Quantification of Cardiac Iron Overload at 3 T MRI in a Rabbit Model Utilizing ME-GRE T2* Sequence.

Abstract

Background: Myocardial iron overload can lead to myocardial dysfunction, muscle cell injury, and end-stage heart failure. The enhanced signal-to-noise ratio and technical advancements have made 3 T magnetic resonance imaging (MRI) more accessible in clinical settings. However, 3 T assessments for early diagnosis of myocardial iron overload are scarce.

Purpose: To evaluate the feasibility of myocardial iron quantification using 3 T MRI in a rabbit model of iron overload.

Study type: Animal model.

Animal model: Overall, 40 male New Zealand white rabbits were categorized into control (N = 8; no treatment) and experimental (N = 32; weekly 200 mg/kg iron dextran injections) groups.

Sequence: 3 T MRI with multi-echo gradient echo (ME-GRE) T2* sequence.

Assessment: Each week, two experimental rabbits were randomly selected for blood collection to determine serum iron (SI) levels; their tissue was harvested to assess myocardial and hepatic iron deposition.

Statistical tests: Spearman's rank correlation tests were used to evaluate the correlations among R2*, cardiac iron concentration (CIC), liver iron concentration (LIC), total amount of iron injected, and SI levels. P ≤ 0.05 was considered statistically significant.

Results: The myocardial T2* value in the experimental group was significantly lower than that of the control group. An excellent correlation was observed between R2* values and CIC (r = 0.854). CIC moderately correlated with LIC (r = 0.712) and the total amount of iron injected (r = 0.698). A strong correlation was observed between the total amount of iron injected and LIC (r = 0.866). SI levels poorly correlated with the total amount of iron injected (r = 0.205, P = 0.277) and LIC (r = 0.170, P = 0.370) but fairly correlated with CIC (r = 0.415, P = 0.022).

Data conclusion: A 3 T MRI with an ME-GRE sequence may serve as a noninvasive method for evaluating cardiac iron content.

Evidence level: N/A TECHNICAL EFFICACY: Stage 1.