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Clinical Cases

fMRI, DTI and Perfusion in a Patient Presenting with a Brain Tumor

To illustrate the functionalities of BrainMagix, Imagilys's neuroimaging software, we study the case of a 31-year-old male patient presenting with a left temporo-parieto-occipital glioma.

A rapidly progessing tumor can be observed as a hyposignal on T2 images. The tumor is surrounded by a large amount of edema extending towards the left hippocampus with mass effect on the ventricles. The core has an elevated signal on DWI images, but intermediate ADC. Enhancement can be observed after injection of a contrast agent, and an rCBV 4- to 6-times higher than normal on perfusion images. On DTI images, one can see fibers (mainly optical radiations) pushed medially. On spectroscopy, NAA peak is largely decreased, and there is a very high choline peak. All these facts were strongly suggestive of a high-grade tumor.

Anatomical T2 image (top left), apparent diffusion coefficient (ADC) (top right), cerebral blood volume (CBV) (bottom left), functional MRI (fMRI) and diffusion tensor images (DTI) overlaid on a T2 image (bottom right).

As the tumor was close to language areas, fMRI was performed for surgical planning. The paradigms were a semantic word generation task based on short sentence processing transmitted orally and visually with feedback from the patient. There is an activation of the junction between middle and superior temporal gyri at the posterior part corresponding to Wernicke's area. Just ahead of the edema, an activation appeared too close (8-9 mm) to the antero-superior part of the tumor for a safe resection. Also, there was activation of similar regions (Wernicke’s and Broca’s) on the right, suggesting partial compensation of language on the right side.

Intraoperative T2-weighted image shows a complete resection of the hot spot of the tumor. Intraoperative image quality is very good, like diagnostic one.During the neurosurgical procedure, the hot spot of the tumor was completely removed. The colder spots were largely but incompletely removed. In particular, the temporal lobe was preserved for language, resulting in no aphasia post-operatively. Histological analysis revealed an anaplastic astrocytoma. The surgical treatment was followed by radiotherapy and chemotherapy.

 

MRI, Perfusion and PET scan in a Patient Presenting a Brain Tumor

To illustrate the functionalities of BrainMagix, Imagilys's neuroimaging software, we study the case of a 32-year old male patient presenting a right temporo-parieto-occipital glioma.

Methionine PET demonstrated a large area of methionine uptake with a hot spot in the infero-posterior area of the tumor, indicating a high grade component. This zone was manually outlined, and the region of interest (ROI) was superimposed on T1- and T2-weighted MR images (Fig. 1)Fig. 1: ROI defined on the methionine PET superimposed on T1 and T2 MR images..

Fig. 2: The hottest spot as defined on MR perfusion (red/yellow) and methionine PET (blue), superimposed on the T2 MRI.Perfusion MRI showed a very high rCBV, 14 times higher in the hotspot than in the normal contra-lateral tissue. The hottest spots as defined by PET and MR perfusion imaging were compared (Fig. 2). The results display partial overlap, but the perfusion hot spot is more anterior.

Fig. 3: Intra-operative FLAIR showed a complete resection at this level. Brain shift can be observed. Intra-operative MRI (iMRI) was performed during the tumor resection. FLAIR showed a complete resection of the tumor on the slice depicted in Fig. 3. However, the brain shift during the surgical procedure makes a comparison with the pre-operative tumor delineation more complex. In the inferior part of the original tumor, intra-operative FLAIR indicates possible residual tumor as dark areas medial to the cavity (Fig. 4 middle). The resection had been completed after iMRI as shown in the T2 image of Fig. 4. Histological analysis revealed an anaplasic astrocytoma. Fig. 4. Pre-operative T1, intra-operative FLAIR with potential residual tumor seen as gray areas in the edema. Post-operative T2 indicated the complete resection of the tumor.

 

Clinical Cases

 

Functional MRI (fMRI) and Segmentation for Surgical Planning: Right Parietal Tumor

fMRI for brain tumor
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