Evaluation of functional tumor blood flow map using dynamic MRI and compartment analysis

血管生成与肿瘤的生长、侵袭和转移密切相关。尽管肿瘤血流量通过血管生成而增加，但目前还没有建立无创测量体内肿瘤血流量的方法。在本研究项目中，我们开发了一种利用动态增强磁共振成像(MRI)和隔室分析来定量测量体内肿瘤血流量(TBF)的新方法。采用反转恢复准备快速场回波(IR-FFE)序列(TR/TE/TT7.7/3.9/280 msec，翻转角10度，视野380×190 mm，矩阵256×128，层厚6 mm)进行动态增强扫描。通过对来自动脉和肿瘤的信号强度-时间曲线进行去卷积分析，逐个像素地生成定量的TBF图(ml/100ml/min)。TBF图清楚地显示了TBF的异质性，即肿瘤周围因血管生成而导致的TBF增加，而肿瘤中心的TBF较低。在接受化疗的患者中，在化疗周期后，TBF发生了实质性的变化，反映了治疗效果。在手术标本上，与常规增强的T1加权图像相比，TBF图能更好地预测活体和非活体肿瘤细胞的分布和化疗效果。因此，TBF MAP是一种很有前途的评估肿瘤血流的工具，并可能有助于评估治疗反应。

Angiogenesis correlates with tumor growth, invasion and metastasis. Although tumor blood flow increased by angiogensis, it has not been established to noninvasively measure tumor blood flow in vivo. In this research project, we have developed a new method for quantitative measurement of tumor blood flow(TBF) in vivo by using dynamic contrast-enhanced magnetic resonance imaging(MRI) and compartment analysis. Dynamic contrast-enhanced MRI was performed using inversion recovery-preparation fast field echo(IR-FFE) sequence(TR/TE/TT 7.7/3.9/280msec, flip angle 10 degree, FOV 380x190mm, matrix 256x128, slice thickness 6mm). Quantitative TBF maps(ml/100ml/min) were generated pixel-by-pixel by deconvolution analysis of the signal intensity-time curves obtained from arteries and tumors. TBF map clearly demonstrated heterogeneity ofTBF, i.e. increased TBF in tumor periphery due to angiogenesis and low TBF in center of tumor. In patients who received chemotherapy, substantial changes of TBF were demonstrated after chemotherapeutic cycles, reflecting the therapeutic response. On surgical specimens, the distribution of viable and non-viable tumor cells and the chemotherapeutic effects were better predicted by the TBF maps rather than the conventional contrast-enhanced T1-weighted MR images. Thus, TBF map would be a promising tool for evaluating tumor blood flow and may be useful to evaluate treatment response.