Sulcal hyperintensity on magnetic resonance imaging with fluid-attenuated inversion recovery sequence in patients with chronic subdural hematoma

Addition of 1.5-Tesla arterial spin labeling magnetic resonance perfusion imaging to routine electroencephalography in pathophysiological diagnosis of first-onset generalized convulsive seizures in patients with dementia at neurological emergency

“…The main reason for this is that MRI was performed promptly, with a mean of 2.8 h after arrival. In Patients 1 and 2, in whom a tight anatomical relationship was observed between the organic lesion and the area of periictal ASL hyperperfusion, the ASL findings strongly suggested structural focal epilepsy and acute symptomatic seizure, respectively [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Furthermore, in Patient 1, EEG performed 7 h after MRI showed LPDs localized to Fp1, corresponding to the region in the left medial frontal lobe where ASL hyperperfusion was observed.…”

“…As one of the multimodal examinations to compensate for the limitations of EEG at the neurological emergency, we have emphasized the usefulness of magnetic resonance imaging (MRI) examinations centered on arterial spin labeling (ASL) perfusion images, using 3-Tesla (T) MRI [5,[7][8][9][10][11][12][13] or 1.5-T MRI [6,[14][15][16][17][18][19][20]. ASL uses a magnetic field to label the spins in the cervical carotid artery, and after a certain period of time (post-labeling delay, PLD), the blood flow into the brain can be imaged.…”

“…ASL uses a magnetic field to label the spins in the cervical carotid artery, and after a certain period of time (post-labeling delay, PLD), the blood flow into the brain can be imaged. Depicting ictal hyperperfusion associated with seizures, especially in structural focal epilepsy, clearly demonstrates the tight anatomical relationship between the epileptogenic lesion and the epileptically activated area [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In addition, although ictal hyperperfusion depends on seizure intensity and duration, it continues for some time after the seizure, and can be visualized as periictal hyperperfusion, which is expected to have a high diagnostic ability [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

“…Depicting ictal hyperperfusion associated with seizures, especially in structural focal epilepsy, clearly demonstrates the tight anatomical relationship between the epileptogenic lesion and the epileptically activated area [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. In addition, although ictal hyperperfusion depends on seizure intensity and duration, it continues for some time after the seizure, and can be visualized as periictal hyperperfusion, which is expected to have a high diagnostic ability [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. We previously reported a patient with stroke-related epilepsy, in whom ASL performed 3 h after several minutes of FBTCS did not show periictal hyperperfusion, whereas ASL performed 18 h after FBTCS lasting 30 min revealed periictal hyperperfusion [12].…”

Absence of periictal hyperperfusion on arterial spin labeling perfusion images in a patient with posttraumatic epilepsy and underdevelopment of ipsilateral internal carotid and middle cerebral arteries

“…Since ASL is influenced by arterial transit time (ATT), evaluation of slower CBF is difficult when using a conventional postlabeling delay (PLD) of 1.5 seconds (s), leading to underestimation of CBF [20][21][22][23]. Thus, a slower PLD of 2.5 s, in addition to the conventional PLD of 1.5 s, is commonly selected for evaluation using 3-Tesla (T) pseudocontinuous ASL [13,[20][21][22][23][24][25]. However, because of the limitations of 1.5-T ASL (rapid T1 decay occurs when the PLD is too slow to provide sufficient labeling compared to 3-T), a PLD of 2.0 s, instead of 2.5 s, was opted for use [5-9, 17, 18,26].…”