Rad abdomen Flashcards by Anna Wilburn

Describe the systematic approach to the abdomen ?

Systematic approach to the abdomen

Quality assessment
Peritoneum and retroperitoneum (increased serosal detail; pneumopertonium)
Solid organ (liver, kidney and spleen)
abdominal masses
hollow organs, stomach, small intestine, caecum, colon
caudal abdomen; sublumbar LNS, colon, bladder, prostate / uterus
Bladder and urethra
vomiting / gastrointestinal tract

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Describe the anatomical difference between the peritoneum and retroperitoneum, how could we differentiate these ?

Pertoneum and Retroperitoneum

These are 2 seperate compartments in the abdomen which do not communicate.

Pertoneum
The serous membrane lining the abdominal cavity. Most abdominal organs are inside the peritoneum.

Retroperitoneum
This is the space in the dorsal abdomen (outside the peritoneum) between the peritoneum and the dorsal abdomen
- contains kidneys, ureters, adrenals
- retroperitoneum communicates caudally with the pelvic cavity and cranially with the mediastinum

The retroperitoneum can only be assessed on lateral projection.

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Identify this pathology on radiograph ?

Pathology = reduced serosal detail

Identify by how well the organs are seen in the abdomen
- called serosal detail because the serosa is the outside layer of organs.
- decreased serosal detail indicates abdominal fluid but there can be imposters.

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Identify this pathology, and list all the possible differentials ?

Reduced serosal detail

My - mass (overcrowding)

Father - fluid (blood, ruptured ureter/bladder, transudate, exudate, bile)

Says - Skinny

Thank - Technique

You - Young

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As a clinician how would you confirm there is fluid in the abdomen ?

AFAST

AFAST is a point of care ultrasound that just looks for abdominal fluid

ultrasound is more sensative than radiology for abdominal fluid.

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Identify this pathology and its potential causes ?

Pneumoperitoneum
(This is gas in the peritoneal space)
Identified in two ways
- gas bubbles in the falciform fat
- identification of both sides of the diaphragm (must be severe).

Caused by
- latrogenic laparotomy
- from the outside, bite wounds, hit by car, gun shot
- from the inside; rupture of the GI tract (other causes are uncommon)

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Identify this pathology and describe all possible radiographic signs ?

Pneumoperitoneum - radiographic signs

Gas bubbles
In areas where there are no intestines, in the falciform fat in the cranioventral abdomen.
Diaphragm - visualisation of both sides of the diaphragm

due to gas against the abdominal side of D
less common and is only usually seen when there is a greater volume of gas.
in health only the thoracic side is visualised due to gas in the lungs

If in doubt - do a horizontal beam radiograph

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Your patients radiogragh makes you suspicious of pneumopertitoneum, what could you do too confirm this pathology ?

If in doubt do a horizontal beam radiograph

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You suspect pneumoperitoneum post spay; is the gas due to surgery or is new gas being introduced eg dehiscence ?

Spey
(the cut off is two weeks).

Spey healthy small incision - 24 -48hrs
exploratory laparotomy large incision and longer surgery about ten days.

The cut off is two weeks
after this time it is likely due to a new gas leak eg. dehiscence
(up to this point rely mostly on clinical signs to determine dehiscence).

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Describe the technique for carrying out a horizontal beam radiography ?

Horizontal beam radiography
(carry out when we suspect pneumoperitoneum)

Technique
- X ray beam is horizontal to the floor (care)
- casette on the opposite side of the animal with the edge of the casette on the table
- sensitive 2-5ml of free gas
- centre the beam on the diaphragm at the highest point of the animal
- place foam mat under the animal to elevate it above the cassette
- elevate chest + gently massage animal to dislodge gas
- dorsal recumbancy is most sensitive and easiest to interpret, but any recumbancy can be used.

Ensure animal has been positioned for a minimum of three minutes before taking an exposure.

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Describe the steps you would take to assess the retroperitoneum ?

Assessment of the retroperitoneum on radiograph

Use the lateral view only
- how well can i see the muscles ventral to the spine
- is the normal fat opacity seen
- are the kidneys well defined (kidneys are well seen in the cat as they are surrounded by fat, this is not always the case in the dog).

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Identify this pathology and its possible causes ?

Pathology = decreased retroperitoneal detail
(due to increased soft tissue opacity from fluid)

The cause (2 clinical scenarios)
1. trauma
causes are haemorrhage or urine (ruptured ureter) - next step excretory urogram
2. Spontaneous
Usually due to a bleeding adrenal gland mass
- next step abdominal ultrasound or CT

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Describe your next step when you have a patient with a history of trauma, and decreased retroperitoneal detail ?

Trauma
haemorrhage or urine (ruptured ureters).

