Epilepsy is a chronic disease, characterized by seizures that manifest themselves as a sudden and transient disturbance of the brain's electrical activity. In truth, it would be more accurate to refer to epilepsy in the plural, as the symptoms and their evolution are so diverse.
Some epilepsies (known as focal epilepsies) are located in a specific area of the brain. As they are often resistant to medication, surgical removal of the epileptic focus – the area of the brain responsible for the seizures – remains the only therapeutic solution. These epilepsies can be associated with very focalized brain abnormalities known as focal cortical dysplasias (FCD).
These FCDs are sometimes difficult to identify by MRI. In this case, positron emission tomography (PET) with 18F-FDG (a radioactive fluorine-18 labelled glucose analogue) is useful. In this context, could there be any benefit to simultaneous PET-MRI recording on the same machine?
To find out, the Nuclear physician researchers and their partners compared images from 25 patients with refractory focal epilepsy, between 2017 and 2020:
- using 18F-FDG PET and then MRI (PET+MRI);
- using simultaneous 18F-FDG PET and MRI (PET/MRI), via a hybrid machine in the Frederic Joliot Hospital Department.
The quality of the images was visually analyzed in a double-blind fashion. The results show that the sensitivity of PET/MRI exceeds that of PET+MRI by 13%.
PET/MRI therefore allowed:
- the detection of new structural lesions (mainly FCDs) in 6 patients;
- the modification of surgery planning in 4 patients;
seizure suppression in 12 out of 14 patients who underwent cortical surgery.
By improving the detection of epileptogenic lesions, PET/MRI can optimize the presurgical work-up and the results of surgical treatment, even in the most challenging cases.