Inter-modality comparison of non-invasive quantitative myocardial perfusion: dynamic myocardial perfusion computed tomography vs stress magnetic resonance

Abstract Background Stress myocardial blood flow (MBF) estimated from dynamic myocardial perfusion computed tomography (DynCTP-MBF) and cardiac magnetic resonance (CMR-MBF) due to their accessibility have emerged as promising modalities that could allow for the widespread use of non-invasive quantitative perfusion analysis in clinical practice. However, the underlying method of obtaining these measurements differs significantly between modalities and vendors. Consequently, the agreement between DynCTP-MBF and CMR-MBF is not well understood. Purpose To assess the agreement between DynCTP-MBF and CMR-MBF in pharmacological stress conditions. Methods We retrospectively enrolled consecutive patients who underwent both DynCTP-MBF and cardiac magnetic resonance (CMR) scans with pharmacological stress perfusion sequences within 23 days (IQR: 15–140). Stress MBF values were quantified through blinded analysis dedicated software tools for both CT and CMR. We investigated correlation and agreement of stress MBF on per-segment basis using Spearman’s method and Bland-Altman plots, respectively. We additionally examined proportional bias by regressing the difference between CMR-MBF and DynCTP-MBF on the average of the two measurements. We assessed inter-class correlation (ICC) using single fixed raters method for per-segment analyses and using average fixed raters method for per-segment and per-patient analyses. For concordance analysis, reduced CMR-MBF and DynCTP were defined as