Next step Excretory urogram (EU)
- determine if the ureters are intact, if they are it must be haemorrhage
- contrast is injected intravenously and evaluated on radiographs or CT as it is excreted into the bladder and ureters

Two indications
- ectopic ureter evaluation
- ureter rupture post trauma

Treatment
Ureter rupture is treated surgically
Haemorrhage is treated medically

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Identify the best imaging modality to answer the question
1. is there abdominal fluid ?
2. Is fluid in the retroperitoneum or peritoneum ?
3. Trauma is there a ruptured ureter ?
4. identify the retroperitoneal fluid without trauma ?

Answers imaging modality

AFAST as radiographs are less sensitive
lateral radiograph
excretory urogram
ultrasound, CT usually requires a specialist

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Know which imaging modality (radiographs, ultrasound or contrast study) is best for which indication in the kidney ?

Kidney imaging evaluation

Plain radiographs
- only exception for use is to view minerlisation
Ultrasound
- best modality, not difficult
- mostly replaced contrast procedures for the unrinary tract
Contrast study
Excretory urogram; used to assess ureters (which are not normally seen on ultrasound or radiograph).

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Describe the normal location of the kidneys ?

The right kidney is more cranial, righty tighty

Left is lower

In cats the kidneys are more easily visualised, being more parallel and mobile.

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Describe how the use of the triad can help identify the kidney on a ventral radiograph ?

Triad

Right kidney is not visable in most dogs on the VD view.

Triad
Locate the splenn and stomach which can be used to locate the position of the left kidney.
Spleen
kidney (left kidney)
stomache

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Describe how you could assess kidney size on radiograph and ultrasound?

Kidneys

Assess two things radiogragh
- same size as each other
- normal size compared to L2

Size compared to L2
- this comparison can only be made on the VD view (kidneys are a similar view from the imaging plate).
- cat: 1.9-2.6
- Dog: 2.5-3.5

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Identify this pathology of the kidney and interpret its meaning clinically ?

Radiograph minerlisation (easier to visualise on rads)
(lateral view is best) prevents colon superimposing on the kidneys

Common in cats and dogs;
- calculi in renal pelvis
- normally of no clinical significance
- may cause pathology if passed and cause a blockage of the ureters
- hydronephrosis
- ignored if renal function is normal / renal enzymes SDMA, USG

The significance is assessed by labwork
- renal enzymes, SDMA and USG

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Identify and describe this pathology ?

Chronic renal insufficiency
Both kidneys are small compared to L2

Very common in cats; uncommon in dogs
- almost expected in an old cat
- presentation PU/PD
- it is always worth having a look at the kidneys on ultrasound as it may be treatable or treated differently
- pyelonephritis = culture urine

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Identify this pathology (whats our next step) ?

End stage kidney disease
(presumed chronic renal failure - follow with ultrasound which is more sensitive)
This could be a treatable condition, or treated differently.

usually unilateral in an older animal
small kidney with marked loss of normal renal architecture
- ureter obstruction, hydronephrosis
- pyelonephritis, culture urine
- nodules / masses

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Identify this pathology seen bilaterally on ultrasound in a young animal ?

Renal dysplasia

easily diagnosed by ultrasound / bilateral
- abnormal appearance of kidneys in a young dog
- appears the same as end stage kidney but in a young animal and bilateral

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You observe degenerative changes within the kidney on ultrasound, what your next step ?

Degenerative changes observed on ultrasound

This may make a suspicious of renal compromise
- this should always be followed up with observation of renal enzymes SDMA and USG
- renal enzymes directly indicate functionality of the kidney

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Identify and describe this pathology on ultrasound ?

Renal lymphoma
(more common in cats)

Bilateral renomegaly >4.3cm with hpoechoic rim
- this may occur without disease in a large cat/ normal
- on ultrasound changes are diffuse so kidney appears normal
- hyperechoic whiter kidney
- hypoechoic black rim around them
- differentials; lymphoma or FIP

Dx - Fine needle aspirate only usually used for masses and nodules

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Identify this patholgy

Polycycstic kidney disease large kidney with an irregular margin

Describe what you could observe on ultrasound of a patient in acute renal failure ?

Acute renal failure Kidneys usually look normal on imaging - may appear smaller on follow up ultrasound images - often not detected initial ultrasound as within normal reference range

You have a case of big kidney little kidney what do you do ?

Found on ultrasound one big kidney and one small Asymetric kidney size Very common in cats, less common in dogs - caused by chronic pyelonephritis or ureter obstruction - often not detected when first kidney affected, recover after a few days and then the other kidney hypertrophies to take on extra function - same process second kidney - present renal failure This process may be able to be reversed in the second kidney. What to do Ultrasound - to look for hydronephrosis (obstructed ureter) Culture urine = pyelonephritis

Ultrasound; observation of a wine glass bottom in the kidney may indicate ?

Pyelectasia (fluid in the kidney) One or both kidneys are infected. Pyelonephritis Often found to appear normal on ultrasound - small amount of fluid within the renal pelvis (pyelectasia) - There are however many causes for pyelonephritis IV fluids, renal insufficiency, PU/PD

How do you identify hydronephrosis and what are its potantial causes ?

