OBJECTIVES: This study sought to explore the potential role of noncontrast 
myocardial T1 mapping for detection of cardiac involvement in patients with 
primary amyloid light-chain (AL) amyloidosis.
BACKGROUND: Cardiac involvement carries a poor prognosis in systemic AL 
amyloidosis. Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) 
is useful for the detection of cardiac amyloid, but characteristic LGE patterns 
do not always occur or they appear late in the disease. Noncontrast 
characterization of amyloidotic myocardium with T1 mapping may improve disease 
detection. Furthermore, quantitative assessment of myocardial amyloid load would 
be of great value.
METHODS: Fifty-three AL amyloidosis patients (14 with no cardiac involvement, 11 
with possible involvement, and 28 with definite cardiac involvement based on 
standard biomarker and echocardiographic criteria) underwent CMR (1.5-T) 
including noncontrast T1 mapping (shortened modified look-locker inversion 
recovery [ShMOLLI] sequence) and LGE imaging. These were compared with 36 
healthy volunteers and 17 patients with aortic stenosis and a comparable degree 
of left ventricular hypertrophy as the cardiac amyloid patients.
RESULTS: Myocardial T1 was significantly elevated in cardiac AL amyloidosis 
patients (1,140 ± 61 ms) compared to normal subjects (958 ± 20 ms, p < 0.001) 
and patients with aortic stenosis (979 ± 51 ms, p < 0.001). Myocardial T1 was 
increased in AL amyloid even when cardiac involvement was uncertain (1,048 ± 48 
ms) or thought absent (1,009 ± 31 ms). A noncontrast myocardial T1 cutoff of 
1,020 ms yielded 92% accuracy for identifying amyloid patients with possible or 
definite cardiac involvement. In the AL amyloidosis cohort, there were 
significant correlations between myocardial T1 time and indices of systolic and 
diastolic dysfunction.
CONCLUSIONS: Noncontrast T1 mapping has high diagnostic accuracy for detecting 
cardiac AL amyloidosis, correlates well with markers of systolic and diastolic 
dysfunction, and is potentially more sensitive for detecting early disease than 
LGE imaging. Elevated myocardial T1 may represent a direct marker of cardiac 
amyloid load. Further studies are needed to assess the prognostic significance 
of T1 elevation.