Elsevier

World Neurosurgery

Volume 83, Issue 6, June 2015, Pages 982-986
World Neurosurgery

Original Article
The Safe Area in the Parieto-Occipital Lobe in the Human Brain: Diffusion Tensor Tractography

https://doi.org/10.1016/j.wneu.2015.02.020Get rights and content

Objective

A recent study reported on the relatively safe area in the frontal lobe for performance of neurological interventions; however, no study on the posterior safe area has been reported. In this study, using diffusion tensor tractography, we attempted to identify the safe area in the parieto-occipital lobe in healthy subjects.

Methods

A total of 47 healthy subjects were recruited for this study. Eleven neural tracts were reconstructed in and around the parieto-occipital area of the brain using diffusion tensor tractography. The safe area, which is free from any trajectory of 10 neural tracts, was measured anteriorly and medially from the line of the most posterior and lateral margin of the brain at 5 axial levels (from the cerebral cortex to the corona radiata).

Results

The anterior boundaries of the safe area in the upper cerebral cortex, lower cerebral cortex, centrum semiovale, upper corona radiata, and lower corona radiata levels were located at 31.0, 32.6, 32.7, 35.1, and 35.2 mm anteriorly from the line of the most posterior margin of the brain, respectively, and the medial boundaries were located at an average of 34.7, 38.1, 39.2, 36.1, and 33.6 mm medially from the line of the most lateral margin of the brain, respectively.

Conclusions

According to our findings, the safe area was located in the posterolateral portion of the parieto-occipital lobe in the shape of a triangle. However, we found no safe area in the deep white matter around the lateral ventricle.

Introduction

Invasive neurological interventions could often result in neural injury of the brain 4, 8, 14, 21, 25. These interventions comprise the operation, procedures of the shunt operation, radiotherapy, or radiosurgery 4, 8, 14, 21, 25. These interventions have been performed based on known neuroanatomy or experience (5). Anatomic identification of the safe area for performance of invasive neurological interventions could provide useful information for clinicians in the neuroscience field. However, due to limitations of previous neuroimaging techniques, such as conventional brain computerized tomography or magnetic resonance imaging, in identification and evaluation of neural tracts in the live human brain, research on this topic has been neglected.

In contrast, diffusion tensor tractography (DTT), which is derived from diffusion tensor imaging (DTI), enables identification and localization of neural tracts in 3 dimensions in the live human brain (18). A recent study (11) reported on the relatively safe area in the frontal lobe for performance of invasive neurological interventions. However, few DTT studies on the posterior safe area have been reported 2, 17. We hypothesized that the safe area in the parieto-occipital lobe could be identified using the reconstructed neural tracts for the cingulum, superior longitudinal fasciculus (SLF), middle longitudinal fasciculus (MLF), inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF), arcuate fasciculus (AF), and optic radiation (OR) 1, 3, 6, 9, 7, 10, 15, 16, 19, 24.

In the present study, using DTT, we attempted to identify the safe area in the parieto-occipital lobe in healthy subjects.

Section snippets

Subjects

We recruited 47 healthy subjects (men, 27; women, 20; mean age, 34.3 ± 11 years; range, 20–54 years) with no previous history of neurological, physical, or psychiatric illness. All subjects understood the purpose of the study and provided written, informed consent before participation. The study protocol was approved by the Institutional Review Board of a university hospital.

Diffusion Tensor Tractography

DTI data were acquired using a 6-channel head coil on a 1.5-T Philips Gyroscan Intera (Philips, Ltd., Best, the

Results

A summary of the anterior and medial boundaries of the safe area in 5 axial levels is shown in Table 1. In the upper cerebral cortex level, the anterior boundary of the safe area was located at 31.0 mm (24.7%) anteriorly from the line of the most posterior margin of the brain and the medial boundary was located at an average of 34.7 mm (60.6%) medially from the line of the most lateral margin of the brain. The anterior boundaries of the safe area in the lower cerebral cortex, CS, upper CR, and

Discussion

In the current study, we attempted to find the safe area in the parieto-occipital lobe for performance of invasive neurological interventions. We reconstructed all important neural tracts in the parieto-occipital area of the brain, the cingulum, SLF, MLF, ILF, IFOF, and OR, as well as other important neural tracts located in the middle portion of the brain, the CST, SST, CRP, and fornix. Our findings showed that the safe area was located in the posterolateral portion of the parieto-occipital

Conclusion

We investigated the safe area in the parieto-occipital lobe for performance of invasive neurological procedures and found that the safe area was located in the posterolateral portion of the parieto-occipital lobe in the shape of a triangle. However, we found no safe area in the deep white matter around the lateral ventricle. Therefore, research on the severity of neurological deficit and prognosis after injury of each neural tract would be helpful in selection of any neural tract when

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  • Conflict of interest statement: This work was supported by the DGIST R&D Program of the Ministry of Science, ICT and Future Planning (15-BD-0401).

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