Examination of the navicular region of the horse by using magnetic resonance imaging (Methodical study)

Abstract

Over the past ten years, noninvasive imaging techniques used in human medicine have shown extremely rapid progress in terms of increased resolving power and improved visualisation. Magnetic resonance imaging (MRI) is a technique which, unlike computed tomography (CT), enables accurate visualisation of soft tissues in addition to bones. Therefore, MRI facilitates are used for early recognition and accurate localisation of pathological changes developing in soft tissue structures constituting the navicular region in the horse. By the use of different MRI modalities (spin echo, gradient echo and inversion recovery sequences) the anatomical structures of the navicular region (navicular bone, impar ligament, navicular bursa, deep digital flexor tendon) are excellently visualised. On T1 weighted images the tissues characterised by rapid T1 relaxation (spongy substance of bone, pars torica pulvinis digitalis, synovia, corium) show high signal intensity, while T2 weighted sequences facilitate detailed evaluations of the fluid spaces and the study of pathological processes causing small changes in water content. Owing to the above characteristics, MRI enables accurate evaluation of the soft tissue structures of the navicular region on the basis of signal intensity differences specific of the individual tissue types. Its routine use in the everyday practice would thus result in more accurate differential diagnosis of diseases affecting that anatomical region, helping equine practitioners select the appropriate therapeutic procedures and monitor their success.