Imaging description

Subjacent to the radial attachment of the triangular fibrocartilage (TFC) is the mildly increased signal of hyaline articular cartilage of the distal radius.

Importance

At radial attachment, the TFC inserts on hyaline cartilage and not on cortex; as a result, there is a focus of intermediate signal intensity that represents cartilage between the low-signal intensity radial cortex and low-signal intensity TFC (Figure 32.1).

Typical clinical scenario

A misdiagnosis of a TFC tear may be made if an intermediate to high signal intensity is noted at the radial attachment of the TFC.

Differential diagnosis

Radial hyaline cartilage should not be misinterpreted as a tear. The areas of increased signal intensity at the hyaline cartilage interface can be distinguished from tears by their lack of increased signal on MR images with T2-type contrast. A radial-sided TFC tear, which is usually slit-like, lies medial to the radial articular cartilage.

Teaching point

The MR imaging appearance of TFC is a hypointense disc in all sequences. However, the radial attachment of the TFC often shows an intermediate to high signal intensity which may be a potential imaging pitfall.