Battal Bilal, Kocaoglu Murat, Akgun Veysel, Karademir Ibrahim, Deveci Salih, Guvenc Inanc, Bulakbasi Nail
Department of Radiology, Gulhane Military Medical School, Ankara, Turkey.
J Comput Assist Tomogr. 2011 May-Jun;35(3):326-31. doi: 10.1097/RCT.0b013e318216efeb.
The objective of the study was to assess the value of visual assessment of signal intensities on b800 diffusion-weighted images and apparent diffusion coefficient (ADC) maps in differentiation of benign and malignant focal liver lesions (FLLs).
Approval for this retrospective study was obtained from the institutional review board. One hundred forty-three FLLs in 65 patients (38 women, 27 men; mean age, 50.8 years) underwent magnetic resonance (MR) imaging and diffusion-weighted imaging (DWI) with a respiratory-triggered single-shot echo-planar imaging sequence. Focal liver lesions were evaluated visually according to the signal intensities on b800 and ADC map images, and ADC values were also calculated. The conventional MR imaging, follow-up imaging findings, and histopathologic data were regarded as gold standard. Normal distribution was assessed with Kolmogorov-Smirnov test. The accuracies of visual assessment and ADC values in differentiating benign and malignant FLLs were assessed with the Student t test, and threshold values were determined with receiver operating characteristic curve analysis.
By using a cutoff value of 1.21 × 10⁻³ mm²/s, ADC had a sensitivity of 100%, a specificity of 89.3%, and an accuracy of 92.3% in the discrimination of malignant FLLs. With the visual assessment of the DWIs and ADC maps, malignant lesions were differentiated from benign ones, with 100% sensitivity, 92.2% specificity, and 94.4% accuracy. Although some benign lesions were interpreted as malignant, no malignant lesion was determined as benign in visual assessment.
Most FLLs are benign ones such as hemangiomas and cysts, which can be readily and practically characterized only by using visual assessment of DWIs without requiring time-consuming conventional and dynamic contrast-enhanced imaging sequences. Some benign lesions that are falsely interpreted as malignant can be further characterized by using conventional and contrast-enhanced MR studies.
本研究的目的是评估在b800扩散加权图像和表观扩散系数（ADC）图上对信号强度进行视觉评估在鉴别肝脏局灶性病变（FLL）良恶性方面的价值。
本回顾性研究获得了机构审查委员会的批准。65例患者（38例女性，27例男性；平均年龄50.8岁）的143个FLL接受了磁共振（MR）成像和采用呼吸触发单次激发回波平面成像序列的扩散加权成像（DWI）。根据b800和ADC图图像上的信号强度对FLL进行视觉评估，并计算ADC值。将传统MR成像、随访成像结果和组织病理学数据视为金标准。采用柯尔莫哥洛夫-斯米尔诺夫检验评估正态分布。采用学生t检验评估视觉评估和ADC值在鉴别良恶性FLL方面的准确性，并通过受试者操作特征曲线分析确定阈值。
以1.21×10⁻³mm²/s为截断值时，ADC在鉴别恶性FLL方面的敏感性为100%，特异性为89.3%，准确性为92.3%。通过对DWI和ADC图进行视觉评估，恶性病变与良性病变得以区分，敏感性为100%，特异性为92.2%，准确性为94.4%。尽管一些良性病变被误诊为恶性，但在视觉评估中没有恶性病变被判定为良性。
大多数FLL是良性的，如血管瘤和囊肿，仅通过对DWI进行视觉评估就可以轻松且实际地进行特征性诊断，无需耗时的传统和动态对比增强成像序列。一些被误诊为恶性的良性病变可以通过传统和对比增强MR研究进一步进行特征性诊断。
