Identification of cerebral perfusion using arterial spin labeling in patients with seizures in acute settings

Abstract

This study aimed to explore the utility of arterial spin labeling perfusion-weighted imaging (ASL-PWI) in patients with suspected seizures in acute settings. A total of 164 patients who underwent ASL-PWI for suspected seizures in acute settings (with final diagnoses of seizure [n = 129], poststroke seizure [n = 18], and seizure mimickers [n = 17]), were included in this retrospective study. Perfusion abnormality was analyzed for: (1) pattern, (2) multifocality, and (3) atypical distribution against vascular territories. Perfusion abnormality was detected in 39% (50/129) of the seizure patients, most (94%, 47/50) being the hyperperfusion pattern. Of the patients with perfusion abnormality, multifocality or hemispheric involvement and atypical distribution against vascular territory were revealed in 46% (23/50) and 98% (49/50), respectively. In addition, seizures showed characteristic features including hyperperfusion (with or without non-territorial distribution) on ASL-PWI, thus differentiating them from poststroke seizures or seizure mimickers. In patients in whom seizure focus could be localized on both EEG and ASL-PWI, the concordance rate was 77%. The present study demonstrates that ASL-PWI can provide information regarding cerebral perfusion status in patients with seizures in acute settings and has the potential to be used as a non-invasive imaging tool to identify the cerebral perfusion in patients with seizures.

Fig 1. A 49-year-old woman who showed a convulsive seizure in the intensive care unit.

(A) Brain parenchyma appears normal on the T2 FLAIR image. (B) Ill-defined and subtle diffusion restriction is noted at the left parietal cortex (arrows). (C) Arterial spin labeling perfusion-weighted image, however, clearly depicts hemispheric hyperperfusion (arrows) in the left cerebral hemisphere. (D) No apparent steno-occlusive lesion is found on the MR angiography.

Fig 2. A 71-year-old man with underlying cavernous malformation who presented to the emergency department with a seizure.

(A) T2 FLAIR MR image demonstrates a cavernous malformation (arrow) with a hemoderin rim and typical popcorn ball appearance secondary to multiple locules containing hemorrhage at the left frontal lobe. (B) Diffusion-weighted image shows no abnormal signal change around the cavernous malformation (arrow). (C) Arterial spin labeling perfusion-weighted MR image, however, reveals prominent perilesional hyperperfusion (arrowheads) surrounding the cavernous malformation (arrow) at the left frontal lobe. (D) Additional hyperperfusion foci (arrowheads) are also noted at the left parietal lobe.

Fig 3. A 87-year-old woman who showed a convulsive seizure in the patient ward.

(A) Brain parenchyma appears normal on the T2-weighted image. (B) A tiny dot-like diffusion restriction is noted at the left frontal cortex (arrowhead). Subtle cortical hyperintensities at the left occipital lobe are artifacts. (C) Arterial spin labeling perfusion-weighted MR image depicts hypoperfusion at the left middle cerebral artery territory (arrows). (D) MR angiography shows occlusion at the left M1 segment.

Fig 4. A 33-year-old woman who visited the emergency department for a nonconvulsive seizure.

(A) Brain parenchyma appears normal on the T2 FLAIR image. (B) A tiny dot-like diffusion restriction is noted at the left parietal cortex (arrowhead). (C) Arterial spin labeling perfusion-weighted MR image depicts hyperperfusion at the left middle cerebral artery territory (arrow). Note the combined hypoperfusion portion adjacent to the hyperperfused area (arrowhead). (D) MR angiography reveals occlusion at the left M2 segment (arrowhead).