An MRI-Compatible Robot for Intracerebral Hemorrhage Removal

Intracerebral Hemorrhage (ICH) is the deadliest form of stroke and occurs when blood, leaked from a ruptured vessel pools in the brain forming a pool of semi-coagulated blood called a hematoma. 1 in 50 people will have an ICH in their lifetime [1] and the 30-day mortality rate is 43% with half of the deaths occurring in the acute phase, which motivates the need for safe and rapid treatment. However, literature reviews show no significant benefit of surgical removal vs. “watchful waiting”, despite the potential value of decompressing the brain. It has been hypothesized that this is due to the significant disruption of healthy brain tissue required to reach the hemorrhagic site in open brain surgery. Recent studies conducted on phantom models have shown that a robotic needle made from curved, concentric, elastic tubes can reach a hemorrhagic site through a needle-sized path to successfully aspirate the hematoma. This approach has the potential to decompress the brain with far less disruption to surrounding brain tissue [4]. Those initial experiments were conducted under guidance from periodic (low rate) CT [2]. The need for intraoperative imaging was motivated by the fact that the brain shifts during aspiration, collapsing to fill the cavity left by voided blood. This approach has the potential advantage of “one stop shopping”, since ICH is typically diagnosed in the CT scanner. It is appealing to treat ICH immediately after diagnosis, while the patient is still in the scanner. However, CT also has the drawback of requiring ionizing radiation, as well as providing only intermittent images rather than real-time information. In this paper, we consider a Magnetic Resonance Imaging (MRI) guided approach, which provides the converse in terms of both benefits and drawbacks. MRI is not typically used to diagnose ICH, but it can provide detailed soft-tissue and hematoma contrast [3], and fast image updates, enabling realtime monitoring of brain deformation during the aspiration process. Toward performing ICH aspiration with a concentric tube robot in an MRI environment, this paper presents accuracy and MR-compatibility tests for a new MRcompatible robot designed for ICH removal.