Value of intravoxel incoherent motion and diffusion kurtosis imaging to differentiate hepatocellular carcinoma and intrahepatic cholangiocarcinoma

Abstract

Background: The differential diagnosis between hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) is crucial. The individual differences of patients increase the complexity of diagnosis. Currently, imaging diagnosis mainly relies on conventional computed tomography and magnetic resonance imaging (MRI), but few studies have investigated MRI functional imaging. This study combined MRI functional imaging including intravoxel incoherent motion (IVIM) and diffusion kurtosis imaging (DKI), facilitating differential diagnosis.

Aim: To explore the differential diagnostic value of IVIM imaging and DKI in differentiating between HCC and ICC.

Methods: A total of 58 patients who underwent multi-b-value diffusion weighted imaging (DWI) on a 3.0 T magnetic MRI scanner were enrolled in this study. Standard apparent diffusion coefficient (SADC), IVIM quantitative parameters, including pure diffusion coefficient (D), pseudo diffusion coefficient (Dstar), and perfusion fraction (f), as well as the DKI quantitative parameters mean diffusion coefficient (MD) and mean kurtosis coefficient (MK) were computed by multi-b DWI images. The χ ² test was used for classified data, and a one-way analysis of variance was performed for counted data. P < 0.05 indicated statistical significance. The diagnostic value of parameters in HCC and ICC was analyzed using the receiver operating characteristic (ROC) curve.

Results: The SADC, D, and MD values were significantly lower in the HCC group compared to the ICC group, whereas MK was significantly higher in the HCC group than in the ICC group (P < 0.05). No significant difference in Dstar and f was observed between the HCC group and the ICC group (P > 0.05). The optimal cutoff levels of the total values of SADC, D, MK, MD and all associated parameters were 1.25 × 10^-3 mm²/second, 1.32 × 10^-3 mm²/second, 650.2 × 10^-3 mm²/second, 1.41 × 10^-3 mm²/second and 0.46 × 10^-3 mm²/second, respectively. The sensitivity of diagnosis was 95%, 80%, 90%, 100%, and 70%, respectively, the specificity of diagnosis was 67.39%, 69.57%, 67.39%, 43.48%, and 93.48%, respectively, and the area under the ROC curve was 0.874, 0.793, 0.733, 0.757, and 0.895, respectively.

Conclusion: SADC, D, MK, and MD could be used to distinguish HCC from ICC, with the diagnostic value reaching a maximum after establishing a joint model.

Keywords: Diffusion kurtosis imaging; Hepatocellular carcinoma; Intrahepatic cholangiocarcinoma; Intravoxel incoherent motion; Magnetic resonance imaging.

Figure 1

Bland-Altman analysis of differences between two radiologists in determining the standard apparent diffusion coefficient, imaging intravoxel incoherent motion (pure diffusion coefficient, perfusion fraction, pseudo diffusion coefficient), and diffusion kurtosis imaging (mean kurtosis coefficient, mean diffusion coefficient) parameters with hepatocellular carcinoma and intrahepatic cholangiocarcinoma. The mean of methods axis represents the geometric mean of both methods. The difference between methods axis represents the difference between both methods. The upper and lower brown dashed horizontal lines indicate the upper and lower limits of the 95% consistency limit; the blue solid horizontal line in the middle represents the average value of the difference, and the green dotted line indicates the 95%CI of the average value of the difference. Dstar: Pseudo diffusion coefficient; MD: Mean diffusion coefficient; MK: Mean kurtosis coefficient; SADC: Standard apparent diffusion coefficient.

Figure 2

Surgically confirmed moderately differentiated hepatocellular carcinoma in a 65-year-old man. A: T2-weighted imaging image; B: Diffusion-weighted image with b = 800 mm²/second; C: Pure diffusion coefficient (D) map; D: Perfusion fraction (f) map; E: Standard apparent diffusion coefficient (SADC) map; F: Pseudo diffusion coefficient (Dstar) map; G: Mean kurtosis coefficient (MK) map; H: Mean diffusion coefficient (MD) map. The mean D, f, SADC, Dstar, MK, and MD values for the tumor were 0997 × 10^-3 mm²/second, 92.62 × 10^-3 mm²/second, 1.037 × 10^-3 mm²/second, 55.18 × 10^-3 mm²/second, 651 × 10^-3 mm²/second, and 1.179 × 10^-3 mm²/second, respectively.

Figure 3

Puncture biopsy confirmed intrahepatic cholangiocarcinoma in a 52-year-old man. A: T2-weighted imaging image; B: Diffusion-weighted image with b = 800 mm²/second; C: Pure diffusion coefficient (D) map; D: Perfusion fraction (f) map; E: Standard apparent diffusion coefficient (SADC) map; F: Pseudo diffusion coefficient (Dstar) map; G: Mean kurtosis coefficient (MK) map; H: Mean diffusion coefficient (MD) map. The mean D, f, SADC, Dstar, MK, and MD values for the tumor were 1609 × 10^-3 mm²/second, 143.89 × 10^-3 mm²/second, 1.630 × 10^-3 mm²/second, 134.59 × 10^-3 mm²/second, 552.6 × 10^-3 mm²/second, 2.064 × 10^-3 mm²/second, respectively.

Figure 4

Receiver operating characteristic curves of the standard apparent diffusion coefficient, pure diffusion coefficient, mean kurtosis coefficient, and mean diffusion coefficient for differentiating between hepatocellular carcinoma and intrahepatic cholangiocarcinoma. D: Pure diffusion coefficient; MD: Mean diffusion coefficient; MK: Mean kurtosis coefficient; SADC: Standard apparent diffusion coefficient.