Bone contusions of the knee: increased lesion detection with fast spin-echo MR imaging with spectroscopic fat saturation.

PURPOSE

To demonstrate that T2-weighted fast spin-echo (FSE) imaging with spectroscopic fat saturation (FS-FSE) increases the conspicuity between normal marrow and bone contusions in posttraumatic knees.

MATERIALS AND METHODS

Seventy-six magnetic resonance (MR) studies of the knee were prospectively evaluated in 73 consecutive patients with knee pain. Conspicuity of regions of microtrabecular trauma (bone contusions) was evaluated with conventional T2-weighted imaging in the sagittal plane, T2-weighted FSE imaging in the coronal plane, T2-weighted FS-FSE imaging in the sagittal plane, and conventional T1-weighted imaging in the sagittal plane.

RESULTS

Twenty-six foci of bone contusion were identified in 21 knees with the FS-FSE technique. Only 16 foci were demonstrated with conventional T2-weighted imaging. Six of the sites of bone contusion were not demonstrated with the FSE technique alone (without fat saturation). Four of the bone contusions were not seen on T1-weighted images; these sites of bone contusion were substantially more conspicuous on the FS-FSE images. In addition, FS-FSE imaging was more sensitive in demonstrating the extent of microtrabecular trauma.

CONCLUSION

T2-weighted FS-FSE imaging is a sensitive and rapid method of identifying and assessing the extent of microtrabecular trauma about the knee.