MUSCULOSKELETAL IMAGING: Metabolic/Hematologic

Case Author: Daniel E. Wessell, MD, PhD, Mallinckrodt Institute of Radiology at Washington University in Saint Louis

History

27-year-old man with left knee pain.

Imaging Findings

Coronal fat-suppressed T2-weighted fast spin-echo (A) and T1-weighted spin-echo (B) MR images of the left knee show nodular replacement of the normal fatty marrow. T1-weighted MR image (B) shows at least one of these nodules is darker than muscle and several nodules are in the epiphysis of the tibia.

Diagnosis

Acute myelogenous leukemia

Teaching Points

The MRI findings of myeloproliferative disorders are nonspecific; bone marrow biopsy is often required for definitive diagnosis.

Normal bone marrow consists of a hematopoietically active component called red marrow and a hematopoietically inactive component composed primarily of fat, called yellow marrow.

On T1-weighted images, the signal intensity of normal red and yellow marrow is greater than that of skeletal muscle.

The distribution of red and yellow marrow in the skeleton varies with age; the conversion of red marrow to yellow marrow proceeds in an orderly and predictable manner. In the appendicular skeleton, this process occurs from distal to proximal; in each bone, it occurs from diaphysis to metaphysis. The epiphyses are an exception in that they rarely contain hematopoietically active marrow (i.e., red marrow).

Suggested Readings

Hwang S, Panicek DM. Magnetic resonance imaging of bone marrow in oncology, Part 2. Skeletal Radiol 2007;
36:1017–1027

Vanel D, Dromain C, Tardivon A. MRI of bone marrow disorders. Eur Radiol 2000; 10:224–229

This page is updated with new content weekly. It was last updated on May 21, 2018.