骨髓坏死¹⁸F-FDG PET/CT与MRI对照分析

A comparative analysis of ¹⁸F-FDG PET/CT and MRI in bone marrow necrosis

摘要

目的  探索骨髓坏死氟-18-脱氧葡萄糖（¹⁸F-fluorodeoxyglucose,¹⁸F-FDG）正电子发射断层显像/计算机断层显像（positron emission tomography/computed tomography,PET/CT）表现，提高对该病的认识。方法  回顾性分析9例磁共振成像（magnetic resonance imaging,MRI）诊断为骨髓坏死患者的PET/CT及临床资料，对照MRI影像，总结病变分布，选择最大病变，分析¹⁸F-FDG代谢特点及CT征象。结果  患者男6例，女3例，中位年龄28.0岁，均患淋巴瘤。MRI检查髋部6例、胸腰椎2例、膝部1例。6例髂骨病变，内部均为T1加权像（T1-weighted image,T1WI）高信号，T2脂肪抑制像（T2-fat suppressed image,T2FSI）低信号，伴T1WI边缘环状低信号，其中5例内部代谢减低，边缘代谢增高伴骨质硬化；1例密度及代谢未见异常，MRI显示病变狭长。2例脊柱病变T1WI呈等、低信号，T2FSI高信号，其中1例为等代谢，密度稍高；1例代谢减低，密度未见异常。1例股骨病变T1WI高信号，T2FSI低信号，代谢及密度增高。8例PET/CT发现MRI检查范围之外更多病变。8例更早期的PET/CT发现部分病变呈低代谢、等密度。结论  ¹⁸F-FDG代谢减低，后期可伴有边缘线状代谢及密度增高，是骨髓坏死的常见PET/CT影像特点。PET/CT有助于检出骨髓坏死，发现多骨病变。

Abstract

Objective To explore the fluoro-18-deoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) features of bone marrow necrosis and improve the understanding of the disease. Methods  The PET/CT and clinical data of 9 patients with bone marrow necrosis diagnosed by magnetic resonance imaging (MRI) were retrospectively analyzed. Compared to MRI,the distribution of lesions was summarized. The ¹⁸F-FDG metabolic and CT features of the selected largest lesion were analyzed.  Results  There were 6 males and 3 females with a median age of 28.0 years. All patients were diagnosed with lymphoma. MRI scans of the hip,spine and knee were performed in 6,2,and 1 case respectively. The iliac lesions in 6 cases showed internal high signal intensity on T1-weighted images (T1WI),low signal intensity on T2-fat suppressed images (T2FSI),and peripheral linear hypointensity on T1WI. The iliac lesions in 5 cases demonstrated internal decreased ¹⁸F-FDG metabolism,peripheral linear increased ¹⁸F-FDG uptake and density on PET/CT. The iliac lesion in one case did not show abnormal ¹⁸F-FDG metabolism and density on PET/CT,the lesion was narrow and long on MRI. The vertebral lesions in two cases showed isointensity to hypointensity on T1WI and hyperintensity on T2FSI. On PET/CT,one vertebral lesion was isometabolic with slightly higher density,the other vertebral lesion showed reduced ¹⁸F-FDG metabolism with normal density. One femoral lesion showed high signal intensity on T1WI and low signal intensity on T2FSI,with increased ¹⁸F-FDG metabolism and density on PET/CT. PET/CT revealed more lesions beyond the scan range of MRI in 8 cases. In 8 cases,abnormal signs were demonstrated on much earlier PET/CT scans performed at a median time about 13.5 (8.25,32.75) months before the MRI scan,but no one complained of any related discomfort at that time. The iliac lesions in 5 cases had decreased ¹⁸F-FDG uptake,of which 3 lesions showed peripheral linear high-density,and 2 lesions showed no abnormal density. The iliac lesion in one case did not show abnorma^{l 18}F-FDG metabolism and density. One vertebral lesion showed reduced metabolism and isodensity. In the case with knee MRI,the earlier PET/CT showed multiple linear increased ¹⁸F-FDG uptake in the bilateral femoral heads and the humerus heads,without abnormal density. During follow up PET/CT scans,the femoral head lesions in 3 cases showed cortical fracture and collapse,the vertebral lesions 2 cases demonstrated multiple Schmorl's nodules or compression fracture. Conclusion  Decreased ¹⁸F-FDG uptake,with probably subsequent peripheral linear increased metabolism and density,is a common PET/CT feature of bone marrow necrosis. PET/CT is helpful to detect bone marrow necrosis and find multiple skeletal lesions.

关键词

骨髓坏死 / 骨坏死 / 氟-18-脱氧葡萄糖 / 正电子发射断层显像/计算机断层扫描

Key words

bone marrow necrosis / osteonecrosis / ¹⁸F-fluorodeoxyglucose / positron emission tomography/computed tomography