Increased Methylene Diphosphonate Uptake in the Rectus Abdominis After Strenuous Exercise

Area of Science:

• Nuclear medicine
• Oncology
• Musculoskeletal imaging

Background:

• Papillary thyroid cancer staging requires assessment for osseous metastasis.
• Bone scintigraphy is a common imaging modality for detecting bone metastases.

Observation:

• A 28-year-old male patient with papillary thyroid cancer underwent bone scintigraphy.
• The patient reported vigorous exercise involving multiple muscle groups 5 days prior to the scan.
• Imaging revealed increased radiotracer uptake in the rectus abdominis muscle.

Findings:

• No evidence of osseous metastasis was identified on bone scintigraphy.
• Increased activity was localized to the rectus abdominis, with no significant uptake in other exercised muscles.
• This finding suggests exercise-induced muscle activity can cause focal radiotracer uptake.

Implications:

• Exercise-induced muscle uptake can mimic bone metastasis on bone scintigraphy.
• Careful patient history regarding recent physical activity is crucial for accurate interpretation of bone scans.
• This case highlights the importance of considering physiological changes in diagnostic imaging interpretation.