Abdominal & Thoracic Ultrasound Flashcards by Inès O'Connor

What are the 4 diferent probes u may use?

2-5MHz curvilinear (adult abdomen and thorax, pelvis, lumbar region)
4-8 MHz microconvex (also sector shaped, foal thorax/abdomen, ocular,
some MSK)
7.5MHz (7.5-12) tendon probe (tendon, ligament, ocular, vascular, other
superficial structures)
6.0Mhz (5-10) rectal probe (reproductive mainly)

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Describe low frequency US?

– high penetration (20-40cm), sacrifice
resolution in near field. abdomen, cardiac

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Describe medium frequency US?

– midrange penetration (10-20cm) and
resolution. thorax, abdomen, reproductive

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describe High frequency US?

high resolution, sacrifice penetration. MSK,
umbilicus, ocular US, vessels

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What patient prep for US?

» Ideal: Clip and wash away dirt & debris & apply US gel
» Alternative: alcohol saturation
(Isopropyl alcohol)
» Be sure to clean off probes after use!
» Cobs/obese/very hairy animals will generally need clipping

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What are some non-acute indications for abdominal US?

Weight loss
Chronic colic
PUO
Suspected mass/abscess or neoplasia
Evidence of organ disease

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What are soem Acute indications for abdo US?

colic > FLASH

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What is the systematic approach for a full abdo scan?

R & L paralumbar regions
R & L ICSs from ventral lung margins to CC junctions
Entire ventral abdomen (sternum-inguinal)
Rectal US if indicated (if want to further examine L kidney, palpable masses, bladder)

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Describe locations of organs - where would you find everything?

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What do you find on the LEFT of th ehorse?

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What do we find on the RIGHT?

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Left side liver view?

ICS 7-10
- relatively hyperechoic but less so than the spleen

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Liver on right side?

ICSs 8-14
Should be dorsal to CC junction of ribs
If more ventral than that: Hepatomegaly

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View of spleen & stomach?

Spleen:
* Large amount of left side
Stomach:
* LHS ICS 8-15 deep to spleen and ventral to lung
* If extending beyond ICS 16-17 implies Gastric distension

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View of the descending duodenum?

ventral to R kidney
Deep to R liver lobe

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Where are we going to find Abnormalities in colic cass?

SI
LI
Peritoneal effusion

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Describe SI colic abnormalities?

Increased wall thickness (≤3mm), distension, abnormal motility.
Obstructive/surgical lesions: severe distension – lack of progressive motility, wall thickness can
be normal
Enteritis – can have similar appearance due to ileus (but may have wall thickening >3mm)

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Large colon colic abnoramlities?

Intraluminal gas/feed precludes evaluation of contents, distension and far wall
Wall thickness difficult to measure in normal horses
Normal is ≤3mm
Left dorsal displacement (Nephrosplenic entrapment): L kidney and dorsal border of spleen may
be obscured by large colon
Right dorsal displacement or colon torsion – colonic mesenteric vessels abnormal size/location

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Peritoneal effusion ?

If increased, assess quantity and echogenicity

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How would you visualise body wall -> spleen & left kidney?

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What would you see with nephrosplenic entrapment?

describe R dorsal displacement on US?

Image shows normal
colonic mesenteric
vessel
With RDD: ~10th to
12th ICS, run
~parallel with the ribs
& look engorged.

What does FLASH stand for?

Fast Localised Abdominal Sonography of Horses

Describe FLASH scanning?

» Quick, useful in emergency setting
» Extensive US experience not required
» Main usefulness: Diagnosing strangulating SI
lesions
» Can help indicate whether referral (or
euthanasia) required

What probe ot use for FLASH?

LOW frequency probe

What are the 7 topographical regions to look at with FLASH scan?

1. Ventral abdomen 2. Gastric window 3. Spleno-renal window 4. Left middle third of abdomen 5. Duodenal window 6. Right middle third of abdomen 7. Thoracic window (cranial ventral thorax)

What to look at in zone 1 - ventral abdomen?

Abnormalities: - DSIs - Si thickening - Abnormal motility - Free fluid

What to look for in Gastric window (2)

- Gastric distention

What abnormalities to look for in 3. spleno-renal window?

- Is L kidney visible? - If not, poss LLD

What abnormalities to look for in 4. Left middle third of abdo?

- DSIs - Colon wall thickeneing - Abnormal motility

What to look for in duodenal window (5)?

- Thickening of duodenum of RDC - Abnormal motility

What to look for in 6. Right middle third of abdo?

* Engorged colonic mesenteric vessels (Right dorsal displacement or 180o torsion) * Large colon wall thickening * Duodenum – wall thickening, motility issues

What abnormalities to look for in 7. thoracic window?

Free pleural fluid

What are some indications for thoracic US?

» Suspectediastinal mass d or confirmed lower respiratory tract infection » Poor response to therapy » PUO Also: - Cranial mediastinal mass (lymphoma) - Rib fract - Pneumothorax/haemoT

Review yoru anaotmy of lungs?

Discuss Pros and Cons of US?

What transducer to use for thoracic US?

» Transducers: dependent on availability and patient size. * Usually curvilinear best » Depth 4-10cm (15-25cm if severe pathology)

What technique for Thoracic US

» Start at the last (17th) ICS » Scan from dorsal to ventral in each ICS to ventral lung margin » Evaluate cranial mediastinum if any abnormalities identified in other ICS

What do normal lungs look like on US?

What are normal findings on lung US

» Aerated lung: ultrasound reflected by air -> Only the surface of normal lung can be evaluated. » Lung should glide freely with inspiration and expiration » Pericardiodiaphragmatic ligament (visible in horses with pleural effusion) *don’t confuse with fibrin* » Pleural fat

What does perocardodiaphragmatic lig?

What are some abnormal findings?

»Comet tail artefacts »Consolidated lung (“hepatised”) »Pulmonary abscessation »Pleural effusion »Atelectasis »Fibrin »Adhesions

Describe Comet tail findings?

Any irregularities of pleural surface: - Early pneumonia - Scarring from previous LRT infection

How to evaluate comet tails?

Interpret within current clinical picture & whether other pathology is visible * Size? Number? Distribution? * Very fine comet tails wnl (esp neonates)

What are B lines?

o Artefact from the pleural line o Suggestive of alveolarinterstitial pathology o Common finding in various lung parenchymal disease

What does consolidated lung look like?

* Non-aerated lung * Fluid and/or cellular infiltrate * Usually cranioventral * Various pathology from pneumonia to neoplastic disease

What does pukmonary abscessation look like?

* Well circumscribed area(s) of consolidation * Only see peripheral abscesses

Abscess & fluid pockets?

Pleural effusion and atelectasis?

PNEUMOTHORAX

» Hard to differentiate from normal lungs » Both pneumothorax and normal air-filled lungs will result in a hyperechoic line » Clinical signs…