Besonderheiten des Anasthesiemanagements fur die Magnetresonanztomografie (MRT) und die Computertomografie (CT) bei Kleintierpatienten

Anesthesia for magnetic resonance imaging (MRI) and computed tomography (CT) requires special considerations. The environment with the magnet and the ionizing radiation poses challenges for the medical staff and the handling of the patient. Artifacts that can compromise image quality, mimic pathologic findings, and lead to prolongation of anesthesia times due to repeat examinations must be avoided. Depending on the patient's condition (state of consciousness, anesthesia risk) and the available technical MRI or CT equipment, the type of modality and the duration of the examination play a decisive role in the method of immobilization, anesthesia, maintenance, as well as accessibility to the patient and ensuring the safety of medical personnel and patients. Ferromagnetic materials may severely compromise the homogeneity of the magnetic field and not only lead to so-called susceptibility artifacts, but also pose a high safety risk to staff and patients. Reducing respiratory movements as a result of optimized positioning or controlled apnea phases can minimize respiratory-related artifacts. While positive pressure ventilation can reduce anesthesia-induced atelectasis and optimize diagnostic assessment of the lungs, increased inspiratory oxygen concentration results in a significant signal increase in the cerebrospinal fluid of the CSF suppression sequence. These factors, as well as the location of the examination room and, depending on the modality and available equipment, limited accessibility to the patient and noise exposure, must be considered into the overall anesthesia planning process. Regarding contrast agent administration, it is imperative to review predisposing factors and adverse side effects in the perioperative evaluation for anesthesia in MRI and CT. An emergency plan should be known by the entire MRI team. Several mechanical and clinical methods are available to the anesthesiologist and can help optimize clinical monitoring, which can be severely limited, and ensure the safety of staff and patients.