Feasibility of Gadolinium-enhanced T1* Ratio Mapping for Myocardial Tissue Characterization.

Purpose To evaluate the diagnostic performance of T1* ratio mapping, a novel postprocessing algorithm applied to standard inversion time (TI) scout images for cardiac tissue characterization. Materials and Methods This retrospective study included patients who underwent cardiac MRI examinations between 2015 and 2023 and were diagnosed with cardiac amyloidosis (CA), myocarditis, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), or no disease (healthy controls). Motion-corrected postcontrast T1* ratio maps were generated from TI scout images using blood pool, skeletal muscle, and spleen as reference tissues. Diagnostic performance was evaluated using receiver operating characteristic curve analysis; group differences were assessed with nonparametric tests; and correlations between T1* ratio mapping and late gadolinium enhancement (LGE) quantification were analyzed. Results The study included 130 patients (mean age, 63 years ± 21 [SD]; 90 male patients; 30 with CA, 20 with myocarditis, 20 with DCM, 30 with HCM, and 30 controls). Spleen-referenced T1* ratio showed the highest area under the receiver operating characteristic curve (AUC) of the reference tissues for distinguishing pooled disease cases from controls (AUC = 0.76 [95% CI: 0.68, 0.84]). It achieved excellent discriminatory ability for CA cases versus controls (AUC > 0.99 [95% CI: >0.99, >0.99]), CA versus other pooled diseases (AUC = 0.97 [95% CI: 0.94, >0.99]), and differentiating affected from unaffected myocarditis segments (AUC = 0.93 [95% CI: 0.86, 0.98]). Spleen-referenced T1* ratio strongly correlated with LGE quantification (R = 0.85) and identified a greater extent of myocardial involvement than LGE in cardiomyopathies (r_b = 0.22). Conclusion T1* ratio mapping showed potential in identifying pathologic myocardial changes in various conditions. Easy integration into existing setups as a postprocessing algorithm may facilitate broader access to myocardial tissue characterization. Keywords: MRI, Cardiomyopathies, Tissue Characterization Supplemental material is available for this article. © RSNA, 2025.