Liver vessel density can be evaluated by an imaging biomarker diffusion-derived vessel density (DDVD): DDVD/area(b0b2) = Sb0/ROIarea0 – Sb2/ROIarea2, where Sb0 and Sb2 refer to the liver signal when b is 0 or 2 (s/mm²); ROIarea0 and ROIarea2 refer to the region of interest (ROI) on b = 0 or 2 images; and Sb2 may be replaced by Sb15 (b = 15). This concept was validated in this study. Liver diffusion images were acquired at 1.5 T. For a scan-rescan repeatability study of six subjects, b values of 0 and 2 were used. The validation study was composed of 26 healthy volunteers and 19 consecutive suspected chronic viral hepatitis B patients, and diffusion images with b values of 0, 2, 15, 20, 30, 45, 50, 60, 80, 100, 200, 300, 600, and 800 were acquired. Four patients did not have liver fibrosis, and the rest were four stage 1, three stage 2, four stage 3, and one stage 4 patients, respectively. The intraclass correlation coefficient for repeatability was 0.994 for DDVD/area(Sb0Sb2) and 0.978 for DDVD/area(Sb0Sb15). In the validation study, DDVD/area(Sb0Sb2) and area(Sb0Sb15) were 14.80 ± 3.06 and 26.58 ± 3.97 for healthy volunteers, 10.51 ± 1.51 and 20.15 ± 2.21 for stage 1–2 fibrosis patients, and 9.42 ± 0.87 and 19.42 ± 1.89 for stage 3–4 fibrosis patients. For 16 patients where IVIM analysis was performed, a combination of DDVD/area, PF, and Dfast achieved the best differentiation for nonfibrotic livers and fibrotic livers. DDVD/area were weakly correlated with PF or Dfast. Both DDVD/area(Sb0Sb2) and area(Sb0Sb15) are useful imaging biomarkers to separate fibrotic and nonfibrotic livers, with fibrotic livers having lower measurements.

肝血管密度可以通过成像生物标志物扩散衍生的血管密度 (DDVD) 进行评估：DDVD/area(b0b2) = Sb0/ROIarea0 – Sb2/ROIarea2，其中 Sb0 和 Sb2 指的是b为 0 或 2时的肝脏信号（秒/毫米² ); ROIarea0 和 ROIarea2 指的是b = 0 或 2 张图像上的感兴趣区域（ROI）；Sb2 可以由 Sb15 ( b = 15)代替。这一概念在本研究中得到了验证。肝脏扩散图像是在 1.5 T 下采集的。对于六名受试者的重新扫描重复性研究，使用了 0 和 2 的b值。验证研究由 26 名健康志愿者和 19 名连续疑似慢性病毒性乙型肝炎患者组成，扩散图像带有b获取了 0、2、15、20、30、45、50、60、80、100、200、300、600 和 800 的值。4例患者未发生肝纤维化，其余分别为4例1期、3例2期、4例3期和1例4期患者。DDVD/区域(Sb0Sb2) 和 DDVD/区域(Sb0Sb15) 重复性的组内相关系数为 0.994。在验证研究中，健康志愿者的 DDVD/面积(Sb0Sb2) 和面积 (Sb0Sb15) 分别为 14.80 ± 3.06 和 26.58 ± 3.97，1-2 期纤维化患者为 10.51 ± 1.51 和 20.15 ± 2.21，以及 09 ± 2.42 和 19.42。 3-4 期纤维化患者为 1.89。对于进行 IVIM 分析的 16 名患者，DDVD/面积、PF 和 Dfast 的组合实现了对非纤维化肝脏和纤维化肝脏的最佳区分。DDVD/面积与PF或Dfast弱相关。