Abstract 17540: Diagnostic Accuracy of Myocardial T1-Mapping to Detect Cardiac Amyloidosis

Abstract

Introduction: Cardiac amyloidosis often demonstrates a typical diffuse, predominantly subendocardial pattern of myocardial delayed contrast enhancement (DCE) in cardiac magnetic resonance (CMR). A quantitative method for amyloid burden estimation could be useful in these patients.

Hypothesis: Quantification of contrast-induced reductions in myocardial T1 times with T1-mapping is accurate to diagnose cardiac amyloidosis.

Methods: We retrospectively reviewed consecutive patients referred for CMR for clinically suspected cardiac amyloidosis. The diagnosis of cardiac amyloid was defined as positive cardiac biopsy or typical DCE. The ratio of myocardial/blood T1 times after Gd-DTPA administration was quantified on Look-Locker sequences using dedicated software. Diagnostic accuracy was evaluated with the area under the curve (AUC) in receiving operator characteristics analysis.

Results: We analyzed 85 patients (59 males [69.4%], age 63 ±14 years) evaluated at 1.5 Tesla (n=48) or 3 Tesla (n=37) magnets. Cardiac amyloid was present in 36 patients (42.4%). The myocardial/blood T1 ratio was lower in patients with cardiac involvement than those without (1.14 vs 1.69, respectively; p<0.001). T1 mapping had good diagnostic accuracy for the detection of cardiac amyloidosis (AUC = 0.80, 95% CI -0.701-0.897, p<0.001; Figure), slightly better for 3.0 Tesla (AUC=0.83, 95% CI 0.69-0.98; p=0.001) than for 1.5 Tesla studies (AUC 0.76, 95% CI 0.61-0.90; p= 0.003). A cutoff-value of 1.27 provided a sensitivity of 80% and a specificity of 76% for the diagnosis.

Conclusion: The ratio of myocardial/blood T1 times as quantified with T1-mapping provides an objective and quantitative method to demonstrate myocardial amyloid infiltration with good accuracy, as demonstrated in this large clinical series.