Wu Zhou1, Kaixin Wang1, Lijuan Zhang1, Zaiyi Liu2, Guangyi Wang2, and Changhong Liang2
1Key Laboratory for Health Informatics, Shenzhen Institutes of Advanced Technology, Shenzhen, China, People's Republic of, 2Department of Radiology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Shenzhen, China, People's Republic of
Synopsis
Lesion characterization
based on imaging features is essential to the successful treatment of
hepatocellular carcinomas (HCC). In this work, we investigate the malignant of
HCC from Contrast-enhanced MR images based on the analysis of texture features.
Our study demonstrated that the texture feature (average intensity value and
grey level nonuniformity) of HCC in contrast-enhanced MR images was a good
predictor to characterize the malignant of HCC. By quantitatively
comparing the texture parameters in well differentiated and moderately
differentiated HCCs, the values of average intensity remarkably decreased and
GLN significantly increased according to the increasing degree of malignant for
HCCs. Purpose
Hepatocellular
Carcinoma (HCC) is most common malignant neoplasm of the liver and the third
leading cause of cancerous death worldwide$$$^1$$$. Lesion
characterization based on imaging features is essential to the successful
treatment of HCC. Various methods have been proposed based on different image features,
such as texture, derived from the first- and second- order intensity statistics,
to demonstrate the intrinsic characterization of HCC $$$^2$$$.
To our knowledge, the correlation between the image feature and malignant of
HCC has not been fully investigated in a quantitative manner before $$$^3$$$. In this work, we investigate the malignant of HCC
from Contrast-enhanced MR images based on the analysis of texture features, in
order to contribute the procedure of HCC diagnosis.
Method
This retrospective
study was approved by the local Institute of Review Board. Twenty-four MR
images were acquired with a 3.0T MR scanner (Signa Excite HD 3.0T, GE
Healthcare, Milwaukee, WI, USA) using eight-channel phase-array coil with a BH
Ax LAVA+C(1iver acquisition with volume acceleration, LAVA) sequence. The malignant
differentiation of HCCs for all the anticipated patients was pathologically
verified as the ground-truth and categorized as well-differentiated and
moderately HCCs. Regions of interest (ROIs) of HCCs were manually drawn on the contrast-enhanced
MR image (arterial phase) for all the anticipated patients (Fig.1). The texture
parameters of the average intensity value and grey level nonuniformity (GLN)
were chosen as the discriminate feature to characterize the malignant of HCCs. Note
that the texture parameter GLN was measured in four different directions($$$0^\circ$$$, $$$45^\circ$$$,
$$$90^\circ$$$, $$$135^\circ$$$), denoted as GLN_0, GLN_45, GLN_90, and GLN_135, respectively. The
average intensity value and GLN values of HCCs were expressed as the mean standard deviation. A Student $$$t$$$ test was used
to differentiate the average intensity value and GLN values of HCCs. Give the
quantitative measurements, the optimal threshold value of differentiate HCC malignant
was determined by a receiver operating characteristic (ROC) analysis. Computer
software packages (SPSS software, version 21; SPSS, Chicago, IL, USA) were used
for the statistical analyses. P values less than 0.05 were considered
statistically significant.
Results
The mean intensity value of the well
differentiated HCCs (1324.95$$$\pm$$$397.47) was significantly larger than that of the
moderately differentiated HCCs (701.75$$$\pm$$$185.85) (p=0.004, unpaired $$$t$$$ test) (Table
I). With regard to the texture parameter GLN, all values of GLN towards four
directions of well differentiated HCCs were relatively smaller than those
values of the moderately differentiated HCCs (Table I). By ROC analysis, the
optimal threshold value of the average intensity was 739 for optimal
sensitivity (100$$$\%$$$, 13/13)
and specificity (81.8$$$\%$$$, 9/11)
of HCC differentiation. The optimal threshold values of the GLN in four
different directions were 38.72, 66.59, 31.51 and 77.06, for optimal
sensitivity (90.9$$$\%$$$, 90.9$$$\%$$$, 81.8$$$\%$$$, 81.8$$$\%$$$) and optimal specificity (92.3$$$\%$$$, 92.3$$$\%$$$,
100$$$\%$$$, 100$$$\%$$$), respectively (Table 2). The area under the ROC curve (AUC) for the
average intensity was 0.951 (Fig.2a), followed by 0.823, 0.916, 0.888 and 0.930
for the GLN in four different directions (Fig.2b).
Discussion and conclusion
Our study demonstrated that the texture
feature (average intensity value and GLN) of HCC in contrast-enhanced MR images
was a good predictor to characterize the malignant of HCC. The reason that we
chose contrast-enhanced MR images for texture extraction was that 3.0T MR with Gd-EOB-DTPA
provided higher-resolution images of HCCs, especially for their vascular. By
quantitatively comparing the texture parameters in well differentiated and
moderately differentiated HCCs, our quantitative results imply the values of average
intensity remarkably decreased and GLN significantly increased according to the
increasing degree of malignant for HCCs. These findings of the texture analysis
in contrast enhanced MR images for HCCs may reflect changes of malignant as the
HCC develops.
Acknowledgements
This research is supported by the grant from National Natural Science Foundation of China (NSFC: U1301258), in part by grants from National Natural Science Foundation of China (NSFC: 61302171) .References
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