RT Journal Article SR Electronic T1 99mTc-Interleukin-8 for Imaging Acute Osteomyelitis JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1257 OP 1264 VO 42 IS 8 A1 Stefan Gratz A1 Huub J.J.M. Rennen A1 Otto C. Boerman A1 Wim J.G. Oyen A1 Pieter Burma A1 Frans H.M. Corstens YR 2001 UL http://jnm.snmjournals.org/content/42/8/1257.abstract AB Early and accurate diagnosis of osteomyelitis remains a clinical problem. Acute osteomyelitis often occurs in infants and most often is located in the long bones. Radiologic images show changes only in advanced stages of disease. Scintigraphic imaging with 99mTc-methylene diphosphonate (MDP), or bone scanning, is much more sensitive in detecting acute osteomyelitis but lacks specificity. We evaluated the performance of 99mTc-interleukin-8 (IL-8) in an experimental model of acute osteomyelitis. Methods: Acute pyogenic osteomyelitis was induced in 10 rabbits by inserting sodium morrhuate and Staphylococcus aureus into the medullary cavity of the right femur. The cavity was closed with liquid cement. A sham operation was performed on the left femur. Routine radiographs were obtained just before scintigraphy. Ten days after surgery, the rabbits were divided into 2 groups of 5 animals, received an injection of either 18.5 MBq 111In-granulocytes or 18.5 MBq 67Ga-citrate, and were imaged both 24 h after injection and 48 h after injection. On day 12, the rabbits received either 18.5 MBq 99mTc-MDP or 18.5 MBq 99mTc-IL-8, and serial images were acquired at 0, 1, 2, 4, 8, 12, and 24 h after injection. Uptake in the infected femur was determined by drawing regions of interest. Ratios of infected femur (target) to sham-operated femur (background) (T/Bs) were calculated. After the final images were obtained, the rabbits were killed and the right femur was dissected and analyzed for microbiologic and histopathologic evidence of osteomyelitis. Results: Acute osteomyelitis developed in 8 of 10 rabbits. All imaging agents correctly detected the acute osteomyelitis in these animals. The extent of infection was optimally visualized with 67Ga-citrate and delayed bone scanning, whereas diaphyseal photopenia was noted with both 99mTc-IL-8 and 111In-granulocytes. In 1 rabbit with osteomyelitis, imaging results were falsely negative with 111In-granulocytes and falsely positive with 99mTc-MDP. Quantitative analysis of the images revealed that the uptake in the infected region was highest with 67Ga-citrate (4.9 ± 0.8 percentage injected dose [%ID]) and 99mTc-MDP (4.7 ± 0.7 %ID), whereas the uptake in the infected area was significantly lower with 99mTc-IL-8 (2.2 ± 0.2 %ID) and 111In-granulocytes (0.8 ± 0.2 %ID) (P < 0.0042). In contrast, the T/Bs were significantly higher for 99mTc-IL-8 (T/B, 6.2 ± 0.3 at 4 h after injection) than for 67Ga-citrate, 99mTc-MDP, and 111In-granulocytes, which had ratios of 1.5 ± 0.4, 1.9 ± 0.2, and 1.4 ± 0.1, respectively (P < 0.0001). Radiography correctly revealed acute osteomyelitis in only 2 of 8 rabbits. Conclusion: In this rabbit model of osteomyelitis, 99mTc-IL-8 clearly revealed the osteomyelitic lesion. Although the absolute uptake in the osteomyelitic area was significantly lower than that obtained with 99mTc-MDP and 67Ga-citrate, the T/Bs were significantly higher for 99mTc-IL-8 because of fast background clearance. The ease of preparation, good image quality, and lower radiation burden suggest that 99mTc-IL-8 may be a suitable imaging agent for the scintigraphic evaluation of acute osteomyelitis.