Which imaging modality helps map muscle involvement and guide biopsy in muscular dystrophy?

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

Answer: (A)

Muscle MRI is the imaging modality that best maps muscle involvement in muscular dystrophy and guides biopsy. It provides excellent soft-tissue contrast, revealing where muscles are progressively replaced by fat and where there may be edema or active disease. By imaging targeted regions or the whole body, clinicians can create a detailed map showing which muscles are affected and to what degree. That map is crucial for choosing a biopsy site—the aim is to sample tissue that is representative of the disease process, often from the most affected muscle or a region with clear involvement, to obtain a diagnostic and informative specimen. MRI sequences like T1-weighted images show fat replacement clearly, while other sequences highlight edema or inflammation, and this information can also help monitor disease progression over time without exposing the patient to radiation.

Ultrasound can assess some muscle changes and is useful in dynamic or initial evaluations, but it is more operator-dependent and less reliable for comprehensively mapping distribution or guiding biopsy with the same precision as MRI. X-ray mainly visualizes bone and calcifications, not muscle tissue. CT provides better soft-tissue detail than X-ray but involves radiation and does not offer the same sensitivity for early fat infiltration or detailed whole-muscle mapping as MRI.