Injury of the dentato-rubro-thalamic tract in a patient with intentional tremor after mild traumatic brain injury: a case report.

OBJECTIVES: We imaged the dentato-rubro-thalamic tract (DRTT) and cortico-ponto-cerebellar tract (CPCT) using diffusion tensor tractography (DTT) to evaluate the cortico-cerebellar-cortical circuit in a patient with tremor in both hands after mild TBI. We found bilateral DRTT injury in the DTT. METHOD: A 50-year-old male presented with action tremor in both hands 1 week after mild TBI. One month before the visit, the patient had a head injury from a fall on a bus. The patient lost consciousness for 1 min and experienced post-traumatic amnesia for approximately 5 min after the accident. His Glasgow Coma Scale score was 15. The action tremor presented with a frequency of 3 Hz in both hands. No specific lesion was observed with a conventional brain MRI. RESULTS: DTT, performed 1.5 months after TBI, showed that the right DRTT was not reconstructed and the left DRTT had thinned. However, CPCT integrity was well-preserved in both hemispheres. The tremor disappeared after oral treatment with 30 mg/day indenol. The patient's tremor would have been caused by disruption of the bilateral DRTT following mild TBI. CONCLUSION: DRTT and CPCT analysis using DTT would be useful for diagnosing abnormal movement problems, including tremor and ataxia, in patients following mild TBI.

Differences of the medial lemniscus and spinothalamic tract according to the cortical termination areas: A diffusion tensor tractography study.

We investigated differences of the medial lemniscus and its thalamocortical pathway (ML), and the spinothalamic tract and its thalamocortical pathway (STT) according to the cortical termination areas. We found that the ML and STT terminated in the motor cortex and the somatosensory cortex. The ML may be closely related to the motor cortex for motor planning and execution, while the STT may be closely related to the cerebral cortex for somatosensory function and motor execution.

Traumatic thalamic injury demonstrated by diffusion tensor tractography of the spinothalamic pathway.

BACKGROUND: This study reports on a patient with traumatic brain injury (TBI) with a thalamic lesion in the ventroposterolateral nucleus which was demonstrated by diffusion tensor tractography (DTT) for the spinothalamic tract and its thalamocortical pathway (STP). METHODS: One patient with TBI and eight normal control subjects were recruited. A 64-year-old woman who had suffered a motor vehicle accident presented with a persisting tingling sensation and pain in her right upper and lower extremities at 3 weeks after onset. The patient showed impaired touch sensation, but normal proprioception. Diffusion tensor imaging was performed at 1 month after onset. Fractional anisotropy (FA) and mean diffusivity were measured using a region of interest method along the STP. RESULTS: DTT showed normal STP integrities as compared with normal controls. However, the FA values of the left STP at the thalamus were more than 2 SD decreased. The diminished FA value of the left STP in the left thalamus seems to indicate injury of the left ventrolateroposterior nucleus. Central pain and impaired touch sensation of right extremities supports the presence of left STP injury at the ventroposterolateral nucleus in this patient. CONCLUSION: It is believed that DTT for the STP provides a useful means of detecting thalamic injury in TBI.