PURPOSE OF REVIEW: This article reviews the important aspects of managing patients undergoing anaesthesia and monitoring for MRI and PET. RECENT FINDINGS: The use of MRI and PET is expanding and an increasing number of specialized procedures are being undertaken on patients who require anaesthesia or critical care management. Magnetic resonance systems are using more powerful magnetic fields, whereas PET involves imaging patients following administration of radioactive isotopes. Patients who undergo such procedures require careful anaesthesia and monitoring within an isolated and unfamiliar environment, which poses a risk to staff and patients. SUMMARY: The availability of high-field MRI and other complex imaging studies, like PET is increasing. This requires that anaesthesiologists and critical care physicians understand the principles, safety concerns and appropriate management of patients undergoing imaging within such environments.