Added value of labeled leukocytes SPECT-CT in diagnosing osteomyelitis (OM)

Objectives Assess added value of SPECT-CT to improve diagnostic accuracy of OM.

Methods A multicenter open label study. 86 (55 males) pts with suspected OM, (age 52±1, 25-83 years); 54 patients with prosthesis or metal implants (PMI), 25 post-traumatic OM (PtOM) and 7 with diabetic foot (DF). Planar and SPECT/CT images were reviewed for the presence of abnormal uptake and for tracer localization to the bone or soft tissue. Bone marrow scan was performed if needed. Scans results were defined as positive or negative or equivocal for osteomyelitis. Results were compared regarding positivity and localization to bone or soft tissue. The results of WBC scintigraphic were confirmed by either tissue sampling (n=39) or clinical follow-up (n=47). Nineteen patients had follow up WBC scans.

Results Abnormal accumulation on planar found in 38/86 pts vs. 44/86 positive and 43 negative on SPECT/CT. In 38 positive planar scans, SPECT/CT improved localization in 5 pts with PtOM and 8 pts with suspected PMI discriminating soft tissue from bone involvement. In 48 neg. planar scans; SPECT/CT in 3 pts with PtOM and in 3 PMI showed evidence of abnormal accumulation. In total SPECT/CT provided additional valuable information in 19/86 patients (22%): better localization, delineation or differentiating soft tissue infection from osteomyelitis.

Conclusions SPECT/CT is more sensitive in detecting abnormal activity accumulation in addition to improved anatomical localization of leukocytes accumulation to bony structures probably exempting the need to perform additional bone marrow scan as recommended for planar imaging.

Research Support IAEA, CRP#E1303