Hydronephrosis Identify - severe dilation of the renal pelvis - ultrasound - excretory urogram Causes - obstruction downstream of pelvis eg calculus in the ureter

Describe the role of radiography, ultrasound and CT in the evaluation of the liver and gall bladder ?

Modality for liver assessment Radiography - used to assess gastric axis and liver size Ultrasound - nodules and masses, may not be seen in radiographs - diffuse liver disease - gall bladder Biopsy - diffuse parenchymal disease CT - parenchymal disease (mass, abscess) - helps assess if liver masses are surgically retractable - portosystemic shunts

Describe the role of ultrasound when it comes to evaluation of the liver ?

Describe which image modality is most appropriate for assessment of the kidney, ruptured ureter, obstructed ureter and ectopic ureter ?

The best image modality Kidney = ultrasound Ruptured ureter = excretory urogram obstructed ureter = ultrasound specialist ectopic ureter = CT

Describe how you could assess the size of the liver ?

Assess the liver size through the gastric axis (lateral radiograph) Gastric axis = line between the fundus and pylorus. - pylorus must be seen to make a gastric axis (not always possible) - location of the fundus can be presumed if not seen (cranial dorsal abdomen next to diaphragm) held there by the oesophagus Normal axis - perpendicular to the spine - or parallel with the ribs - any change in the axis is only due to change in the location of the pylorus - pendulum.

Describe all factors which could influence your interpretation of liver size ?

Liver size The gastric axis may appear different - on right vrs left lateral - conformation eg barrel chested dogs (brachys it appears larger) or deep chested dogs - young animals liver is relatively larger - obese animals - geriatric (stretching of the ligaments that attach the liver to the diaphragmso the liver sags further caudally in the abdomen)

Identify this pathology ?

Hepatomegaly - caudal displacement of the gastric axis - rounding of the caudoventral margin - subjectively more liver on the ventral view (greater distance between the diaphragm and stomach) - U shaped stomache on ventral view Do not use how far the liver extends beyond the costal arch to assess the size of the liver; this is affected by conformation and phase of respiration.

Great you have identified hepatomegaly, what is your next step ?

Hepatomegaly and your next step It can be normal for a patient so assess your Blood work - ALT, GGT - ultrasound liver for masses and nodules - Test for Cushings clinical signs if indicated by clinical signs + bloodwork FNA - can be used to rule out lymphoma - masses and nodules to rule out neoplasia and fungal granulomas.

Identify this pathology ?

Microhepatica - cranial displacement of the gastric axis - subjectively less distance between the diaphragm and the stomach on VD

Great you have identified microhepatia, what should you do now >

Microhepatia It is usually normal for the patient Differentials and their further work up - if there is no indication of disease on blood work, then the patient is normal - cirrhosis ultrasound specialist - portosystemic shunt CT specialist - if there is no indication of these diseases on blood work, then it is normal.

What is a portosystemic shunt and what is the best image modality ?

Porto systemic shunt Blood from the intestine goes straight to the systemic circulation (from the portal vein to the caudal vena cava) without first being 'detoxified' in the liver CT - specialist

Describe this change ?

Minerlisation of the biliary tract (liver opacity) Normal liver opacity is soft tissue opacity - minerlisation of the wall of the biliary tract - mineral opaque branching structures No clinical significance

Identify and describe this pathology ?

Hepatic abscess + hepatomegaly Predisposed - diabetes mellitus - biliary disease - pancreatitis 25% have gas producing bacteria - and gas can be seen on radiograph

Describe the location of the gall bladder in a cat and dog ?

Gall bladder location Cat - ventral margin sometimes seen / ventral to the liver - do not confuse with a biliary mass in the cat - the ventral margin is not always visible in the cat Dog - not seen - VD, ventral right side of spine central - ventral on a lateral view in the centre of the liver - it is important to know the location as it may assist in identifying pathology.

Identify this pathology ?

Cholelith - calculi in the gall bladder are common - no clinical significance

Describe how you would determine the thickness of the wall of the gall bladder ?

Ultrasound (Can be used to calculate gall bladder wall thickness) - in health the wall is so thin that it is just a line and very difficult to measure A thickened gall bladder wall indicates - cholecystitis - hypoproteinaemia - hypoalbuminaemia portal hypertension RSHF

Identify and discuss this pathology ?

Gall bladder Mucocoele A semi solid mucoid material replaces normal bile in the gall bladder Dogs only - ultrasound - 7-44% unsymptomatic - TX = surgery even if they are asymptomatic

Describe the location of the spleen in cats and dogs ?

Spleen location Head - VD view only - every cat and dog - use the triad stomache and left kidney to identify it Tail - only seen on lateral view - normal to be seen or not seen in dogs - should not be seen in cats (it indicates splenomegaly)

Identify this pathology and describe its causes ?

Splenomegaly Assessed subjectively Dog - 'normal' size is variable Cat - less variable, if tail visable splenomegaly - ultrasound >12mm FNA to rule out neoplasia/ lymphoma

Describe the potential causes of splenomegaly ?

