The role of the right and left ventricular blood pool T2 on cardiac magnetic resonance in cardiac amyloidosis

Background: Cardiac amyloidosis (CA) is an infiltrative cardiomyopathy caused by extracellular deposition of misfolded proteins. While cardiovascular magnetic resonance (CMR) is established for myocardial tissue characterization, emerging evidence suggests that ventricular blood T2 mapping may provide non-invasive insights into cardiopulmonary oxygenation and hemodynamic. This study aimed to investigate the diagnostic and prognostic role of right and left ventricular blood T2 values in patients with CA. Methods: This is a single-center observational study including n=53 patients with biopsy-proven or non-invasively diagnosed CA (25 AL, 28 ATTR) referred to Padova University Hospital. Patients were compared with n=65 patients with left ventricular hypertrophy (LVH) and preserved ejection fraction and n=43 healthy controls. All participants underwent CMR, including cine imaging, T1 and T2 mapping, and late gadolinium enhancement (LGE). Right (RV) and left ventricular (LV) blood T2 values were measured at the T2 mapping sequences of the mid ventricle. Clinical, functional, and prognostic correlations were assessed. Results: RV and LV blood T2 values were significantly lower in CA patients compared with both LVH patients and healthy controls (RV blood T2: 130 vs. 146/159 ms; LV blood T2: 170 vs. 181/182 ms; p < 0.05). The ΔT2 (LV–RV difference) was increased in CA patients, reflecting impaired cardiopulmonary oxygen dynamics. Lower RV and LV blood T2 values were associated with increased myocardial wall thickness, higher T1 mapping values, and reduced longitudinal systolic function (lateral MAPSE). The diagnostic performance of RV and LV blood T2 was modest (AUC 0.65 and 0.63, respectively). During a median follow-up of 21 months, patients with lower RV and LV blood T2 experienced significantly higher rates of heart failure hospitalization and all-cause mortality (p = 0.028 and p = 0.040). Concomitant reduction of both RV and LV blood T2 identified a subgroup with particularly poor prognosis (12-month event-free survival: 68% vs. 94%). Conclusions: This study demonstrates that patients with CA show significant reductions in RV and LV blood T2 values, reflecting altered oxygenation dynamics secondary to restrictive amyloid infiltration. Lower blood T2 values were associated with more advanced structural and functional impairment and with worse clinical outcomes, including higher rates of heart failure hospitalization and mortality. These results highlight the potential of blood T2 mapping as a novel, non-contrast, and physiologically informative imaging biomarker for the integrated assessment and risk stratification of CA.