Intense Septal Enhancement on Cardiac MRI Flags Cardiac Amyloidosis

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.

Results 

• The thickness of IAS did not differ between patients with and without LGE, including patients with intensive LGE; however, the anterior and posterior parts of IAS were more common in patients with CA (83.3% and 86.8%, respectively) than in patients with HCM (15.4% and 42.3%, respectively) and DCM (26.9% and 65.4% respectively; P < 0.001 for all comparisons).
• LV atria was more common in patients with CA than in patients with HCMP and DCMP (74.1% versus 30.8% and 32.7%, respectively; P < 0.001 for all comparisons), and hypertrophy of the left atrium wall, although infrequent, was observed exclusively in patients with KA (n = 3).
• Intense (grade 2) IAS LGE was detected in 55.6 % of patients with CA, but only in one patient with HCM (1.9 %) and one patient with DCM (1.9 %; overall P < 0.001); no significant difference was observed in pairwise comparisons between HCM and DCM.
• Intensive anterior imaging of the IAS demonstrated high specificity — 98.1% (95% CI, 93.3%–99.5%) — and positive predictive value — 93.8% (95% CI, 79.9%–98.3%).

The authors concluded that a systematic assessment of the interatrial septum and atrial walls using gadolinium‑based contrast enhancement provides highly specific diagnostic information about the presence of cardiac amyloidosis. Routine integration of the assessment of the interatrial septum using gadolinium‑based contrast enhancement into the process of interpreting cardiac MRI can improve differentiation from phenocopies of cardiomyopathies encountered in everyday clinical practice.

 

https://www.medscape.com/viewarticle/intense-septal-enhancement-cardiac-mri-flags-cardiac-2026a1000xfy