Patient-Specific Detection of Cerebral Blood Flow Alterations as Assessed by Arterial Spin Labeling in Drug-Resistant Epileptic Patients

Abstract

Electrophysiological and hemodynamic data can be integrated to accurately and precisely identify the generators of abnormal electrical activity in drug-resistant focal epilepsy. Arterial Spin Labeling (ASL), a magnetic resonance imaging (MRI) technique for quantitative noninvasive measurement of cerebral blood flow (CBF), can provide a direct measure of variations in cerebral perfusion associated with the epileptic focus. In this study, we aimed to confirm the ASL diagnostic value in the identification of the epileptogenic zone, as compared to electrical source imaging (ESI) results, and to apply a template-based approach to depict statistically significant CBF alterations. Standard video-electroencephalography (EEG), high-density EEG, and ASL were performed to identify clinical seizure semiology and noninvasively localize the epileptic focus in 12 drug-resistant focal epilepsy patients. The same ASL protocol was applied to a control group of 17 healthy volunteers from which a normal perfusion template was constructed using a mixed-effect approach. CBF maps of each patient were then statistically compared to the reference template to identify perfusion alterations. Significant hypo- and hyperperfused areas were identified in all cases, showing good agreement between ASL and ESI results. Interictal hypoperfusion was observed at the site of the seizure in 10/12 patients and early postictal hyperperfusion in 2/12. The epileptic focus was correctly identified within the surgical resection margins in the 5 patients who underwent lobectomy, all of which had good postsurgical outcomes. The combined use of ESI and ASL can aid in the noninvasive evaluation of drug-resistant epileptic patients.

Dual‐echo ASL contributes to decrypting the link between functional connectivity and cerebral blow flow

“…The quantitative CBF values were consistent with the results on normal groups obtained in a previous work [Boscolo Galazzo et al, ]. The mean CBF maps across subjects for some slices of interest are reported in Figure , along with the corresponding SD maps.…”

Accuracy of arterial spin labeling magnetic resonance imaging (MRI) perfusion in detecting the epileptogenic zone in patients with drug‐resistant neocortical epilepsy: comparison with electrophysiological data, structural MRI, SISCOM and FDG‐PET

“…In epilepsy, the series of patients studied with ASL include mostly subjects with mesial temporal lobe epilepsy [7,8]. Overall, these studies show increased perfusion during the peri-ictal period [9][10][11][12] and decreased perfusion during the post-ictal period [9,11,13], and these findings are globally concordant with electrophysiological studies, PET and/or singlephoton emission computed tomography (SPECT). Only individual cases with neocortical epilepsy have been reported [9,11,[13][14][15][16][17].…”

Clinical Value of Hybrid TOF-PET/MR Imaging–Based Multiparametric Imaging in Localizing Seizure Focus in Patients with MRI-Negative Temporal Lobe Epilepsy

“…Previous studies have shown increased perfusion during the periictal period, decreased perfusion during the postictal period, and hemispheric hemodynamic asymmetry in patients with epilepsy. 14,15 Thus, ASL perfusion MR imaging might help to confirm the location and extent of the EZ in the presurgical work-up of epilepsy. 16,17 Previous studies were obtained with separate PET, MR imaging, and coregistered PET/MR imaging.…”