MRI-Detected Regional Alterations of Postictal Brain Perfusion.
Abstract number :
1.249
Submission category :
Year :
2001
Submission ID :
943
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
T. Ludwig, Neurology, University, Essen, Germany; J. Weber, MD, Neuroradiology, University, Essen, Germany; S. Marks, Neurology, University, Essen, Germany; A. de Greiff, Neurology, University, Essen, Germany; A. Hufnagel, MD, Neurology, University, Essen
RATIONALE: Assessment of dynamic regional alterations of brain perfusion in focal and non-focal areas during the immediate postictal state
METHODS: We studied 6 patients with longstanding medically intractable epilepsy (age-range: 23 - 47; average: 32 years; sex: f = 3; m = 3). The focus localization was as follows: TLE (n = 4; left n = 2; right n = 2); ETE (extratemporal lobe epilepsy; n = 1); TLE + ETE (n = 1). We utilized Gd DTPA-BMA (Omniscan) and acquired a series of 60 fast MR images (Siemens Sonata 1.5T, TE= 45ms, TR=1500ms, Matrix=128x128, FOV: 230 mm, 8 slices). First scans were performed 2-50minutes (mean 24) postictally. Data were post-processed with MEDx to assess cerebral blood volume (CBV), cerebral blood flow (CBF), bolus peak ratio (BPR), and mean transit time (MTT). Post-processing included motion correction and deconvolution with the arterial input function. As a semiquantitative measure we used an asymmetry-index comparing ictogenic with non-ictogenic side. Postictal examinations were compared to interictal reference scans of the same patient.
RESULTS: In the hippocampus (AH): BPR decreased in all patients from baseline to 22-55min postictally by maximal 61% (mean: 37%) indicating relative hypoperfusion on the ictogenic side. Thereafter it increased back towards baseline in 4 patients within 56-100min. CBV decreased in 4/6 patients (all TLE) from baseline postictally by 45% (mean) within 1-12min. In 2/6 patients (ETE + TLE) there was an increase within the same time by approximately 79%. CBF decreased in 5/6 patients in the acute postictal period. In the gyrus parahippocampalis (GPH): BPR increased in 5/6 patients from baseline within 25-55min postictally by 22-92%. CBV increased in 5/6 patients during 1-12min postictally. In 3 of these 5 patients, scanned for a longer period, CBV increased further by 58-139% within 55min postictal. One patient showed a decrease during that period. In the thalamus no relevant changes were seen. No clear cut correlation of MTT with postictal perfusion could be established.
CONCLUSIONS: 1. Interictally, BPR indicated relative hyperperfusion in AH on the ictogenic side of TLE patients.
2. Postictally, BPRs decreased in all patients indicating relative hypoperfusion in AH on the ictogenic side compared to baseline.
3. A postictal BPR-increase during 1-55min after seizure indicated relative hyperperfusion on the ictogenic side in GPH.
4. Changes of CBV in TLE-patients were similar to BPR measurements.
5. In 2 patients with prolonged postictal monitoring the CBV values in AH and GPH recovered back to baseline within 3-4 hours postictally.