Question:medium
The delta sign on imaging is seen in which of the following conditions?
The delta sign on imaging is seen in which of the following conditions?
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An empty triangle with rim enhancement on contrast CT points to a thrombosed venous sinus.
Updated On: Jun 24, 2026
- Petrositis
- Acute mastoiditis
- Sigmoid sinus thrombosis
- Glomus tumor
Show Solution
The Correct Option is C
Solution and Explanation
Step 1: When asked about the delta sign, think of a thrombosed dural venous sinus on contrast imaging.
Step 2: On axial post-contrast CT, the sinus appears as a triangle whose wall enhances while the centre stays dark because of the non-enhancing clot, giving the empty delta look.
Step 3: This is the hallmark of sigmoid (or superior sagittal) sinus thrombosis and can also be appreciated on contrast-enhanced MRI.
Step 4: The other choices, namely petrositis, acute mastoiditis and glomus tumor, have their own findings but do not show a delta sign.
\[\boxed{\text{Sigmoid sinus thrombosis}}\]
Step 2: On axial post-contrast CT, the sinus appears as a triangle whose wall enhances while the centre stays dark because of the non-enhancing clot, giving the empty delta look.
Step 3: This is the hallmark of sigmoid (or superior sagittal) sinus thrombosis and can also be appreciated on contrast-enhanced MRI.
Step 4: The other choices, namely petrositis, acute mastoiditis and glomus tumor, have their own findings but do not show a delta sign.
\[\boxed{\text{Sigmoid sinus thrombosis}}\]
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