Abdominal Interpretation Paradigm & Serosal Margin Detail Flashcards
What is summation?
when objects if different planes are superimposed, causing a resultant additive opacity of both superimposed objects
Summation:
What is border effacement?
when 2 objects of the same opacity are in contact with one another, their borders cannot be distinguished
What are the common indications for abdominal radiographs?
- vomiting - obstruction, pancreatitis
- inappetence
- palpable abdominal mass
- monitoring response to therapy
What are the 4 compartments used when interpreting abdominal radiographs?
- peritoneal and retroperitoneal space - serosal margin detail
- GI tract + spleen, liver, pancreas, and stomach
- urogenital system, adrenal glands, medial iliac lymph nodes
- extra-abdominal structures - body wall, partial thorax, musculoskeletal
What is the minimal projections required for proper abdominal radiograph interpretation? What is best practice? Why?
R lateral and VD - orthogonal
R and L lateral + VD
- orthogonal views aid in triangulation and location of lesions
- three projections allow for movement of gas that can help identify or rule out lesions
What affects serosal margin detail? What patients do you expect to have excellent and poor detail?
patient body condition —> presence of fat where contrast in the abdomen is created by peritoneal and retroperitoneal fat surrounding the serosal margins of soft tissue organs
- EXCELLENT - obese patients
- POOR = thin, athletic, or cachexic patients lacking fat or immature animals with high levels of brown fat containing more fluid
Obese patient, serosal margin detail:
excellent detail
How does peritoneal fluid affect serosal margin detail?
causes border effacement or blurring of the soft tissue organ margins, typically with a streaky/mottled appearance
Peritoneal effusion:
How is the type of peritoneal effusion determined?
CANNOT be done on radiographs - blood, urine, pus, bile, water, and carcinomatosis look identical (poor serosal margin detail, organs seem like they’re floating in fluid)
must perform a thoracocentesis
Other than obesity, what can cause increased serosal margin detail?
presence of peritoneal gas - margins enhanced or unexpectantly visible, especially the peritoneal margin of the diaphragm where the liver usually border effaces
When is it common for peritoneal gas to be accompanied by fluid?
- ruptured GI tract
- recent surgery
In what 2 ways is positional radiography used to identify smaller volumes of free peritoneal gas?
use horizontal, cross table beams (rotate tube of X-ray machine)
- L LATERAL - avoids confusion with gas in fundus
- DORSAL RECUMBENCY - center on non-dependent point of abdomen in the cranioventral abdomen
(allow gas to percolate 5 mins before imaging)
What is the serosal margin detail like in this radiograph?
normal
- some abdominal fat, but not obese
- margins of spleen and small intestines in mid ventral abdomen are well-visualized
- normal crowding of cranial abdominal organs
What is the serosal margin detail like in this radiograph?
peritoneal fluid decreases detail
- heterogeneity of the fat in the ventral abdomen - wispy, ill-defined regions of soft tissue opacity within the fat
- margins of spleen and mid-abdomen small intestines are fuzzy and ill-defined
What is the serosal margin detail like in this radiograph?
free peritoneal gas increases detail
- greater contrast between gas surrounding serosal margins or organs and soft tissue of organ parenchyma
- gas and fluid = likely leakage of GIT
- regions of gas bubbles do not coincide with position of intestinal segments
- accumulation of gas around soft tissue organs
- visibility of the peritoneal surface of the diaphragm
What is the likely cause of mineral opacity seen within the abdomen that is not localised to the GIT?
dystrophic mineralization in areas of focal inflammation —> considered benign and not clincially significant
- suture material left from surgery - most common in caudal abdomen from orchidectomies or OVH
- modular fat necrosis (Bate’s bodies)