Causes of splenomegaly - normal in some breeds eg German sheperd - anaesthesia/sedation - neoplasia / lymphoma - torsion - rare

Provide a definition of organomegaly, mass and nodule ? How can we different these ?

Definitions Generalised organomegaly - the whole organ is enlarged eg renamegaly, hepatomegaly Mass - A mass is a focal enlargement >2cm Nodules - These are a focal enlargement < 2cm, often undedectable on radiographs due to their small size Sometimes on radiograph it is difficult to differentiate between organomegaly or a focal mass may require CT.

Define mass and mass effect ?

Definitions Mass The actual mass itself > 2 cm Mass effect The displacement of organs away from their normal location by the mass. The intestines are the most mobile so easiest to see. The displacement of organs can be used to indicate the mass location. Pictured a fat cat (normal) causes mass effect without any mass being present.

Identify the location of this pathology ?

How to identify the location of a mass through the mass affect - 1. mass affect - mass affect can see intestine displaced to the right on VD - mass visable in left mid abdomen Visability of suspected organ - head of spleen is visable no summation not this organ - left kidney is not visable in contact with the mass possible summation, indicating the mass is likely in this organ. Further imaging ultrasound, CT or exploratory laparotomy is usually required to definitively determine the location.

What differentials are there for a mass identified on radiographs ?

Ddx mass = Chang C = cyst H = haematoma A = abscess N = neoplasia G = granuloma

Disscuss how you could accurately describe a mass ?

Use the Roentgen signs 1. Size 2. Shape 3. Margins 4. Opacity 5. Number 6. Location

Use your knowledge of the Roentgen signs to describe this mass ?

Mass description 1. Size, usually measured 2. Shape oval 3. Number = one 4. Margins definitive margin ventrally 5. Opacity fat opacity, which is unusual as most masses are soft tissue opacity. 6. Location = dorsal right abdomen, potentially retroperitoneal

What radiographic signs would be seen to identify a cranial mass ?

Cranial mass - mass in the cranial abdomen - caudal displacement of the stomach - if the mass is in the stomach or caudal to the stomach then the stomach will not be caudally displaced, but the small intestine will be caudally displaced.

Describe the differentials of a identified cranial mass on radiograph ?

Cranial abdominal mass Ddx - liver (most common) - dilated stomach - stomach wall mass, gall bladder, pancreas but these are extremely rare

Identify the location of this mass ?

Liver mass in the right side of the liver (VD view only) - cranial mass - displacement of stomach caudally and to the left Note; A definitive diagnosis may require further imaging US, CT or lapratomy

Identify the location and pathology ?

Dilated stomach - mass effect - can see caudal displacement of the intestine - caudal caudal caudal to locate liver margin - stomach is not displaced - intestine displaced to the left and caudally

What are the radiographic signs of mid abdominal mass ?

Mid abdominal mass Mass observed mid abdomen - small intestine displaced cranially, caudally and dorsally - observation of a mass in mid abdomen - loss of serosal detail may occur due to haemoabdomen can be present due to a bleeding splenic mass.

What are the four locations within the abdomen we can view a mass ?

What are the differentials for a mid abdominal mass ?

Mid abdominal mass Ddx - spleen (most common by far - pedunculated hepatic mass - connected to liver by a stalk - uncommon intestine + usually present with GIT signs / anorexia/ vomiting / diarrhoea (caecal masses may not present with GIT signs) - mesenteric mass (usually very large mesenteric lymph nodes (central abdomen on all views).

Why can we not use displacement of the gastric axis to find to identify the location of a mass?

Identify the mass ?

Splenic mass - displacement of intestine caudally, cranally and dorsally - visualisation of mass - inability to visualise the spleen

You identify a splenic mass what your next step ?

Splenic mass Not all are haemagiosarcoma or a death sentence Do not euthanase without histopathology - 1/3 benign haematoma - 2/3 malignant usually haemangiosarcoma - many different types of masses can bleed - all large masses in any organ should be removed even if benign, especially cavitated masses FNA in solid mass lymphoma can be treated medically cavitated mass remove entire mass with out FNA due to high risk of bleeding

Identify this pathology ?

Mesenteric mass - central abdomen on all views - rarely get this large - usually due to a huge mesenteric lymph node

Identify this pathology ?

Retroperitoneal mass Left renal mass - opacity soft tissue - location mid right dorsal abdomen - displacement of colon ventrally - summation with left kidney

What are the radiographic signs of a retroperitoneal mass ?

Retroperitoneal mass Dorsal aspect of abdomen even when the mass becomes large - ventral displacement of colon - kidney and adrenal most common

Discuss the differentials for a retroperitoneal mass ?

Retroperitoneal mass - kidneys, neoplasia, hydronephrosis - adrenal glands, neoplasia - retroperitoneal fluid often causes a mass effect, ventrall displacing the colon and small intestine Retroperitoneal mass / key points - Dorsal abdominal mass (even if it is large) - colon displaced ventrally - kidney and adrenal most common

Discuss the differentials for a caudal abdominal mass ?

