Q-25. Bone scan in multiple myeloma shows-: (AIIMS 06)
a) Hot spot
b) Cold spot
c) Diffusely increased uptake
d) Diffusely decreased uptake
Answer: Cold spot
Explanation:
Bone scans are the most sensitive routine imaging modality to try and identify both sclerotic and lytic lesions.
In most cases they demonstrate increased uptake (hot spot) although occasionally (in very aggressive purely lytic lesions) a photopaenic defect (cold spot) may be visible.
Myeloma is a disease that results in over-activity of osteoclasts, with resultant liberation of bone and suppression of osteoblasts.
Important point:
Nuclear medicine bone scans rely on osteoblastic activity (bone formation) for diagnosis.
99mTc-MDP (Technetium-99m linked to Methylene dis-phosphonate) bone Scan has highest affinity for Osteogenic bone site.