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Hemodynamic state of periictal hyperperfusion revealed by arterial spin-labeling perfusion MR images with dual
Kenta Takahara1,2, Takato Morioka1,3, Takafumi Shimogawa1,2,3
1Department of Neurosurgery, Kyushu Rosai Hospital, 1-1 Sonekitamachi, Kokura Minami-Ku, Kitakyushu, Japan.
Background:
Magnetic resonance imaging (MRI), including perfusion MRI with arterial spin labeling (ASL) and diffusion-weighted imaging (DWI), are applied in the periictal detection of circulatory and metabolic consequences associated with epilepsy. Although previous report revealed that prolonged ictal hyperperfusion on ASL can be firstly detected and cortical hyperintensity of cytotoxic edema on DWI secondarily obtained from an epileptically activated cortex, the hemodynamic state of the periictal hyperperfusion has not been fully demonstrated.
Methods Study-1:
We retrospectively analyzed the relationship between seizure manifestations and the development of periictal MRI findings, in Case 1 with symptomatic partial epilepsy, who underwent repeated periictal ASL/DWI examination for three epileptic ictuses (one examination for each ictus). Study-2: We evaluated the hemodynamic state of periictal hyperperfusion with the ASL technique using a dual postlabeling delay (PLD) of 1.5 and 2.5 s in nine patients, according to the presence or absence of the localized epileptogenic lesion (EL) on conventional 3 T-MRI, who were divided into Group EL+ (six patients) and Group EL- (three patients).
Results:
Study-1 confirmed that the stratified representation of the periictal MRI findings depends on the time interval between the ictal cessation and MRI examination in addition to the magnitude and duration of the epileptic activity. In Study-2, two types of periictal hyperperfusion were noted. In all six Group EL+ patients, periictal ASL findings showed "fast flow type". Markedly increased ASL signals were noted at the epileptically activated cortex, having a tight topographical relationship with EL, on ASL with a PLD of 1.5 s, which is decreased on ASL with a PLD of 2.5 s. In all three Group EL- patients, periictal ASL findings showed "gradual flow type", which is characterized by gradual signal increase of the epileptically activated cortex on ASL with a PLD of 1.5 and 2.5 s.
Conclusion:
We confirmed that ASL hyperperfusion is superior to DWI in the periictal detection of epileptic events. ASL with dual PLD offers the ability to document two types of hemodynamics of periictal hyperperfusion.
Insights
Arterial spin labeling (ASL) MRI detects periictal hyperperfusion in epilepsy, outperforming diffusion-weighted imaging (DWI). Dual postlabeling delay (PLD) ASL reveals two distinct hemodynamic patterns, differentiating between localized lesions and generalized activity.
Area of Science:
- Neuroimaging
- Epilepsy Research
- Cerebrovascular Physiology
Background:
- Magnetic resonance imaging (MRI), including arterial spin labeling (ASL) and diffusion-weighted imaging (DWI), assesses periictal circulatory and metabolic changes in epilepsy.
- Previous studies indicated prolonged ictal hyperperfusion on ASL and secondary cytotoxic edema on DWI, but the hemodynamics of periictal hyperperfusion remain underexplored.
Purpose of the Study:
- To analyze the relationship between seizure manifestations and periictal MRI findings.
- To evaluate the hemodynamic characteristics of periictal hyperperfusion using ASL with dual postlabeling delay (PLD).
Main Methods:
- Retrospective analysis of periictal ASL/DWI in a patient with symptomatic partial epilepsy across three seizures.
- Evaluation of ASL with dual PLD (1.5s and 2.5s) in nine epilepsy patients, categorized by the presence (Group EL+) or absence (Group EL-) of a localized epileptogenic lesion (EL) on conventional MRI.
Main Results:
- Peri-ictal MRI findings stratification depends on the time from seizure cessation, seizure magnitude, and duration.
- Two types of periictal hyperperfusion were identified: 'fast flow type' in EL+ patients (increased ASL signal at 1.5s PLD, decreased at 2.5s PLD, correlated with EL) and 'gradual flow type' in EL- patients (gradual signal increase at both 1.5s and 2.5s PLD).
Conclusions:
- Arterial spin labeling (ASL) hyperperfusion is more effective than diffusion-weighted imaging (DWI) for periictal detection of epileptic events.
- Dual PLD ASL can differentiate two distinct hemodynamic patterns of periictal hyperperfusion, aiding in the characterization of epileptic activity.
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