Limits...
Visualization of the medial forebrain bundle using diffusion tensor imaging

View Article: PubMed Central

ABSTRACT

Diffusion tensor imaging is a technique that enables physicians the portrayal of white matter tracts in vivo. We used this technique in order to depict the medial forebrain bundle (MFB) in 15 consecutive patients between 2012 and 2015. Men and women of all ages were included. There were six women and nine men. The mean age was 58.6 years (39–77). Nine patients were candidates for an eventual deep brain stimulation. Eight of them suffered from Parkinson‘s disease and one had multiple sclerosis. The remaining six patients suffered from different lesions which were situated in the frontal lobe. These were 2 metastasis, 2 meningiomas, 1 cerebral bleeding, and 1 glioblastoma. We used a 3DT1-sequence for the navigation. Furthermore T2- and DTI- sequences were performed. The FOV was 200 × 200 mm2, slice thickness 2 mm, and an acquisition matrix of 96 × 96 yielding nearly isotropic voxels of 2 × 2 × 2 mm. 3-Tesla-MRI was carried out strictly axial using 32 gradient directions and one b0-image. We used Echo-Planar-Imaging (EPI) and ASSET parallel imaging with an acceleration factor of 2. b-value was 800 s/mm2. The maximal angle was 50°. Additional scanning time was < 9 min. We were able to visualize the MFB in 12 of our patients bilaterally and in the remaining three patients we depicted the MFB on one side. It was the contralateral side of the lesion. These were 2 meningiomas and one metastasis. Portrayal of the MFB is possible for everyday routine for neurosurgical interventions. As part of the reward circuitry it might be of substantial importance for neurosurgeons during deep brain stimulation in patients with psychiatric disorders. Surgery in this part of the brain should always take the preservation of this white matter tract into account.

No MeSH data available.


MRI axial view, T1, DBS, blue: right MFB, green: left MFB.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4628102&req=5

Figure 3: MRI axial view, T1, DBS, blue: right MFB, green: left MFB.

Mentions: We were able to portray the MFB in all our patients. In 12 of our patients the MFB could be visualized bilaterally and in the remaining three patients we depicted the MFB on one side. The MFB was missing on the ipsilateral side of the lesion. These were 2 meningiomas and 1 metastasis. In one case the lesion was surrounded by edema. We put our ROI as mentioned above in the VTA and in the medial orbitofrontal cortex. If one of these parts of the brain was influenced by a lesion e.g., edema we segmented the edema and included a part of it in our ROI. We assume that the fibers which could be portrayed were indeed correct and for sure but we never forgot that other fibers might be there too which couldn't be depicted due to the lesion. One case showed the MFB running laterally of the glioblastoma which was situated in between of the two MFB (Figure 1). Here we have the MFB depicted in blue and green. What is striking here, is the fact that a good part of the fibers are identified despite the big tumoral lesion, however they seem to have a small volume in comparison with Figure 3 or Figure 7. This might be due to the tumor which has invaded or destructed them or due to the limitation of DTI to depict WMT next to cerebral lesions completely. With other words we are sure about the correctness of the depicted fibers, however, there might be other fibers which are destroyed or disrupted by this tumor which couldn't be depicted with the DTI. This fact should always be kept in mind when visualizing WMT by means of DTI. This patient was put under antidepressive treatment in the follow up. In this respect it might be possible that the fibers of both MFB were compromised. When a certain number of fibers isn't working then symptoms might appear. The fibers pass through the superior cerebellar penduncle. They ascend through the pons and pass through two important areas. One of them is the area posterior of the red nucleus and the other one is the periaqueductal gray. The tract reachs furthermore the lateral hypothalamus. Furthermore, its fibers run through the lateral wall of the third ventricle and are situated next to the anterior horn of the lateral ventricle The fibers of this WMT are localized under the thalamus before they border the anterior limb of the internal capsule. The STN seems to be situated laterally and posteriorly of the MFB. Partially the MFB is directed latero-caudally at the level of the substantia nigra. The MFB ran from the VTA to the NAC, the medial and lateral orbitofrontal contex, and the dorsolateral prefrontal cortex. Ultimately it seems that the fibers reach out to the olfactory bulb. The MFB was situated cranially to the optic chiasm and the optical tract in his part concerning the frontal lobe. In Figure 2 we depicted the MFB on the healthy side only. On the ipsilateral side of the metastasis we couldn't portray the MFB. The patient however wasn't depressive and didn't need any treatment in this direction later on. This can be due to the presence of a good developed MFB on the contralateral side which is able to take over the task alone. Figures 3, 4 can show the fibers without being compromised by a lesion. Here we can see precisely the size of the ROI and their location. Figure 5 describes the case in which fibers of the MFB can differ in volume in one and the same patient without being compromised by a lesion. These differences can appear between the right and the left MFB in the same patient or there can be interindividual differences without any presence of special symptoms. The latter case can be seen if we compare Figure 6 with Figure 7. In Figure 8 we recognize the edema which is surrounding the tumor, in this case a metastasis. We can deduce that a lesion like edema can hinder the depiction of WMT by means of DTI. In Figure 2 there was a lesion without edema which hindered the portrayal of the MFB. In this case we have the presence of the two. We didn't remark any differences in our patients concerning the fractional anisotropy. We have to say that none of our patients sufferend from a MD. Based on the Hamilton scale for depression no one from our patients fulfilled the criteria for MD. We have to admit however that when you announce to a patient a diagnosis like brain cancer, he might feel hopeless or sad but this is only one of the criteria in this scale and it is something expected. None of our patients needed a psychiatric surveillance and they were stable during their whole stay in the hospital.


