Magnetic Resonance Imaging (MRI) Detection of Iron Overload In Patients with Myelodysplastic Syndrome (MDS)

Transfusion dependent anemia and iron overload are associated with reduced survival in patients with MDS. Increased iron absorption at the gastrointestinal tract may also contribute to iron overload. Serum ferritin is the most common method of assessing body iron content, but it can be elevated in patients with inflammatory conditions, and may not correlate with iron overload in specific organs such as the heart. T2* MRI is a non-invasive method for detecting iron overload in patients with transfusion-dependent anemia, and its efficacy has been validated in patients with thalassemia major. There are few studies reporting on the efficacy of T2* MRI for detection of iron overload in patients with MDS.

To evaluate the efficacy of T2* MRI in detection of iron overload in patients with MDS, the prevalence of iron overload in this disease and correlate MRI findings with iron indexes (ferritin, transferrin and non-transferrin bound iron [NTBI]).

Patients with MDS or chronic myelomonocytic leukemia (CMML), independent of transfusion requirements, were recruited into a prospective, single center trial to assess the efficacy of T2* MRI for detection of iron overload in this scenario. Patients receiving iron chelation therapy were excluded. Iron indexes were measured at the time of T2* MRI evaluation. Hepatic iron overload was considered in patients with a hepatic iron concentration (HIC) ≥ 2 g/mg. Cardiac iron overload was considered in patients with a T2* value < 20 milliseconds. Mann-Whitney and Fischer exact tests were used to compare baseline continuous and categorical variables among patients with and without iron overload as assessed by HIC. Correlation between HIC and iron indexes was assessed with Spearman correlation.

A total of 37 patients with MDS and one patient with CMML were recruited. Three patients were not evaluated by MRI due to claustrophoby, so 35 patients remain for the analysis. Median age was 68 years (range 18–84). MDS subtypes by the WHO classification include refractory anemia (N=3), refractory anemia with ring sideroblasts (N=5), 5q- syndrome (N=3), refractory cytopenias with multilineage dysplasia (N=13), refractory anemia with excess blasts-I (N=6) and –II (N=3) and unclassifiable MDS (N=1). Information about transfusion requirement was available for 28 patients, and 14 (50%) were transfusion dependent. Twenty-two patients could be classified by the WHO Prognostic Score System (WPSS) and were categorized as very low-risk (N=6), low-risk (N=3), intermediate risk (N=6) and high risk (N=7). Median ferritin, transferrin saturation and NTBI values were 1079.6 ng/mL (range 21.8–12738 ng/mL), 63% (range 6–100%) and 0.34 microM (range 0–12.93 microM), respectively. Median cardiac T2* value was 45.3 ms (range 19.7–70.1 ms), and only one patient had a T2* value indicative of cardiac iron overload. Median HIC value was 3.31 g/mg (range 0.2–9.97 g/mg), and 66% of patients had hepatic iron overload. Patients with hepatic iron overload had higher ferritin levels (1181 ng/mL vs. 131 ng/mL, p=0.007) and transferrin saturation (64% vs. 39%, p=0.02), but no differences in NTBI (0.29 microM vs. 0.22 microM, p=0.42). Patients with elevated HIC had a higher prevalence of transfusion dependency but the difference was not significant (50% vs. 33%, p=0.67). Ferritin levels and transferrin saturation correlated with HIC (r = 0.552, p=0.001 [ferritin]; r = 0.609, p=0.001 [transferrin saturation]).

T2* MRI can detect iron overload in patients with MDS. Iron overload in MDS cannot be solely explained by transfusion dependent anemia. The study is currently ongoing and updated results will be presented at the meeting.

No relevant conflicts of interest to declare.