MRI联合PET诊断原发性骨淋巴瘤

MRI combined with PET in diagnosis of primary lymphoma of bone

目的观察原发性骨淋巴瘤的MRI及PET影像特征,探讨MRI联合PET的诊断价值。方法收集经病理证实的原发性骨淋巴瘤16例,回顾性分析其MRI和PET表现。结果单骨侵犯15例(股骨5例,椎体3例,髂骨3例,胫骨2例,桡骨1例,上颌骨1例);多骨侵犯1例(胸骨上段及右侧第7肋骨各一病灶)。MRI表现:①16例均见髓腔内局部片状或弥漫性不均匀异常信号,T1WI呈等或稍低或混杂信号,T2WI呈稍高信号,不均匀或均匀强化;②均见明显软组织肿块,15例范围超过骨病变,1例与骨病变相当;T1WI多呈均匀等或稍低信号,T2WI呈均匀或不均匀稍高信号,轻度或中度均匀强化或不均匀强化;3例椎体者为单一椎体压缩性骨折伴局部呈硬膜外和(或)椎旁软组织,软组织范围超过病变椎体。PET:术前PET检查13例,均提示病变局部糖代谢增高,局部放射性浓聚,全身其他部位无异常代谢;3例椎体者均为术后PET检查,术后2个月术区局部复发1例。结论MRI上原发性骨淋巴瘤骨质破坏小而软组织肿块大,T2WI信号相对较低,具有一定特征性;PET对骨原发性淋巴瘤无特异性,但对确定病变性质、鉴别原发与继发、以及术后随访具有优势。MRI与PET相结合为检查原发性骨淋巴瘤的适当方法。

Objective To observe the imaging features of primary lymphoma of bone （PLB） on MRI and PET, and to assess the value of MRI combined with PET for PLB. Methods Sixteen patients with pathologically confirmed PLB were collected, and the MRI and PET appearances were analyzed retrospectively. Results Single bone infiltration was detected in 15 patients （5 in femurs, 3 in vertebro, 3 in right iliums, 2 in tibias, 1 in radius and 1 in maxillae）, while multiple bones infiltration were noticed in 1 patient （lesion located in manubrium sterni and the 7th right rib）. MRI demonstrated heterogeneous focal-lamellar or diffuse signal intensity within marrow, isointense or hypointense on T1WI and slightly hyperintense on T2WI with homogeneous or heterogeneous enhancement. Severe soft tissue mass was seen in all 16 patients, the range of soft tissue mass was larger than osseous lesion in 15 patients and equal to osseous lesion in 1. Most PLB were homogeneous isointense or slightly hypointense on T1WI and homogeneous or heterogeneous slight-hyperintense on T2WI with slightly or moderately homogeneous or heterogeneous enhancement, while in 3 patients showed single vertebral compression fracture with local epidural- and/or paravertebral-soft tissue, and the range of soft tissue larger than the pathologic vertebrae. PET was performed before operation in 13 patients, showing local increasement of glycometabolism and uptake of radioactive nuclide without abnormality for other sites. For three patients of primary lymphoma of vertebrae underwent PET after operation, and recurrence was detected in 1 patient after 2 months. Conclusion Large soft mass with small osseous destruction and relatively hypointensity on T2WI is somehow characteristic for PLB. PET features of PLB are not specifie, but has some advantages in determining the nature of lesion, differentiating lesions and follow-up after operation. MRI combined with PET is an appropriate imaging method for PLB.