Initial changes of non-traumatic osteonecrosis of femoral head in fat suppression images: bone marrow edema was not found before the appearance of band patterns

The present study examined initial changes in non-traumatic osteonecrosis o f the femoral head (ONF) on T1- and T2-weighted MR images, and fat suppress ion images. The subjects were 57 renal transplant recipients (37 males and 20 females), whose median age at the time of transplantation was 31.5 years old (range, 10 to 58 years). Twelve patients developed band patterns (sign of established ONE) at an early postoperative period. Among them, 4 joints of 3 patients had a localized, faint signal abnormality in fat suppression images, where band pattern was confirmed later in T1- and T2-weighted imag es. In all the 57 patients, no bone marrow edema preceding to ONF was obser ved. Bone marrow edema would not be the cause of ONF in renal transplant pa tients. Early changes depicted in our fat suppression images would be usefu l information in the studies on pathogenesis of ONF. (C) 2001 Elsevier Scie nce Inc. All rights reserved.