Usefulness of brain perfusion CT in focal-onset status epilepticus

To evaluate the perfusion computed tomography (PCT) patterns in patients with status epilepticus (SE).

We included consecutive SE patients, diagnosed by ictal encephalography (EEG) findings and clinical semiology, who prospectively underwent a dedicated PCT study of SE in the ictal phase. The perfusion maps were visually analyzed. For the quantitative assessment, regions of interest in areas where the maps suggested abnormalities were compared with the corresponding area in the unaffected contralateral cortex. Asymmetry indices between affected and unaffected hemispheres were calculated for the regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), time to peak (TTP), and mean transit time (MTT). Nine patients underwent a follow-up PCT after SE resolution, and the corresponding maps were compared to the ictal maps. In addition, we included a control group of 10 sex- and age-matched patients with SE mimics or postictal phenomena, who also underwent acute PCT during the study period.

The study included 19 patients: mean age 69.47 ± (standard deviation) 15.9 years, 68.4% men. On visual analysis of parametric perfusion maps during the ictal phase, regional cortical hyperperfusion was depicted in 78.9% of patients. Quantitative analysis showed significantly increased rCBF (P = 0.002) and rCBV (P = 0.004) values and decreased TTP (P < 0.001) and MTT (P = 0.001) in cortical areas of the affected vs the unaffected side. The mean asymmetry index was 12.8 for rCBF, 13.7 for rCBV, -3.0 for TTP, and -3.7 for MMT. In the nine patients with a follow-up PCT, eight showed decreased intensity, rCBV (P = 0.035), and rCBF (P = 0.024) in the hyperperfusion areas. The sensitivity of hyperperfusion detection for the diagnosis of SE was 78.95%, specificity 90%, positive predictive value 93.75%, and negative predictive value 69.23%. Comparative quantitative analysis of asymmetry indices for rCBF, rCBV, and MTT between ictal PCT and control patients showed significant differences for all parameters (rCBF P = 0.001; rCBV P = 0.002; TTP P = 0.001; and MTT P = 0.001).

Visual and quantitative analysis of perfusion maps detects regional hyperperfusion in SE patients with good diagnostic capability. Perfusion was increased in PCT maps of the affected cerebral hemisphere as compared to the contralateral region during the ictal phase. PCT may provide valuable diagnostic information in patients with SE and complement the diagnostic value of EEG.