磁共振弥散加权成像对良恶性腮腺肿瘤鉴别诊断的效果分析

目的 分析磁共振弥散加权成像(DWI)对良恶性腮腺肿瘤鉴别诊断的效果.方法 回顾性分析55例疑似腮腺肿瘤患者的磁共振成像(MRI)和DWI资料,比较良恶性腮腺肿瘤影像学表现和表观扩散系数(ADC),分析MRI动态增强扫描中时间-强度曲线(TIC)分型在良恶性腮腺肿瘤中的差异,以病理检查结果 为准,分析常规MRI诊断、DWI诊断和两者联合诊断恶性肿瘤的效果.结果良性肿块边界多清晰,以腺瘤和腺淋巴瘤最常见,T2WI呈等信号或低信号,增强扫描显著强化;恶性肿瘤形态不规则,边界模糊,信号不均匀,增强扫描均匀或不规则强化,伴周围结构侵犯和颈部淋巴结肿大.良性腮腺肿瘤中腺淋巴瘤和良性淋巴上皮病变的ADC值均较低,其他良性肿瘤的ADC值较高,恶性肿瘤的ADC值多数介于两者之间;良性腮腺肿瘤中多形性腺瘤和其他良性肿瘤及恶性腮腺肿瘤的ADC值分别为(1.185±0.113)×10-3、(1.430±0.524)×10-3、(0.996±0.254)×10-3 mm2/s,均高于良性肿瘤中腺淋巴瘤(0.768±0.133)×10-3 mm2/s,差异均有统计学意义(P﹤0.05).良性肿瘤的TIC曲线分型中缓升型34.29％、平台型25.71％、速升速降型40.00％与恶性肿瘤10.00％、75.00％、15.00％比较,差异均有统计学意义(P﹤0.05).MRI联合DWI诊断恶性腮腺肿瘤的灵敏度85.00％和准确度87.27％高于单纯MRI诊断或DWI诊断(P﹤0.05),特异度比较差异无统计学意义(P﹥0.05).结论 DWI应用于鉴别良恶性腮腺肿瘤的效果较好,值得临床推广应用.

Magnetic resonance diffusion-weighted imaging in the differential diagnosis of benign and malignant parotid tumors

Objective To analyze the value of magnetic resonance diffusion-weighted imaging (DWI) in the differen-tial diagnosis of benign and malignant parotid tumors. Method The magnetic resonance imaging (MRI) and DWI data of 55 patients with suspected parotid tumors were retrospectively analyzed. The imaging findings and apparent diffusion coefficient (ADC) of benign and malignant parotid tumors were compared. The differences of time-intensity curve (TIC) in MRI dynamic enhanced scan between benign and malignant parotid tumors were analyzed. The efficacy of MRI, DWI and their combination in diagnosing malignant tumors was analyzed, based on pathological findings. Result Boundaries of benign mass were generally clear, and most of them were adenomas and adenolymphomas, which showed equal or low signal on T2WI, and enhanced scan showed marked enhancement;malignant tumors were irregular in shape, with fuzzy boundaries, showing inhomogeneous signal, and enhanced scan showed homogeneous or irregular enhancement, compli-cated by surrounding structure invasion and swollen cervical lymph nodes. ADC values of adenolymphomas in benign pa-rotid gland mass and benign lymphoepithelial lesions were relatively lower, while it was higher in other benign tumors, and most malignant tumors had an intermediate ADC value; ADC values of pleomorphic adenomas, adenolymphomas and parotid malignant tumors were (1.185±0.113)×10-3 mm2/s, (1.430±0.524)×10-3 mm2/s and (0.996±0.254)×10-3 mm2/s, re-spectively, and were higher than that in benign adenolymphoma at (0.768±0.133)×10-3 mm2/s, the differences were of sta-tistically significance (P<0.05). Among all type of TIC curve of benign tumors, the proportions of slow-rise type, plat-form type and fast-rise-fast-down type were 34.29％, 25.71％and 40.00％, respectively. Compared with those of malig-nant tumors (10.00％, 75.00％, 15.00％), there were significant differences (P<0.05). The sensitivity (85.00％) and accura-cy (87.27％) of MRI combined with DWI in the diagnosis of parotid malignant tumors were significantly higher than those of MRI or DWI diagnosis alone (P<0.05), and there was no significant difference in specificity (P>0.05). Conclu-sion Magnetic resonance DWI is effective for differential diagnosis of benign and malignant parotid tumors.