Which imaging modality can reveal the wink sign in cervical spine involvement of rheumatoid arthritis?

• A. MRI
• B. X-ray
• C. CT scan
• D. Ultrasound

Answer: (C)

The key idea is that this sign reflects a bony misalignment at the craniovertebral junction caused by rheumatoid arthritis. Detecting subtle erosions and precise alignment of the atlas and axis requires excellent bone detail, which CT provides. With CT you can get axial images and high-quality sagittal reconstructions that clearly show the relationship between the odontoid (dens) and the anterior arch of C1, quantify any atlantodental interval, and reveal vertical or subluxation patterns that might be missed on standard X-rays. MRI is excellent for soft-tissue changes like pannus and ligament inflammation, but it doesn’t visualize bone as crisply as CT. X-ray is useful for quick screening but is limited by two-dimensional projection and may miss subtle subluxations. Ultrasound isn’t used for assessing the craniovertebral junction. Therefore, CT is the modality that best reveals the wink sign in this setting.