Diffusion-Tensor Magnetic Resonance Imaging for Hand and Foot Fibers Location at the Corona Radiata: Comparison with Two Lesion Studies

Abstract

The corticospinal tract is the motor pathway in the human brain, and corona radiata (CR) is an important location to diagnose stroke. We detected hand and foot motor fiber tracts in the CR to investigate accurate locations using diffusion-tensor imaging (DTI) and functional imaging. Ten right-handed normal volunteers participated in this study. We used a probabilistic tracking algorithm, a brain normalization method, and functional imaging results to set out region of interests. Moreover, our results were compared to previous results of lesion studies to confirm their accuracy and usefulness. The location measurements were performed in two index types; anteriority index on the basis of the anterior and posterior location of lateral ventricle and laterality index on the basis of the left and right location. The anteriority indices were 56.40/43.2 (hand/foot) at the upper CR and lower CR 40.72/30.90 at the lower CR. The measurements of anteriority and laterality of motor fibers were represented as anteriority index 0.40/0.31 and laterality index 0.60/0.47 (hand/foot). Our results showed that the hand and foot fibers were in good agreements with previous lesion studies. This study and approaches can be used as a standard for DTI combined with lesion location studies in patients who need rehabilitation or follow-up.

Functional MRI vs. navigated TMS to optimize M1 seed volume delineation for DTI tractography. A prospective study in patients with brain tumours adjacent to the corticospinal tract

“…Secondly, the position of different somatotopic fibres within the PLIC overall agreed well with previous findings and neuroanatomical knowledge: Fibres originating from the non-lesional M1 representation of the hand passed almost exclusively through the dorsal two thirds of the PLIC as previously described by various neuroanatomical (Kretschmann, 1988) and neuroimaging studies (Han et al, 2010) and mostly anteriorly to the foot-related tracts (Lee et al, 2014, Kwon et al, 2014). In contrast, the corticobulbar CST fibres originating from the tongue M1 representation mostly passed through the middle or, at least for nTMS-based tractography results, central segment of the PLIC and hence most anteriorly amongst the somatotopic tracts.…”

Symmetrical Location Characteristics of Corticospinal Tract Associated With Hand Movement in the Human Brain

“…Based on the DTT method, various studies have been performed to verify the characteristics of the CST including FLs, somatotopic arrangements between motor fibers, and differences in between normal subjects or patients. 2 , 8 – 10 , 12 , 22 , 23 However, the results from previous studies of CST somatotopy indicated some controversial issues and discrepancies due to the differences in approach and the accuracy of the analysis. In addition, interestingly, there are only few studies on finding symmetries of CST, and it is not dealt as an important issue in the research areas using DTT method although providing the symmetrical information of CST was a branch of somatotopy research considering its clinical importance for neurosurgery or neurorehabilitation.…”

“…They also found that the anteriority distances for hand CST between upper CR and lower CR have some differences although they did not provide the statistical analysis results. 8 , 24 However, in our anteriority index measurement process, we defined the basis distance for the ratio using whole brain length, which is measured from the distance between the most anterior and the most posterior point of the normalized brain template structures in the CR brain level. Therefore, our results should be different from those of previous studies, and our measurement processes may also affect the statistical analysis results, although we measured the anteriority indices in a similar way to the previous studies.…”

“…A 8-mm full width at half maximum sized Gaussian kernel was applied to all fMRI data to increase the validity of statistics. 8 , 15 The fMRI data were realigned and co-registered based on the nondiffusion weighted image (b = 0 image) because the analyzed fMRI activation results, which were spatially registered to b = 0 image, were used for the ROI setting in the fiber tracking process.…”

“…Based on the methods and results in the previous literatures, the accurate CST extraction in the human brain should be approached by using the probabilistic fiber tracking algorithm and the functional activation area of specific motor movement. 8 , 9 , 13 , 14 The use of probabilistic fiber tracking algorithm, which is different from the deterministic algorithm, can solve the crossing fiber problem in the brain. The CST is well known fiber that has the fiber crossing regions with superior longitudinal fasciculus (SLF).…”