Caudal abdominal differentials Sub lumbar lymph nodes Colon Uterus / uterine stump Bladder Prostate The assessment of the caudal abdomen - always work dorsal to ventral - location of colon entering the pelvic inlet (should be half way between the spine and pubis. - small intestine displaced cranially

Describe how you should assess the caudal abdomen ?

Assessment of the caudal abdomen Main points - assess each organ from dorsal to ventral - assess the location of the colon at the pelvis inlet (should be half way between spine and pelvis) - assess for a caudal abdominal mass effect eg cranial displacement of intestine

Identify this pathology ?

Sublumbar LN enlargement - soft tissue opacity - ventral displacement of the colon (if large enough) - usually caused by neoplasia - metastasis or multicentric neoplasia (such as lymphoma)

What are the radiographic signs for a enlarged prostate, and what are the main differentials ?

Prostateomegaly Identification - colon displaced dorsally - cranial abdominal mass effect - intestine + bladder displaced cranually Differentials - benign prostatic hyperplasia, entire dogs only - prostatitis usually entire dogs - prostatic neoplasia = neutered dogs Ultrasound is the best imaging modality for the prostate can also guide FNA. (Ultrasound was made for the prostate).

Identify and disscuss this pathology ?

Prostatic neoplasia Radiographic support of neoplasia (usually neutered dog) - sublumbar lymph node enlargement - periosteal new bone (metastasis) on the vertebrae and sacrum - minerlisation in the prostate

You observe dorsal displacment of the colon in the caudal abdomen - what are your differentials ?

Differentials for Uteromegaly - pyometra - pregnancy (no minerlisation < 45 days) - bladder

Identify this pathology ?

Pyometra why - mass effect in caudal abdomen, intestines displaced cranially - colon is displaced dorsally and to the midline (as there is left and right uterine horns) - Uterus coilded soft tubular structures in the caudal abdomen (usually approximately 2x the diameter of the small intestine). Best imaging modality Ultrasound - more easily identified - large fluid filled tubular structures - can also be used to rule out pregnancy as early as day ten (Do not FNA from inside the uterus to confirm pus, there is a high risk of rupture).

What is the best imaging modality to detect pyometra or prostatic neoplasia ?

Ultrasound

What is the best imaging modality to detect pregnancy and provide a foetal number estimation ?

Pregnancy diagnosis - Ultrasonud best - as early as day 10 cat / dog (usually reccomned 30 days post mating) - radiographs must wait 45 days for the foetus to become minerlised Foetal estimation best to use a radiograph > 50 days most accurate, but must ensure the foetuses are well minerlised - take two views - count by heads and spines

When assessing the bladder what are the best imaging modalities ?

The best imaging modality to assess the bladder 1. Ultrasound is the best - inexpensive and easy - detects bladder pathology except rupture Plain radiographs - most pathology is not detected on radiograph - calculi only Contrast studies Cystograms - almost entirely replaced by ultrasound - bladder rupture positive contrast cystogram to determine the size of the rupture - more invasive, more risk - if you have no access to an ultrasound you will have to use contrast studies

What is the best imaging modality to detect cystitis, neoplasia, calculi and rupture in the bladder ?

Best imaging modality Cystitis = ultrasound + cystocentesis Neoplasia = ultrasound + catheter biopsy Calculi = radiogrphy or ultrasound Rupture = positive contrast cystogram for location + ultrasound guided collection of fluid in abdomen for analysis to determine if it is urine.

Demonstrate an understanding of the pathology of cystitis in dogs and cats ?

Cystitis Dog - bacterial - most common in bitches Cat - idiopathic cystitis (sterile), bacterial cystitis is uncommon - both females and male cats - male cats may obstruct, a common presentation in practice

Describe the best imaging modality and what you would observe when looking for cystitis ?

Cystitis = ultrasound ( also US guided cystocentesis) - often the bladder appears normal - thickened bladder wall - cranioventrally (where the urine sits) - sediment sludge in the urine, sometimes seen Radiographs are useless bladder appears normal

Describe how you would identify neoplasia in the bladder ?

Neoplasia bladder - imaging findings Ultrasound required - irregular thickened wall - most urothelial cell neoplasms are located in the trigone region (must always ultrasound to assess if the mass has obstructed the ureters). Must confirm diagnosis - ultrasound guided catheter biopsy / safest and most diagnostic - no FNA (could seed the neoplasm) + often a low yeild of cells

You observe a loss of serosal detail in the peritoneum, how could you locate and confirm a bladder rupture ?

Bladder rupture Best AFAST - free abdominal fluid Radiograph - loss of serosal detail Abdominocentesis - presence of urine observed through the creatine / potassium ratio compared to blood Positive contrast cystogram - is the imaging modality of choice to identify the location of rupture - bladder - urether - proximal ureter

Describe best imaging modality to identify calculi in the bladder ?

