Kate Hanneman MD, Presenter: Nothing to Disclose

Elsie Nguyen MD, Abstract Co-Author: Nothing to Disclose

Dinesh Thavendiranathan MD, Abstract Co-Author: Nothing to Disclose

Richard Ward MSc, MRCP, Abstract Co-Author: Grant, Novartis AG Grant, Apotex, Inc

Andreas Greiser PhD, Abstract Co-Author: Employee, Siemens AG

Issac Y. Yang, Abstract Co-Author: Nothing to Disclose

Marshall Stephen Sussman PhD, Abstract Co-Author: Nothing to Disclose

Bernd J. Wintersperger MD, Abstract Co-Author: Speakers Bureau, Bayer AG Speakers Bureau, Siemens AG

We sought to quantify left ventricular (LV) myocardial interstitial fibrosis in patients with thalassemia major using cardiac MRI based extracellular volume fraction (ECV), and to correlate ECV with the degree of myocardial iron overload.

In this prospective case-control study, myocardial T1 mapping was performed at 1.5T pre- and 12 minutes post-contrast administration using a prototype modified Look-Locker inversion recovery (MOLLI) technique in patients with thalassemia major receiving regular transfusions (n=30; 53% male, 34.6±9.5years) and healthy volunteers (n=10; 50% male, 31.5±4.4 years). Standard cine SSFP, late gadolinium enhancement (LGE), and T2* mapping were also performed. LGE (>5SD threshold), ECV and T2* were analyzed for each myocardial segment (AHA 16 segment model). Same day hematocrit values were used for ECV calculation. Statistical analysis included two-sample t-test, Pearson correlation, and ANOVA with Tukey’s post-hoc analysis.

LV end-diastolic volume (89.8±15.7ml/m2 and 99.8±15.3ml/m2, p=0.12) and ejection fraction (60.5±6.3% and 60.1±3.1%, p=0.83) were not significantly different between patients and volunteers. Pre-contrast T1 values were lower in patients compared to volunteers (892.5±117.9ms vs. 1005.5±33.5ms, p=0.005), and correlated strongly with T2* values (r=0.89, p<0.001). After a significance difference between groups (p=0.002, ANOVA), post hoc analysis demonstrated higher ECV in patients with prior history of iron overload (T2*<20ms, n=19, 31.5±2.9%) compared to those without (n=11, 28.3±3.4%, p=0.030) and volunteers (27.1±0.1%, p=0.003). There was no difference in ECV between patients without iron overload and volunteers (p=0.66). ECV correlated with same-day T2* (r=-0.33, p=0.04), but had better correlation with lowest historical T2* (r=-0.49, p=0.007). Segmental LGE among patients was low (median 0.6%; range 0.3-2.1%), and did not correlate with ECV (r=-0.040, p=0.81).

In patients with thalassemia major, cardiac MRI demonstrated elevated ECV in keeping with diffuse interstitial myocardial fibrosis related to iron overload. Patients without a history of iron overload had no evidence of fibrosis despite receiving regular transfusions.

Early aggressive chelation therapy may be warranted in patients receiving chronic transfusions to prevent diffuse interstitial myocardial fibrosis due to myocardial iron overload. 

Hanneman, K, Nguyen, E, Thavendiranathan, D, Ward, R, Greiser, A, Yang, I, Sussman, M, Wintersperger, B, Quantification of Diffuse Myocardial Interstitial Fibrosis in Thalassemia Major with Cardiac Magnetic Resonance Imaging.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001883.html