Age-related normal variants of sternal uptake on bone scintigraphy

The purpose of this study was to describe the variable age-related normal appearance of the sternal area on bone scintigraphy.

We studied 334 patients (158 males and 176 females) aged 15 days to 85 years, mean age 32.5 +/- 19.9 years, who did not have symptoms associated with the sternum and chest wall or a history of malignancy. All patients underwent whole-body bone scan 3 hours after intravenous injection of Tc-99m MDP.

In patients younger than 10 years, sternal uptake was equal to nearby ribs with homogeneous uptake and poorly defined outlines. In older patients, the sternum showed markedly greater uptake than nearby ribs and the borders became well defined. Different patterns of sternal uptake were noted: 1) increased uptake in the manubrium; 2) hot spots in the angle of Louis, body and xiphoid; 3) a photopenic area just above the xiphoid process; 4) heterogeneous sternal body uptake; and 5) hyperactivity along the sternal body borders. Of these variants, the angle of Louis hot spot was the most common finding (63.5%). A linear pattern of hot spots in the sternal body was seen most frequently between 10 and 30 years old and corresponded to 3 transverse ridges of bone, representing the sites of union. Increased tracer uptake only at the medial end of the clavicle in the SC joints was seen in 42.13% of patients younger than 30 years.

This study showed age-related normal variants of sternal uptake on bone scanning in asymptomatic patients. Understanding these variants may be helpful in differentiating normal and abnormal patterns of uptake in the sternum on radionuclide bone imaging.