Selected topics in orthopedic nuclear medicine

The application of a scintigraphic grading system to equine tibial stress fractures: 42 cases

REASONS FOR PERFORMING STUDY

Tibial stress fractures are an important cause of lameness in the Thoroughbred racehorse. While it is recognised that these injuries can vary in clinical presentation and radiographic or scintigraphic appearance, little has been done to quantify lesion severity. By contrast the scintigraphic grading of tibial stress fractures in human athletes is widely reported and assists in the selection of appropriate management regimes.

OBJECTIVES

To determine the relationship between scintigraphic grade, clinical severity and radiographic appearance of tibial stress fractures.

METHODS

The current study involved the retrospective analysis of records from 42 Thoroughbreds with abnormal tibial scintigraphic activity.

RESULTS

There was a significant association between lesion site and scintigraphic grade and good correlation of scintigraphic scoring between investigators. No significant association was found between scintigraphic grade and either radiographic grade or degree of lameness.

CONCLUSIONS

The study confirmed that radiographic appearance is an unreliable measure of clinical severity or stage of progression of lesions. The scintigraphic grading system used in the study was not of use in defining stress fracture severity in the equine tibia.

POTENTIAL RELEVANCE

Despite this finding, there is clearly a need for prospective investigations to explore the potential for targeted management regimes for tibial injuries based on lesion site or clinical criteria.

The use of nuclear medicine techniques in the emergency department

Nuclear medicine techniques have received little attention in the practice of emergency medicine, yet radionuclide imaging can provide valuable and unique information in the management of acutely ill patients. In this review, emphasis is placed on the role of these techniques in patients with bone injuries, non-traumatic bone pain and in those with pleuritic chest pain. New developments such as single photon emission computed tomography (SPECT) in myocardial infarction are outlined and older techniques such as scrotal scintigraphy are reviewed. Radionuclide techniques are discussed in a clinical context and in relation to alternative imaging modalities or strategies that may be available to the emergency medicine physician. Aspects of a 24 hour nuclear medicine service are considered.

When to use bone scintigraphy. It can reveal things other studies cannot

Despite advances in nuclear medicine, bone scintigraphy remains an important imaging technique. It is sensitive in detecting stress fractures and bone metastases and can assess suspected injury that is difficult to see on plain films (e.g., rib fracture). Scintigraphy is useful in evaluating new symptoms, response to therapy, and prognosis in patients with known malignant tumor. In patients with low back pain, the technique can determine the age of fractures to help identify osteoporosis and can uncover other causes of the pain (e.g., spondylolysis, arthritis). When Paget's disease is suggested by unexplained bone pain or an elevated serum alkaline phosphatase level, bone scintigraphy is a useful screening test. Combined with other appropriate nuclear medicine studies, it helps in early identification and localization of osteomyelitis. Scintigraphic scans can provide a general indicator of malignant versus benign disease (according to the amount of lesion activity seen) and may produce characteristic findings in certain primary tumors (e.g., osteoid osteoma) that are difficult to evaluate with other methods.