The detection of chronic cerebral hemorrhage in rabbits with magnetic induction

Chronic cerebral hemorrhage (CCH) in the brain is an important clinical problem that is often monitored and studied with expensive devices such as MRI and PET, which are not readily available in low economical resource parts of the world. We have developed a less expensive tool for non-contact monitoring of CCH in the brain. The system measures the phase shift between the electromagnetic signals on the two coils. CCH was induced in the brain of rabbits by stereotactic method. Intracranial pressure (ICP) and Electrocardiograph (ECG) of subjects were monitored for 1.5h. Signals were continuously monitored up to t=1.5h at exciting frequency 10.7MHz. From 0.8 to 2.4 ml of autologous blood was injected (each injection quantity of 0.8 ml, the interval time for 30 minutes). The results show significant phase shifts increase as a function of injection volume. ICP and phase shift were directly proportional to the related, while HRV were stable around 200beats*min-1. Our system has high sensitivity that even 0.8 ml can also be detected. In this study, the curves of inductive phase shift are significantly related to ICP. This observation suggests that the method could be valuable, in addition to continuous monitoring, also for early warning in emergency medicine and critical care units.