Applicability Study Of Breast MR Using LAVA Dynamic Enhancement Imaging And Image Registration

Objectives: Performance assessment of using the LAVA dynamic enhancement imaging and image registration technique to improve the quality of breast MR images and correct the Signal-time curve of suspected tumor focuses.Materials and methods: A total of 28 patients suspected for the occurrence of breast cancer via the precious X-ray inspections were scanned using LAVA as well as conventional MR imaging sequences. These subjects were divided into three groups according to different pathologies: malignant breast cancer (BC, n=10), breast fibroadenoma (BF, n=6) and breast hyperplasia (BH, n=12). The rigid, affine and non-rigid image registration was performed on all datasets using the ITK (Image Registration Toolkit) software. The region-of-interests (ROI) were selected around the focuses and the corresponding signal-time (SI) curves were estimated on both pre- and post-registration images. The qualitative comparisons were achieved by visual inspection and manually rating the results (3 to 1 from the best to the worst), while the quantitative assessment was based on estimating the changes of intensity slope (IS) of SI curves and early-phase enhancement rates (EP-ER).Results: Specifically, before registration 11 of all subjects (39.29%) were rated at level 3 while 9 subjects were at level 2 and 8 images were at level 1. After the registration, the image quality was clearly improved as 26 images (92.86%) were rated at level 3 and only 2 subjects were at level 2. No images were classified as the worst any more. For the purpose of qualitative evaluation, the Chi-square test was performed to compare the image quality (X2=18.536 , p<0.05). For the purpose of quantitative evaluation, the Wilcoxon signed rank test was performed to compare both the intensity slope of SI curves and the early-phase enhancement rates (SI: BC group Z=-2.191,p=0.028<0.05; BF Z=-2.130,p=0.033<0.05; BH Z=-2.353,p=0.019<0.05; EP-ER: BC Z=-1.998 and p=0.047<0.05; BF Z=-2.215,p=0.027<0.05; BH Z=-2.392,p=0.017<0.05).Conclusion:The image registration technique was applied to correct the LAVA MR images. Both qualitative and quantitative evaluation showed the image registration technique did effectively improve the quality of LAVA breast images and correct the signal-time curves, which leads to more accurate estimation of early-phase enhancement rates (EP-ER). The diagnosis of malignant breast cancer is therefore improved.