Visualization of the medial forebrain bundle using diffusion tensor imaging
MRI axial view, T1, DBS, blue: right MFB, green: left MFB.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4628102&req=5

Figure 3: MRI axial view, T1, DBS, blue: right MFB, green: left MFB.
Mentions: We were able to portray the MFB in all our patients. In 12 of our patients the MFB could be visualized bilaterally and in the remaining three patients we depicted the MFB on one side. The MFB was missing on the ipsilateral side of the lesion. These were 2 meningiomas and 1 metastasis. In one case the lesion was surrounded by edema. We put our ROI as mentioned above in the VTA and in the medial orbitofrontal cortex. If one of these parts of the brain was influenced by a lesion e.g., edema we segmented the edema and included a part of it in our ROI. We assume that the fibers which could be portrayed were indeed correct and for sure but we never forgot that other fibers might be there too which couldn't be depicted due to the lesion. One case showed the MFB running laterally of the glioblastoma which was situated in between of the two MFB (Figure 1). Here we have the MFB depicted in blue and green. What is striking here, is the fact that a good part of the fibers are identified despite the big tumoral lesion, however they seem to have a small volume in comparison with Figure 3 or Figure 7. This might be due to the tumor which has invaded or destructed them or due to the limitation of DTI to depict WMT next to cerebral lesions completely. With other words we are sure about the correctness of the depicted fibers, however, there might be other fibers which are destroyed or disrupted by this tumor which couldn't be depicted with the DTI. This fact should always be kept in mind when visualizing WMT by means of DTI. This patient was put under antidepressive treatment in the follow up. In this respect it might be possible that the fibers of both MFB were compromised. When a certain number of fibers isn't working then symptoms might appear. The fibers pass through the superior cerebellar penduncle. They ascend through the pons and pass through two important areas. One of them is the area posterior of the red nucleus and the other one is the periaqueductal gray. The tract reachs furthermore the lateral hypothalamus. Furthermore, its fibers run through the lateral wall of the third ventricle and are situated next to the anterior horn of the lateral ventricle The fibers of this WMT are localized under the thalamus before they border the anterior limb of the internal capsule. The STN seems to be situated laterally and posteriorly of the MFB. Partially the MFB is directed latero-caudally at the level of the substantia nigra. The MFB ran from the VTA to the NAC, the medial and lateral orbitofrontal contex, and the dorsolateral prefrontal cortex. Ultimately it seems that the fibers reach out to the olfactory bulb. The MFB was situated cranially to the optic chiasm and the optical tract in his part concerning the frontal lobe. In Figure 2 we depicted the MFB on the healthy side only. On the ipsilateral side of the metastasis we couldn't portray the MFB. The patient however wasn't depressive and didn't need any treatment in this direction later on. This can be due to the presence of a good developed MFB on the contralateral side which is able to take over the task alone. Figures 3, 4 can show the fibers without being compromised by a lesion. Here we can see precisely the size of the ROI and their location. Figure 5 describes the case in which fibers of the MFB can differ in volume in one and the same patient without being compromised by a lesion. These differences can appear between the right and the left MFB in the same patient or there can be interindividual differences without any presence of special symptoms. The latter case can be seen if we compare Figure 6 with Figure 7. In Figure 8 we recognize the edema which is surrounding the tumor, in this case a metastasis. We can deduce that a lesion like edema can hinder the depiction of WMT by means of DTI. In Figure 2 there was a lesion without edema which hindered the portrayal of the MFB. In this case we have the presence of the two. We didn't remark any differences in our patients concerning the fractional anisotropy. We have to say that none of our patients sufferend from a MD. Based on the Hamilton scale for depression no one from our patients fulfilled the criteria for MD. We have to admit however that when you announce to a patient a diagnosis like brain cancer, he might feel hopeless or sad but this is only one of the criteria in this scale and it is something expected. None of our patients needed a psychiatric surveillance and they were stable during their whole stay in the hospital.

View Article: PubMed Central

ABSTRACT

Diffusion tensor imaging is a technique that enables physicians the portrayal of white matter tracts in vivo. We used this technique in order to depict the medial forebrain bundle (MFB) in 15 consecutive patients between 2012 and 2015. Men and women of all ages were included. There were six women and nine men. The mean age was 58.6 years (39–77). Nine patients were candidates for an eventual deep brain stimulation. Eight of them suffered from Parkinson‘s disease and one had multiple sclerosis. The remaining six patients suffered from different lesions which were situated in the frontal lobe. These were 2 metastasis, 2 meningiomas, 1 cerebral bleeding, and 1 glioblastoma. We used a 3DT1-sequence for the navigation. Furthermore T2- and DTI- sequences were performed. The FOV was 200 × 200 mm2, slice thickness 2 mm, and an acquisition matrix of 96 × 96 yielding nearly isotropic voxels of 2 × 2 × 2 mm. 3-Tesla-MRI was carried out strictly axial using 32 gradient directions and one b0-image. We used Echo-Planar-Imaging (EPI) and ASSET parallel imaging with an acceleration factor of 2. b-value was 800 s/mm2. The maximal angle was 50°. Additional scanning time was < 9 min. We were able to visualize the MFB in 12 of our patients bilaterally and in the remaining three patients we depicted the MFB on one side. It was the contralateral side of the lesion. These were 2 meningiomas and one metastasis. Portrayal of the MFB is possible for everyday routine for neurosurgical interventions. As part of the reward circuitry it might be of substantial importance for neurosurgeons during deep brain stimulation in patients with psychiatric disorders. Surgery in this part of the brain should always take the preservation of this white matter tract into account.

No MeSH data available.