Maria Vittoria Mattoli MD, Abstract Co-Author: Nothing to Disclose

Francesco Fraioli MD, Presenter: Nothing to Disclose

Ilaria Boscolo Galazzo, Abstract Co-Author: Nothing to Disclose

Francesca Pizzini MD, Abstract Co-Author: Nothing to Disclose

Jamshed Bomanji, Abstract Co-Author: Nothing to Disclose

Ashley McAllister Groves MBBS, Abstract Co-Author: Investigator, GlaxoSmithKline plc Investigator, General Electric Company Investigator, Siemens AG

The aim of this study was to assess the concordance between perfusion, as measured with arterial-spin-labelling (ASL) MR, and metabolism, as measured with FDG-PET SUV interictally in refractory focal epileptic patients.

Seventeen consecutive patients with drug-resistant focal epilepsy discordant in localisation with ictal scalp EEG-video telemetry (EEG-VT) recordings were studied in simultaneous PET/MR scanner. Standardized uptake values (SUVs) were extracted and Cerebral Brain Flow (CBF) maps were estimated with ASL. CBF and SUV maps were registered to individual high-resolution anatomical images and normalized to the Montreal Neurological Institute brain template (MNI). Asymmetry index (AI) were calculated voxel-wise as the difference in SUV or CBF between corresponding voxels in the right and left hemisphere, normalized by the mean value of the two. Subsequently, a z-score map was calculated based on mean and standard deviation of all AI values across the brain. Voxels with a z-score greater or lower than 1.64, corresponding to p<0.05, were considered to be significantly different between hemispheres, indicating abnormal asymmetry of cerebral metabolism or perfusion. The concordance between ASL, PET and EEG-VT data was assessed.

Data from 15 patients (6 right-sided, 9 left-sided ictal onset) were available (two patients excluded for movement artefacts). PET showed hypometabolism in the same hemisphere and lobe of EEG-VT in 11/15 patients. ASL maps showed hypoperfusion in 12/15 patients, which correctly lateralised and localized the same lobes as EEG-VT and PET in 8 patients. In one PET negative patient the ASL correctly lateralised but not localised the affected lobe. Five patients, all with normal MRIs, showed complete concordance in side and lobe for PET, ASL and EEG-VT. In three patients with discordant MRI and EEG-VT findings, both PET and ASL were concordant in lateralisation and localization in two patients and both normal in one patient. 

The combined simultaneous acquisition of ASL and PET provides concordant and complimentary non-invasive information about seizure-foci in patients with refractory focal epilepsy.

PET/MR allows the simultaneous acquisition of information about perfusion and metabolism in refractory focal epileptic patients by using a modality with low ionization radiation exposure.

Mattoli, M, Fraioli, F, Boscolo Galazzo, I, Pizzini, F, Bomanji, J, Groves, A, Metabolism and Perfusion in Drug-resistant Epileptic Patients Assessed by Simultaneous Acquisition of PET and Arterial Spin Labelling MR.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14015512.html