Surgical treatment of cerebral abscess with the use of a mobile ultralow-field MRI.

Surgical intervention in cerebral abscess is indicated to confirm diagnosis, to identify pathogens for specific antibiotic therapy, or to reduce mass effect. Regarding long-term outcome, freehand or stereotactic aspiration are equally efficient compared to surgical resection. However, direct observation of relief of mass effect is not possible by either method. Six patients presenting with neurological symptoms and laboratory signs of infection and diagnosed with an intra-axial cystic lesion underwent frameless stereotactic aspiration of a cerebral abscess in our institution with the use of a mobile intraoperative magnetic resonance imaging (MRI) with a field strength of 0.15 T. Images were acquired before and during the procedure and used for neuronavigation. In all six cases, complete evacuation of the abscess with collapse of the cyst could be achieved and documented intraoperatively. No complications were observed. All patients showed clinical improvement postoperatively. We highlight the advantages of using a mobile intraoperative MRI unit with an illustrative case of a patient who had already undergone abscess evacuation without alleviation of symptoms before using intraoperative MRI. Finally, we discuss surgical treatment options of cerebral abscesses.