Myocardial Tissue Characterization By Cardiac MR Imaging In Myelodysplastic Syndromes

Magnetic Resonance Imaging (MRI) provides unique insight regarding tissue characterization in the heart. We reported the baseline MRI findings at the end of the recruitment in the MIOMED (Myocardial Iron Overload in MyElodysplastic Diseases) study. In particular, we evaluated the distribution of iron overload in the whole left ventricle (LV) and he presence of myocardial fibrosis in patients with myelodysplastic syndromes (MDS); the association with LV function was also investigated. No data are available in the literature about this issue.

MIOMED is an observational, MRI multicentre study in low and intermediate-1 risk MDS patients who have not received regular iron chelation therapy. Out of the 51 MDS patients enrolled, 48 underwent the baseline MRI exam. Mean age was 71.7±8.5 years and 17 patients were females. MIO was assessed using a multislice multiecho T2* approach. Biventricular function parameters were quantified by cine sequences. Myocardial fibrosis was evaluated by late gadolinium enhancement acquisitions.

We found 27 (56.3%) patients with no MIO (all 16 segmental T2* values >20 ms). The remaining patients showed an heterogeneous MIO (some segments with T2* values >20 ms and other segments with T2* values <20 ms) and of them 2 (9.5%) showed a global T2* value <20 ms, indicating significant MIO. A reduced LV ejection fraction (EF) was found in the 29.5% of cases and a reduced RV EF in the 23.3%. There was not a significant association between heart T2* values and LV EF.

Myocardial fibrosis was detected in the 35.9% of the patients. Three patients showed an ischemic pattern and one of them had a transmural fibrosis in the LV apical region. Out of the 3 patients with an ischemic pattern, only one patient had a positive history for a previous myocardial infarction. The majority of the patients had two or more foci of myocardial fibrosis, involving more frequently the septal segments. Patients with myocardial fibrosis were significantly older (75.4±7.9 vs 68.9±7.6 yrs; P=0.019). Global heart T2* and LV volumes were not significantly different between patients with and without fibrosis. The LV EF was lower in fibrotic patients but the statistical significance was not reached (58.4±11.7 vs 64.8±8.9 %; P=0.067).

Although a significant heart iron was found only in two cases, nearly half the patients had abnormal T2* values in at least one myocardial segment. This finding underlines the importance to use a multislice approach in order to perform an early diagnosis and prevent a more diffuse iron distribution by chelation therapy. This goal could be critical in patients with myocardial fibrosis that seems to be a relative common findings in the old MDS patients. In fact, an underlying heart damage as represented by fibrosis could make the hearts of the old MDS patients more sensitive to lower levels of accumulated iron.

No relevant conflicts of interest to declare.