Avascular necrosis - bilateral femoral heads

MRI has proved its ability for early diagnosis and accurate staging of AVN of the femoral heads which have significantly impacted the patients' management and prognosis.

The patient is usually presented with unilateral hip pain or sometimes referred knee pain.

Past Past history of prolonged corticosteroid intake is typical. Other possible causes include pancreatitis, trauma and sickle cell disease. 

The bilateral femoral heads show geographic-shaped areas of abnormal signal intensities involving the superior articular surface, with the right femoral head is more severely affected.

On the right side, the area of the abnormal signal presentedpresent mixed signal pattern with areas of high signal in the T1 and T2 WIs mixed with areas of low signal intensity in the T1 and T2 WIs. There is a serpentine low signal intensity line surrounding the area of the abnormal signal representing the reactive interface that separates normal marrow from infarcted marrow. The STIR WIs show ill-defined zone of marrow oedema extending to the femoral neck. There are articular surface flattening and cortical irregularity. Narrowing of the lateral aspect of the joint space is seen. 

On the left side, the area of bone necrosis presents fat-signal pattern in the different pulse sequences. The double line sign is more distinct on the left side, where the boundaries of the lesion have an outer dark signal layer and inner bright signal layer. 

According to Ficat & Alert Classificationclassification, Rightright grade III and left grade II AVN of the femoral heads.