MSK imaging: avascular necrosis: 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 · MSK imaging: avascular necrosis

Sample item

A patient on long-term steroids has hip pain with normal radiographs. Which investigation is most sensitive for early avascular necrosis of the femoral head?

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

The answer and the reasoning

B. MRI

MRI shows the double-line sign and marrow oedema before radiographic changes occur, and is nearly 100 percent sensitive. Plain films later show sclerosis, the crescent sign and flattening of the head. Bone scan is less sensitive.

Option by option

  • A. Repeat plain film at one week

    Plain films remain normal early.

  • B. MRI (correct)

    Correct. MRI is the most sensitive test for early AVN.

  • C. Ultrasound

    Ultrasound is not useful for the femoral head marrow.

  • D. Bone density scan

    A DEXA scan measures density, not necrosis.

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.

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Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is B, MRI. MRI shows the double-line sign and marrow oedema before radiographic changes occur, and is nearly 100 percent sensitive.

Why is "Repeat plain film at one week" not the answer?

Plain films remain normal early.

Why is "Ultrasound" not the answer?

Ultrasound is not useful for the femoral head marrow.

Why is "Bone density scan" not the answer?

A DEXA scan measures density, not necrosis.

What concept does this question test?

It tests MSK imaging: avascular necrosis in Radiology. Plain films later show sclerosis, the crescent sign and flattening of the head. Bone scan is less sensitive.

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 MSK imaging: avascular necrosis?

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.