Animal anaesthesia for in vivo magnetic resonance.

Almost all animal patients, including research subjects, presented for MRI/MRS studies are anesthetized. As MR moves rapidly beyond simple anatomic studies, becoming a powerful tool for defining physiologic processes, it is imperative that investigators become familiar with the physiologic effects of the anaesthetic drugs. This decreases confounding variables, making data interpretation more accurate and more applicable to future uses. This article is intended to be a basic resource for investigators wishing to increase their understanding of the anesthetic drugs. The following is a general discussion describing the mechanism of action and physiologic effects of the more common anaesthetic drugs used in laboratory animals. A dosing table of common anaesthetics and analgesics used in mice and rats is included because these two species comprise a great majority of MRI/MRS research subjects.