Pednekar Amol S, Muthupillai Raja, Lenge Veronica V, Kakadiaris Ioannis A, Flamm Scott D
Department of Radiology, St. Luke's Episcopal Hospital and Texas Heart Institute, Houston, Texas 77030, USA.
J Magn Reson Imaging. 2006 May;23(5):641-51. doi: 10.1002/jmri.20552.
To evaluate the technical feasibility of two approaches--dual-contrast (DC) cluster analysis, and scout geometry (SG)--for automatic identification of the left ventricular (LV) cavity in short-axis (SA) cine-MR images.
The DC algorithm uses Fuzzy C-Means (FCM) cluster analysis of SA images from a black-blood double-inversion recovery turbo spin-echo (dual IR TSE) sequence, and bright-blood images from a steady-state free precession (SSFP) sequence. The SG algorithm employs geometric information from scout views (i.e., vertical long-axis (VLA) and four-chamber (4CH) views). Both algorithms incorporate additional geometric continuity constraints along with LV region segmentation to identify the LV. The performance of both algorithms was compared on images of eight healthy volunteers, and the SG algorithm was further evaluated on images of 13 clinical patients.
The DC algorithm identified the LV in 89% (72/75 at end-diastole (ED) and 47/59 at end-systole (ES)) of the images from healthy volunteers, compared to 98% (74/75 at ED and 57/59 at ES) by the SG algorithm. Both methods are robust against interslice signal variations and misalignment. The DC method suffers from misregistration between the dual IR TSE and SSFP images near the apex at ES. The SG method identified the LV in 91% (112/122 at ED and 91/102 at ES) of the images from clinical patients.
The SG method requires no additional scan, is robust and accurate, and performs better than the DC method for automatic identification of the LV.
评估两种方法——双对比(DC)聚类分析和定位扫描几何(SG)——在短轴(SA)心脏磁共振成像(cine-MR)图像中自动识别左心室(LV)腔的技术可行性。
DC算法对来自黑血双反转恢复快速自旋回波(双IR TSE)序列的SA图像以及稳态自由进动(SSFP)序列的亮血图像进行模糊C均值(FCM)聚类分析。SG算法利用定位扫描视图(即垂直长轴(VLA)和四腔心(4CH)视图)的几何信息。两种算法都结合了额外的几何连续性约束以及LV区域分割来识别LV。在8名健康志愿者的图像上比较了两种算法的性能,并在13名临床患者的图像上进一步评估了SG算法。
健康志愿者图像中,DC算法在舒张末期(ED)识别出LV的比例为89%(72/75),收缩末期(ES)为47/59;而SG算法在ED时为98%(74/75),ES时为57/59。两种方法对层间信号变化和错位都具有鲁棒性。DC方法在ES时心尖附近的双IR TSE和SSFP图像之间存在配准错误。SG方法在临床患者图像中ED时识别出LV的比例为91%(112/122),ES时为91/102。
SG方法无需额外扫描,稳健且准确,在自动识别LV方面比DC方法表现更好。