Motor function reorganization in a patient with a brainstem lesion: DTT, fMRI and TMS study

Abstract

Objective: We report on a hemiparetic patient who showed a new motor pathway posterior to the lesion in the midbrain and upper pons, demonstrated by three combined method of diffusion tensor tractography(DTT)/functional MRI(fMRI)/transcranial magnetic stimulation(TMS). Methods: A 21-year-old left hemiparetic male who suffered from tuberous meningitis at the age of 12 months after birth. The evaluations were performed at 20 years after onset. Brain MRI showed focal encephalomalatic lesions due to infarcts in right anterior thalamus, midbrain and upper pons. DTT, fMRI and TMS were performed simultaneously. Results: The contralateral primary sensori-motor cortex was activated during either affected or unaffected hand movements. DTT showed that the motor tracts descended along the known pathway of the CST, with the exception of the motor tract of the affected hemisphere, which descended along the posterior portion to the lesion in the right midbrain and the pons, and then rejoined the CST in the mid-pons. The TMS results suggested that the motor tract of the affected hemisphere had the characteristics of a CST. Conclusion: We believe that the motor function of the affected hand in this patient had been recovered through the pathway posterior to the lesion in the midbrain and upper pons.

A supplementary grading scale combining lesion-to-eloquence distance for predicting surgical outcomes of patients with brain arteriovenous malformations

“…15,22 However, structural anatomy defined by the traditional MRI as eloquent does not always equate with functional anatomy, because a brain harboring a BAVM often relocates functional areas that lie too close to the nidus. 2,3,14,19 Preoperative imaging with fMRI and DTI tractography have helped us more precisely localizes a patient's eloquent cortex and white matter functional fiber tracts. Moreover, the relationship between the nidus and eloquent brain areas can be quantified by the LED with the aid of BOLD fMRI and DTI tractography.…”

Connectivity of thalamo‐cortical pathway in rat brain: combined diffusion spectrum imaging and functional MRI at 11.7 T

“…The combination of functional brain activation and fiber tracking has recently been reported by several groups for the human brain , and has even been applied to clinical cases of functional deficits . However, all of these studies were performed with DTI using only a small number of independent directions (between 6 and 60 directions), thus limiting the resolution of crossing fibers.…”

“…For the detection and characterization of such structural correlates of functional aspects, DSI is expected to contribute an important part, as it allows the assessment of the intactness or degree of damage done to the connectivity of the stimulation paradigm tested – in this case, the thalamo‐cortical connectivity. Thus, this combination of fMRI and fiber tracking (mostly DTI only) has already been demonstrated to be successful in clinical applications . It is foreseen that this combination will also be applied more often in the future when correlations between structural damage and functional deficit are investigated in controlled animal disease models, in order to better understand the mechanisms of lesion evolution and the assessment of therapeutic success.…”

“…brain tumors, and to preoperative planning . More recently, fiber tracking has been combined with functional MRI (fMRI) in human studies, with the focus of providing an improved determination of the relevant fiber bundles for a defined stimulation pathway or in clinical situations . Although diffusion spectrum imaging (DSI) has been shown in individual cases to provide superior resolution, in particular, in the discrimination of crossing fibers , the application of this experimental set‐up has remained limited because of its demands on scan time and signal‐to‐noise ratio (SNR).…”