Nordli Håkon, Taxt Torfinn, Moen Gunnar, Grüner Renate
Department of Radiology, Haukeland University Hospital, Bergen, Norway.
Acta Radiol. 2010 Apr;51(3):334-43. doi: 10.3109/02841850903536094.
Arterial input functions may differ between brain regions due to delay and dispersion effects in the vascular supply network. Unless corrected for, these differences may degrade quantitative estimations of cerebral blood flow in dynamic susceptibility contrast magnetic resonance perfusion imaging (DSC-MRI).
To investigate in a healthy population (n=44) the properties of voxel-specific arterial input functions that were obtained using a recently published blind estimation approach.
The voxel-specific arterial input functions were qualitatively and quantitatively assessed, through visual inspection or by comparing time-to-peak (delays) and peak amplitude (dispersion) values between eight regions of the brain. Furthermore, they were compared to arterial input functions selected manually in the middle cerebral artery (MCA), where normally no delay or dispersion of the contrast agent was expected.
The estimated voxel-specific arterial input functions varied between brain regions. Differences in delays and dispersion were larger within one brain region among all participants than between regions in one participant. A good correlation was typically found between the estimated voxel-specific arterial input functions and the manually selected arterial input functions in the MCA region.
Given knowledge of neurovascular anatomy, the current blind approach seemingly produced reasonable estimates of voxel-specific arterial input functions. In addition to potentially reducing quantification errors in DSC-MRI, these user-independent voxel-specific arterial input functions could be useful for visualizing abnormal blood supply patterns in patients.
由于血管供应网络中的延迟和弥散效应,不同脑区的动脉输入函数可能存在差异。在动态磁敏感对比磁共振灌注成像(DSC-MRI)中,若不对此进行校正,这些差异可能会降低脑血流量定量估计的准确性。
在健康人群(n = 44)中研究使用最近发表的盲估计方法获得的体素特异性动脉输入函数的特性。
通过视觉检查或比较大脑八个区域之间的达峰时间(延迟)和峰值幅度(弥散)值,对体素特异性动脉输入函数进行定性和定量评估。此外,将其与在大脑中动脉(MCA)中手动选择的动脉输入函数进行比较,在MCA中通常预计造影剂不会有延迟或弥散。
估计的体素特异性动脉输入函数在不同脑区之间存在差异。所有参与者中,一个脑区内延迟和弥散的差异大于单个参与者不同脑区之间的差异。在MCA区域,估计的体素特异性动脉输入函数与手动选择的动脉输入函数之间通常具有良好的相关性。
基于对神经血管解剖结构的了解,当前的盲估计方法似乎能够合理地估计体素特异性动脉输入函数。除了可能减少DSC-MRI中的量化误差外,这些独立于用户的体素特异性动脉输入函数可能有助于可视化患者异常的血液供应模式。