Christen Thomas, Ni Wendy, Qiu Deqiang, Schmiedeskamp Heiko, Bammer Roland, Moseley Michael, Zaharchuk Greg
Department of Radiology, Stanford University, Stanford, California, USA.
Magn Reson Med. 2013 Sep;70(3):705-10. doi: 10.1002/mrm.24500. Epub 2012 Sep 21.
Cerebral blood volume maps are usually acquired using dynamic susceptibility contrast imaging which inherently limits the spatial resolution and signal to noise ratio of the images. In this study, we used ferumoxytol (AMAG Pharmaceuticals, Inc., Cambridge, MA), an FDA-approved compound, to obtain high-resolution cerebral blood volume maps with a steady-state approach in seven healthy volunteers. R2* maps (0.8 × 0.8 × 1 mm(3)) were acquired before and after injection of ferumoxytol and an intraindividual normalization protocol was used to obtain quantitative values. The results show excellent contrast between white and gray matter as well as fine highly detailed vascular structures. An average blood volume of 4% was found in the brain of all volunteers, consistent with prior literature values. A linear relationship was found between ferumoxytol dose (mg/kg) and ΔR2* (1/s) in gray (R(2) = 0.98) and white matter (R(2) = 0.98). A quadratic relationship was found in the sagittal sinus (R(2) = 0.98). The cerebral blood volume maps compare well with lower resolution dynamic susceptibility contrast-MRI and their use should improve the evaluation of small and heterogeneous lesions and facilitate intrapatient and interpatient comparisons.
脑血容量图通常采用动态磁敏感对比成像来获取,这本质上限制了图像的空间分辨率和信噪比。在本研究中,我们使用了经美国食品药品监督管理局(FDA)批准的化合物铁羧麦芽糖(AMAG制药公司,马萨诸塞州剑桥),采用稳态方法在7名健康志愿者中获得高分辨率脑血容量图。在注射铁羧麦芽糖前后采集R2图(0.8×0.8×1 mm³),并使用个体内归一化方案来获得定量值。结果显示白质和灰质之间以及精细高度详细的血管结构之间具有出色的对比度。所有志愿者大脑中的平均血容量为4%,与先前的文献值一致。在灰质(R² = 0.98)和白质(R² = 0.98)中发现铁羧麦芽糖剂量(mg/kg)与ΔR2(1/s)之间存在线性关系。在矢状窦中发现了二次关系(R² = 0.98)。这些脑血容量图与低分辨率动态磁敏感对比MRI相比效果良好,它们的应用应能改善对小的和异质性病变的评估,并便于患者内和患者间的比较。