Abdominal Ultrasound

Imaging Control Buttons

Depth

The organ imaged should take up 3/4 of the screen

Frequency = Penetration

Use high frequencies (harmonics) for fluid filled and superficial structures

If the far field (lower part) of the image loses detail (blurry, darkened, fuzzy, etc.) decrease the

frequency for more penetration. You may also need to change to a lower frequency transducer

Gain = Brightness

Adjust the gain to see the borders of all structures clearly. This usually would be around 50-60%, but

will differ with anatomy, depth, and frequency

Map = Shades of gray

The overall image will slightly change. Shades of gray will get brighter as your go up, or will get

darker as you go down

Use this function when the frequency and gain is at it’s best, but still want to fine tune the image

Transducers

Linear (L14-5)

Typically used for smaller animals and superficial structures. Can also be used to image the GI system

in larger animals.

Microconvex (MC9-4)

Typically used for medium - large animals and all echocardiograms. Can also be used on smaller

animals to image deeper organs (liver, right kidney, etc.) and when a large amount of gas is present.

Curvilinear (C7-3)

Typically used for large animals and deep structures

NOTE: The choice of transducer is dependent on many factors such as body habitus, depth of organs

imaged, and presence of gas. It is important to use multiple transducers and find what is right for that ani-

mal and organ being imaged.

Scanning Movements

Slide

Move the transducer

Example: Slide Cranial - move the transducer toward the patients

head

Rotate/Twist

To move from one plane to another

Example: moving from a long axis image to a short axis image

Tilt

Hold the transducer in the same spot and point the transducer towards

area of interest

Example: Tilt the beam to the left to image the left (to image the left

side of the body) or tilt the beam to the right (to image the right side of

the body).

Rock or Heel/Toe

Apply more pressure to one end of the long axis of the transducer

Example: rock the transducer to image underneath the rib cage - more

pressure is placed on the end of transducer without the notch (heel of

the transducer)

Image Orientation

Long Axis: Notch pointed to the patients head

Short Axis: Notch pointed to the patients r ight side

Ventral

Dorsal

Cranial Caudal Patient’s

Right

Patient’s

Left

Ventral

Dorsal

Bladder

Tips:

Use the linear transducer with harmonics when possible

Should appear anechoic (black)

Be aware of pressure used - it can be compressed if too much pressure is used

When excessive artifact is present try adjusting the gain, TGC, frequency, and/or map

Be care not to darken the image too much or you could potentially miss debris or lesions

Lesions vs debris- If echogenic material is noted on the dorsal side of bladder stand the animal upright

and revaluate the echogenic material (lesions will stay at the dorsal portion of bladder and debris should

move to the ventral portion since it is gravity dependent)

Images:

Cranial

Caudal (trigone)

Videos:

Cranial and Caudal (Rt - Lt)

Short Axis - cranial to caudal

Bounce on the bladder and look for floating debris

Cranial Trigone

Prostate

Tips:

Follow the trigone caudal

Intact Males: round to oval shaped

Neutered Males: very small and may not always been seen

If you suspect abnormality: take additional images with Color

Images:

Long Axis Image

Measurement of length and height

Videos:

Long Axis (Rt - Lt)

Bladder

Measurements

Left Kidney

Tips:

Increase the depth after scanning the bladder

You may need to lower the frequency (or switch to a lower frequency transducer) after scanning the

bladder

Palpate the last rib: Kidney is located posterior and medial to the caudal aspect of spleen

Renal Pelvis: Look for backwards C or U shape with a hyperechoic (bright) break in the cortex

When the kidney is difficult to evaluate try using a lateral decubitus or standing position

Images:

Long Axis

Long Axis with measurement

Short Axis at the Renal Pelvis

Videos:

Long Axis (Rt - Lt)

Renal Pelvis

Left Adrenal

Tips:

Start at the cranial portion of the kidney and tilt the beam medial. The transducer beam should be

pointing medial towards the aorta

Look for the renal artery (the adrenal gland is located cranial to the artery). Use Color Doppler to follow

the renal artery from the kidney

If the dorsal position does not work, try to reposition the animal into a lateral recumbent positon

You may have to rotate the transducer slightly to elongate the gland in a dorsal position

Lateral recumbent position

Slide lateral to the last rib and rotate the transducer so the back is pointing towards the animal’s

left knee (this is about a 30° angle from a long axis position)

Images:

Long Axis

Long Axis with measurement

Videos:

Long Axis (Kidney - Ao/CVC)

Spleen

Tips:

Use a high frequency when possible

Cranial Spleen - locate the margins of the cranial spleen. Then increase depth and tilt the transducer

towards the patients right (point the transducer to the patients left) until you see the spleen dive down on

the screen. Standing the animal upright (especially larger animals) will allow for better visualization at

times.

Mid Spleen - Image should be taken at the hilum where the splenic vein can be seen (split screen with

color)

Splenic Tail -

Cats: Slide caudal until you see the caudal margins

Dogs: Once you find the caudal margins, follow all the way through to the tail of the spleen by sliding

the transducer to the patients right.

Cranial

Mid

Mid

Tail

Spleen

Images:

Long Axis Cranial Head

Long Axis Body

Long Axis Splenic Vein w/ Color

Long Axis Caudal Tail

Split Screen Liver and Spleen (do not change any settings for this image)

Videos:

Cranial half of spleen

Caudal half of spleen

Spleen Liver

Liver

Tips:

May need to increase depth, lower frequency, and/or switch transducers

Make sure you can ALWAYS see the diaphragm

Apply adequate pressure (usually more than you think)

When a subcostal approach does not image well due to gas, body habitus, etc. try the following:

Reposition the animal into a lateral recumbent position or standing position

Use intercostal approach (especially in deep chested dogs). You can sometimes use both a left and

right intercostal approach

Left Lobe - Use the stomach as a landmark. The liver will appear more wedge shaped

Mid Liver - Look for the portal vein as a landmark. Located just medial to the GB

Right Lobe - Use the GB as a landmark.

