pASL versus DSC perfusion MRI in lateralizing temporal lobe epilepsy.
BACKGROUND
Accurate lateralization of the epileptogenic focus in temporal lobe epilepsy (TLE) is crucial. Pulsed arterial spin labeling (pASL) has the capability of quantifying local relative cerebral blood flow (rCBF) by measuring the inflow of electromagnetically labeled arterial blood into the target area, and can be used in the presurgical workup of refractory TLE.


OBJECTIVE
To evaluate pASL in detecting mesial temporal lobe (mTL) perfusion asymmetry for the lateralization of the epileptogenic focus in patients with refractory TLE and to compare it with dynamic susceptibility contrast enhanced (DSC) magnetic resonance imaging (MRI) technique.


METHODS
This study was approved by the local ethical committee, and written informed consent was obtained in each patient. Thirty-six patients with medically refractory TLE and 11 healthy volunteer was enrolled in this study. Following brain MRI, pASL and DSC perfusion were performed in all subjects at 3T. rCBF measurements with two different perfusion MRI technique were compared between the patient and healthy volunteers. Lateralization based on perfusion asymmetry index (AI) were also evaluated and compared with clinical lateralization.


RESULTS
rCBF ratios measured in healthy volunteers by two different perfusion technique did not show any statistically significant difference. In TLE patients rCBF ratio of the ipsilateral (affected) side was found to be significantly lower than the contralateral (unaffected) side with both technique. The AI in the patient group was 8.86 ± 3.88 with pASL and 8.39 ± 4.06 with DSC. Correlation coefficient between clinical laterality and perfusion AI were 0.86 for pASL and 0.83 for DSC.


CONCLUSIONS
pASL can successfully detect interictal asymmetry in patients with TLE and can readily be combined with routine structural assessment for lateralization, providing an alternative to DSC perfusion.
Department of Radiology, Gazi University School of Medicine, Ankara, Turkey yusuf@tr.net.
A Yusuf
AY
Oner
Department of Radiology, Gazi University School of Medicine, Ankara, Turkey.
Bulent
B
Eryurt
Department of Radiology, Gazi University School of Medicine, Ankara, Turkey.
Murat
M
Ucar
Department of Neurology, Gazi University School of Medicine, Ankara, Turkey.
Irem
I
Capraz
Department of Neurosurgery, Gazi University School of Medicine, Ankara, Turkey.
Gokhan
G
Kurt
Department of Neurology, Gazi University School of Medicine, Ankara, Turkey.
Erhan
E
Bilir
Department of Radiology, Gazi University School of Medicine, Ankara, Turkey.
Turgut
T
Tali
D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D003287:Contrast Media; D017352:Echo-Planar Imaging / Q000379:methods; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013113:Spin Labels; D013702:Temporal Lobe / Q000473:pathology; D055815:Young Adult
D003287:Contrast Media; D013113:Spin Labels; C064925:gadodiamide; D019786:Gadolinium DTPA
Epilepsy; arterial spin labeling; perfusion MRI