Huang Hua, Che-Nordin Nazmi, Wang Li-Fei, Xiao Ben-Heng, Chevallier Olivier, Yun Yong-Xing, Guo Sheng-Wen, Wáng Yì Xiáng J
Department of Radiology, The Third People's Hospital of Shenzhen, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen 518000, China.
Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China.
Ann Transl Med. 2019 Feb;7(3):39. doi: 10.21037/atm.2018.12.33.
Recently a small cohort study demonstrated that intravoxel incoherent motion (IVIM) diffusion MRI can detect early stage liver fibrosis. Using modified IVIM data acquisition parameters, the current study aims to confirm this finding.
Twenty-six healthy volunteers, three patients of chronic viral hepatitis-b but without fibrosis and one mild liver steatosis subject, and 12 viral hepatitis-b patients with fibrosis (stage 1-2=7, stage 3-4=5) were included in this study. With a 1.5-T MR scanner and respiration-gating, IVIM diffusion imaging was acquired using a single-shot echo-planar sequence with a -value series of 2, 0, 1, 15, 20, 30, 45, 50, 60, 80, 100, 200, 300, 600, 800 s/mm. Signal measurement was performed on right liver parenchyma. The first three very low -values were excluded to improve the curve fitting stability, and bi-exponential segmented fitting was performed using the 12 -values of 15~800 s/mm. Both threshold -values of 60 s/mm and 200 s/mm were tested. With a 3-dimensional tool, Dslow (), PF () and Dfast () values were placed along the x-axis, y-axis, and z-axis, and a plane was defined to separate healthy volunteers from liver fibrosis patients.
Threshold -value of 60 s/mm was preferred over 200 s/mm for separating healthy volunteers and liver fibrosis patients. The IVIM measures of the four patients without fibrosis resembled those of healthy volunteers. When threshold -value =60 s/mm was applied, PF (PF <6.49%) could differentiate healthy livers and all fibrotic livers with 100% sensitivity and specificity. For the patients' measurement, PF and Dfast were highly correlated with a Pearson correlation coefficient r of 0.865 (P<0.001); while the correlations between slow diffusion compartment (Dslow) and fast diffusion compartment (Dfast or PF) were not statistically significant.
This study confirms previous report that IVIM diffusion MRI has high diagnostic performance in detecting viral hepatitis-b induced liver fibrosis.
最近一项小型队列研究表明，体素内不相干运动（IVIM）扩散磁共振成像（MRI）能够检测早期肝纤维化。本研究采用改良的IVIM数据采集参数，旨在证实这一发现。
本研究纳入了26名健康志愿者、3名慢性乙型病毒性肝炎但无纤维化的患者、1名轻度肝脂肪变性受试者以及12名患有纤维化的乙型病毒性肝炎患者（1-2期=7例，3-4期=5例）。使用1.5-T MR扫描仪并采用呼吸门控，通过单次激发回波平面序列采集IVIM扩散成像，b值系列为2、0、1、15、20、30、45、50、60、80、100、200、300、600、800 s/mm²。在肝脏右叶实质进行信号测量。排除前三个极低b值以提高曲线拟合稳定性，并使用15~800 s/mm²的12个b值进行双指数分段拟合。对60 s/mm²和200 s/mm²这两个阈值均进行了测试。使用三维工具，将慢扩散系数（Dslow）、灌注分数（PF）和快扩散系数（Dfast）值分别置于x轴、y轴和z轴上，并定义一个平面以区分健康志愿者和肝纤维化患者。
在区分健康志愿者和肝纤维化患者方面，60 s/mm²的阈值优于200 s/mm²。4名无纤维化患者的IVIM测量值与健康志愿者相似。当应用阈值b=60 s/mm²时，灌注分数（PF<6.49%）能够以100%的灵敏度和特异性区分健康肝脏和所有纤维化肝脏。对于患者测量，PF与Dfast高度相关，Pearson相关系数r为0.865（P<0.001）；而慢扩散部分（Dslow）与快扩散部分（Dfast或PF）之间的相关性无统计学意义。
本研究证实了先前的报告，即IVIM扩散MRI在检测乙型病毒性肝炎所致肝纤维化方面具有较高的诊断性能。
