Segment-by-segment assessment of left ventricular myocardial affection in Anderson-Fabry disease by non-enhanced T1-mapping

Background: Anderson-Fabry disease (AFD) is an X-linked lysosomal enzyme disorder associated with an intracellular accumulation of sphingolipids, which shorten myocardial T1 relaxation times. Myocardial affection, however, varies between different segments. Purpose: To evaluate the specific segmental distribution and degree of segmental affection in AFD patients. Material and Methods: Twenty-five patients with AFD, 14 patients with hypertrophic cardiomyopathy (HCM), and 21 controls were included. A Modified Look-Locker Inversion Recovery sequence (MOLLI) was used for non-enhanced T1 mapping at 1.5 T in addition to standard cardiac imaging in 10-12 short axis views. T1 values were evaluated with a mixed model ANOVA and regression analysis to determine the best diagnostic cutoff values for T1 for each myocardial segment. Results: Regression analysis showed the best diagnostic cutoff compared to controls in cardiac segments 1-4, 8-9, and 14. Mean differences between T1 for AFD versus HCM were greatest in segment 3, 4, and 9 (99ms, 103ms, 86ms, respectively). Overall T1 times were 88870ms and 903 +/- 14ms (AFD with and without LVH); 1014 +/- 17ms and 1001 +/- 22ms (HCM and controls, P<0.05). Conclusion: Myocardial segments are affected by a varying degree of T1 shortening in AFD patients. Segment-specific cutoff values allow the most specific detection and quantification of the extent of myocardial affection.