case_images: PMC11782241_01
case_images: Case 1 sagittal and axial MRI T1 sequences with contrast on follow-up. (A) MRI from May 2018 illustrating a space occupying lesion arising from the left foramen of Luschka with contrast-enhancement (arrow). (B) Post-surgical resection MRI control revealing gross total resection. (C) MRI from December 2020 revealing a new periventricular lesion frontal left, suspected of ependymoma metastasis. (D) MRI from April 2021 showing lesion progression after proton-therapy and Cyberknife treatment.
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case_images: F1
case_images: An 11-year-old boy was operated for non-metastatic posterior fossa (PF) ependymoma (Figure 1A), with a gross total resection being accomplished in May 2018 (Figure 1B). In December 2019, a new periventricular lesion frontal left (Figure 1C) was found during a magnetic resonance imaging (MRI)-follow-up, suspected to be a metastatic tumor progression. After an initial partial response, a follow-up MRI in April 2021 revealed progression of the same lesion (Figure 1D).
case_images: Case 1 sagittal, axial and coronal MRI during LITT and on follow-up. Upper section: (A) T1-sequences from May 2021 showing the placement of the catheters for the stereotactic magnetic resonance-guided LITT procedure. (B) Sagittal view with both catheters reaching the lesion (final positioning about 1-2 mm deeper). (C) Coronal view with the trajectory of the electrodes through the superior and medial frontal gyrus left-sided. (D) (sagittal) and (E) (axial) hologram views illustrating the relationship between the tumor and position of the two LITT electrodes during treatment. Lower section: (a) Tumor expansion observed on MRI from September 2021, in which the direction of growth anatomically correlates with the trajectory of the LITT catheter placed. (b,d) Sagittal views showing the tumor expansion along the cingulate gyrus, but with preservation of the cingulate sulcus [which in (B) could be seen as not being perforated by the catheter]. (c) The triangular shaped tumor growth can also be observed in the coronal view. (d,e) Hologram views of the tumor growth along the initial trajectories of the LITT catheters, without invasion of the ventricular system.   on (A-C) illustrates the trajectory of the LITT catheters during treatment;   on (a-c) shows the pattern of tumor spread after LITT; * represents the location of the LITT catheter on pictures (A-C) and the cavity of the LITT's catheter on (a-c).
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case_images: F2
case_images: In May 2021, two catheters were placed along the superior and medial frontal gyrus on the left side (Figures 2A-E). Two months later, a tumor expansion in the left cingulate gyrus and superior frontal gyrus along the trajectory of both previously placed LITT catheters was radiologically observed (Figures 2a-e).
case_images: PMC11782241_02
case_images: (A) Case 2 sagittal, axial and coronal MRI T1 sequences with contrast. (A) MRI showing an intra-axial tumor on the left fusiform gyrus with contrast enhancement and central necrosis. (B) Postoperative MRI showing a gross total resection. (C) Three months after surgery and adjuvant radiotherapy, radio-necrosis reaction (arrows) was superiorly and anteriorly observed. (D) One month later, regression of the radio-necrosis but evidence of tumor progression on the left tapetum (arrow). (E)
  18F-fluoroethyltyrosin positron emission tomography-MRIs showing an increase in the FET-activity around the resection cavity, indicating tumor progression.
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case_images: F3
case_images: A brain MRI showed an intra-axial tumor in the left fusiform gyrus with peripheral edema and necrosis (Figure 3A). A treatment with dexamethasone was initiated and 2 days later the patient was operated with near gross total resection being achieved (Figure 3B). Five months after initial diagnosis, a follow-up MRI showed areas of radionecrosis (Figure 3C) and suspected subcortical tumor progression on the left tapetum (Figure 3D). A positron emission tomography (PET)-MRI (Figure 3E, up), performed to differentiate disease progression from radio-necrosis, showed some tumor activity around the resection cavity, with a progressive recurrence nodule. This was confirmed in a short interval repeated PET-MRI (Figure 3E, down).
case_images: Case 2 sagittal, coronal and axial MRIs during LITT and on follow-up. Upper section: MRI with native T1 sequences during LITT. (A-C) The catheter was placed along the left superior parietal lobule, ending on the superior aspect of the resection cavity. (D) (sagittal) and (E) (coronal) hologram views of the tumor and LITT catheter during treatment. Lower section: Follow-up MRI 2 weeks after LITT, in which a further tumor progression can be observed. (a,b) Show a wider tumor spread in a triangular shape along the trajectory of the inserted LITT catheter, with new tumor infiltration on the superficial cortex of superior parietal lobule (c). (d,e) Hologram views of the tumor growth along the initial trajectory of the LITT catheter up to the surface.   Illustrates the trajectory of the LITT catheter during treatment;   Shows the pattern of tumor spread after LITT; * represents the location of the LITT catheter on pictures (A-C) and the cavity of the LITT catheter on (a-c).
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case_images: F4
case_images: Subsequently, the LITT intervention (Figures 4A-E) was performed without evidence of complications. An MRI performed 2 weeks later revealed an extensive tumor progression (Figures 4a-e) centered on the ablation channel of the LITT catheter, with newly disease extending to the surface of the superior parietal lobule.