Virtual versus true non-contrast dual-energy CT imaging for the diagnosis of aortic intramural hematoma
To assess whether virtual non-contrast (VNC) images derived from contrast dual-layer dual-energy computed tomography (DL-DECT) images could replace true non-contrast (TNC) images for aortic intramural hematoma (IMH) diagnosis in acute aortic syndrome (AAS) imaging protocols by performing quantitative as well as qualitative phantom and clinical studies.
Materials and methods
Patients with confirmed IMH were included retrospectively in two centers. For in vitro imaging, a custom-made phantom of IMH was placed in a semi-anthropomorphic thorax phantom (QRM GmbH) and imaged on a DL-DECT at 120 kVp under various conditions of patient size, radiation exposure, and reconstruction modes. For in vivo imaging, 21 patients (70 ± 13 years) who underwent AAS imaging protocols at 120 kVp were included. In both studies, contrast-to-noise ratio (CNR) between hematoma and lumen was compared using a paired t test. Diagnostic confidence (1 = non-diagnostic, 4 = exemplary) for VNC and TNC images was rated by two radiologists and compared. Effective radiation doses for each acquisition were calculated.
In both the phantom and clinical studies, we observed that the CNRs were similar between the VNC and TNC images. Moreover, both methods allowed differentiating the hyper-attenuation within the hematoma from the blood. Finally, we obtained equivalent high diagnostic confidence with both VNC and TNC images (VNC = 3.2 ± 0.7, TNC = 3.1 ± 0.7; p = 0.3). Finally, by suppressing TNC acquisition and using VNC, the mean effective dose reduction would be 40%.
DL-DECT offers similar performances with VNC and TNC images for IMH diagnosis without compromise in diagnostic image quality.
• Dual-layer dual-energy CT enables virtual non-contrast imaging from a contrast-enhanced acquisition.
• Virtual non-contrast imaging with dual-layer dual-energy CT reduces the number of acquisitions and radiation exposure in acute aortic syndrome imaging protocol.
• Dual-layer dual-energy CT has the potential to become a suitable imaging tool for acute aortic syndrome.
KeywordsTomography, x-ray computed Humans In vitro Acute disease Aorta
Acute aortic syndrome
Volume CT dose index
Dual-layer dual-energy computed tomography
Dual-source dual-energy computed tomography
Regions of interest
We thank Pr. Emmanuel Coche, Dr. Begum Demirler, and Dr.Matteo Pozzi for helping with the clinical study.
This work has not received any funding.
Compliance with ethical standards
The scientific guarantor of this publication is Professor Loic Boussel.
Conflict of interest
Philippe Coulon, Yoad Yagil, and Nadav Shapira are employees of Philips Healthcare, the manufacturer of the scanner.
Statistics and biometry
Prof. Loic Boussel provided statistical advice for this manuscript.
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was not required.
• Multicenter study
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