEST) can be applied as a noninvasive imaging technique as it would relate to electromechanical indentation and GAG content as measured with biochemical assays. This pilot study applies gagCEST MRI in total knee arthroplasty (TKA) patients to assess substantially damaged articular cartilage. The outcome was verified against electromechanical indentation and biochemical assays to assess the potential of gagCEST MRI. Five TKA patients were scanned on a 7.0 T MRI with a gagCEST sequence. Articular resurfacing cuts after TKA were obtained for electromechanical and biochemical analyses. The gagCEST MRI measurements on the medial condyle showed a moderate correlation with the GAG content, although sensitivity on the lateral condyle was lacking. Additionally, a strong negative correlation of gagCEST MRI with the electromechanical measurements was observed in the regression analysis. Correlation of gagCEST MRI with electromechanical measurements was shown, but the correlation of gagCEST MRI with GAG content was not convincing. In conclusion, gagCEST could be a useful tool to assess the GAG content in articular cartilage noninvasively, although the mismatch in heterogeneity requires further investigation.

AcidoCEST-UTE MRI Reveals an Acidic Microenvironment in Knee Osteoarthritis

“…While T2 mapping offers an estimate of cartilage's water content [25] and T1ρ mapping offers an estimate of cartilage's proteoglycan content [26], other biomarkers may be useful to predict early OA degeneration and progression. For example, glycosaminoglycan (GAG) CEST may estimate the GAG content in cartilage in patients with OA [12,[27][28][29]. Additionally, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) measures are strongly correlated with cartilage's proteoglycan content [30], and with the development of joint-space narrowing [31].…”

Biomarkers of Cartilage Composition

“…Brinkhof et al 54 tried to validate gagCEST imaging at 7 T in patients with total knee arthroplasty with mixed results. During surgery, articular resurfacing cuts were obtained for electromechanical indentation and biochemical assays.…”

Kartogenin (KGN)/synthetic melanin nanoparticles (SMNP) loaded theranostic hydrogel scaffold system for multiparametric magnetic resonance imaging guided cartilage regeneration

“…Magnetic resonance imaging (MRI) has been widely used to assess the morphological changes of biomaterial degradation and new tissue reconstruction for its safety and noninvasive measurement. 15 It has obvious advantages in the evaluation of various regeneration strategies with ideal soft‐tissue resolution and penetration depth. 16 For example, Hong et al 17 reported a chitosan modified Fe 3 O 4 ‐CS/KGN nanoprobe for osteochondral diagnosis and repair.…”