36-year-old male patient with Non- Hodgkin’s lymphoma has undergone allogeneic stem cell transplantation and is now suffering from severe graft versus host disease of the bowel. High dose steroids are therefore applied. Sudden onset of diffuse pain in both knees. Knee MRI is performed to exclude osteonecrosis.

A sagittal T2-weighted DESS image through the body of the lateral meniscus demonstrates the normal bowtie appearance and homogeneous dark signal of the lateral meniscus. (Fig. 1). No tear or intrasubstance degeneration was detected. Sagittal TIRM sequence shows a homogeneous dark signal of the tibial and femoral bone marrow without evidence for bone marrow edema (Fig. 2). No osteonecrosis was found. The sagittal T2-weighted DESS through the area of the intercondylar notch reveals a normal anterior (Fig. 3) and posterior cruciate ligament (Fig. 4) with uniform signal.
T1-weighted TSE shows no bone bruise, normal menisci and collateral ligaments (Fig. 5).

MRI has a high sensitivity to help detecting bone marrow edema of various etilogies, especially with fatsuppressed TIRM images, providing a high contrast between affected and uninvolved bone marrow. Therefore osteonecrosis, tumorous or infectious pathology was excluded in this case.