Fig. 8.

Case 10. (A) On FLAIR images, there is no epileptogenic cortical lesion, although deep white matter rarefaction is noted, especially on the left frontal lobe (white arrow). (B) Interictal EEG fails to reveal localized abnormalities. (C,D) Interictal ASL with dual PLD shows gradual visualization of the entire cortices. (E) On periictal ASL with a PLD of 1.5 s, increased signals are noted at the convexity and interhemispheric surface of the left frontal lobe. (F) On ASL with a PLD of 2.5 s, further increased signals are noted on the convexity, whereas the increased ASL signals are mostly washed out at the interhemispheric surface. (G) Subsequent EEG depicts generalized slow wave activities and the absence of α rhythm on the left frontal lesion (black lines).