Bock M, Schoenberg S O, Floemer F, Schad L R
FS Radiologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum Heidelberg, Germany.
Magn Reson Med. 2000 Mar;43(3):481-7. doi: 10.1002/(sici)1522-2594(200003)43:3<481::aid-mrm21>3.0.co;2-n.
Multiphase contrast-enhanced 3D MR angiography (MRA) data sets allow the separate visualization of the arterial and venous pulmonary vasculature. However, due to short arterial-to-venous bolus transit times in the lung, the generation of pure venograms without arterial overlay is difficult. To suppress arterial signal in venograms, early arterial phase data are typically subtracted from peak venous phase images. In this study, a correlation algorithm is used to postprocess the multiphase 3D MRA data sets. The cross-correlation between a measured arterial or venous reference function and the local signal-time course is computed which highlights image locations with a similar signal-time curve as the reference function and suppresses constant signal. Conventional maximum intensity projections (MIP) are generated from the arterial and venous correlation maps. In a study with five volunteers, an increase in SNR by a factor of 2.1 (1.8) of arterial (venous) correlation MIP images over subtraction MIP images was observed.
多期对比增强三维磁共振血管造影（MRA）数据集能够分别显示肺动脉和肺静脉血管系统。然而，由于肺部动脉到静脉的团注通过时间较短，很难生成没有动脉重叠的纯静脉造影图像。为了在静脉造影中抑制动脉信号，通常从静脉峰值期图像中减去早期动脉期数据。在本研究中，使用一种相关算法对多期三维MRA数据集进行后处理。计算测量的动脉或静脉参考函数与局部信号时间曲线之间的互相关性，这突出显示了与参考函数具有相似信号时间曲线的图像位置，并抑制恒定信号。从动脉和静脉相关图生成传统的最大强度投影（MIP）。在一项对五名志愿者的研究中，观察到动脉（静脉）相关MIP图像的信噪比相对于减法MIP图像提高了2.1（1.8）倍。
