Intrinsic and extrinsic carpal ligaments: evaluation by three-dimensional Fourier transform MR imaging

As evaluation of the anatomic and functional integrity of intrinsic and extrinsic carpal ligaments with conventional imaging methods is difficult, we designed a study to evaluate the ability of three-dimensional Fourier transform MR imaging to show the carpal ligaments.

We obtained coronal MR images of 15 cadaveric wrists and 15 wrists of patients, using three-dimensional volume acquisition with a gradient-recalled echo sequence and a 1.5-T magnet. The MR findings were compared with the findings on dissection in the 15 cadaveric wrists and with the surgical findings in eight patients.

All the volar ligaments had a striated appearance on MR images, with alternating bands of low and intermediate signal intensity. No tears of the extrinsic ligaments were seen. The intrinsic scapholunate and lunotriquetral ligaments were seen as structures with more homogeneously intermediate intensity attaching to their adjacent bone through high-signal-intensity hyaline cartilage. For the cadaveric wrists, MR indications of a tear of the scapholunate ligament were true-positive in three and false-negative in three; indications of a tear of the lunotriquetral ligament were true-positive in five, false-positive in two, and false-negative in one. For the eight patients with surgical confirmation, the MR findings regarding tears were true-positive in two and true-negative in six. Neither surgery nor MR imaging showed any tears of the scapholunate ligament.

Three-dimensional Fourier transform MR imaging with thin slices provides the resolution necessary to visualize the anatomic detail of the extrinsic and intrinsic ligaments of the wrist, but additional clinical experience with this technique will be required to determine its diagnostic capabilities.