Abstract W P248: Cerebral Tissue Iron Quantification on MRI Following Intracerebral Hemorrhage

Abstract

Purpose: Intracerebral hemorrhage (ICH) is a fatal subtype of Hemorrhagic stroke. Tissue iron at the periphery of ICH has been demonstrated to be neurotoxic in animal models. No robust method to quantify tissue iron following ICH currently exists. Our aim is to determine a robust algorithm based on MRI to quantify tissue iron in the wake of ICH. Methods: Following Institutional review board approval we constructed an MRI phantom. Eight 4 cc vials with 50 % decreasing dilutions of Ferraheme (iron for IV therapy) were prepared starting from 0.6 mg/ml ending at 0.005 mg/ml. The vials were stuck to the undersurface of the lid of a water bath container and scanned in a 3T MRI with T2* sequences. The T2* signal magnitudes were calculated for each concentration. Subsequently a human control brain and two patients with left basal ganglia ICH were scanned with identical parameters. The T2* signal magnitude was calculated at 3 ROIs at the periphery of the ICH. Results: The R2* maps demonstrated a near linear correlation with the iron concentration in the phantom. The control T2* signal magnitude corresponded to 0.01 mg/ml iron concentration. The two patients on ICH day 7 had measurements of iron concentration of 0.04 mg/ml (4 x baseline) at the periphery of the hematoma. This corresponds favorably to a threefold increase in measured tissue iron levels in animal ICH model studies. Conclusion: Our experiment demonstrates that quantitative susceptibility measurements on MRI may be a robust technique to assess iron level in brain tissue following ICH. Encouraged by the results we have applied to the NIH (#GRANT11426089) for funding to be able to evaluate the validity of the algorithm. Tissue iron quantification by MRI may assist in judging severity of ICH and act as a surrogate marker for assessing treatment with iron chelator.