MRI analysis of cartilage matrix may play an important role in early detection and
development of therapeutic protocols for degenerative joint disease. Correlations
between MRI parameters and matrix integrity have been established in many studies,
but the substantial overlap in values observed for normal and for degraded cartilage
greatly limits the specificity of these analyses. We implemented established multiparametric
analysis methods to define data clusters corresponding to control and degraded bovine
nasal cartilage in two-, three-, and four-dimensional parameter spaces, and applied
these results to discriminant analysis of a validation data set. Analyses were performed
using the parameters (T(1), T(2), k(m), ADC), where k(m) is the magnetization transfer
rate and ADC is the apparent diffusion coefficient. Results were compared to univariate
analyses. Multiparametric k-means clustering led to no improvement over univariate
analyses, with a maximum sensitivity and specificity in the range of 60-70% for the
detection of degradation using T(1), and in the range of 80% sensitivity but only
36% specificity using the parameter pair (T(1), k(m)). In contrast, model-based analysis
using more general Gaussian clusters resulted in markedly improved classification,
with sensitivity and specificity reaching levels of 80-90% using the pair (T(1), k(m)).
Finally, a fuzzy clustering technique was implemented which may be still more appropriate
to the continuum of degradation seen in degenerative cartilage disease. In view of
its success in identifying mild cartilage degradation, the formal multiparametric
approach implemented here may be applicable to the nondestructive evaluation of other
biomaterials using MRI.