An atlas-based transformation effectively corrected regional and global shape bias between GRE and SSFP cardiovascular magnetic resonance imaging protocols, reducing end-diastolic surface bias from 0.75 mm to 0.06 mm.
Observational (n=451)
Yes
Does an atlas-based transformation correct regional shape bias due to different CMR imaging protocols (GRE vs SSFP) in population studies?
An atlas-based transformation effectively corrects regional and global shape biases between GRE and SSFP CMR protocols, enabling pooled meta-analyses of multi-center imaging data.
Absolute Event Rate: 0.06% vs 0.75%
BACKGROUND: Cardiovascular imaging studies generate a wealth of data which is typically used only for individual study endpoints. By pooling data from multiple sources, quantitative comparisons can be made of regional wall motion abnormalities between different cohorts, enabling reuse of valuable data. Atlas-based analysis provides precise quantification of shape and motion differences between disease groups and normal subjects. However, subtle shape differences may arise due to differences in imaging protocol between studies. METHODS: A mathematical model describing regional wall motion and shape was used to establish a coordinate system registered to the cardiac anatomy. The atlas was applied to data contributed to the Cardiac Atlas Project from two independent studies which used different imaging protocols: steady state free precession (SSFP) and gradient recalled echo (GRE) cardiovascular magnetic resonance (CMR). Shape bias due to imaging protocol was corrected using an atlas-based transformation which was generated from a set of 46 volunteers who were imaged with both protocols. RESULTS: Shape bias between GRE and SSFP was regionally variable, and was effectively removed using the atlas-based transformation. Global mass and volume bias was also corrected by this method. Regional shape differences between cohorts were more statistically significant after removing regional artifacts due to imaging protocol bias. CONCLUSIONS: Bias arising from imaging protocol can be both global and regional in nature, and is effectively corrected using an atlas-based transformation, enabling direct comparison of regional wall motion abnormalities between cohorts acquired in separate studies.
Medrano−Gracia et al. (2013) conducted an observational in Healthy volunteers and myocardial infarction (n=451). Atlas-based transformation (z-score correction) vs. Uncorrected shape models was evaluated on End-diastolic surface bias (root mean squared error). An atlas-based transformation effectively corrected regional and global shape bias between GRE and SSFP cardiovascular magnetic resonance imaging protocols, reducing end-diastolic surface bias from 0.75 mm to 0.06 mm.