Purpose: 

To review and summarize the existing literature surrounding the clinical use of diffusion-weighted imaging and apparent diffusion coefficient (ADC) as diagnostic tools in differentiating common orbital lesions.

Methods: 

A systematic literature review on the use of ADC and diffusion-weighted imaging sequences for orbital imaging was performed. Only original research articles that reported ADC values for benign or malignant lesions were included.

Results: 

Malignant orbital tumors have an overall lower mean ADC value than benign masses. Orbital lymphoma is characterized by consistently lower ADC values compared with other malignant orbital masses; a threshold value less than 0.775 × 10⁻³ mm²/s has been proposed to distinguish orbital lymphoma from other neoplastic and non-neoplastic orbital masses. To differentiate orbital inflammatory disease from lymphoma, an ADC threshold greater than 0.92 × 10⁻³ mm²/s has been proposed.

Conclusions: 

Orbital masses encompass a host of benign and malignant etiologies and can present a diagnostic challenge on both clinical and radiological assessment. Recent advanced MRI techniques such as diffusion-weighted imaging and ADC can improve the diagnostic specificity for orbital disease, particularly in differentiating benign from malignant lesions and lymphoma from orbital inflammatory disease.

中文翻译：

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弥散加权成像和表观弥散系数对常见眼眶病变的诊断效用：综述

目的： 

回顾和总结围绕弥散加权成像和表观弥散系数（ADC）作为区分常见眼眶病变的诊断工具的临床应用的现有文献。

方法： 

对使用 ADC 和扩散加权成像序列进行轨道成像进行了系统的文献综述。仅包含报告良性或恶性病变 ADC 值的原始研究文章。

结果： 

恶性眼眶肿瘤的平均 ADC 值总体低于良性肿块。与其他恶性眼眶肿块相比，眼眶淋巴瘤的特点是 ADC 值始终较低；已提出小于0.775 × 10 ^-3 mm ^{2 /s的阈值来区分眼眶淋巴瘤与其他肿瘤性和非肿瘤性眼眶肿块。}为了区分眼眶炎症性疾病和淋巴瘤，提出了大于0.92×10 ^-3 mm ^{2 /s的ADC阈值。}

结论： 

眼眶肿块包含许多良性和恶性病因，可能对临床和放射学评估提出诊断挑战。最近先进的 MRI 技术，如弥散加权成像和 ADC 可以提高眼眶疾病的诊断特异性，特别是在区分良性病变和恶性病变以及淋巴瘤和眼眶炎症性疾病方面。