To evaluate the application of dual-layer spectral detector CT (DLCT) with low kiloelectron volt (keV) virtual monoenergetic imaging (VMI) reconstruction in the evaluation of small liver cancer.

Clinical imaging data of 28 patients with small liver cancer receiving enhanced DLCT scan of the liver, gallbladder, pancreas and spleen in the Third Affiliated Hospital of Sun Yat-sen University from March 2020 to February 2021 were retrospectively analyzed. Among them,24 patients were male and 4 female, aged from 29 to 67 years, with a median age of 55 years. The informed consents of the patients were obtained and the local ethical committee approval was received. At 1 week before operation, patients received DLCT examination. The holographic spectral imaging data packages were decomposed and reconstructed by post-processing workstation. The patients' images were divided into the conventional CT image group (CI group), 40 keV VMI group (VMI40 group) and 50 keV VMI group (VMI50 group). CT value, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and other objective scores were statistically compared by paired t test. The subjective scores such as the overall image quality, image noise, image sharpness and lesion significance were compared by Wilcoxon signed rank-sum test.

In the objective image quality assessment, the CT value, SNR and CNR in the VMI40 group were 242±51, 14.1±5.9 and 8.9±4.5, significantly higher than 176±32, 12.2±4.4 and 6.7±3.1 in the VMI50 group (t=18.12, 5.08, 7.07; P<0.05). The CT value, SNR and CNR in the VMI50 group were also significantly higher than 114±17, 7.8±2.4 and 3.2±1.4 in the CI group (t=18.01, 5.60, 7.29; P<0.05). In the subjective image quality evaluation, the lesion significance score in the VMI40 group was 5(1), significantly higher than 4(2) and 3(2) in the VMI50 and CI groups (Z=4.00, 4.77; P<0.05).

Compared with CI, DLCT with low keV VMI can improve the image quality and detection rate of small liver cancer lesions.