Figure - available from: Frontiers in Neuroscience
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The primary tumor, the recurrence tumor, and the overlap between the different TCs and the tumor recurrence mask of the representative case of Patient 20 are displayed in this figure. All images are transformed to the MNI152 1 mm space. (A) The preoperative contrast enhanced T1 image. Two small tumors with ring shaped contrast enhancement can be seen in the right frontal region. (B) The size and the location of the tumor recurrence. (C) The 1% TC (red) is overlapped on the tumor recurrence mask (green). (D) The 5% TC (blue) is overlapped on the tumor recurrence mask (green). (E) The 40% TC (red-yellow) is overlapped on the tumor recurrence mask (green). (C–E) Are on the preoperative T1 images. As it can be seen, the TCs are fully overlapping with the tumor recurrence mask and therefore the specificity is 100% at every threshold. On the other hand the recurrence remarkably exceeds the border of the TCs, and the sensitivity is low, even at 1%. Please note that the direction of the recurrence is in correspondence with the TCs, and the low sensitivity is the result of the fast tumor progression.
Source publication
Glioblastoma is the most frequent type of primary brain tumors. Despite the advanced therapy, most of the patients die within 2 years after the diagnosis. The tumor has a typical appearance on MRI: a central hypointensity surrounded by an inhomogeneous, ring-shaped contrast enhancement along its border. Too small to be recognized by MRI, detached i...
Citations
... Glioblastoma is the most frequent type of primary brain tumor. It strongly reduces life expectancy, with most patients dying within 16-20 months after the diagnosis, despite all of the advanced therapy available [21,22]. Glioblastoma is a rapidly growing and highly infiltrative malignant tumor, which propagates primarily along the white matter fiber tracts and infiltrating grey matter during the advanced stage [23]. ...
Gravity is a primary physical force that has a profound influence on the stability of the cell cytoskeleton. In our research, we investigated the influence of microgravity on altering the cytoskeletal pathways of glioblastoma cells. The highly infiltrative behavior of glioblastoma is supported by cytoskeletal dynamics and surface proteins that allow glioblastoma cells to avoid stable connections with the tissue environment and other cells. Glioblastoma cell line C6 was exposed to a microgravity environment for 24, 48, and 72 h by 3D-RPM, a laboratory instrument recognized to reproduce the effect of microgravity in cell cultures. The immunofluorescence for GFAP, vinculin, and Connexin-43 was investigated as signals related to cytoskeleton dynamics. The polymerization of GFAP and the expression of focal contact structured by vinculin were found to be altered, especially after 48 and 72 h of microgravity. Connexin-43, involved in several intracellular pathways that critically promote cell motility and invasion of glioma cells, was found to be largely reduced following microgravity exposure. In conclusion, microgravity, by reducing the expression of Connexin-43, alters the architecture of specific cytoskeletal elements such as GFAP and increases the focal contact, which can induce a reduction in glioma cell mobility, thereby inhibiting their aggressive metastatic behavior.
... In a prospective comparison, MRgRT resulted in reduced doses of healthy brain tissue [35]. Furthermore, recent advances in diagnostic MRI (e.g., spectroscopy or probabilistic tractography to define the true tumour extent) allow for individualised radiation treatment planning [36,37]. Future trials will establish the exact role and benefit of these features. ...
Simple Summary
Malignant brain tumours have a poor prognosis and routinely require brain surgery followed by radiation treatment of the extended tumour cavity. We compared magnetic resonance images (MRIs) of 28 patients at two points in time: immediately after surgery and close before the start of radiation. Even though both MRIs were roughly only 3 weeks apart, we noted substantial differences in the position and size of the tumour cavity, surrounding affected brain tissue, the position of the midline, and bleeding in the surgical area. The brain anatomy, as seen in the MRI, guides the planning of radiation. Older images thus do not reflect the actual anatomy anymore, which might lead to insufficient treatment of the tumour site or increased side effects due to irradiation of healthy tissues. Our data support the use of a second MRI for radiation treatment planning as close to its start as possible.
Abstract
High-grade glioma has a poor prognosis, and radiation therapy plays a crucial role in its management. Every step of treatment planning should thus be optimised to maximise survival chances and minimise radiation-induced toxicity. Here, we compare structures needed for target volume delineation between an immediate postoperative magnetic resonance imaging (MRI) and a radiation treatment planning MRI to establish the need for the latter. Twenty-eight patients were included, with a median interval between MRIs (range) of 19.5 (8–50) days. There was a mean change in resection cavity position (range) of 3.04 ± 3.90 (0–22.1) mm, with greater positional changes in skull-distant (>25 mm) resection cavity borders when compared to skull-near (≤25 mm) counterparts (p < 0.001). The mean differences in resection cavity and surrounding oedema and FLAIR hyperintensity volumes were −32.0 ± 29.6% and −38.0 ± 25.0%, respectively, whereas the mean difference in midline shift (range) was −2.64 ± 2.73 (0–11) mm. These data indicate marked short-term volumetric changes and support the role of an MRI to aid in target volume delineation as close to radiation treatment start as possible. Planning adapted to the actual anatomy at the time of radiation limits the risk of geographic miss and might thus improve outcomes in patients undergoing adjuvant radiation for high-grade glioma.
Diffusion magnetic resonance imaging tractography is a noninvasive technique that enables the visualization and quantification of white matter tracts within the brain. It is extensively used in preoperative planning for brain tumors, epilepsy, and functional neurosurgical procedures such as deep brain stimulation. Over the past 25 years, significant advancements have been made in imaging acquisition, fiber direction estimation, and tracking methods, resulting in considerable improvements in tractography accuracy. The technique enables the mapping of functionally critical pathways around surgical sites to avoid permanent functional disability. When the limitations are adequately acknowledged and considered, tractography can serve as a valuable tool to safeguard critical white matter tracts and provides insight regarding changes in normal white matter and structural connectivity of the whole brain beyond local lesions. In functional neurosurgical procedures such as deep brain stimulation, it plays a significant role in optimizing stimulation sites and parameters to maximize therapeutic efficacy and can be used as a direct target for therapy. These insights can aid in patient risk stratification and prognosis. This article aims to discuss state-of-the-art tractography methodologies and their applications in preoperative planning and highlight the challenges and new prospects for the use of tractography in daily clinical practice.