Bladder calculi / Calculi (Urolithiasis). ( best to also culture urine cystitis is common) Common in both dogs and cats, may be located in the kidneys, ureters, bladder or urether - often obstruct in the narrowest region of the urinary tract Ultrasound best - can detect all calculi Radiograph - mineral opacity (usually seen) + urate calculi are not seen on radiograph (soft tissue opaque and efface with urine) - aften associated with dalmation dogs or portosystemic shunt

Describe a double contrast cystogram ?

Double contrast cystogram Indications = calculi not detected on radiograph or ultrasound - both air and positive contrast agent (iohexol) is instilled into the bladder - contrast settles in dependant part of bladder - diplacement of calculi 'filling defect

You identify a calculis, but are unable to distinguish its location between the colon and bladder - what to do ?

Compression study To seperate the colon and small intestine - prevents superimposing the colon on the bladder - bone was found to be located in the colon not the bladder - apply gentle pressure with a wooden

Describe the normal anatomy of the urethra ?

Normal anatomy of urethra - dog Divided into three parts - prostatic - membranous - penile Cats have a longer neck to the urethra before entering the pelvis, so it is easier to visualise on ultrasound.

What is the best imaging modality for assessment of the urethra ?

Urethra imaging Positive contrast urethrogram - best imaging modality The best imaging modality to assess the entire urethra - rupture - commonly performed in male dogs / rarely cats or bitches Plain radiograph - well visualised urethral calculion well positioned radiograph - cats (iodiopathic cystitis is rarely seen on radiographs) - good screening tool for calculi - best to include the perineum and do a bum view (legs pulled cranially) Ultrasound - proximal and intra-abdominal urethra is visable cranial to the pelvis - the portion within the pelvis is invisable as it becomes shadowed by the bony pelvis

Identify this pathology and radiographic view ?

Urethral obstruction calculi (urolithiasis) Normal lateral view - usually observable if the majority of the perineum is included. Bum view - legs pulled cranially so that they do not superimpose on the urethra

Describe the indications and procedure for a urethrogram ?

Normal urethrogram Procedure positive contrast is injected into a Foley catheter that is inserted inside the urethra - completely fill catheter prevent air bubbles - normal for prostatic urether to be narrower narrower and membranous wider Indications filling defect some type of obstruction - calculi, neoplasia, stricture - extravasation to look for rupture of the urethra

What is the best imaging modality to identify a bladder calculi, urethral calculi, urethral rupture, bladder neoplasia, bladder rupture and prostatic disease ?

The best imaging modality Bladder calculi = ultrasound Urethral calculi = positive contrast Urethral rupture = positive contrast neoplasia of the bladder = ultrasound bladder rupture = positive contrast cystogram prostatic disease = ultrasound

What is the standard size for the kidney in cats and dogs on ultrasound ?

Kidney size ultrasound Cat = 3-4.3 Dog = To much variation between breeds to set a standard size

You have identified a liver mass, what is your next step ?

Liver mass - your imaging plan Plan 1. Ultrasound - to determine if there is one mass so it can be determined if surgical resection is possible. 2. FNA (guided by ultrasound) - this can be used to rule out lymphoma 3. Ct may be referred to determine if mass is surgically resectable a specialist surgery. Even then somtimes if the mass is surgerically resectable may only be determined at surgery.

Describe the common pathologies which affect the urethra in cats and dogs ?

Urethral pathology (Commonly investigated in the cat and dog) Obstruction - usually male dogs and cats - male cats = idiopathic cystitis sludge material which may result in obstruction - dogs and cats / calculi - rupture of the urethra can occur due to trauma Obstruction in female cats and dogs is uncommon.

Describe the normal anatomy of the pancreas ?

Pancreas Left limb (red arrows) - the left limb of the pancreas runs along the caudal aspect of the stomach - this location is difficult to assess by radiograph Right limb (Green arrows) - the right limb runs along the descending duodenum (which is along the lateral aspect of the right side of the abdomen) - this limb of the pancreas can easily be visualised on ultrasound.

Describe what you would observe and your imaging modality of choice in the case of pancreatitis ?

Pancreatitis (the imaging modality of choice is ultrasound) -severe inflammation of the fat within the region of the pancreas (steatitis) - appears as a large hyperechoic (white) area - the pancreas itself can not usually be visualised / or may be seen as a dark area in the middle of the steatitis.

Write a differential list of pathologies which cause vomiting and can be identified through imaging ?

Differential list vomiting that can be investigated by imaging 1. Pancreatitis 2. Hypoadrenocortism (Addison's disease) specialist US 3. GIT disease - functional gastroenteritis / non surgical treatment 4. Mechanical (usually surgical treatment) - gastric foreign body - pyloric outflow obstruction - gastric dilation and volvulus - small intestinal obstruction - linear foreign body - intussusception

Describe the best imaging modalities for the identification of pathology in the GIT ?

Imaging modalities of the gastrointestinal tract. Plain radiographs - most common reason for taking abdomen rads in practice, vomiting - best for assessment of the stomach content Contrast - Upper gastronintestinal barium study - best for the assessment of obstruction in the stomach and small intestine - to identify gastric FB / filling defect Ultrasound - best modality for assessment of the small intestine but only with a skilled clinician - otherwise rads are considered better Endoscopy not considered an imaging modality - can only visualise stomach, proximal Sml I and colon.

