General Abdominal Radiography

Tony Pease, DVM, MSAssistant Professor of Radiology

North Carolina State University

Objectives

• Acquisition of radiographs

• Abdominal radiographic anatomy

• Radiographic patterns of abdominal disease

• Determine normal compared to abnormal

• Determine further evaluations needed

Reading

• Chapter 38– Pages 483-493

Abdominal Radiography

• Generally being replaced with ultrasound– Ultrasound does not give a global picture

• Radiographs are a snapshot of disease– 1/120th of a second picture

• Ultrasound is real time

Abdominal Anatomy

• A lot of organs in a small space

• Rely on location

Acquiring radiographs

• Relatively high kVp (70)– Moderate image contrast– Some of shades of grey– More than bone less than thorax

• Moderate mAs– Minimizes motion artifact– Maximizes contrast

• Enemas and fasting are helpful

Positioning

• Include caudal thorax

• Try to include greater trochanter of femur

• Center beam just caudal to the last rib

Large patients

• May need two films per view– Four films per study

– Make sure to overlap images

Ventrodorsal

• Liver

• Spleen

• Left Kidney

• Right Kidney

• Stomach and duodenum

Left lateral

• Esophagus• Pylorus• Duodenum• Liver• Spleen• Left kidney• Right kidney• Urinary bladder

Right lateral

• Fundus• Liver• Spleen• Left kidney• Right kidney• Urinary

bladder

Normal cat abdomen

Deep circumflex iliac artery

Sometimes confused for medial iliac lymph nodes or ureteral calculi

Positional radiographs

• Remember gas rises

• Can manipulate the animal

Can you see the gas?

Lateral horizontal beam

Horizontal beam

• Place the animal in left lateral– Puts the fundus of the stomach down

– Smaller pylorus is high

• Gas accumulates near the diaphragm

Some incidential findings

• Lucency on the ventral aspect of L3-4

• Cholesterol granulomas

• Spondylosis deformans

Lack of ventral aspect of L4

• It is where the diaphragm attaches

Cholesterol granuloma

• Generally in cats

Smooth bridging bone

Spaces of the abdomen

• Retroperitoneal– Dorsal to the colon

– Contains kidneys, adrenal glands, lymph nodes

– Continuous with mediastinum

• Peritoneal– Surrounds visceral organs

– Generally a potential space

Can compare spaces

Retroperitoneal space

Good detail

Peritoneal space

Poor detail

Loss of serosal detail

• Poor radiographic technique

• Fat content of a puppy or kitten

• Peritoneal fluid (many types)

• Carcinomatosis

• Lack of fat

• Peritonitis

Peritoneal fluid

• Soft tissue and fluid are similar opacity

• Therefore lose detail in the abdomen

• Ultrasound superior for peritoneal fluid

• Emaciation and fluid cause similar appearance, except for overall size of abdomen

Peritoneal fluid

• Multiple causes– Increased hydrostatic pressure– Decreased plasma colloid oncotic pressure– Capillary permeability

• Radiographs very insensitive for detecting• Cannot tell fluid type from radiographs

Mild

Severe Severe

Lack of fat cause loss of detail

Is there peritoneal fluid?

Retroperitoneal space

• Only thing that is dorsal to the colon

Don’t forget that other view

Abdominal lymph nodes

• Many lymph nodes in abdomen

• Generally not seen radiographically– Even if large

• Medial iliac lymph nodes are the exception

• Ultrasound more useful for lymph nodes

Medial iliac lymph nodes

Don’t forget about goats

• Can help diagnose caseous lymphadenitis

Pneumoretropertioneum

• Retroperitoneum communicates with the mediastinum

• Therefore usually associated with:– Subcutaneous emphysema

– Pneumomediastinum

Need large volume of gas

• Ruptured trachea

• Ruptured esophagus– Need aerophagia

Pneumoretroperitoneum

• Not generally clinically important

• Just a sign of another disease

Even in the cow!

Pneumoperitoneum

• Can persist 10-14 days after surgery

• Rupture of a hollow viscus– Gastrointestinal perforation

– Surgical emergency!!

• External puncture wound

Several places to look

What about large animal?

Foals and calves

• Can image abdomen– Usually standing

– See fluid layers

• Can do barium enemas– Strictures or atresia ani

Ileus

Traumatic reticuloperitonitis

Traumatic reticuloperitonitis

All about the belly in 1 hour!

• Good general overview

• Over the next 3 weeks will be focused

• Radiographs are a good overview

• Helpful even if large animal

Questions?