Images:

Long Axis Left Lobe

Long Axis Mid

Long Axis Right Lobe

Videos:

Long Axis - Right Lobe to Mid Liver

Long Axis - Mid Liver to Left Lobe Left Lobe

Mid Liver Right Lobe

Gallbladder

Tips:

Located just right of midline and surrounded by liver tissue

Use a high frequency when possible (harmonics)

Normal appearance: anechoic (black)

To elongate the GB, rotate the transducer until you can see the neck and fundus (may not always be

able to image both on the same image)

Images:

Long Axis Fundus Image

Long Axis Neck Image

Video:

If pathology is seen or if you cannot get the entire organ in one image

Neck

Fundus

Fundus

Right Kidney

Tips:

Palpate the last rib

Increase the depth so you do not miss the kidney. Readjust the depth once it is located

You may need to lower the frequency or switch transducers

Renal Pelvis: Look for backwards C or U shape with a hyperechoic (bright) break in the cortex

When the kidney is difficult to evaluate try using a lateral decubitus or standing position

Images:

Long Axis

Long Axis with measurement

Short Axis at the Renal Pelvis

Videos:

Long Axis (Rt - Lt)

Renal Pelvis

Tips:

Start at the cranial portion of the kidney and tilt the beam medial. The transducer beam should be

pointing medial towards the CVC/Aorta.

Use color Doppler to follow the renal artery from the kidney

If the dorsal position does not work, try to reposition the animal into a lateral recumbent positon

You may have to rotate the transducer slightly to elongate the gland

Lateral recumbent position: slide lateral to the rib cage (some animal’s may require a more lateral

approach than others) and tilt the beam of the transducer until you locate the CVC

Images:

Long Axis

Long Axis with measurement

Videos:

Long Axis (Kidney - Ao/CVC)

Right Adrenal

Duodenum

Tips:

Use linear transducer in harmonics when possible

Duodenum is larger than the rest of the small intestine

Using the Rt. Kidney as your landmark, you may need to either tilt lateral or slightly medial

depending on the position of the transducer on the abdomen. The duodenum should lengthen

across the screen.

Images:

Long Axis

Long Axis with measurement

Short Axis

Videos:

If pathology is seen

Pancreas

Tips:

Normal tissue may not always be seen

Right Limb - Duodenum is the landmark.

When scanning from a lateral approach the pancreas can be seen dorsal to the duodenum

Short Axis - start at the right kidney and slide cranial following the duodenum

Left Limb - Triangle of landmarks: greater curvature of the stomach, cranial spleen, and left kidney

Follow the splenic vein from the spleen

Videos:

Long Axis Right Limb

Short Axis Right Limb

Long Axis Left Limb

Images:

If pathology is seen

Left Limb Landmarks

Stomach

Tips:

Use a high frequency when possible (harmonics)

Start at the sternal notch and apply pressure to the heal of the transducer

To elongate the stomach rotate the transducer to an oblique angle (about 45°)

Standing the animal upright can shift the gas making it easier to visualize portions of the stomach

If you are concerned about a stomach mass, stand the animal upright and re-evaluate

Images:

Long Axis Images of greater/lesser curvatures

Short Axis Image

Video:

Long Axis lesser curvature

(from the body of stomach to the pylorus)

Long Axis greater curvature

(from the body of stomach to the patient’s left)

Empty Stomach

Small Intestine

Tips:

Use the linear transducer in harmonics when possible

Apply more gel!

All the small intestine should be similar in size

Scan the abdomen systematically

Videos:

Short Axis Right (Cranial - Caudal)

Short Axis Mid (Cranial - Caudal)

Short Axis Left (Cranial - Caudal)

Images:

Images and measurements should be taken if there is any concern for GI disease or abnormalities

are visualized

Iliacs at Aortic bifurcation

Tips:

Use the linear transducer in Harmonics when possible

Normal lymph nodes may not always be seen

Characteristics: Well defined, smooth, and fusiform to oval shaped

Isoechoic or slightly hypoechoic (slightly darker) to surrounding fatty tissue

When using a high frequency transducer you may also see a hyperechoic (bright) central line

representing the hilum

Patient is scanned in a lateral decubitus position, transducer in a vertical position. Start dorsal, near

back musculature and slowly slide ventral until Aorta appears. Slide caudal on Aorta until you see it

bifurcate into iliac vessels. Fan through the bifurcation Lateral/Medial

Videos:

Right Iliac Video (fan through the vessel at Aortic bifurcation)

Left Iliac Video (fan through the vessel at Aortic bifurcation)

Images:

If large lymph nodes are seen images should be taken

(measure the largest)

Right Iliac

Left Iliac

With Color Normal Lymph Node

Imaging Abnormalities

When abnormalities are noted on an exam additional images should be taken in addition to the protocol

Additional Images for Lesions

Long AND Short Axis Images

If lesion is small use split screen

Image with measurements

Smaller lesions can be measured on split screen

Image with color Doppler

Multiple lesions on the same organ that have similar appearance

Measure the largest 2 lesions and include images of the others

Make sure that on your video that the lesions are included

May need to take 1-2 additional videos

Large masses

Try to locate the organ it is originating from (this may be difficult at times depending on

location and size)

Abdominal Fluid

Capture an image of any ascites that you note

Use organs as landmarks if only a small amount is seen so the specialist can document where the fluid

is seen on reports

Fluid-filled Intestine

Can be a normal finding or a sign of an abnormality

Follow intestine until you no longer see the fluid or until you scan come across an abnormal/suspicious

area