Jakubovic R, Sahgal A, Ruschin M, Pejovic-Milic A, Milwid R, Aviv R I
Department of Medical Imaging, Division of Neuroradiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
Technol Cancer Res Treat. 2014 Apr 16. doi: 10.7785/tcrtexpress.2013.600279.
To evaluate early perfusion changes in normal tissue following stereotactic radiosurgery (SRS). Methods: Nineteen patients harboring twenty-two brain metastases treated with SRS were imaged with dynamic susceptibility magnetic resonance imaging (DSC MRI) at baseline, 1 week and 1 month post SRS. Relative cerebral blood volume and flow (rCBV and rCBF) ratios were evaluated outside of tumor within a combined region of interest (ROI) and separately within gray matter (GM) and white matter (WM) ROIs. Three-dimensional dose distribution from each SRS plan was divided into six regions: (1) <2 Gy; (2) 2-5 Gy; (3) 5-10 Gy; (4) 10-12 Gy; (5) 12-16 Gy; and (6) >16 Gy. rCBV and rCBF ratio differences between baseline, 1 week and 1 month were compared. Best linear fit plots quantified normal tissue dose-dependency. Results: Significant rCBV ratio increases were present between baseline and 1 month for all ROIs and dose ranges except for WM ROI receiving <2 Gy. rCBV ratio for all ROIs was maximally increased from baseline to 1 month with the greatest changes occurring within the 5-10 Gy dose range (53.1%). rCBF ratio was maximally increased from baseline to 1 month for all ROIs within the 5-10 Gy dose range (33.9-45.0%). Both rCBV and rCBF ratios were most elevated within GM ROIs. A weak, positive but not significant association between dose, rCBV and rCBF ratio was demonstrated. Progressive rCBV and rCBF ratio increased with dose up to 10 Gy at 1 month. Conclusion: Normal tissue response following SRS can be characterized by dose, tissue, and time specific increases in rCBV and rCBF ratio.
评估立体定向放射外科治疗（SRS）后正常组织的早期灌注变化。方法：对19例患有22个脑转移瘤并接受SRS治疗的患者在基线、SRS后1周和1个月时进行动态磁敏感对比磁共振成像（DSC MRI）检查。在肿瘤外的联合感兴趣区（ROI）以及分别在灰质（GM）和白质（WM）ROI内评估相对脑血容量和血流（rCBV和rCBF）比值。每个SRS计划的三维剂量分布分为六个区域：（1）<2 Gy；（2）2 - 5 Gy；（3）5 - 10 Gy；（4）10 - 12 Gy；（5）12 - 16 Gy；和（6）>16 Gy。比较基线、1周和1个月时的rCBV和rCBF比值差异。最佳线性拟合图量化正常组织的剂量依赖性。结果：除接受<2 Gy的WM ROI外，所有ROI和剂量范围在基线和1个月之间均出现显著的rCBV比值增加。所有ROI的rCBV比值从基线到1个月最大增加，最大变化发生在5 - 10 Gy剂量范围内（53.1%）。在5 - 10 Gy剂量范围内，所有ROI的rCBF比值从基线到1个月最大增加（33.9% - 45.0%）。rCBV和rCBF比值在GM ROI内升高最为明显。剂量、rCBV和rCBF比值之间显示出微弱的正相关但不显著。在1个月时，rCBV和rCBF比值随剂量增加至10 Gy而逐渐升高。结论：SRS后正常组织反应可表现为rCBV和rCBF比值随剂量、组织和时间的特异性增加。
