Synthetic multi‐contrast late gadolinium enhancement imaging using post‐contrast magnetic resonance fingerprinting

Abstract

AbstractLate gadolinium enhancement (LGE) MRI is the non‐invasive reference standard for identifying myocardial scar and fibrosis but has limitations, including difficulty delineating subendocardial scar and operator dependence on image quality. The purpose of this work is to assess the feasibility of generating multi‐contrast synthetic LGE images from post‐contrast T1 and T2 maps acquired using magnetic resonance fingerprinting (MRF). Fifteen consecutive patients with a history of prior ischemic cardiomyopathy (12 men; mean age 63   13 years) were prospectively scanned at 1.5 T between Oct 2020 and May 2021 using conventional LGE and MRF after injection of gadolinium contrast. Three classes of synthetic LGE images were derived from MRF post‐contrast T1 and T2 maps: bright‐blood phase‐sensitive inversion recovery (PSIR), black‐ and gray‐blood T2‐prepared PSIR (T2‐PSIR), and a novel “tissue‐optimized” image to enhance differentiation among scar, viable myocardium, and blood. Image quality was assessed on a 1–5 Likert scale by two cardiologists, and contrast was quantified as the mean absolute difference (MAD) in pixel intensities between two tissues, with different methods compared using Kruskal–Wallis with Bonferroni post hoc tests. Per‐patient and per‐segment scar detection rates were evaluated using conventional LGE images as reference. Image quality scores were highest for synthetic PSIR (4.0) and reference images (3.8), followed by synthetic tissue‐optimized (3.3), gray‐blood T2‐PSIR (3.0), and black‐blood T2‐PSIR (2.6). Among synthetic images, PSIR yielded the highest myocardium/scar contrast (MAD = 0.42) but the lowest blood/scar contrast (MAD = 0.05), and vice versa for T2‐PSIR, while tissue‐optimized images achieved a balance among all tissues (myocardium/scar MAD = 0.16, blood/scar MAD = 0.26, myocardium/blood MAD = 0.10). Based on reference mid‐ventricular LGE scans, 13/15 patients had myocardial scar. The per‐patient sensitivity/accuracy for synthetic images were the following: PSIR, 85/87%; black‐blood T2‐PSIR, 62/53%; gray‐blood T2‐PSIR, 100/93%; tissue optimized, 100/93%. Synthetic multi‐contrast LGE images can be generated from post‐contrast MRF data without additional scan time, with initial feasibility shown in ischemic cardiomyopathy patients.