Background When reporting bone scans, it is important to distinguish between normal variants and skeletal pathology involving the sternum. There are only limited reports dealing with age-related normal variants of the sternum on bone scintigraphy.Methods We have studied the age-related variants of sternal uptake on bone scintigraphy. In a prospective study, 152 consecutive patients (66 males and 86 females) undergoing whole-body bone scanning, and who had no symptoms associated with the sternum, were evaluated for patterns of normal sternal uptake. Three hours after intravenous injection of Tc-99m-methylene diphosphonate (Tc-99m-MDP), whole-body bone scans in the anterior and posterior projections were acquired. Patterns of sternal uptake, including the sites and distribution of increased and decreased uptake, were analysed using age-related groups.Results Three patterns of tracer uptake in the sternum were recognized: a uniform pattern was most common in children ( <= 12 years); a heterogeneous uptake pattern was frequently seen in adolescents, young adult and adult groups; and a segmented pattern was commonly seen in the geriatric group (> 60 years). A predominant focal finding was a hot spot at the angle of Louis. In addition, there were focal spots of decreased tracer uptake in the lower sternum, just above the xiphoid process, and spots of increased tracer uptake in the body of the sternum. Such focal spots were not seen in subjects of less than 12 years of age.Conclusion Evolutionary changes of the sternum appear to exist throughout life. There are age-related normal variants of sternal uptake on bone scintigraphy. Nucl Med Commun 26:253-257 (c) 2005 Lippincott Williams & Wilkins.

NADDAF, SLEIMAN Y. M.D.; ALFEELI, MAHMOUD A. M.D.; DAVID COLLIER, BERT M.D. Author Information

Osteopetrosis is an inherited defect in bone resorption leading to cortical sclerosis, marrow space compression, and skeletal deformity. Biochemically and genetically heterogeneous, the disease has three clinical presentations: precocious onset osteopetrosis, osteopetrosis tarda (Albers-Scholenberg disease), and osteopetrosis with renal tubular acidosis. A 3-year-old boy diagnosed with osteopetrosis tarda at 18 months of age was examined for fever and left lower leg pain. Radiographs of the long bones showed only cortical sclerosis and metaphyseal deformity typical of osteopetrosis. To exclude osteomyelitis, three-phase bone scintigraphy was requested.

Antidiarrheal medications are a pitfall for physicians interpreting In-111 pentetreotide scans. In-Ill octreotide scanning is sensitive for detecting neuroendocrine tumors located within the abdomen. However, lack of familiarity with the normal patterns of activity, such as may occur in the large bowel, may lead to false-positive interpretations. For patients taking such medications, colon activity is often very prominent, and the intensity of uptake cannot be used to distinguish tumor from physiologic large-bowel activity. Usually, additional views are obtained 24 hours later or a repeated examination will show a shifting pattern of large-bowel activity. Unfortunately, when the patient is constipated or is taking antidiarrheal medications, intense large-bowel activity may persist for days. The authors describe a patient in whom prominent right colon activity on two sequential examinations was erroneously interpreted as tumor uptake. Only a third In-111 octreotide examination, obtained after antidiarrheal medications were discontinued, yielded the correct diagnosis.

MOHAMMED YOUSEF BAQER, MUNA M.D.; QURTOM, MOHAMMED A.F. M.D.; ABDULHADI ALI AL-AJMI, JAWAHER M.D.; COLLIER, B. DAVID M.D.; ELGAZZAR, ABDELHAMID H. M.D. Author Information

Heterotopic ossification (HO) is the presence of bone in soft tissue where bone normally does not exist. The acquired form of HO most frequently is seen with either musculoskeletal trauma, spinal cord injury, or central nervous system injury. For example, patients who have recently undergone total hip arthroplasty or have paraplegia after spinal cord injury are at risk for HO, The fever, swelling, erythema, and occasional joint tenderness seen in early HO can be difficult to distinguish from cellulitis, osteomyelitis, or thrombophlebitis. Bone scanning and other imaging tests frequently are used to distinguish between these diagnostic possibilities. As treatment or prophylaxis for HO, either a nonsteroidal anti inflammatory drug (such as indomethacin), a diphosphonate (such as ethane-1-hydroxy-1,1-diphosphate), or local radiation therapy is recommended. Before therapy begins, bone scanning may be requested to confirm the diagnosis of HO. In addition, surgical resection of HO is used to preserve joint mobility; however, HO is likely to recur and possibly progress if resection is undertaken before the lesion has become mature. With a view toward avoiding recurrent HO and other operative complications, serial quantitative bone scans are used as an aid to time surgical intervention.