In vitro localization of intracranial haematoma using electrical impedance tomography semi-array

Electrical Impedance Tomography is a non-invasive and portable method that has good potential as an ‎alternative to the conventional modalities for early detection of intracranial haematomas in high risk patients. ‎Early diagnosis can reduce treatment delays and most significantly can impact patient outcomes. Two eight-‎electrode layouts, a standard ring full array (FA) and a semi-array (SA), were investigated for their ability to ‎detect, localise and quantify simulated intracranial haematomas in vitro on ovine models for the purpose of ‎early diagnosis. SA layout speeds up electrode application and avoids the need to move and lift the patient's ‎head. Haematomas were simulated using gel samples with the same conductivity as blood. Both layouts, FA ‎and SA, could detect the presence of haematomas at any location within the skull. The mean of the relative ‎radial position error with respect to the brain radius was 7% for FA and 6% for SA, for haematomas close to the ‎electrodes, and 11% for SA for haematomas far from the electrodes at the back of the head. Size estimation ‎was not as good; the worst size estimation error for FA being around 30% while the best for SA was 50% for ‎simulated haematomas close to the electrodes.

Haematoma detection using EIT in a sheep model

Performance evaluation of a portable digital electrical impedance tomography system to detect haematomas using a sheep model is presented. Two different experiments have been performed using 8-electrode full array configuration. Artificial haematomas were introduced in the first experiment by injecting blood-like conductivity solution via the brainstem, and in the second by placing blood-like conductivity gel at a certain position on top of the parietal lobes of the brain on the left and right sides. For the first experiment, the Electrical Impedance Tomography (EIT) images were reconstructed sequentially for different injection volumes and the quantity index (QI) was calculated as a function of the injected solution volume. The results show a linear relationship of QI to the injected volume. For the second experiment, the images were successfully reconstructed and haematoma was clearly detected and localised using our developed system. The promising results of sheep experiments prove that our developed EIT system is able to detect and quantify small haematomas in head