TOPLINE

Intense late gadolinium enhancement (LGE) of the anterior interatrial septum (IAS) on routine cardiac MRI (CMR) demonstrated a specificity of 98% for cardiac amyloidosis (CA) when compared with hypertrophic cardiomyopathy (HCM) and dilated CM (DCM), a retrospective study found.

METHODOLOGY

• Researchers conducted a retrospective analysis of 159 patients who underwent CMR, including 55 consecutive patients with CA between 2007 and 2024 and two comparator groups (52 consecutive patients with HCM and DCM each) at a single centre in France.
• The diagnosis of CA was established through histologic confirmation (endomyocardial or extracardiac biopsy), bone scintigraphy, monoclonal protein screening, and genetic testing when necessary.
• IAS thickness and LGE patterns were assessed on anterior and posterior aspects relative to the fossa ovalis in four-chamber cine views.
• IAS LGE was visually analysed and graded on a three-stage scale, with 0 indicating no LGE, 1 indicating the presence of LGE, and 2 indicating intense LGE (defined as enhancement greater than or equal to ventricular LGE).
• The researchers assessed IAS thickness, atrial morphology, LGE patterns, left atrial volume index, atrial wall thickness, and T1 and T2 mapping values.

TAKEAWAY

• IAS thickness did not differ between patients with and without LGE, including those with intense LGE; however, anterior and posterior IAS LGE were more frequent in those with CA (83.3% and 86.8%, respectively) than in those with HCM (15.4% and 42.3%, respectively) and DCM (26.9% and 65.4%, respectively; P < .001 for all comparisons).
• Atrial LGE was more frequent among patients with CA than among those with HCM and DCM (74.1% vs 30.8% and 32.7%; P < .001 for all comparisons), and left atrial wall hypertrophy, although uncommon, was observed exclusively in those with CA (n = 3).
• Intense (grade 2) IAS LGE was identified in 55.6% of patients with CA but in only one patient with HCM (1.9%) and one patient with DCM (1.9%; overall P < .001); no significant difference in pairwise comparisons was observed between HCM and DCM.
• Intense anterior IAS LGE yielded a high specificity of 98.1% (95% CI, 93.3%-99.5%) and a positive predictive value of 93.8% (95% CI, 79.9%-98.3%).

IN PRACTICE

"Systematic assessment of the interatrial septum and atrial walls using late gadolinium enhancement provides highly specific diagnostic information for cardiac amyloidosis. Routine integration of IAS LGE evaluation into CMR interpretation may improve differentiation from cardiomyopathy phenocopies encountered in daily clinical practice," the authors wrote.

SOURCE

The study was led by Audrey Menard, University of Angers, Angers, France. It was published online on August 31, 2026, in the European Journal of Radiology.

LIMITATIONS

The study was limited by its retrospective, single-centre design and the lack of healthy control individuals and other cardiomyopathies. CMR spatial resolution remained limited for atrial wall evaluation. Chemical shift artefacts hindered the interpretation of cine CMR and T1-weighted imaging in some cases, although LGE analysis remained largely unaffected. The relatively small group sizes may have limited the robustness of sensitivity and specificity estimates. Because the diagnosis of CA in this cohort partly relied on conventional CMR features such as ventricular LGE, IAS LGE's apparent diagnostic value might be inflated by circularity, and the findings showed an association rather than proven independent value. Furthermore, prognostic implications of atrial or IAS LGE were not assessed.

DISCLOSURES

Funding information for the study was not provided. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.