Equine ultrasound Flashcards
In horses, on what body parts can ultrasound be used? (7)
Thorax
Abdomen
Reproduction
Musculoskeletal system
Ophthalmology
Soft tissue swellings
Vascular
Preparing the equine patient for U/S.
Sedation +/- (not good for abdo U/S cause induces hypomotility)
Clipping +/- (some sport horses are kept clipped all year round)
Washing the skin
Rinse with 40-70% alcohol
Massage gel into the skin (though gel is not always necessary at all)
Thoracic ultrasound in horses.
Pleural cavity
Pleura
Ribs
Diaphragm
Heart
Good for evaluating for free fluid and pleuropneumonia.
Air filled lung will obscure a lot of pathologies (a bit of cranial abdomen is hidden between the caudal lung tails).
Use convex or linear probes.
thoracic U/S
left: white hyperechoic line is the pleural line. to the right of the pleural line, you have 2 white lines, thats the diaphragm.
right: deeper view of the pleural surface with thicker muscle layer overlaid (view is more cranial on the thorax).
reverberation artefact lines ventrally in both images.
thoracic U/S
consolidation in lung parenchyma
comet tails/B-lines due to wet lung
thoracic U/S
lung abscessation, fluid
+ reverberation artefact lines
right: upper right edge is diaphragm and liver
diaphragmatic hernia
NB! left side of image is DORSAL, right side of image is VENTRAL direction.
the diaphragm should normally be against the body wall in this view but in this image there is dark space with free fluid.
What you can view with Abdominal U/S in horses?
What probe?
Gastrointestinal tract
Kidneys
Liver
Spleen
Peritoneum
Things that do not belong – tumors, abscesses, free fluid.
You NEED a low frequency probe for abdo in adult horses, 2 – 3 MHz for adult horse (convex or microconvex). High frequency probes do not have enough penetration (maybe deep enough only for foals).
Stomach U/S in horses.
Semi circular echo on the left side, usually in 9-12 intercostal space (ICS).
Only large curvature is visible. Gas filled stomach so artefact will occur.
Finding the splenic vein is a good landmark for finding the stomach, the gastrosplenic ligament in that region.
Gastric wall thickness around 7,5mm (thicker than SI). Black line in prev image is due to thick gastric muscle with higher water content. Intestine won’t have this line.
Gastric size has to stay under 5 ICSs (not a hard rule).
The stomach is potentially over filled if it reaches further than the 13th ICS or is bigger than 6 ICSs.
In this image there is something wrong (“reflux line”). You should not be able to see excess fluid in the stomach like that. Rupture risk, pass nasogastric tube asap.
The last intercostal space is the (what number)
17th one.
Always begin counting from the caudal end.
Describe equine duodenum U/S.
Visualization: 10th– 15th ICS at the right side, between liver and right dorsal colon.
16th– 17th ICS at the right side, next to the right kidney.
Normal wall thickness < 3mm, 2 – 6 contractions per minute.
Describe equine jejunum U/S.
Can be imaged in transverse sections as complete loops.
Often imaged ventrally in mid abdomen and in inguinal area, mobile.
Jejunum have continuous movement.
Normal wall thickness < 3mm.
Normally have an angular appearance. If dilated, the angles will be gone.
Describe equine ileum U/S.
Often not visible in healthy horses and hard to differentiate from the rest of the small intestines.
Has an extra prominent muscle layer.
Visually slightly thicker compared to the rest of SI.
Proximal part can be visualized ventrally.
Distal part is craniomedially from the caecum.
small intestines
left: anechoic fluid content. a-motile, something is wrong.
right: sedimentation in SI lumen, hypomotility again. Remember left is dorsal, right is ventral.
left image: edematous intestinal walls (e.g. enteritis, inflammation etc.)
right: edematous intestinal walls. measurement of 2 intestinal walls at the same time. divide result by two.
intussusception with bullseye sign
euthanasia or surgery. will not self-resolve.
Describe equine large intestines/large colon on U/S.
Left dorsal and ventral colon:
imaged from the left paralumbar fossa, ventrally and more deep from the spleen. Sacculated appearance.
Right dorsal colon: 10th– 15th ICS at the right flank, ventral to the liver.
Less sacculated appearance.
Right ventral colon: Cranial to the paralumbar fossa, in the ventral third of the abdomen. Sacculated with peristalsis.
Wall thickness of the colon around 3– 3,5 mm.
Describe equine large intestines/small colon on U/S.
Visualized on both sides caudo-dorsally.
Has a sacculated appearance like the rest of the colon.
Often difficult to distinguish from the rest of the large intestines.
What is the difference between the small and large colon in horses?
The colon consists of three parts; ascending, transverse and descending. The first part of the colon has the greatest capacity and is known as the large colon.
In contrast, the descending part of the colon is known as the small colon.
Describe equine cecum on U/S.
Imaged in paralumbar fossa on the right and ventrally.
Sacculated echoes with peristalsis.
Wall thickness around 3– 3,5 mm.
Lateral cecal band vessels also visible
normally. Bands differentiate it from colon.
Bands on equine colon versus cecum.
The right and left ventral colons typically have four bands, while the dorsal colon segments have fewer (one to three bands).
The cecum generally has four distinct taeniae/bands that run longitudinally along its structure; namely, the dorsal, medial, ventral, and lateral bands.
Describe equine kidneys on U/S.
Left kidney: Located deep to the spleen,
15th– 17th ICS. Scanning depth 20- 30 cm.
Can also be visualized transrectally as well.
Right kidney: at the 15th– 17th ICS. Scanning depth 15– 20cm.
Describe equine liver on U/S. (blue is spleen)
Right liver lobe: at the 8th– 15th ICS on the right side. The right liver lobe is visible ventral to the lung margins. Visibility can be variable.
Left liver lobe: at the 7th 10th ICS. Left cranioventral abdomen, caudal to the heart.
congested liver due to chronic heart failure.
pathologically large liver window.
Describe equine spleen on U/S.
Predominant feature of the left abdomen, visible throughout most ICS, paralumbar fossa region and ventral abdomen.
Might extend slightly to the right over the ventral midline even in normal horses.
Less vascular and more hyperechoic than the liver.
Things that should not be there.
Left: liver window but there is a sarcoma mass to the right of the liver.
Right: uroperitoneum in a foal. The “stalks” are mesentaric attachments only visible due to uroabdomen.
What is abdominal U/S flash?
fast localized abdominal sonography of horses
(equine AFAST)
Who? Acute colic patients during emergencies.
Goal: fast overview about potential pathologies in the abdomen.
Time estimate 10– 15 minutes, 7 locations.
Vascular U/S in horses.
Linear probe
Always visualize in 2 directions: transverse and longitudinal.
You have to distend the jugular to visualize it. Artery is thicker and doesn’t need distension to view it.
e.g. thrombophlebitis
upper right image: thrombus in vein
