Abstract Body (Do not enter title and authors here): Introduction:
Late gadolinium enhancement (LGE) observed on cardiac magnetic resonance imaging (CMR) has emerged as a potential indicator of myocardial involvement in cardiac amyloidosis (CA). However, discerning which LGE patterns in amyloidosis distinguish it from other cardiomyopathies remains unclear. This study aims to compare LGE characteristics in a predominantly African American cohort who underwent endomyocardial biopsies. Despite advancements in cardiac imaging techniques, the endomyocardial biopsy remains the gold standard for amyloidosis diagnosis. Insights garnered from this analysis could enhance diagnostic precision and facilitate earlier detection.

Methods:
In this retrospective study at MedStar Union Memorial Hospital in Baltimore, MD, patients who underwent both endomyocardial biopsy and CMR were included. The study compared individuals with biopsy-proven amyloidosis (both AL and ATTR) to those with negative biopsy results. LGE patterns were selected based on their frequent use in CMR interpretation. Statistical analysis employed Pearson chi-square and t-tests.

Results:
The cohort comprised 42 patients who underwent biopsy, with 13 patients (31%) with positive biopsy results. Among them, 24 were men (57%), and 81% identified as African American. Demographic, anthropomorphic, and objective clinical findings are detailed in Table 1. The average age of the cohort was 68 years, with those with biopsy-proven amyloidosis significantly older (75 vs. 61 years, p = 0.002). Although the biopsy-positive group exhibited a lower absolute NT-pro-BNP, the difference was not statistically significant. The most prevalent LGE patterns among the biopsy-positive group were diffuse (62%) and basal (31%). Notably, 69% of biopsy-positive patients exhibited an LGE pattern described as infiltrative. However, 38% of the biopsy-negative group also manifested infiltrative patterns on LGE, a difference not statistically significant compared to the biopsy-positive group. The positive predictive value of an infiltrative LGE pattern was low (45%).

Conclusion:
This study compares CMR LGE patterns in biopsy proven CA. Despite findings of an infiltrative LGE pattern on CMR, when using endomyocardial biopsy as the gold standard, the positive predictive value of LGE in differentiating CA patients was low. Further research and larger studies are warranted to explore additional imaging modalities or biomarkers that may complement or refine the diagnostic algorithm for CA.