3 cm以下的肝脏常见病变磁共振扩散成像的量化研究

目的　通过量化分析 3cm以下的肝脏常见良恶性病变磁共振扩散加权成像 (DWI)影像特点 ,提高对肝脏有关病变的诊断准确性。方法　在肝细胞癌、肝转移瘤、肝血管瘤和肝囊肿 4种常见病变病例中 ,选取 97个病灶。其中肝细胞癌 2 2个病灶 ,肝转移瘤 2 1个病灶 ,肝血管瘤 2 8个病灶 ,肝囊肿 2 6个病灶 ,测量并计算各种病变DWI图像的表面扩散系数 (ADC值 )以及肝细胞癌和肝转移瘤的瘤 /肝ADC值比值。结果　在扩散敏感系数 (b值 )差为 5 0 0mm2 /s的DWI图像上 ,肝细胞癌的ADC值均值为 (0 .91± 0 .0 7)× 10 -3 mm2 /s,肝转移瘤为 (1.13± 0 .2 7)× 10 -3 mm2 /s,肝血管瘤为 (1.94±0 .37)× 10 -3 mm2 /s,肝囊肿为 (3.2 6± 0 .30 )× 10 -3 mm2 /s;肝细胞癌的瘤 /肝ADC值比值均值为 0 .91±0 .0 7,肝转移瘤的瘤 /肝ADC值比值均值为 1.13± 0 .2 7,二者差异有显著性。结论　综合分析肝脏病变的ADC值及瘤 /肝ADC值比值的变化规律 ,可准确判断肝脏有关病变的性质 ,对肝脏疾病的诊断及鉴别诊断做出准确结论。

Quantitative study of diffusion weighted imaging on magnetic resonance imaging in focal hepatic lesions less than 3 cm

OBJECTIVE: To evaluate the characteristics of MR imaging of hepatic lesions using measurement of apparent diffusion coefficient (ADC) value of hepatic lesions on diffusion weighted imaging. METHODS: MR diffusion weighted images were obtained in patients with 97 hepatic lesions (22 hepatocellular carcinomas, 21 metastatic tumors, 28 hemangiomas, 26 cysts). ADC values were evaluated with different sequences. The ADC ratio of lesion/liver was estimated. RESULTS: Average ADC values of hepatic lesions were as follows: carcinomas (0.91 +/- 0.07) x 10(-3) mm(2)/s, metastatic tumors (1.13 +/- 0.27) x 10(-3) mm(2)/s, cavernous hemangiomas (1.94 +/- 0.37) x 10(-3) mm(2)/s, cysts (3.26 +/- 0.30) x 10(-3) mm(2)/s. The ADC ratio of lesion/liver was significantly different between primary carcinomas and metastatic tumors (P < 0.05). CONCLUSION: Quantitative study in hepatic lesions using ADC values and the ADC ratio of lesion/liver, would improve the accuracy in diagnosing hepatic lesions.