21-year-old female patient with history of sickle cell anemia and severe bilateral knee pain. Evaluate for avascular necrosis. MENISCI: The medial and lateral menisci are intact.ARTICULAR CARTILAGE AND BONE: There is patchy ill-defined increased signal intensity in the distal femoral metaphysis. Increased T1 signal intensity is noted in the lateral femoral condyle, extending to the subarticular surface. Similar findings are seen to a lesser degree in the medial femoral condyle. Within the medial femoral condyle there is an area of increased T1 signal intensity with peripheral low T1 signal intensity, compatible with a bone infarct. This measures up to 3 cm in AP dimension. A similar appearing small lesion is noted in the distal femoral metaphysis (series 7 image 11).There are no focal articular cartilage defects. LIGAMENTS: The anterior cruciate ligament, posterior cruciate ligament, lateral collateral ligament complex, and medial collateral ligament are intact. EXTENSOR MECHANISM: No significant abnormality noted.ADDITIONAL
1.Multifocal small bone infarcts in the distal femur. 2.Abnormal marrow signal secondary to sickle cell anemia.3.Small joint effusion.