SHORT ECHO TIME MAGNETIC-RESONANCE-IMAGING OF TENDON

RATIONALE AND OBJECTIVES. Current clinical magnetic resonance (MR) imaging studies provide almost no useful signal from normal tendon and have no clear advantage over other imaging modalities in the evaluation of tendon injuries. The authors believe that tendon MR signal may be T2-limited, and, if so, could be enhanced by short echo time (TE) pulse sequences. The relationship of tendon signal intensity and tendon infrastructure conspicuity to TE was assessed at three different field strengths. METHODS. Magnetic resonance imaging studies were performed on samples of normal equine tendon at 3 different field strengths with spin echo or gradient-recalled-echo sequences of varying TE. Tendon signal-to-noise ratios (SNR) were determined for each study and images were evaluated for visual evidence of tendon infrastructure. RESULTS. Tendon SNR demonstrated a strong inverse relationship to TE at each field strength. Signal-to noise ratio values of 10 to 40 were achieved on the shortest TE studies (TE < 3 msec). Tendon infrastructure could be visualized and was primarily dependent on in-plane resolution and to a lesser extent on SNR. CONCLUSIONS. Short echo time MR imaging enhances tendon signal. Under optimal imaging conditions, tendon infrastructure can be evaluated. As high-performance gradient coil systems become available for clinical imaging systems, the authors believe similar results will be achievable on routine diagnostic studies and foresee an expanding role for MRI in the evaluation of tendon disease.