Gliomas are the most common malignant primary central nervous system (CNS) tumours. When high-grade gliomas (HGG) recur, subsequent magnetic resonance (MRI) imaging, with additional sequences is required.The Positron Emission Tomography (PET) radiotracer \[18F\]-fluorodeoxyglucose (FDG) will be used in this study to distinguish between changes seen on MRI which can be a reflection of pseudoprogression, radiation necrosis, or recurrence.
Molecular imaging has been used to distinguish recurrent tumor from post-treatment changes through the use of positron emission tomography (PET) as well as other techniques. The best-studied PET radiotracer for this application is \[18F\]-fluorodeoxyglucose (FDG). Normal brain matter is very FDG-avid, making it more difficult to identify lesions and in addition, inflammation associated with radiation injury has been shown to be FDG avid. In light of this, variations of the standard FDG protocols have been proposed in order to increase overall accuracy, including dual time point imaging (DTPI), consisting of injecting the patient with the standard radiotracer and acquiring two sets of images several hours apart, typically the normal initial images in addition to a delayed acquisition set. There is good reason to suspect that DTPI FDG-PET would be useful a technique for characterizing lesions in the brain. It's been shown that FDG uptake by normal brain parenchyma initially increases then decreases with time, while tumor uptake typically increases and then plateaus. This pattern of increasing and then decreasing FDG activity has also been seen in inflammatory tissue. The difference in FDG uptake at different times is what allows for a better distinction between malignant and benign tissue.
Study Type
OBSERVATIONAL
Enrollment
62
Participants will receive an intravenous injection of 250 MBq (megabecquerels) of 18F-Fluorodeoxyglucose (18F-FDG). The first Positron Emission Tomography (PET) acquisition of the head will occur one hour post-injection. The second acquisition will take place 3 hours post-injection. Both early and late PET images will be manually co-registered with the participant's most recent magnetic resonance images.
The Ottawa Hospital
Ottawa, Ontario, Canada
RECRUITINGsensitivity and specificity percentages
The sensitivity and specificity of dual time point imaging (DTPI) FDG-PET/CT will be compared to the sensitivity and specificity of MR imaging obtained as standard of care for identifying glioma recurrence post-treatment.
Time frame: 3 years
Cost efficiency analysis
At the conclusion of the trial, a cost-efficiency analysis will be performed in an attempt to determine an optimally accurate and cost-efficient imaging strategy for the diagnosis of glioma recurrence.
Time frame: 3 years
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.