Case Author(s): Gregg Schubach,M.D./Keith Fischer, M.D. , 8/8/95 . Rating: #D2, #Q4

Diagnosis: Osteomyelitis of the right tibia

Brief history:

73-year old woman with fevers and an elevated white blood cell count.


Anterior and posterior images of the whole body; spot images of the lower extremities.

View main image(iw) in a separate image viewer

View second image(xr). Two views of the proximal tibia

View third image(mr). T2 weighted axial MR images just below the prosthesis

Full history/Diagnosis is available below

Diagnosis: Osteomyelitis of the right tibia

Full history:

73-year old woman with end- stage renal disease had a left total knee replacement approximately one year ago. Two month following the surgery, the patient had aseptic arthritis of the left knee, which was treated with intravenous antibiotics and debridement. The patient now presents with fevers and an elevated white blood cell count.


24-hour delayed whole body scintigraphy was obtained following the administration of In-111 white blood cells. There is no abnormality. However, additional images over the lower extremities demonstrate increased activity in the left tibia just beyond the level of the prosthesis. The plain radiographs demonstrate the left knee prosthesis and no frank evidence of osteomyelitis. Fast spin echo images through the left lower extremity just distal to the prosthesis demonstrate increased signal intensity within the marrow cavity. This corresponds to the region of radiopharmaceutical uptake on the In-111 white blood cell scintigraphy.


Plain radiographs are often normal or nonspecific during the early phases of osteomyelitis. Although bone scintigraphy with Tc- 99m MDP demonstrates increased activity in the regions of osteomyelitis, the etiology of uptake is often uncertain when osteomyelitis is suspected in regions of prior surgery. In-111 labeled white blood cell uptake is more specific for infection. Indeed, In-111 labeled white blood cell uptake would not be expected as a postoperative finding in a sterile surgical site. The initial scintigraphic images do not include the entire lower extremities.


Shortly following the MRI, needle aspiration of the left tibia just distal to the prosthesis demonstrated gram positive cocci.

Major teaching point(s):

This case emphasizes the importance of imaging the entire body when the site of infection is unknown.

ACR Codes and Keywords:

References and General Discussion of Indium -111 WBC Scintigraphy (Anatomic field:Skeletal System, Category:Inflammation,Infection)

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Case number: iw002

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