In imaging, which modality is more appropriate when evaluating articular surfaces?

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

Answer: (C)

When you need to assess the exact contour and congruity of a joint surface, you want the modality that shows bone with the highest spatial precision. CT provides thin-slice imaging, exceptional bone detail, and the ability to reconstruct in multiple planes and in 3D. This makes it possible to detect tiny step-offs, depressions, and gaps along articular surfaces that might be hidden on other studies. While MRI excels at cartilage and soft tissue evaluation, and ultrasound is limited for deep, complex joints, plain X-rays can miss subtle intra-articular irregularities due to two-dimensional overlap. Therefore, CT is the most reliable choice for detailed evaluation of articular surfaces.