Depth-dependent profiles of glycosaminoglycans in articular cartilage by microMRI and histochemistry.
OBJECTIVE
To quantify the distribution profile of glycosaminoglycans (GAGs) in articular cartilage with the magnetic resonance imaging (MRI) gadolinium (Gd) contrast method (the dGEMRIC procedure in clinical MRI) and correlate with histochemical results.


METHODS
Fresh canine cartilage from seven humeral heads was harvested. Sixteen cartilage specimens were imaged at 13 microm pixel resolution using the microMRI T1-Gd method to generate 2D GAG maps in cartilage. Nineteen cartilage specimens from adjacent locations on the same joints were papain-digested to quantify the bulk GAG content in tissue. In addition, six cartilage specimens were microtomed into 40-microm serial sections that were parallel with the articular surface. These sections were biochemically analyzed individually to determine the depth-dependent profiles of GAG concentration.


RESULTS
The GAG concentrations between the microMRI measurement and the bulk biochemical method have statistically significant agreement. The depth-dependent GAG profiles from the histochemical method (40 microm depth resolution) have similar line shapes as that determined by microMRI at 13 microm resolution.


CONCLUSIONS
The GAG concentration as measured by microMRI T1-Gd contrast method provides an accurate account of the macromolecular content in articular cartilage.
Xia
Yang
Y
Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309, USA. xia@oakland.edu
Zheng
Shaokuan
S
Bidthanapally
Aruna
A
D000818:Animals; D002358:Cartilage, Articular / Q000737:chemistry*; D004285:Dogs; D005682:Gadolinium; D006025:Glycosaminoglycans / Q000032:analysis*; D006651:Histocytochemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*
D006025:Glycosaminoglycans; D005682:Gadolinium