眼眶淋巴瘤的CT和MRI影像学特征

CT and MRI Imaging Features of Orbital Lymphomas

【目的】分析眼眶淋巴瘤CT和MRI影像特点，提高诊断正确率。【方法】回顾性分析21例经病理证实的眼眶淋巴瘤，患者均行CT平扫，其中17例同时行增强扫描，6例行MRI平扫及增强扫描。【结果】13例为单侧发病，8例为双侧发病，均累及隔前眶周组织；7例呈肿块型，14例呈浸润型，其中6（6／14）例呈弥漫软组织影，沿肌锥外向眶内浸润生长，呈“铸型样”改变，8（8／14）例软组织包绕大部分眼环，呈“星芒状”改变；CT平扫肿瘤为等密度软组织影，增强后病灶轻至中度均匀强化；MRI平扫肿块在T1WI呈中等偏低信号，在T2wI呈低信号或稍高信号，增强后病灶中度至明显均匀强化；CT诊断与病理结果的符合率为81％（17／21），MRI诊断结果均符合病理结果（100％，6／6）。【结论】眼眶淋巴瘤的CT和MRI表现具有特征性，可为本病的诊断提供依据。

[Objective] To analyze the CT and MRI imaging features of orbital lymphoma in order to improve the rate of correct diagnosis. [Methods] Twenty one cases of orbital lymphoma confirmed by pathology were analyzed retrospectively. All patients were examined by plain CT scan. Among them, 17 patients underwent contrast-enhanced CT scan simultaneously. Plain and contrast MR scans were performed in 6 patients. [Results] The lesions of 13 cases were unilateral and 8 cases wel：e bilateral. Periorbital preseptal tissues were involved in all cases. Focal masses ap- peared in 7 patients. Among 14 cases with infiltrating type of lesions, the lesions of 6 cases were diffusive soft tissue sign and infiltrated into the orbit along muscle cone with ＂casting sign＂, and soft tissues of 8 cases enveloped most of eye ring with ＂starry sign＂. The tumors were isodensity soft tissue sign on plain CT scan, and the lesions were mildly and moderately intensified evenly after enhancement. The masses were low to intermediate signal intensity on T1WI MRI and low or slightly high signal intensity on T2WI, and the lesions were moderately and obviously intensified e- venly after enhancement. The coincidence rate of CT and pathology diagnosis was 81% （17/21） and that of MRI and pathology diagnosis was 100 % （6/6）. [Conclusion]CT and MRI imaging features of orbital lymphomas are character- istic, and can provide the evidence for the diagnosis of the disease.