Grayscale-inverted bright-blood late gadolinium enhancement improves reader confidence in ischemic scar detection: a...

Bright-blood late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) is standard for myocardial scar detection, yet subendocardial infarcts may be difficult to identify due to limited scar-blood contrast. Grayscale inversion is a simple, vendor-independent post-processing technique that may enhance visual contrast. We assessed whether grayscale inversion improves diagnostic accuracy or reader confidence, and whether its effect varies by reader experience or scanner vendor.

In this single-center, multivendor study, 120 patients (90 with and 30 without ischemic scar) underwent 2D bright-blood LGE on GE, Philips, and Siemens 1.5 T scanners. Three short-axis slices per patient were evaluated in standard bright-blood and grayscale-inverted visualizations by nine readers (three per EACVI experience level). Readers assessed scar presence, transmurality, and diagnostic confidence (4-point scale). Consensus of two Level-3 experts served as reference.

Across 34,560 segment-level assessments, diagnostic accuracy was high (91.5%, 95% CI 91.0-91.9%) and similar for standard vs. inverted images (90.7% vs. 91.9%, p = 0.27), with no differences across experience levels or in low-transmurality lesions. In contrast, reader confidence increased significantly with grayscale-inversion (3.25 ± 0.81 vs. 2.78 ± 0.88, p < 0.0001), with the greatest relative improvement among Level-1 readers (2.63 ± 0.89 → 3.00 ± 0.83, p < 0.001). Interobserver agreement and transmurality reproducibility remained unchanged. Results were consistent across vendors.

Grayscale-inverted bright-blood LGE significantly increases reader confidence without compromising diagnostic accuracy or interobserver agreement. This simple, vendor-neutral technique may support training and improve interpretive certainty in routine clinical LGE assessment.