Metabolic Bone Disease

Abstract

Metabolic bone disease (MBD) includes a wide range of clinically distinct diseases that cause changes in bone structure, mineralization, and/or mass. MBD can be inherited or acquired. Skeletal dysplasia is a heterogeneous group of genetic disorders caused by defective genes during the bone formation process. These disorders overlap with MBD. In MBD, most pathological processes accelerate osteoblast and osteoclast activity, resulting in increased bone turnover. Although MBD is common, clinical diagnosis based on radiological findings may be challenging. ^99mTc-labeled diphosphonate binding to hydroxyapatite crystals depends on the degree of local bone formation regulated by osteoblastic activity. Bone scan has the advantage of high sensitivity with the capacity to easily image the whole body. Bone scan can provide a functional map of bone turnover, displaying pathology that is global, focal, or multifocal. Understanding the diverse manifestations of MBD using nuclear medicine imaging studies assists in early and specific diagnosis.

In this chapter, we will review the application of nuclear medicine imaging studies in various MBDs that exhibit abnormal bone loss or osteosclerosis. Osteoporosis, the most common MBD, will be dealt with in a separate chapter.