Differentiation of rib fractures from metastases by bone scanning.

The bone scans of 471 cancer patients revealed 103 (22%) with one or more rib lesions. Of 69 patients who had serial studies, five (7%) had proven rib fractures, 13 (19%) had probable fractures, 25 (36%) had proven metastases, and 26 (38%) had probable metastases. By analyzing the intensity and appearance of rib lesions in serial bone scans, it was concluded that there is a high probability that rib lesions detected by bone scanning are fractures if 1) they are focal as opposed to linear, and 2) they decrease in intensity within three to six months or they are aligned so as to involve two or more ribs in the same location.