Backgrounds:Imaging of parotid tumors is crucial for surgery planning, but it cannot distinguish malignant from benign lesions with absolute reliability. The aim of the study was to establish a diagnostic MRI algorithm to differentiate parotid tumors.Methods:A retrospective study was conducted including all patients with parotid tumors, who underwent 3T-MRI and surgery. Morphological characteristics and normalized T2 and late postcontrast T1 signal intensities (SI) were assessed. “Ghosting sign” on late postcontrast T1 sequence was defined as indistinguishability of the tumor except for a thin peripheral enhancement. Patients were divided according to histology and imaging data were compared. A diagnostic MRI algorithm was established.Results:Thirty-six patients were included. The combination of normalized late T1 postcontrast SI, normalized T2 SI and “ghosting sign” allowed for the distinguishing of malignant from benign parotid tumors with high sensitivity (100%), specificity (93%), positive predictive value (80%), negative predictive value, (100%) and accuracy (94%). Moreover, pleomorphic adenomas often showed a homogeneous T2 signal and a complete capsule (p< 0.01), Warthin tumors protein-rich cysts and calcifications (p< 0.005 andp< 0.05), and malignant tumors an inhomogeneous contrast enhancement (p< 0.01).Conclusions:High field MRI represents a promising tool in parotid tumors, allowing for an accurate differentiation of malignant and benign lesions.
背景：腮腺肿瘤的影像学检查对于手术规划至关重要，但无法绝对可靠地区分恶性与良性病变。本研究旨在建立一种用于鉴别腮腺肿瘤的诊断性MRI算法。 方法：本研究为回顾性研究，纳入了所有接受3T-MRI检查并行手术治疗的腮腺肿瘤患者。评估内容包括形态学特征、标准化T2信号强度及延迟增强后T1信号强度。延迟增强T1序列上的“鬼影征”定义为除薄层周边强化外肿瘤无法清晰辨识。根据组织学结果对患者进行分组，并比较影像学数据，据此建立诊断性MRI算法。 结果：共纳入36例患者。结合标准化延迟增强T1信号强度、标准化T2信号强度及“鬼影征”，能够以高灵敏度（100%）、特异度（93%）、阳性预测值（80%）、阴性预测值（100%）和准确率（94%）区分腮腺良恶性肿瘤。此外，多形性腺瘤常表现为均匀的T2信号和完整包膜（p<0.01），沃辛瘤多见富含蛋白质的囊变和钙化（p<0.005和p<0.05），而恶性肿瘤则多呈现不均匀的对比增强（p<0.01）。 结论：高场强MRI在腮腺肿瘤诊断中展现出良好前景，能够实现良恶性病变的精确鉴别。
High Field MRI in Parotid Gland Tumors: A Diagnostic Algorithm
肿瘤(癌症)患者之家