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Table 2 Brain disease impedance spectra

From: Advances in electrical impedance tomography-based brain imaging

Disease Model/species Trends of impedance changes
Epilepsy In vivo/rat Impedance decreased gradually during a seizure and reached a minimum at the end of the seizure. Following seizure activity, the impedance returned to the interictal baseline or increased to a level above the baseline
Stroke Ex vivo/rabbit
In vivo/rabbit
Impedance spectra of stroke lesions significantly differed to those of normal brain tissue; the ratio of change in impedance of ischemic and hemorrhagic tissue with regard to frequency was distinct; tissue type could be distinguished according to impedance spectra
Brain injuries and cerebral edema 23 patients with brain edema Overall impedance across the brain increased significantly before and after mannitol dehydration treatment (P = 0.0027)
Ex vivo/male rats After the first 6 h following the onset of ischemic brain injury, the resistivity of brain tissue increased (P < 0.05); from 6 to 24 h, the resistivity of brain tissue decreased
Patients with cerebral hemorrhage Dehydration effects induced changes in average reconstructed impedance value and intracranial pressure exhibited a strong negative correlation in all patients (mean correlation: R2 = 0.78 ± 0.16, P < 0.001)
Brain abscess In vivo canine model Relative conductivity contrast ratios (rCCR, %) of central abscess lesions were higher than those of surrounding areas at 6, 12, and 18 h (P < 0.01). Over 12 h, the relationship between induction time and rCCR exhibited a positive correlation followed by a negative correlation (P < 0.01)
Brain neoplasms Three-dimensional finite element model Tumor-like anomalies with 200% conductivity contrast were straightforwardly detected and imaged using an existing 3 T system with total acquisition time under 30 min