Abstract
In order to diagnose osteoarthritis in its early stages, it is desirable to detect changes in the main components of the knee cartilage such as proteoglycan (PG) and collagen (CG). In the present study, we first fabricated physical phantoms containing different concentrations of PG or CG and then acquired MR images of these phantoms with a clinical MRI scanner using a variety of pulse sequences. The ratio of the MR signal intensity of each phantom to that of a reference object was then calculated. We also acquired MR images of the PG phantoms using an MR microscope and calculated the T1 relaxation time. The results showed a high correlation between the PG component concentration and the ratio of the MR signal intensity for the clinical scanner. A high correlation between the PG component concentration and the T1 relaxation time was also observed. The results of this study suggest that image acquisition of the knee joint together with a suitable reference object for calibration using a clinical MRI scanner may be a practical method for evaluating changes in PG in the knee cartilage.
