Bone scan in metabolic bone diseases. Review

Abstract

Metabolic bone disease encompasses a number of disorders
that tend to present a generalized involvement of the whole
skeleton. The disorders are mostly related to increased bone
turnover and increased uptake of radiolabelled diphosphonate.
Skeletal uptake of 99mTc-labelled diphosphonate depends primarily
upon osteoblastic activity, and to a lesser extent, skeletal
vascularity. A bone scan image therefore presents a functional
display of total skeletal metabolism and has valuable role to
play in the assessment of patients with metabolic bone disorders.
However, the bone scan appearances in metabolic bone
disease are often non-specific, and their recognition depends
on increased tracer uptake throughout the whole skeleton. It
is the presence of local lesions, as in metastatic disease, that
makes a bone scan appearance obviously abnormal. In the
early stages, there will be difficulty in evaluating the bone scans
from many patients with metabolic bone disease. However, in
the more severe cases scan appearances can be quite striking
and virtually diagnostic.