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Download General Abdominal Radiography - North Carolina State University
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General Abdominal Radiography Tony Pease, DVM, MS Assistant Professor of Radiology North Carolina State University Objectives • • • • • 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 • • • • • 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 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 • • • • • • 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?
