Tendons are predominantly composed of dense collagen fiber bundles.

The extracellular compartment consists of collagen fibers bundles embedded in ground substance.

Through a fat suppressed T2-weighted spin echo, MRA can reproduce an extreme high fat-water-contrast, which helps to detect water-deposits with better damage diagnosis in structurally changed collagen fiber bundles.

In particular, a study showed that disuse of the Achilles tendon in rats resulted in a decrease in the average thickness of the collagen fiber bundles comprising the tendon.