Technique of the abdominal ultrasonography in newborn foals and normal findings

Under field conditions, the diagnosis of foal's diseases relies almost excl usively on the physical examination. As the signs of illness in the equine neonate are frequently vage and non-localizing,the diagnosis of diseases ma y be problematic. This often causes misinterpretations and leads to ineffec tive prophylaxis and treatment. The purpose of this study was to evaluate t he usefulness of diagnostic ultrasonography of the foal's abdomen under fie ld conditions to provide an optimized technique and to describe the normal findings. Diagnostic ultrasonography of the abdomen was performed after obtaining cli nical history and passing the physical examination of 25 foals without sign s of abdominal problems. The foals were scanned in a stable box, being rest rained by three persons in semi-lateral recumbency. Usually, sedation was n ot necessary. The ventral abdominal wall was clipped, a generous amount of ultrasound coupling gel was applied and massaged on the skin surface. The u ltrasonographic examination was carried out using a portable sector scanner ("Microimager 2000", Ausonics) with 5.0 and 7.5-MHz transducers or a combi ned 5.0 and 7.5-MHz transrectal linear-array scanner ("450 Enhanced", Pie M edical). Employing the 5.0-MHz sector scanner first, the abdomen was explor ed from caudal to cranial in left and right semi-lateral recumbency. The 7, 5-MHz scanner was used to attain higher resolution of certain structures. T he sector scanner turned out to be suitable under field conditions and adeq uate to examine the abdominal organs. The transrectal linear-array scanner also provided the most important informations, although it was difficult to maintain a good contact area of the scan head. By ultrasonography it was p ossible to identify the urinary bladder, kidneys, spleen, liver and part of the gastrointestinal tract. Thus, application of ultrasound could successf ully be performed on newborn foals under field conditions.