Thrombus discrimination with electron density: potential implications for non-contrast computed tomography imaging

Gaston A Rodriguez-Granillo; Juan Cirio; Celina Morales; Jorge Safady; Lucia Fontana; Martin Fernandez; Pablo Diluca; Pedro Lylyk

doi:10.21037/cdt-24-28

Thrombus discrimination with electron density: potential implications for non-contrast computed tomography imaging

Cardiovasc Diagn Ther. 2024 Apr 30;14(2):304-310. doi: 10.21037/cdt-24-28. Epub 2024 Apr 22.

Authors

Gaston A Rodriguez-Granillo¹, Juan Cirio², Celina Morales³, Jorge Safady², Lucia Fontana¹, Martin Fernandez¹, Pablo Diluca⁴, Pedro Lylyk²

Affiliations

¹ Department of Cardiovascular Imaging, Instituto Medico ENERI, Clinica La Sagrada Familia, Buenos Aires, Argentina.
² Stroke Unit, Instituto Medico ENERI, Clinica La Sagrada Familia, Buenos Aires, Argentina.
³ Departament of Pathology, Faculty of Medicine, Instituto de Fisiopatología Cardiovascular, Universidad de Buenos Aires, Buenos Aires, Argentina.
⁴ Department of Radiology, Instituto Medico ENERI, Clinica La Sagrada Familia, Buenos Aires, Argentina.

Abstract

The potential clinical usefulness of electron density (ED) imaging, that can be directly estimated using dual-layer spectral computed tomography (CT), has been poorly investigated. We explored whether ED imaging might improve thrombus identification compared to conventional imaging in vitro. We evaluated mechanical thrombectomy material obtained from patients with acute ischemic stroke (AIS) treated in a tertiary level stroke center and immediately fixed in 10% neutral buffered formalin and stored in polystyrene test tubes. The test tubes were immersed in a bucket of water for evaluation by spectral CT, along with scattered control tubes. All images were obtained using a dual-layer detector CT scanner. Each tube was assessed using multiparametric side-by-side view of conventional CT (120 kVp), low monoenergetic imaging (40 keV), and ED images. Fifty-eight polystyrene tubes were analyzed, comprising 52 tubes with thrombectomy material of at least 1 mm² size obtained from 52 AIS patients, and six control tubes filled with formalin. ED imaging identified accurately the presence of material in all tubes, whereas 2 (3%) of the tubes containing thrombus were not identified by conventional CT, leading to a very good agreement between observers for the presence of material using conventional CT and ED imaging (kappa =0.84, P<0.001). Using ED imaging, thrombus material showed a mean density of 108.8±2.9 percent ED relative to water (%EDW), water had a mean density of 100.0±0.3 %EDW, and formalin a mean density of 103.5±1.2 %EDW. Compared to conventional imaging and 40 keV monoenergetic, ED imaging had a significantly higher signal-to-noise ratio (conventional 10.4±7.0, vs. 40 keV 11.5±8.4, vs. ED 490.0±304.5, P<0.001) and contrast-to-noise ratio (CNR) (conventional 4.3±4.3, vs. 40 keV 5.7±11.2, vs. ED 37.8±29.1, P<0.001). In this in-vitro study, we demonstrated improved visualization of thrombus with ED imaging compared to conventional imaging and low monoenergetic imaging, with a significant increase in CNR.

Keywords: Dual energy; computed tomography (CT); spectral; thrombus; tissue characterization.