Yanwei Zeng, Kai Deng, Haitao Yang, Yi Tan, Jun Liu, Daoying Geng, Jun Zhang


August 2019, Volume 28, Issue 8, pp 1783 - 1792 Original Article Read Full Article 10.1007/s00586-019-05984-5

First Online: 30 April 2019

Noise‐optimised virtual monoenergetic imaging of dual‐energy CT

Purpose

The purpose of this study was to evaluate the effects of noise-optimised virtual monoenergetic imaging (VMI+) reconstructions on reducing metal artefacts compared to traditional virtual monoenergetic imaging (VMI) and linearly blended (M_0.6) reconstructions in patients with lumbar metal internal fixation in dual-energy CT (DECT).

Methods

Forty patients who underwent DECT were evaluated in this retrospective study. Images were reconstructed with M_0.6 and with VMI+ and VMI at 10-keV intervals from 40 keV to 190 keV. Attenuation and noise were measured in the hyperdense artefacts, hypodense artefacts, spinal canal, abdominal aorta (AA), and inferior vena cava (IVC). An artefact index (AI) was calculated. A subjective evaluation of the metal–bone interface, surrounding soft tissue, spinal canal, AA, and IVC was conducted.

Results

The AI values for the hypodense artefacts, spinal canal, and IVC were lowest in the 130 keV VMI+ series, for the hyperdense artefacts in the 120 keV VMI+ series, and for the AA in the 190 keV VMI+ series. Except for the hypodense artefacts, the AI values were lower compared to the M_0.6 images and all the VMI series (all p < 0.05). The subjective image quality was highest at 130 keV VMI+ for the metal–bone interface, surrounding soft tissue, AA, and IVC, and at 120 keV VMI+ for the spinal canal. Except for the AA, these rating scores were higher compared to the M_0.6 images and the entire VMI series (all p < 0.05).

Conclusions

DECT with high-keV VMI+ efficiently reduces metal artefacts and shows superior image quality in patients with lumbar internal fixation.

Graphical abstract

These slides can be retrieved from Electronic Supplementary Material.[Figure not available: see fulltext.]


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