High resolution, short echo time sodium imaging of articular cartilage.

The sodium present in articular cartilage interacts with the negatively charged proteoglycan aggregates in the matrix of the cartilage. Sodium images of short echo time may be useful for detecting changes that occur in the proteoglycan content of the cartilage. Such changes are indicative of early osteoarthritic damage, for example. Using an asymmetric short echo technique, sodium images of high resolution and signal-to-noise ratio that demonstrate anatomic features of the cartilage are presented. These images were obtained with echo times as short as 1 msec, at an in-plane resolution of 39 microns by 117 microns and signal-to-noise ratios of up to 40:1.