For occult hip fracture suspicion with negative X-ray, which imaging modality has the best sensitivity?

• A. Nuclear bone scan
• B. Ultrasound
• C. CT
• D. MRI

Answer: (D)

In suspected occult hip fracture with a negative X-ray, the imaging study with the highest sensitivity is MRI because it can detect bone marrow edema and tiny fracture lines that may not break the cortex yet. This makes MRI capable of identifying acute fractures earlier than other modalities. CT can visualize fracture fragments but may miss nondisplaced or subtle fractures in the very early phase. Bone scintigraphy is sensitive but often becomes positive only after several hours to days, delaying diagnosis. Ultrasound is not reliable for assessing bony hip injuries. So MRI provides the most reliable, early detection when radiographs are negative.