Case Author(s): Samuel Wang, M.D. and Barry A. Siegel, M.D. , 5/18/97 . Rating: #D3, #Q4

Diagnosis: Bone infarctions.

Brief history:

18-year-old male with sickle cell anemia and left leg pain.

Images:

Delayed 18-hour anterior and posterior whole-body images.

View main image(iw) in a separate image viewer

View second image(bm). Anterior and posterior whole-body images after injection of a second radiopharmaceutical.

View third image(bm). Spot views comparing the distribution of the two radiopharmaceuticals

Full history/Diagnosis is available below

Diagnosis: Bone infarctions.

Full history:

18-year-old male with a history of sickle cell anemia (hemoglobin SS disease) who presented with a one-week history of pain in the left tibia. The patient's white blood cell count was 28,000/µL, the ESR was 60 mm/hr, and he had fevers. The patient was referred to help differentiate osteomyelitis from bone infarction. Approximately 18 hours after injection of In-111 labeled leukocytes, anterior and posterior whole-body images (main image) were obtained along with additional spot images of the left leg (third image, 2nd row). After In-111 imaging of the left leg was complete, imaging of the marrow distribution in the left leg was performed by injecting Tc-99m sulfur colloid (third image, 1st row). The patient was not moved between the In-111 WBC imaging and the Tc-99m SC imaging of the left leg. Finally, anterior and posterior whole-body Tc-99m sulfur colloid images were obtained (second image).

Radiopharmaceutical:

0.45 mCi In-111 labeled autologous leukocytes i.v. and 10.1 mCi Tc-99m sulfur colloid i.v.

Findings:

There are no significant differences in the distribution of marrow activity on the In-111 WBC images and the Tc- 99m SC images. Specifically, on both sets of images there are focal areas of absent activity seen in the left proximal tibia and in the distal third of the left tibia. Normal marrow activity is seen with both radiopharmaceuticals in the mid left tibia. These findings are not consistent with osteomyelitis of the tibia and more likely represent infarcts of the proximal and distal portions of the left tibia.

Both the In-111 WBC and the Tc-99m SC images demonstrate absent activity in the right clavicle and left humeral head, compatible with previous infarctions. Heterogeneous activity in the lower lumbar spine also likely represents previous infarction. There is non-visualization of the spleen with both radiopharmaceuticals consistent with autosplenectomy. Mild hepatomegaly is noted.

Discussion:

It is often clinically difficult to differentiate between bone infarction and osteomyelitis in patients with sickle cell anemia who present with pain. Leukocyte scintigraphy is often used in conjunction with marrow scintigraphy in these circumstances. In-111 WBC imaging alone can lead to false positive studies because of the compensatory expansion of the marrow in these patients, as well as the irregular distribution of marrow due to previous infarcts. Thus, careful comparison with Tc-99m SC marrow images isatgamma required to identify sites of "mismatch" that suggest osteomyelitis.

Followup:

1The patient improved with hydration and symptomatic treatment.

ACR Codes and Keywords:

References and General Discussion of Bone Marrow Scintigraphy (Anatomic field:Skeletal System, Category:Effect of Trauma)

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Case number: bm001

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