Differentiation of bone and bone marrow infarcts from osteomyelitis in sickle cell disorders

To determine whether imaging techniques can differentiate osteomyelitis from bone infarction in sickle cell disorders, 39 sets of bone scans (BS) and bone marrow scans (BMS) were performed on 31 patients with sickling disorders and bone pain. In addition, three patients who had either a BS or a BMS were included. Results were analyzed according to whether scans were performed three days or less (Period 1), four to six days (Period 2), or seven or more days (Period 3) after the onset of pain. Regardless of the period, all but five BMS for 34 episodes of assumed infarction showed decreased uptake. BS findings varied depending on the time interval, with none of the ten in Period 1 showing increased uptake, but all 11 in Period 3 showing increased uptake. However, in Period 2, about half of the 13 BS showed increased uptake. All three patients with osteomyelitis in Period 3 had increased uptake on BS. The BMS done in one of these patients showed decreased uptake. Three patients with cellulitis had normal BS and BMS. One patient with septic arthritis had normal BMS, but slightly increased uptake on BS. Although typical imaging patterns are present in early and late infarction (Periods 1 and 3), the patterns for late infarction may not differ from those of advanced osteomyelitis. Therefore, imaging studies are only of value in differentiating infarction from osteomyelitis when both BS and BMS are performed soon after the appearance of symptoms.