Abstract WMP23: Dynamic Imaging Of Blood Coagulation Within The Hematoma Of Patients With Acute Intracerebral Hemorrhage

Abstract

Objective: To serially quantify the blood coagulation within hematoma of patients with hyper-acute intracerebral hemorrhagic (ICH) stroke using non-invasive quantitative susceptibility mapping (QSM) MRI. Introduction: A blood clot is a combination of aggregated red blood cells, fibrin, platelets, hemosiderin, and other cell debris. An accurate evaluation of clot formation within hematoma could advance the clinical management of hematoma expansion, blood pressure management, and reversal of anticoagulants. Post-ICH hemolysis changes the heme iron oxidation state from oxy to deoxyhemoglobin (deoxy-Hb) resulting in unpaired iron electrons on aggregated RBC’s deoxy-Hb inducing magnetic susceptibility (χ). Therefore, a region with a higher number of aggregated RBC deoxy-Hb molecules, the dominant component of clots, will exhibit a higher positive χ susceptibility. We hypothesized that coagulated blood within hematoma will exhibit a higher positive χ in comparison to the non-clotted which can be quantified using quantitative susceptibility mapping (QSM), which is an advanced MRI image-processing algorithm. Methods: For proof of concept, we measured susceptibilities of 5 human blood phantoms with various percentages of the clot. Twenty-four patients with acute spontaneous ICH were enrolled and serially imaged 3 times within 12-24 (T1), 36-48 (T2), and 60-72(T3) hours of last known well (LNW). A 3D anatomical and multi-echo gradient echo images were obtained using a 3T MRI system. Hematoma and edema volumes were segmented and used as a region of interest (ROI). The rate of coagulation was assessed by measuring the change in susceptibilities within the hematoma. Results: The blood phantom exhibited a linear relationship between the percent coagulation and χ (R 2 =0.91). The QSM maps showed a significant increased in hematoma susceptibility over time (T1=0.29 ± 0.04, T2=0.36 ± 0.04, T3= 0.45 ± 0.04 ppm, p<0.0001). The overall average rate of coagulation was 0.00290 ± 0.0029 ppm per hour. No significant change in hematoma volume (18.9 ±3.1 cc) over time. A significant edema growth over time (T1=25.3 ± 3.6, T2= 28.1 ± 3, T3= 32.37 cc, p<0.05). Conclusion: In conclusion, we present novel surrogate imaging markers of coagulation within the hematoma of ICH.