RESUMO
Magnetic resonance imaging (MRI) is now widely used in equine veterinary practice. However, the mandatory European legislation regarding horse identification imposes the implantation of a transponder within the fatty tissue of the neck cervical ligament. While performing brain MRI for scientific purposes in ponies, we faced artifacts produced by such transponder and reported here this problem. Indeed, pony mares were anesthetized for 2 hours and placed, bedded on their back, in a 3T MRI scanner. A four-element flexible antenna positioned around the head was used. Three MRI sequences were performed on each animal: three-dimensional T1, three-dimensional T2, and two-dimensional T1. The anesthesia allowed the acquisition of MRI for 2 hours. The images for the three MRI sequences for each pony exhibited great quality on all the anterior parts of the brain but began to become distorted posteriorly to the pineal pituitary axis and completely disappeared at the level of the cerebellum. To find the origin of the artifact, the transponder used for the identification of the animal was inserted in an inert gel and imaged in the same conditions as the ponies. The images obtained looked similar to the observed artifact. Our study thus advocates for the further exploration of such kind of artifact when using 3T MRI in brain imaging in horses.