Diffusion tensor imaging has prognostic value on return to play in hamstring injuries: A prospective cohort study

Predicting an accurate return to play (RTP) time after hamstring injury remains difficult. The ability of diffusion tensor imaging (DTI) to detect muscle micro-trauma may help to overcome this limitation.

To investigate the predictive value of DTI-derived parameters for RTP prognosis following hamstring injury.

In this single-centre prospective cohort study, athletes with an acute hamstring injury were included. Athletes underwent a 3 T MRI scan of the upper legs, including DTI acquisition within 7 days after injury. DTI parameters were calculated as the relative difference between legs, including the first, second and third eigenvalues, mean diffusivity, radial diffusivity and fractional anisotropy. RTP was defined as the self-reported time needed to return to full unrestricted training in days. Linear regression analysis was performed to determine the association between DTI parameters and RTP. To investigate the added value of DTI to conventional MRI. DTI parameters that met a p < 0.05 threshold in the univariate analyses were selected for multivariate linear regression. In the multivariate linear regression, the selected DTI parameters were individually combined with the conventional modified Peetrons classification.

From 116 athletes, 91 were included in the analysis. The median RTP time was 37 days (IQR 41). We found univariate associations between all DTI parameters and the RTP time, explaining between 5.4 % to 15.0 % of the variance in RTP time. Multivariate analysis showed that all DTI parameters except the first eigenvalue were independently associated with RTP time.

Univariate associations between all six DTI parameters and RTP time were found, explaining between 5.4% and 15% of the variance in RTP time. Multivariate analysis showed DTI parameters that included information on diffusivity in the radial axes had the most added value in RTP prognosis.

In athletes with an acute diagnosis of hamstring injury, multivariate linear regression analysis revealed associations between diffusor tensor imaging-derived parameters (eigenvalues, mean diffusivity, radial diffusivity, and fractional anisotropy) and prognosis for time to return to play prognosis.