Soni Neetu, Kumar Sunil, Srindharan Karthika, Mishra Prabhakar, Gupta Nishant, Bathla Girish, Kalita Jyantee, Behari Sanjay
Neuroradiolgy Department, UIHC, Iowa city, IA.
Radiolgy Department, SGPGIMS, Lucknow, Uttar Pradesh, India.
Curr Probl Diagn Radiol. 2019 Nov-Dec;48(6):547-553. doi: 10.1067/j.cpradiol.2018.09.003. Epub 2018 Oct 9.
To differentiate intra-axial tuberculomas (TB) from metastases based on quantitative differences in the perfusion and diffusion indices of lesion and perilesional edema using arterial spin labeling (ASL) and diffusion tensor imaging (DTI) techniques.
This prospective study included newly diagnosed untreated 12 patients of TB and 13 of metastases who underwent routine magnetic resonance imaging including DTI and ASL sequences. A region of interest analysis was performed and cerebral blood flow (CBF) values of lesion (L), perilesional edema (PE), and normal contralateral white matter (CWM) were calculated. To account for individual patient variation CBF values were normalized (n) to CWM to obtain the nCBFL and nCBFPE ratios. Similarly, DTI data was processed to obtain fractional anisotropy (FA), mean diffusivity, radial diffusivity, and axial diffusivity values from the lesion and PE.
Metastatic lesions revealed statistically significant (p = 0.001) high values of median nCBFL than TB whereas the difference in the median nCBFPE was not statistically significant (p = 0.174). TB showed higher median FAL compared to metastases (p = 0.031) while no statistically significant difference was found in mean values of other diffusion parameters such as mean diffusivity, radial diffusivity and axial diffusivity. Analysis by the receiver operating characteristic curve method revealed a cut-off value of ≥2.865 for nCBFL (Sensitivity = 0.85, Specificity = 0.84, positive predictive value (PPV) = 0.85, Negative predictive value (NPV) = 0.83) and ≤0.073 for FAL (Sensitivity = 0.77, Specificity = 0.58, PPV = 0.67, NPV = 0.70) in differentiating metastases from TB.
Combined analysis of noncontrast ASL perfusion and DTI technique may markedly benefit in differentiation of TB from metastases.
利用动脉自旋标记（ASL）和扩散张量成像（DTI）技术，基于病变及病变周围水肿的灌注和扩散指数的定量差异，鉴别轴内结核瘤（TB）与转移瘤。
本前瞻性研究纳入12例新诊断的未经治疗的结核患者和13例转移瘤患者，他们均接受了包括DTI和ASL序列的常规磁共振成像检查。进行感兴趣区分析，计算病变（L）、病变周围水肿（PE）和对侧正常白质（CWM）的脑血流量（CBF）值。为考虑个体患者差异，将CBF值相对于CWM进行标准化（n），以获得nCBFL和nCBFPE比值。同样，对DTI数据进行处理，以获得病变和PE的分数各向异性（FA）、平均扩散率、径向扩散率和轴向扩散率值。
转移瘤病变的中位nCBFL值高于结核瘤，差异具有统计学意义（p = 0.001），而中位nCBFPE的差异无统计学意义（p = 0.174）。与转移瘤相比，结核瘤的中位FAL更高（p = 0.031），而在平均扩散率、径向扩散率和轴向扩散率等其他扩散参数的平均值方面未发现统计学显著差异。通过受试者工作特征曲线法分析发现，在鉴别转移瘤与结核瘤时，nCBFL的截断值≥2.865（灵敏度 = 0.85，特异性 = 0.84，阳性预测值（PPV） = 0.85，阴性预测值（NPV） = 0.83），FAL的截断值≤0.073（灵敏度 = 0.77，特异性 = 0.58，PPV = 0.67，NPV = 0.70）。
非增强ASL灌注和DTI技术的联合分析可能在鉴别结核瘤与转移瘤方面有显著帮助。
