Metabolic Bone Diseases and Drug-Induced Osteoporosis

Abstract

Bone scintigraphy has traditionally been considered to be not as useful as radiography in the study of metabolic bone diseases including senile or postmenopausal osteoporosis, osteodystrophy, drug-induced osteoporosis, and rickets and osteomalacia. However, aided by the pinhole technique, 99mTc-MDP bone scintigraphy has been shown to be able to portray characteristic features in systemic and local osteoporosis or osteopenia, which is defined as a state of reduced bone mass with increased cavity. Rickets and osteomalacia, a state of deficient formation of inadequately mineralized osteoid, can also be efficiently diagnosed by bone scintigraphy. Indeed, it is well known that bone scintigraphy is highly sensitive and reliable for detecting fractures and infractions in porosis and Looser’s zone (pseudofracture, osteoid seam) in osteomalacia, which often defy radiographic diagnosis when pathological changes are extensive. In addition and importantly, refined whole-body scintigraphy can uniquely demonstrate systemic involvement pattern of porosis and malacia. For example, whole-body scintigraphy shows generally decreased bone uptake in postmenopausal and senile osteoporosis (Fig. 15.1), increased tracer uptake in osteodystrophy of primary hyperparathyroidism with visualized kidneys (Fig. 15.2), increased tracer uptake in renal osteodystrophy without visualized kidneys (Fig. 15.3), and decreased tracer uptake in hepatic osteodystrophy (Fig. 15.4). Such valuable information can easily be extracted from a pair of anterior and posterior views, which are routinely obtainable at no additional expense.