Bone Scan Dx

Synonyms: Bone scintigraphy, radionuclide scintigraphy

CPT Codes: Whole body bone scan 78306; limited area 78300; bone scintigraphy (with Xray correlation) 3570F

Description: Bone scanning is an imaging method used to detect metabolic, inflammatory, infectious or neoplastic skeletal abnormalities.

Method: Standard scintigraphy requires intravenous administration of technetium-99m diphosphate.  99mTc diphosphate is a bone-seeking radionuclide whose uptake is enhanced by blood flow and bone turnover/remodeling or proliferative bone formation. Patients are assessed immediately post-radionuclide (measures blood flow) and 2 to 3 hours later (bone uptake).  The more active the bone turnover, the more uptake observed. The procedure takes 3 to 4 hours to complete, and patients need not fast or be NPO (nothing by mouth).

Normal Results: Normally there is a low level of homogeneous, symmetric tracer uptake in bone. Tracer normally concentrates in the bladder. Normal bone scan is seen in multiple myeloma.

Increased Uptake: The radionucleide is taken up by osteoblastic cells. Thus increased uptake is seen in Paget’s disease, reflex sympathetic dystrophy, osteomyelitis, septic arthritis, infected prosthetic joints, inflammatory arthritis, sacroiliitis, enthesitis, osteoarthritis, metastasis to bone, osteoid osteoma, and osteonecrosis show increased uptake. Although early (infarctive stage) osteonecrosis shows no uptake, later (reparative) stages may demonstrate increased uptake. Increased uptake is seen with inflammatory, degenerative, infectious, and neoplastic spinal disease. Occult fractures (including compression or stress fractures) may be found with delayed imaging (72 hours). Osteomyelitis is suggested by focal hyperperfusion, hyperemia and increased bone uptake.

Complications: Allergic reaction to radionuclide is uncommon.

Indications: Bone scans may be used in the diagnosis of the above noted conditions. It may provide useful information regarding the metabolic status of bone or for detecting infectious or neoplastic involvement of bone and periarticular structures. It may be indicated in total-body skeletal assessments of musculoskeletal disease. Scintigraphy may be useful in the serial evaluation of Paget disease or neoplastic disease or response to treatment in osteomyelitis. Infrequently, a bone scan may be used to assess patients with persistent polyarthralgia and repeatedly normal joint examinations or radiographs.

Other Nuclear Imaging Methods:  Other types of scintigraphy include:  1) Triple phase bone scan:  should be considered if osteomyelitis is suspected; 2) Indium-labeled WBC scans: WBCs are removed from the patient and tagged with the radioisotope Indium-111 and reinfused into the patient to identify areas of focal or localized infection; and 3) Gallium scan: is often used in the evaluation of undiagnosed fever as gallium is preferentially taken up by neutrophils and may be superior to indium labeled WBC in detecting osteomyelitis.

Cost: $400–800.

BIBLIOGRAPHY

Love C, Din AS, Tomas MB, et al. Radionuclide bone imaging: an illustrative review. Radiographics 2003;23:341–358.PMID:12640151