SAEVA Congress 2018 Proceedings | 12-15 February 2018 | ATKV Goudini Spa
However, in cases where this is not possible or a fast localized abdominal sonographic
examination of the horse (FLASH) is being performed to decide if immediate surgical
intervention is indicated, soaking the hair and skin with alcohol will usually suffice. The
FLASH examination is a rapid examination (15 minutes or less) that includes 7
windows for rapid evaluation of specific GI viscera: ventral abdominal, gastric,
nephrosplenic, left middle third of the abdomen, duodenal, right middle third of the
abdomen and thorax. This examination is excellent for the detection of dilated turgid
small intestinal loops where surgical intervention is indicated.
The horse should be scanned standing, if possible. The intraluminal bowel gas will rise
to the more dorsal portions of the abdomen, enabling the clinician to examine a larger
portion of the gastrointestinal tract. If the horse is recumbent, the scan should also be
performed from the most ventral portion of the abdomen.
If performing a FLASH examination, a low frequency convex transducer and alcohol
saturation of the skin and hair will enable the rapid screening examination in a horse
presenting with acute colic. Transrectal ultrasonographic evaluation of abnormalities
detected on rectal palpation can also be performed in adult horses to further clarify abnormal
rectal findings. In a horse presenting with a history of chronic colic, high frequency
transducers should be used to obtain superior images of the bowel wall with lower frequency
transducers used as the deeper portions of the abdomen are investigated.
Normal Ultrasonographic Findings in the Equine Gastrointestinal Tract
Only large intestinal echoes are usually imaged in the intercostal spaces (ICS) and the
flank in the adult horse. Occasionally small intestinal echoes are imaged between the
stomach and spleen and dorsal to the left dorsal colon and in the ventral abdomen
(usually caudally) of the adult horse. The large intestinal echoes are recognized by their
large semi-curved, sacculated appearance, except for the right dorsal colon. The right
dorsal colon has a smoother nonsacculated appearance and is usually imaged from
the right 14 th – 10 th intercostal spaces. The large intestinal wall is hypoechoic to
echogenic with a hyperechoic gas echo from the mucosal surface and normally
measures 3.5 mm or less in thickness. The cecum is normally imaged in the right
paralumbar fossa and right to mid ventral abdomen and has a sacculated appearance
with a hyperechoic gas/ingesta and hypoechoic fluid contents with a wall thickness of
3.5 mm or less. Peristaltic activity is normally visualized. The small intestinal echoes
are recognized by their small tubular and circular appearance. The wall of the jejunum
is hypoechoic to echogenic with a hyperechoic echo from the mucosal surface and is
usually 3 mm or less in thickness. Some anechoic fluid and hyperechoic gas is often
imaged in the lumen of the jejunum. Peristaltic waves are also normally visualized. The
duodenum is imaged around the caudal pole of the right kidney and medial to the right
liver lobe to about the mid abdomen. It appears small and circular (when sliced in its
short axis) with a hypoechoic to echogenic wall, also < 3mm in thickness, and has a
fluid lumen. The duodenum usually appears partially collapsed and its peristaltic motion
is easily visualized during real-time scanning. The gastric fundic echo is visualized in
the left 9 - 12th ICS and is imaged as a large semi-circular structure medial to the
spleen at the level of the splenic vein. The gastric wall is hypoechoic to echogenic with
a hyperechoic gas echo from the mucosal surface and normally measures up to 7.5
mm in thickness. Gastric rugal folds can be often be imaged in adult horses. The
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