Describe the normal opacity observed through out the length of the GIT on radiograph ?

Normal content of the GIT Stomach - is really a radiograph of the food bowl - ingesta, heterogenous gas, soft tissue opacity and gas Small intestine Fluid and gas - potential for ingesta if overflow occurs from the stomach just after eating Colon - faeces and gas

Describe the normal size of the stomach in a healthy animal ?

Stomach size in health (taking 3 views is crucial when studying the abdomen / moves gas around) The stomach size is highly variable depending on when the patient last ate - it is essential to know when your patient last ate - dog stomach will mostly be empty after 24 hrs of not feeding - cat stomach will usually be empty after 8 hours of not feeding. **Rough rule of thumb** Fasting dog - the fundus should < 3 intercostal spaces Fasting cat - the stomach should be empty

Compare the rate at which fluid vrs solid moves through the ingestive tract of a dog ?

Comparing the rate at which fluid vrs solid moves through the digestive tract. (Always fast a patient for a minimum of 12 hours) Fluid eg barium 2 hours Ingesta can remain in the stomach for 3 days, and it remains in the GIT longer in hospital then when the animal is at home.

What is the best imaging modality for assessing the thickness of intestinal wall ?

Ultrasound

When undertaking a radiographic study of the abdomen - what are the two essential requirements ?

The essentials of abdominal radiography 1. Ensure patient is fasted a minimum of 12 hours 2. We need to know the time the patient last ate anything - this is a must know prior to interpreting any radiographs.

How can we distinguish a foreign body and normal ingesta on radiograph ?

Abdominal radiograph Ingesta in the stomach and small intestine can not be distinguished from foreign material on radiographs. - follow up rads after 6-12 hours more fasting - crucial to differentiate foreign material - emptyng can take upto three days in a hospitalised dog - usually shorter in cats - is the ingesta moving through the GIT Yet follow up rads are always helpful.

1. Identify this pathology ? 2. How should this pathology be confirmed through imaging ?

Gastric foreign body, without obstruction - gastric foreign bodies may result in vomiting from their mere presence, they do not nessarily need to cause pyloric outflow obstruction. - may also present clinically silent - may easily be obscured by ingesta It may be best to repeat radiographs 12 hours of fasting later

Identify this pathology ?

Pyloric outflow obstruction / Left lateral view

Identify this pathology and all possible differentials ? What further imaging is required to make a diagnosis ?

Fluid dilation of the stomach Differential High outflow obstruction - either in the pylorus or duodenum Functional ileaus - gastroenteritis + diarrhea or pancreatitis Further imaging - ultrasound (with very good skills) or a contrast / barium study is ofen required to differentiate a functional ileus vrs high obstruction.

What would indicate a foreign body on ultrasound ?

Foreign bodies on ultrasound Observation of a clean acoustic shadow.

Identify this pathology ?

Gastric dilation and volvulus right lateral is theonly view required / rare double bubble Smurfs hat

Describe the rules for assessment of the small intestine on radiograph ?

A healthy small intestine on radiograph should; - only contain fluid and gas (overflow of stomach may cause ingesta to flow into the small intestine). - create smooth, sweeping continuously curving tubes - solid circles or rings in transverse - all segments should have the same circumference as other segments (pathology if segment >1.5x the size of another segment. Normal size - dog<1.6 centre of L5 - cat <2 endplate of L5

1. Describe why we can not assess the width of the wall in the small intestine on radiograph ? 2. How should we assess the width of the sml intestinal wall ?

Assessment of the width of the small intestinal wall 1. Radiogrphs it can not be done - normal fluid may efface with the intestinal wall making the width of the wall appear larger in some segments. 2. Width of small intestinal wall must be assessed on radiograph.

What four layers constitute the small intestine ?

Ultrasound The layers of the small intestine Serosa submucosa muscularis lumen

Is this imaged small intestine normal ?

Healthy small intestine (The rules) 1. size dog < 1.6 centre of L% cat <2 enplate of L5 2. Segments should be roughly equal in size, >1.5x another segment indicates pathology 3. Segments should create smooth sweeping continuously curving tubes.

Describe the rules for the assessment of the duodenum on radiograph ?

Duodenum The duodenum is always superimposed on the ascending colon in all views, so remember this when interpreting both structures - best seen left lateral - often slightly larger than other segments of small intestine on radiograph / requires follow up rads 6-12 hrs of fasting later Carry out an ultrasound / contrast study if concerned about an obstruction.

When assessing the small intestine of the cat different to the dog ?

Cat small intestine compared to the dog Cat - can not visualise the tail of the spleen - a small proximal piece of the duodenum (seperate from the ascending colon) can be visualised on radiograph - the caecum can only be visulised in the dog

Identify this structure ?

