Schwyzer L, Berberat J, Remonda L, Roelcke U
Department of Neurosurgery/Brain Tumor Center, Cantonal Hospital Aarau, Tellstrasse, 5001 Aarau, Switzerland.
Department of Neuroradiology, Cantonal Hospital, Aarau, Switzerland.
J Neuroradiol. 2015 Dec;42(6):332-7. doi: 10.1016/j.neurad.2015.06.002. Epub 2015 Sep 26.
Cell-dense tumors may restrict diffusivity which can be measured by diffusion-weighted MRI (DWI), and which is quantified by the apparent diffusion coefficient (ADC). Little is known about diffusivity in meningiomas. These tumors frequently show hemorrhage and calcification which can be demonstrated using susceptibility weighted MRI (SWI). Both DWI and SWI represent T2-derived MRI sequences. Here we investigated ADC variability in meningiomas and analyzed whether susceptibility changes (SWIpos) alter diffusivity.
We grouped newly diagnosed meningiomas according to the presence (SWIpos) or absence (SWIneg) of susceptibility changes. ADC values were calculated using region-of-interest analysis, and ADC values of SWIpos and SWIneg meningiomas were compared. In addition ADC histograms were created.
We retrospectively studied 36 patients (13 WHO grade I, 8 WHO grade II, 15 suspected meningiomas). Thirteen meningiomas (36%) exhibited SWIpos. Global ADC values were higher in SWIpos (1.00 ± 0.15 × 10-3mm(2)/s) compared to SWIneg (0.82 ± 0.09 × 10-3mm(2)/s) tumors (P<0.0001). Meningiomas showing both SWIpos and SWIneg areas caused two separated histogram peaks, whereas homogeneously appearing meningiomas with either SWIposor SWIneg areas showed one peak only. ADC values did not correlate with age or gender, and showed substantial overlap between WHO grade I and II.
Susceptibility changes (SWIpos) in meningiomas influence measures of diffusivity by increasing ADC values on average by 38%. This shift has to be considered when conclusions on tumor behavior are drawn from DWI. Further studies should address whether ADC changes and histogram patterns can be used to monitor treatment of meningiomas.
细胞密集型肿瘤可能会限制扩散，扩散可通过扩散加权磁共振成像（DWI）测量，并通过表观扩散系数（ADC）进行量化。关于脑膜瘤的扩散情况知之甚少。这些肿瘤常表现出出血和钙化，可通过磁敏感加权成像（SWI）显示。DWI和SWI均代表基于T2的磁共振成像序列。在此，我们研究了脑膜瘤中ADC的变异性，并分析了磁敏感变化（SWI阳性）是否会改变扩散情况。
我们根据磁敏感变化的有无（SWI阳性或SWI阴性）对新诊断的脑膜瘤进行分组。使用感兴趣区分析计算ADC值，并比较SWI阳性和SWI阴性脑膜瘤的ADC值。此外，还创建了ADC直方图。
我们回顾性研究了36例患者（13例世界卫生组织一级，8例世界卫生组织二级，15例疑似脑膜瘤）。13例脑膜瘤（36%）表现为SWI阳性。与SWI阴性肿瘤（0.82±0.09×10-3mm(2)/s）相比，SWI阳性肿瘤的整体ADC值更高（1.00±0.15×10-3mm(2)/s）（P<0.0001）。同时显示SWI阳性和SWI阴性区域的脑膜瘤产生两个分开的直方图峰，而仅表现为SWI阳性或SWI阴性区域的均匀脑膜瘤仅显示一个峰。ADC值与年龄或性别无关，且在世界卫生组织一级和二级之间有大量重叠。
脑膜瘤中的磁敏感变化（SWI阳性）会影响扩散测量，平均使ADC值增加38%。从DWI得出关于肿瘤行为的结论时，必须考虑这种变化。进一步的研究应探讨ADC变化和直方图模式是否可用于监测脑膜瘤的治疗。
