Halvorsen used 4 findings seen on CT scans to distinguish ascites and a right pleural effusion. The authors are from the Veterans Administration Medical Center and Duke University in Durham, North Carolina.
Possible conditions:
(1) ascites
(2) right pleural effusion
(3) both
Signs seen on CT:
(1) diaphgram sign
(2) displaced crus sign (affecting the crus of the diaphragm)
(3) fluid/liver interface sign
(4) bare area sign
|
Sign |
Finding |
Interpretation |
|
diaphragm |
fluid visible inside |
ascites |
|
|
fluid not visible |
indeterminate |
|
|
fluid visible outside |
right pleural effusion |
|
displaced crus |
fluid does not elevate crus |
ascites |
|
|
fluid not at level of crus |
indeterminate |
|
|
fluid elevates crus |
right pleural effusion |
|
fluid/liver interface |
distinct interface |
ascites |
|
|
uncertain |
indeterminate |
|
|
indistinct interface |
right pleural effusion |
|
bare area |
posterolateral to the liver |
ascites |
|
|
uncertain |
indeterminate |
|
|
posteromedial to liver |
right pleural effusion |
where:
• Some of the signs may show a combination of findings if both are present.
Interpretation:
• Accurate diagnosis requires consideration of all 4 criteria.
• No single criteria alone was definite in all cases.
Potential pitfalls for interpretation:
(1) diaphragm sign in a patient with an inverted hemidiaphragm
(2) bare area sign in a CT section taken above or below the bare area
(3) fluid/liver interface at the dome of the liver (ascites may have an indistinct interface because of the oblique orientation of the dome)
Specialty: Gastroenterology
