To evaluate the value of Ktrans and HPI (hepatic arterial perfusion index), and their radiomics features in the differential diagnosis of hepatocellular carcinoma (HCC) and hepatic metastases from colorectal cancer (HM) using dynamics contrast enhanced MRI (DCE-MRI). Exchange model with dual input-based arterial input function was used to obtain the radiomics features that can provide a comprehensive assessment of tumors’ physiologic properties including vascular permeability, microcirculation and hemodynamic information. Our results indicated that IDM (Ktrans), inertia and correlation (HPI) are of great significance to differentiate HM and HCC.
Median values of both ktrans and HPI had no statistical difference between the two groups. Inverse Difference Moment (IDM) from Ktrans, Inertia and Correlation from HPI were statistically significant between the two groups, P values were 0.011, 0.020 and 0.032, respectively. There were no differences between HCC and HM about other texture features (Shown in Table 1). The corresponding color maps were shown in Figure 1.
When IDM (Ktrans)≥0.29, Inertia (HPI)≤247.53 or Correlation(HPI)≥0.0018, area under the ROC curve (AUC) related to the diagnosis of HCC were 0.772, 0.750 and 0.732, respectively. Sensitivity were 91.7%, 100% and 91.7%, respectively. Specificity were 63.2%, 52.6% and 63.2%, respectively. (Shown in Figure 2)
The liver is a dual vascular supplied organ which is supplied by both the portal vein (75%) and the hepatic artery (25%)[1]. A new vascular network in both HCC and HM that increases the arterial supply rather than the portal supply develops to meet increased oxygen and metabolic demands[2]. Hemodynamic change of a lesion is one of the essential factors for diagnosing liver disease because most liver diseases and tumors affect blood flow either regionally or in general. The median HPI values obtained from the HM and HCC were significantly higher than those obtained from the whole liver[3]. The dual input pharmacokinetics model and extracted radiomics features made it possible to reflect vascular permeability, microcirculation and hemodynamic information so as to provide a more comprehensive assessment of tumors’ physiologic properties including heterogeneity and make individual treatment plan as well as therapeutic effect evaluations.
The GLCM texture features include the surface structure of the object arrangement of important information[4], IDM value reflects the local homogeneity of image texture. The larger the value is, the more uniformity the local image is. Correlation shows the linear dependency of gray level values in the GLCM and characterize the degree of fluctuation. Inertia measures the resolution of the image texture, the deeper the grooves are, the better the contrast is.
[1] Keiko Miyazaki, David J. Collins, Simon Walker-Samuel, et al. Quantitative mapping of hepatic perfusion index using MR imaging: a potential reproducible tool for assessing tumor response to treatment with the antiangiogenic compound BIBF 1120, a potent triple angiokinase inhibitor. Eur Radiol. 2008, 18(7): 1414-1421.
[2] Kim KW, Lee JM, Kim JH, et al. CT color mapping of the arterial enhancement fraction of VX2 carcinoma implanted in rabbit liver: comparison with perfusion CT. Am J Roentgenol. 2011, 196(1):102-108.
[3] Kim KW, Lee JM, Klotz E, et al. Quantitative CT color mapping of the arterial enhancement fraction of the liver to detect hepatocellular carcinoma. Radiology. 2009,250(2):425-434.
[4] Haralick RM, Shanmugam K, dInstein IH. Textural features for image classification. System, Man and Cybernetics, IEEE Transactions on, 1973,(6):610-621.