PMC4423626_01
Relapse of GBM after resection and radiochemotherapy. A Native T1-weighted MRI shows a tumor involving the right basal ganglia. B Gadolinium-enhanced T1-weighted MRI shows strong peripheral and irregular enhancement of the tumor. C T2-weighted FLAIR demonstrates pronounced surrounding edema and mass effect. D In the PET/CT scan and E the fusion of PET and MRI, the lesion described in the MRI corresponds with focal increased 18 F-FET uptake exhibiting Tu/Bg ratio of 2.4.
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Fig1
The native and Gadolinium-enhanced T1-weighted cerebral magnetic resonance imaging (cMRI) showed a tumor involving the right basal ganglia with strong peripheral and irregular contrast enhancement (Figure 1A and B). In the T2-weighted FLAIR a pronounced surrounding edema and mass effect was seen in the area of the basal ganglia (Figure 1C). To confirm this we performed 18 F-fluoroethyltyrosine-positron emission tomography/computer tomography (FET-PET/CT) scan (Figure 1D and E). The PET/CT (Figure 1D) showed a focally increased 18 F-FET uptake corresponding to the contrast enhancement described in cMRI, which was emphasized in the fusion of PET and MRI (Figure 1E). A very low level of 18 F-FET tracer uptake was noted (Figure 4), which was substantially lower than the tracer uptake observed before treatment (Figure 1D and E).
GBM after three courses of bevacizumab. Gadolinium-enhanced T1-weighted MRI shows a reduction in tumor size as well as decreasing and discontinuous tumor enhancement.
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Fig2
After three courses, a reduction in tumor size from 51 x 21 x 25 mm to 39 x 17 x 17 mm was observed at Gadolinium-enhanced T1-weighted cMRI, and the degree of contrast enhancement within the tumor had decreased (Figure 2).
Treatment response after 17 courses of bevacizumab in cMRI. A Non-enhanced T1-weighted MRI reveals further decrease in lesion size. Hyperintense hemorrhagic changes are present within the medial portion of the tumor. B Gadolinium-enhanced T1-weighted MRI documents lack of contrast enhancement in the lateral portions of the tumor. Only a slight enhancement in addition to the hyperintense hemorrhagic changes in the medial portion of the tumor was observed. C T2-weighted FLAIR demonstrates a decrease of peritumoral edema.
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Fig3
T1-weighted sequences (Figure 3A) and a lack of contrast enhancement in the lateral portions of the tumor in the Gadolinium-enhanced T1-weighted sequences (Figure 3B). T2-weighted FLAIR demonstrated a significant decrease of peritumoral edema (Figure 3C).
Treatment response after 17 courses of bevacizumab in
18 F-FET-PET/CT and fusion of PET with MRI. A The native and B the contrast-enhanced T1 cMRT scans show a decrease of the lesion initially described. C In the PET/CT and D the fusion of PET and MRI, the 18 F-FET uptake is slightly diffuse increased with Tu/Bg uptake ration of 1.3 consitent with reactive changes after treatment and arguing against vital tumor tissue.
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Fig4
A very low level of 18 F-FET tracer uptake was noted (Figure 4), which was substantially lower than the tracer uptake observed before treatment (Figure 1D and E). Moreover, Tu/Bg ratio in the post treatment PET/CT scan was 1.3 consistent with reactive changes after treatment (Figure 4).