Abstract
Longitudinally beads-shaped hot area visualized in serial three or more ribs in bone scintigram was investigated retrospectively to determine its characteristic appearance and mechanism in reference to clinical course, past history and so on. Of 1531 consecutive cases studied by bone scintigraphy, a total of fourteen cases, consisting of 7 male and 7 female (mean age of 65 years) and of 7 cancer, 2 multiple myeloma and 5 benign disease, had the beads-shaped hot areas (incidence of approximately 1%). Bone scintigraphy was performed with 99mTc-MDP and a rotatory gamma-camera equipped with a lowenergy high-resolution collimator. The hot areas were found in the 3rd to the 10th ribs at the anterolateral or other sites along the insertions of the thoracic muscles. In a typical case, 6 lines of the hot areas were noticed bilaterally and 8 ribs per line were involved. In all of the 6 cases followed up by reimagings during 3 months to 3 years, the hot areas became faint or invisible. All of the 7 cases capable of hearing the past history have had a thoracic contusion or other traumatic accident. And, the hot area is thought to be due to costal fracture in conclusion. However, costal metastases may be incident to the hot area particularly in multiple myeloma. Therefore it is not always able to differentiate nonpathological from pathological costal fractures.
