Quantitative Analysis of Diffusion-Restricted Lesions in a Differential Diagnosis of Status Epilepticus and Acute Ischemic Stroke

Lukas Machegger; Pilar Bosque Varela; Giorgi Kuchukhidze; Jürgen Steinbacher; Andreas Öllerer; Tanja Prüwasser; Georg Zimmermann; Slaven Pikija; Johannes Pfaff; Eugen Trinka; Mark Mc Coy

doi:10.3389/fneur.2022.926381

Quantitative Analysis of Diffusion-Restricted Lesions in a Differential Diagnosis of Status Epilepticus and Acute Ischemic Stroke

Front Neurol. 2022 Jul 7:13:926381. doi: 10.3389/fneur.2022.926381. eCollection 2022.

Authors

Lukas Machegger¹, Pilar Bosque Varela², Giorgi Kuchukhidze^{2

3}, Jürgen Steinbacher¹, Andreas Öllerer¹, Tanja Prüwasser^{2

4}, Georg Zimmermann^{4

5

6}, Slaven Pikija², Johannes Pfaff¹, Eugen Trinka^{2

3

7}, Mark Mc Coy^{1

3}

Affiliations

¹ Department of Neuroradiology, Christian Doppler University Hospital, Paracelsus Medical University, Salzburg, Austria.
² Department of Neurology, Christian Doppler University Hospital, Member of the European Reference Network EpiCARE, Paracelsus Medical University of Salzburg, Salzburg, Austria.
³ Centre for Cognitive Neuroscience Salzburg, Neuroscience Institute, Christian Doppler University Hospital, Salzburg, Austria.
⁴ Department of Mathematics, Paris-Lodron University, Salzburg, Austria.
⁵ IDA Lab Salzburg, Team Biostatistics and Big Medical Data, Paracelsus Medical University, Salzburg, Austria.
⁶ Research and Innovation Management, Paracelsus Medical University, Salzburg, Austria.
⁷ Karl Landsteiner Institute for Neurorehabilitation and Space Neurology, Salzburg, Austria.

Abstract

Background and purpose: Distinction between acute ischemic stroke (AIS) and status epilepticus (SE) on MRI can be challenging as restricted diffusion may occur in both conditions. In this study, we aimed to test a tool, which could help in differentiating AIS from SE when restricted diffusion was present on MRI.

Materials and methods: In diffusion weighted imaging (DWI) with a b-value of 1,000 and apparent diffusion coefficient (ADC) maps, we compared the ratios of intensities of gray values of diffusion-restricted lesions to the healthy mirror side in patients with AIS and SE. Patients were recruited prospectively between February 2019 and October 2021. All patients underwent MRI and EEG within the first 48 h of symptom onset.

Results: We identified 26 patients with SE and 164 patients with AIS. All patients had diffusion-restricted lesions with a hyperintensity in DWI and ADC signal decrease. Diffusion restriction was significantly more intense in patients with AIS as compared to patients with SE. The median ratios of intensities of gray values of diffusion-restricted lesions to the healthy mirror side for DWI were 1.42 (interquartile range [IQR] 1.32-1.47) in SE and 1.67 (IQR 1.49-1.90) in AIS (p < 0.001). ADC decrease was more significant in AIS as compared to SE with median ratios of 0.80 (IQR 0.72-0.89) vs. 0.61 (IQR 0.50-0.71), respectively (p < 0.001). A cutoff value for ratios of DWI signal was 1.495 with a sensitivity of 75% and a specificity of 85%. Values lower than 1.495 were more likely to be associated with SE and higher values were with AIS. A cutoff value for ADC ratios was 0.735 with a sensitivity of 73% and a specificity of 84%. Values lower than 0.735 were more likely to be associated with AIS and higher values were with SE.

Conclusion: Diffusion restriction and ADC decrease were significantly more intense in patients with AIS as compared to SE. Therefore, quantitative analysis of diffusion restriction may be a helpful tool for differentiating between AIS and SE when restricted diffusion is present on MRI.

Keywords: MRI; acute ischemic stroke; diffusion restriction; quantification; status epileptics.