The caecum The caecum can only be visualised in the dog - located at approximately the level of L3 on both views - care must be taken not to mistake the caecum with a dilated section of small intestine - usually filled with gas but may have similar content to the colon eg gas, fluid. In the cat the caecum is empty and not seen on radiographs.

Provide a differential list for small intestinal dilation ?

Pathology Small intestinal dilation (dog; <1.6x centre L%, cat<2 endplate L5) Differential list of intestinal dilation **Obstruction (mechanical ileus)** - 2 population of small intestine, proximal to the FB becomes dilated - rarely neoplasia, stricture or intussception **Gastronenteritis (Functional ileus)** - the small intestine is dilated but similar in size - a partial obstruction may not dilate the intestine proximally and appear the same as gastroenteritis Too confirm a diagnosis follow up with ultrasound (excellent skills) or a barium contrast study where needed.

Identify this pathology on radiographs ?

Small intrstinal obstruction (Two populations of small intestine).

After identifying an obstruction; The main question becomes is the dilated bowel in the small intestine or colon ?

Obstruction small intestine or colon Colon (Best place to find is the pelvic inlet) - on the lateral view divides the abdomen in half - the ascending colon, transverse colon and proximal part of the descending colon are superimposed. (VD also needed to assess) - VD = colon appears as a question mark Tips to identify the colon - only part which contains faeces - consistent width - easily located by searching from the pelvic inlet - orientation of the colon - the observation of too many dilated segments for it to be only the colon.

If you are unable to distinguish a obstruction from the small intestine and colon - what should you do ?

Pneumocolonogram; best tip ever gas is instilled into the rectum this identifies the colon, so the rest must be small intestine

What technique can be utilised to assist the veternarian in visualising the FB on radiographs ?

Know the opacity If you can obtain part of the ingested Foreign body - submerge in a glass of water - this way you can view the opacity of the FB before trying to locate it on radiograph

IF an obstruction is unclear in our survey radiographs, what should be our next move ?

Upper gastrointestinal contrast study (upper part means stomach and small intestine) A particular volume of barium is instilled into the stomach via a stomach tube - monitor transit time through GIT - asssits in looking for an obstruction - look for abnormal shape - linear foreign body

Identify this pathology and provide all relevant differentials ?

Gastroenteritis Identification - varying degrees of stomach dilation and small intestine - small intestinal segments are usually similar in size to other segments - dilation is usually resulting from fluid - often associated with diarrhea and vomiting (only 10% with concurrent diarrhea will have an obstruction) Differentials - dietary indiscretion - food intolerance - parvovirus - inflammatory bowel disease - the specific cause is often not investigated (transient) unless chronic or infectious.

Identify this pathology on ultrasound ?

Ultrasound gastroenteritis - dilation hypoechic / anechic fluid stomach + small intestine - mild dilation of small intestine - fluid observed in the colon - follow any of the dilated segments of small intestine to ensure they do not lead to a foreign body

How do you identify a linear foreign body on radiographs ?

Linear foeign body on radiographs - abnormal gas pattern rather than dilated bowel, as they usually do not cause a complete obstruction - truncated pattern / fragmented gas opacities which may be unusual in shape - this is the gas caught in the folds of the gathers

Identify and describe this pathology in cat ?

Linear foreign body in a cat (The most common cause of GIT disease in cats as they like to play with string). In cats - typically small truncated gas opacities - often so tight there is no gas and it appears bunched tightly / gathered. This is caused by long flexible string, hosiery - one end is fixed (cat tongue, dog pylorus) with the opposite end dangling into the intestine - perstalsis causes intestine to climb and bunch - intestine becomes pleated or plicated over the linear FB - can perforate especially in dogs

Identify this pathology in a dog ?

Linear foreign body in a dog Typically largish truncated gas opacities - in a dog death from linear foreign body is death due to the high risk of perforation / never delay surgery

Describe the steps you would take to make a definitive diagnoses of a linear foreign body ?

Linear foreign body A linear FB often can be diagnosed definitively on survey radiographs If this is not possible follow up with; **Contrast barium studies Ultrasound** - hyperechoic linear structure that shadows when images directly on it, with plication of the small intestine. Iohexol oftenbetter for cats (small volume it is expensive), transits quickly and less of a concern if it leaks into the abdomen.

Identify this pathology ?

Intussusception Telescoping of one piece of bowel into another - often no obstruction so can not be differentiated from gasroenteritis on radiographs - most common location ileocolic Definitive diagnosis achieved through - barium enema - pneumocolon - ultrasound - pictured is the meniscal sign - gas in the colon outling the ilieum (not viewed If I occurs in the small intestine).

Identify this pathology ?

Intussception pictured on radiograph. Transverse is easier to recognise

Identify and describe this pathology ?

Constipation It is difficult to tell if a patient is constipated - ask the owner when the animal last passed faeces - look for underlying cause eg prostatomegaly, renal failure or dehydration Constipation faeces - cracks dry - more hyperechoic

Describe the steps you would take to investigate vomiting on rads in a cat or dog ?

Rad abdomen Flashcards

Diagnostic imaging