Comparison of electrical impedance tomography and intracranial pressure during dehydration treatment of cerebral edema

Abstract

Cerebral edema after brain injury can lead to brain damage and death if diagnosis and treatment are delayed. This study investigates the feasibility of employing electrical impedance tomography (EIT) as a non-invasive imaging tool for monitoring the development of cerebral edema, in which impedance imaging of the brain related to brain water content is compared with intracranial pressure (ICP). We enrolled forty patients with cerebral hemorrhage who underwent lateral external ventricular drain with intraventricular ICP and EIT monitoring for 3 h after initiation of dehydration treatment. The average reconstructed impedance value (ARV) calculated from EIT images was compared with ICP. Dehydration effects induced changes in ARV and ICP showed a close negative correlation in all patients, and the mean correlation reached R 2 = 0.78 ± 0.16 ( p < .001). A regression equation ( R 2 = 0.62, p < .001) was formulated from the total of measurement data. The 95% limits of agreement were − 6.13 to 6.13 mmHg. Adaptive clustering and variance analysis of normalized changes in ARV and ICP showed 92.5% similarity and no statistically significant differences ( p > .05). Moreover, the sensitivity, specificity and area under the curve of changes in ICP >10 mmHg were 0.65, 0.73 and 0.70 respectively. The findings show that EIT can monitor changes in brain water content associated with cerebral edema, which could provide a real-time and non-invasive imaging tool for early identification of cerebral edema and the evaluation of mannitol dehydration.

Evaluating and Reducing the Influence of Scalp Dehydration in the Monitoring of Intracranial Dehydration Using Electrical Impedance Tomography

“…In [9], Fu explored the use of dynamic EIT to monitor brain impedance changes of patients with dehydration treatments. The results demonstrated that by classifying the variation trends in the brain EIT signals, we could evaluate the efficacy of dehydration treatments in reducing ICP and estimate the sensitivities of different patients to mannitol [10], [11]. Additionally, the EIT images showed promise in reflecting the dehydration effects in the different areas of the brain.…”

“…In monitoring dehydration treatments for patients with cerebral hypertension, as displayed in Fig. 1(a), a set of EIT electrodes was evenly placed on the scalp of the patients, through which safe currents (1 mA, 50 kHz) were injected into patients and the responding voltage changes were measured based on the instrument FMMU-EIT5 [10], as shown in Fig. 1(b).…”

“…where δρ scalp | scalp , δρ scalp | skull , and δρ scalp | intra represent the reconstructed impedance changes in the scalp, skull, and parenchyma areas in the 2D EIT images, respectively, due to scalp dehydration. With (10), δρ All can be rewritten as:…”

A novel time-difference electrical impedance tomography algorithm using multi-frequency information

“…Several algorithms with different advantages have been derived by applying the distinct regularization method [5]. One such algorithm is the damped least squares algorithm (DLS), which has been successfully applied in clinical researches with high stability and image quality [9–11]. TV is a popular regularization approach that has been applied to a range of imaging modalities [12], with Borsic demonstrating its potential for EIT in 2010 [13].…”

“…Several algorithms with different advantages have been derived by applying the distinct regularization method [5]. One such algorithm is the damped least squares algorithm (DLS), which has been successfully applied in clinical researches with high stability and image quality [9–11].…”