Comparison of scar signal quantification using phase corrected and conventional magnitude inversion recovery delayed enhancement imaging in patients with ischemic and non-ischemic cardiomyopathy

Background Myocardial scar volume quantification has been shown to predict response to medical, surgical, and device therapy. Phase sensitive inversion recovery (PSIR)-based Late Gadolinium Enhancement (LGE) image reconstruction is clinically attractive for its reduced dependence on accurate prescription of the Time from Inversion (TI time), and is becoming a preferred approach for many centers. However, while an efficient approach for the visual interpretation of myocardial injury, the influence of this approach on signal-threshold based scar volume quantification has been poorly explored. Methods A total of 80 patients with obvious myocardial scar by LGE imaging (40 ischemic, 40 non-ischemic) underwent blinded evaluations of total scar volume (%LV mass) using matched MIR and PSIR short axis images. Analysis was performed using the Signal Threshold Versus Reference Myocardium (STRM) technique at ≥2, ≥3, and ≥5 SD thresholds. In those with ischemic scar the Full Width at Half Maximum (FWHM) approach was incrementally evaluated. Linear regression and BlandAltman analyses comparing MIR verses PSIR-based scar quantification was performed. Results Linear regression analysis demonstrated an excellent correlation between PSIR and MIR-based STRM scar volumes at all 3 STRM-based thresholds for both ischemic scar (r=0.96, 0.95, and 0.88, respectively) and non-ischemic scar (r=0.86, 0.89, 0.90, respectively). FWHM analysis showed good correlation in ischemic scar (r=0.83). Bland-Altman analysis of STRM analysis showed a systematic bias with lower scar volumes produced by PSIR reconstruction images for both ischemic and non-ischemic scar. These differences were modest using STRM for ischemic scar (-3.3, -4.0 and -4.9%,