Mammone J F, Schweitzer M E
Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.
Skeletal Radiol. 1995 Feb;24(2):101-4. doi: 10.1007/BF00198070.
Following radiation therapy, marrow abnormalities noted on magnetic resonance imaging (MRI) are frequent and may mimic metastases. Specific radiotherapy changes are usually easily identifiable; however, traumatic lesions cause more interpretive difficulties. We assessed the incidence and MRI characteristics of insufficiency fractures in this population. During a 5-year span (1987-1991), 546 patients received pelvic radiotherapy for primary malignancies. MRI was performed in 25 of these patients at least 3 months after treatment. The mean dose in this group was 53 Gy. These MRI scans were retrospectively reviewed for the appearance of the sacrum with particular attention to the presence of insufficiency fractures. This was correlated with clinical course and scintigraphic findings. Presumed insufficiency fractures on MRI paralleled the sacral side of the sacroiliac joint, enhanced with Gd-DTPA, were most prominent or initially seen anteriorly, and had ill-defined margins on all imaging sequences. The incidence of occult sacral insufficiency fractures was at least 20%. Insufficiency fractures of the sacrum in the post-radiotherapy patient are a relatively frequent occurrence which can mimic metastases. Consideration of this phenomenon and knowledge of differential features may avoid overdiagnosis of osseous metastases.
放射治疗后，磁共振成像（MRI）显示的骨髓异常很常见，可能类似转移瘤。特定的放疗改变通常很容易识别；然而，创伤性病变会带来更多的解读困难。我们评估了该人群中应力性骨折的发生率及MRI特征。在1987年至1991年的5年期间，546例患者因原发性恶性肿瘤接受了盆腔放疗。其中25例患者在治疗后至少3个月进行了MRI检查。该组的平均剂量为53 Gy。对这些MRI扫描进行回顾性分析，观察骶骨的表现，特别注意应力性骨折的存在情况。这与临床病程和骨闪烁显像结果相关。MRI上推测的应力性骨折与骶髂关节的骶骨侧平行，经钆喷酸葡胺（Gd-DTPA）增强，最明显或最初出现在前方，在所有成像序列上边缘均不清晰。隐匿性骶骨应力性骨折的发生率至少为20%。放疗后患者骶骨应力性骨折较为常见，可类似转移瘤。认识到这一现象并了解鉴别特征可避免对骨转移的过度诊断。
