Imaging Technology
Spectral CT monochromatic imaging of hepatocellular carcinoma: effect of image fusion on image quality
Peijie Lyu, Mingyue Wang, Jie Liu, Yonggao Zhang, Jianbo Gao
Published 2015-03-10
Cite as Chin J Radiol, 2015, 49(3): 168-172. DOI: 10.3760/cma.j.issn.1005-1201.2015.03.003
Abstract
ObjectiveTo assess the effects of image fusion of CT spectral monochromatic imaging on image quality in small hepatocellular carcinoma (HCC).
MethodsThirty patients with 40 pathologically proven small HCCs (≤3 cm) underwent upper abdominal plain CT and dual- phase enhanced spectral CT scan were analyzed retrospectively. Conventional 140 kVp polychromatic images (group A) and monochromatic images with energy levels from 40 to 140 keV were reconstructed by using spectral imaging viewer. Monochromatic images with highest CNR(group B) and 70 keV images with lowest noise (group C) were fused to generate fused images (group D) with image fusion software. Objective evaluation of 40 HCCs[contrast-to-noise ratio (CNR) of lesion, image noise in HU] and subjective rating score of 30 patients (image noise score, overall image quality score, and lesion conspicuity score) among the four groups were compared by using One-way ANOVA and Kruskal-Wallis H test.
ResultsCNR (1.3±0.6, 2.1±0.6, 1.5±0.6 and 2.4± 1.3 respectively) and image noise [(20±7), (32±9), (18±3) and (24±6) HU respectively] among group A, B, C and D all had statistical differences(F =5.724 and 13.619, both P values <0.01). CNR in group D was higher as compared with group A and C(both P values<0.05), but was similar to group B(P>0.05). Image noise in group D was lower than group B and higher than group C, but showed no difference from group A(all P values >0.05). Image noise scores [(3.5±0.5),(3.3±0.4),(3.6±0.5) and (3.5±0.4) point, respectively] , overall image quality scores [(3.2±0.4),(3.3±0.3), (3.1±0.3)and(3.7±0.4)point respectively] and lesion conspicuity scores [(3.3±0.4),(3.9±0.4), (3.2±0.4)and(3.7±0.4)point, respectively] among the four groups all had statistical differences(Z = 9.581, 37.495 and 43.436, all P values<0.05). Scores of the four groups were all greater than 3 and met the clinical diagnostic level. Group D was higher than group B in image noise score, higher than the other three groups in overall image quality score, higher than group A in lesion conspicuity score (all P values < 0.05).
ConclusionCombined use of CT spectral monochromatic imaging and image fusion can improve overall image quality while maintaining or increasing CNR in small HCC.
Key words:
Liver neoplasms; Tomography, X-ray computed; Comparative study
Contributor Information
Peijie Lyu
Department of Radiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
Mingyue Wang
Jie Liu
Yonggao Zhang
Jianbo Gao
