The Value of Quantitative Uptake of ^99mTc-MDP and ^99mTc-HMPAO White Blood Cells in Detecting Osteomyelitis in Violated Peripheral Bones

¹ Biomedical Sciences, Lebanese International University, Beirut, Lebanon; Radiologic Sciences, Kuwait University, Kuwait; Nuclear Medicine Department, Kuwait Center for Specialised Surgery, Kuwait
² Radiologic Sciences, Kuwait University, Kuwait; Nuclear Medicine Department, Kuwait Center for Specialised Surgery, Kuwait

^* To whom correspondence should be addressed. E-mail: nasser.ballani{at}liu.edu.lb.

	Abstract

Our objective in this study was to evaluate whether measurement of quantitative uptake of ^99mTc-methylene diphosphate (MDP) and ^99mTc-hexamethylpropyleneamine oxime (HMPAO) white blood cells (WBCs) is useful in detecting osteomyelitis in peripheral bony lesions. Methods: Twenty-four patients (12 men and 12 women; age range, 25-72 y) were referred for imaging because of clinically suspected osteomyelitis. They had a traumatic fracture (n = 10), knee prosthesis (n = 5), hip prosthesis (n = 2), diabetic foot (n = 4), or chronic osteomyelitis (n = 3). Three-phase bone scanning and ^99mTc-HMPAO WBC studies were performed on all patients within the same week. Regions of interest were drawn over the abnormal bony sites and the contralateral normal sites, and the abnormal-to-normal uptake ratios (A/N ratios) were obtained for both studies. Results: All patients had abnormal findings on 3-phase bone scanning, whereas 17 (71%) had abnormal findings on ^99mTc-HMPAO WBC studies, of which 15 were confirmed to be true-positive. In those 15 patients, the mean A/N ratios for ^99mTc-MDP and ^99mTc-HMPAO WBC were 3.0 ± 1.6 (range, 1.3-6.2) and 1.8 ± 0.3 (range, 1.4-2.2), respectively. In the other 9 patients, whose scan results were clinically confirmed to be true-negative, the mean A/N ratios for ^99mTc-MDP and ^99mTc-HMPAO WBC were 2.1 ± 1.2 and 1.2 ± 0.2, respectively. In the group with a ^99mTc-MDP A/N ratio greater than 2 (n = 15), 87% (13/15) had a high ^99mTc-HMPAO WBC A/N ratio (>1.5), including 2 that were false-positive. In the remaining 2 patients, one with chronic osteomyelitis and the other with a recent hip prosthesis, ^99mTc-HMPAO WBC ratios were normal. In the group with a bone A/N ratio of less than 2 (n = 9), only 4 patients (44%) were true-positive for acute osteomyelitis. Conclusion: ^99mTc-MDP bone scanning alone, with an A/N ratio of more than 2, is useful in detecting osteomyelitis in violated bone except in the case of a recent hip prosthesis or chronic osteomyelitis.