Case Author(s): Matt Jaksha, M.D. and Keith Fischer,M.D. , 1/9/98 . Rating: #D2, #Q3

Diagnosis: Osteomyelitis of great toe

Brief history:

60 year old male with infection of left great toe.


Tc-99m MDP Angiographic and Immediate blood pool images are shown

View main image(bs) in a separate image viewer

View second image(bs). 2 hour delayed Tc-99m MDP plantar image

View third image(iw). Delayed Tc-99m MDP and In-111 WBC images obtained simultaneously

View fourth image(xr). Radiographs of the left foot 10 weeks and 2 weeks prior

Full history/Diagnosis is available below

Diagnosis: Osteomyelitis of great toe

Full history:

This is a 60 year old man with a history of diabetes and multiple amputations of toes on the left. The patient has had an infection of the left great toe for 2 months. There is now a draining ulcer at the base of the left great toe, lateral aspect. This study is requested to evaluate for osteomyelitis.


Tc-99m MDP and In-111 leukocytes


The first two phases of the bone scan demonstrate increased blood flow and blood pool activity to the left foot. The 2 hour delayed Tc-99m MDP images show increased activity at the tarso-metatarsal region as well as in the forefoot, in the area of interest. The 24 hour delayed In-111 labelled WBC images show a single focal area of increased acitivity in the distal left foot. Radiographs 10 weeks prior to the current study showed, among other things, a fracture at the base of the first proximal phalanx, lateral aspect. Subsequent radiographs, 2 weeks prior to the current exam, demonstrate dissolution of that fracture fragment with a poorly defined margin of the adjacent phalanx.


An infection is clearly demonstrated by the focal accumulation of leukocytes. However, localizing the infection in this foot which demonstrates extensive Charcot changes is difficult. Not only is there increased osteoblastic activity in the midfoot(typical of a Charcot foot), but there is extensive increased activity in the region of the first and second toes. As this does not conform to the increased WBC acccumulation, it presumably does not all represent infection. In fact, all of the abnormal osteoblastic activity could be related to trauma or a healed infection, with the active site only in the adjacent soft tissues.

Recognizing the fracture fragment on the initial radiographs and its dissolution on the subsequent radiograph is key.


Obtaining the bone scitigraphy and labelled leukocyte images simultaneously allows us to superimpose those images and more precisely localize the infection. The focus in fact lies between the first and second toes, corresponding to the site of the fracture fragment. There is no bony activity at the site because the infection has almost completely destroyed the fracture fragment.

View followup image(iw). Location of the In-111 focus (circle) in the delayed Tc-99m MDP image when cine mode is used to "superimpose" the two studies.

Major teaching point(s):

Perfoming bone scintigraphy and In-111 labelled WBC imaging simultaneously can be useful when there are other abnormalities causing increased uptake of the bone agent(e.g. Charcot foot, healing fracture) and when it may be difficult to localize any abnormal WBC accumulation.

As in this case, it can be difficult to digitally superimpose two studies if one has significantly fewer counts relative to the other. Here, the In-111 leukocyte study has few counts relative to the Tc-99m MDP, and relative to background. The use of the cine mode allows us to display them separately, but localize the activity of the leukocytes relative to the bone.

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: iw007

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