Transcript General Abdominal Radiography - North Carolina State University

General Abdominal
Radiography
Tony Pease, DVM, MS
Assistant Professor of Radiology
North Carolina State University
Objectives
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Acquisition of radiographs
Abdominal radiographic anatomy
Radiographic patterns of abdominal disease
Determine normal compared to abnormal
How ultrasound is helpful
Reading
• Chapters 38-40
– Pages 483-539
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 kVp)
– Moderate image contrast
– Some of shades of grey
– More than bone less than thorax
• Moderate mAs (8-12 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
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Liver
Spleen
Left Kidney
Right Kidney
Stomach and duodenum
Left lateral
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Esophagus
Pylorus
Duodenum
Liver
Spleen
Left kidney
Right kidney
Urinary bladder
Right lateral
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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
Now time for the radiographs!
• Positioning – done
• Exposure – done
• Interpretation!
– Takes radiologists years to become experts
– You have 9 hours!
Quick word on abdominal masses
• Hard to tell what organ is involved
• Best guess based on location
– What organs are displaced
• May need ultrasound to be more specific
Some incidental 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
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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
• Ultrasound superior for peritoneal fluid
• Emaciation versus fluid
– Similar appearance
– Lack of fat to provide contrast
– Difference is overall size of abdomen
Peritoneal fluid
• Radiographs very insensitive for detecting
• Cannot tell fluid type
– Radiographs or ultrasound!
• Multiple causes
– Increased hydrostatic pressure
– Decreased plasma colloid oncotic pressure
– Capillary permeability
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
Pneumoretroperitoneum
• 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, calves and pigs
• Can image abdomen
– Usually standing
– See fluid layers
• Can do barium enemas
– Strictures or atresia ani
Barium enema
Ileus
Traumatic reticuloperitonitis
Traumatic reticuloperitonitis
All about the belly in 1 hour!
• Radiographs helpful even if large animal
• Hard to tell where mass comes from
• Radiographs are a good overview
Questions?