Jornal de Radiologia Clínica e Experimental

Histological Quantification of Defined Thrombi with Spectral CT Analysis: An in vitro-Study using Ovine Blood-Samples

Nico Munnich*, Julia Rozanka, Ana Moya, Stephanie Ritter and Stefan Rohde

Objectives: The histological composition of thrombi is a critical factor in the management of patients with acute stroke as it influences pharmacological and interventional treatment strategies. Mechanical characteristics of the occluding thrombi primarily depend on the proportion between fibrin and Red Blood Cells (RBC). Spectral CT imaging with dual-energy technology enables tissue differentiation depending on the keV specific absorption. We sought to evaluate the feasibility and the potential accuracy of spectral CT in the imaging of thrombus composition in an in-vitro Model using blood samples with defined fibrin/RBC-ratios.

Methods: Five types of defined ovine blood thrombi with a gradually increasing amount of RBC (0%-100%) were scanned with spectral CT imaging using keV-values between 40 and 140 keV. Subsequently, the specific absorption curve was established for each thrombus and statistically correlated using a Kolmogorov-Smirnov test.

Results: The absorption curves showed a statistically significant difference for thrombi with moderate to high levels of RBC (30%-100% RBC fraction, p-value<0.05) with differentiability at keV-levels above 80 keV. Thrombi with an RBC content of more than 40% could be differentiated best.

Conclusion: Spectral CT-imaging can differentiate thrombi with a defined proportion of RBC and fibrin. Discrimination of the histological composition is best achieved in thrombi with an RBC-content of more than 40% and at high keV-levels with a threshold above 80keV. The available data allow for potential further development of this CT-technique in future thrombus.