Neuroimaging: carotid-cavernous fistula: practice question

A Radiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Radiology · Neuroimaging: carotid-cavernous fistula

Sample item

Two weeks after a head injury, a man has pulsatile proptosis, conjunctival chemosis and an ocular bruit. Which imaging finding is expected?

ADilated superior ophthalmic vein with an enlarged cavernous sinusBEnhancing optic nerve sheath thickeningCSubperiosteal orbital abscessDEnlarged extraocular muscle bellies sparing the tendons

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Dilated superior ophthalmic vein with an enlarged cavernous sinus

A direct carotid-cavernous fistula arterialises the cavernous sinus and its draining veins, so the superior ophthalmic vein dilates and the eye pulses. Catheter angiography confirms it, and endovascular closure is the treatment.

Option by option

A. Dilated superior ophthalmic vein with an enlarged cavernous sinus (correct)
Correct. Arterialised venous drainage dilates the superior ophthalmic vein and cavernous sinus.
B. Enhancing optic nerve sheath thickening
Optic nerve sheath thickening suggests a sheath meningioma, which causes painless visual loss.
C. Subperiosteal orbital abscess
A subperiosteal abscess follows sinusitis with fever and a proptosed, painful eye.
D. Enlarged extraocular muscle bellies sparing the tendons
Muscle belly enlargement with tendon sparing is thyroid eye disease, without a bruit.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is A, Dilated superior ophthalmic vein with an enlarged cavernous sinus. A direct carotid-cavernous fistula arterialises the cavernous sinus and its draining veins, so the superior ophthalmic vein dilates and the eye pulses.

Why is "Enhancing optic nerve sheath thickening" not the answer?

Optic nerve sheath thickening suggests a sheath meningioma, which causes painless visual loss.

Why is "Subperiosteal orbital abscess" not the answer?

A subperiosteal abscess follows sinusitis with fever and a proptosed, painful eye.

Why is "Enlarged extraocular muscle bellies sparing the tendons" not the answer?

Muscle belly enlargement with tendon sparing is thyroid eye disease, without a bruit.

What concept does this question test?

It tests Neuroimaging: carotid-cavernous fistula in Radiology. Catheter angiography confirms it, and endovascular closure is the treatment.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neuroimaging: carotid-cavernous fistula?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.