Role of diffusion tensor imaging in the diagnosis and management of post-traumatic anosmia

Introduction: Anosmia is a possible complication of Traumatic Brain Injury (TBI). Psychometric and electrophysiological methods of olfaction measure and Magnetic Resonance imaging (MRI) are the tools to evaluate the post-traumatic olfactory loss. Diffusion Tensor Imaging (DTI) provides useful data for a better understanding of etiopathogenesis TBI-related anosmia, in particular the loss of neural connections and their eventual recovery over time.& para;& para;Materials and methods: This study describes a case of TBI-related anosmia. The olfactory function was evaluated by Sniffin' Sticks Test (SST), Olfactory Event-Related Potentials (OERPs), MRI and DTI at baseline (T0) and after one year (T1).& para;& para;Results: At baseline, SST highlighted a functional anosmia. The OERPs showed the presence of a small N1-P2 complex. MRI confirmed the presence of a scarring involved in the right orbitofrontal cortex (OFC). DTI detected a reduction in the average length and the number of neuronal fibre pathways of right OFC. At T1, a recovery of olfactory function was confirmed by SST and OERPs.& para;& para;Conclusion: While MRI images are unchanged from T0, DTI showed an increase in average length and number of fibre tracts in the right OFC. DTI could be a valid tool to display a post-traumatic loss of neural connections and to better understand TBI-recovery mechanisms.