• Decrease renal function
  • Renal failure
• Increased osteoblastic activity
  • Hematological disorders
    • Aplastic anemia
    • Leukemia
    • Myelofibrosis
    • Waldenström macroglobulinemia
  • Hyperparathyroidism
  • Metastatic disease
    • Prostate carcinoma
    • Breast Carcinoma
  • Diffuse Paget's disease

The two most common mechanisms of bilateral decreased renal uptake are either loss of renal function or increased osteoblastic activity . With end-stage renal disease the kidneys are small with faint uptake or are not visualized. In the case of increased osteoblastic activity, the renal uptake is diminished because there is increased accumulation of radiotracer in the skeleton, with diminished amount of radiotracer available for renal excretion. Superscans are bone scans with uniformly increased bone-to-soft-tissue ratio with resultant faint or absent renal visualization. These can be caused by extensive metastatic disease, usually from prostate or breast carcinoma, widespread Paget's disease, hyperparathyroidism, and a variety of hematological disorders, such as myelofibrosis, aplastic anemia, leukemia, orWaldenström macroglobulinemia. As the kidneys are the principal pathway of excretion of bone seeking radiopharmaceuticals, in the setting ofrenal failure the soft tissue uptake is increased because of decreased renal clearance, whereas in the case of a superscan there is decreased soft tissue activity due to relative increased uptake in the axial skeleton.