Liquid Embolic Agents in Spectral X-Ray Photon-Counting Computed Tomography using Tantalum K-Edge Imaging

Isabelle Riederer,Salim Si-Mohamed,Melanie A Kimm,Peter B Noël,Ernst J Rummeny,Daniel Bar-Ness,Philippe Douek,Daniela Pfeiffer

doi:10.1038/s41598-019-41737-6

Abstract

The aim was to evaluate the potential of Spectral Photon-Counting Computed Tomography (SPCCT) to differentiate between liquid embolic agents and iodinated contrast medium by using tantalum-characteristic K-edge imaging. Tubes with a concentration series of tantalum and inserts with different concentrations of iodine were scanned with a preclinical SPCCT system. Tantalum density maps (TDM) and iodine density maps (IDM) were generated from a SPCCT acquisition. Furthermore, region-of-interest (ROI) analysis was performed within the tubes in the conventional CT, the TDM and IDM. TDM and IDM enable clear differentiation between both substances. Quantitative measurements of different tantalum concentrations match well with those of actually diluted mixtures. SPCCT allows for differentiation between tantalum and iodine and may enable for an improved follow-up diagnosis in patients after vascular occlusion therapy.

Highlights

CT-angiography of the brain after embolization can be necessary to assess possible remaining feeders as well as the nidus in order to plan further procedures
It has been demonstrated that discrimination between gold nanoparticles and iodinated contrast agent is possible in different organs in vivo in animals using the Spectral Photon-Counting Computed Tomography (SPCCT) system[26]
In the obtained tantalum density maps (TDM) (Fig. 2C), already the smallest dilution could be visually discriminated from the control tube containing pure DMSO (100%)

Summary

Introduction

CT-angiography of the brain after embolization can be necessary to assess possible remaining feeders as well as the nidus in order to plan further procedures. Sometimes it is difficult to appropriately assess brain tissue and vessels around the clot of liquid embolic agent (Fig. 1) This might affect diagnosis and therapy management[14,15,16]. Several Spectral Photon-Counting CT (SPCCT) systems have been introduced, where X-ray photons are individually counted and spectrally binned by analyzing the pulse heights generated in a semi-conductor detection layer[18,19,20,21,22,23] This concept allows to incorporate a multiple (more than two) energy bins for energy-selective data acquisition. We intended to analyze the potential of SPCCT for the differentiation between tantalum and iodine for an improved visualization

Methods

Results

Conclusion