Apparent diffusion coefficient value of diffusion-weighted imaging for hepatocellular carcinoma: correlation with the histologic differentiation and the expression of vascular endothelial growth factor.

OBJECTIVE

To evaluate whether the histopathological differentiation and the expression of vascular endothelial growth factor (VEGF) of hepatocellular carcinoma (HCC) do show correlation with the apparent diffusion coefficient (ADC) value on diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

Twenty-seven HCCs from 27 patients who had undergone preoperative liver MRI (1.5T) and surgical resection were retrospectively reviewed. DWI was obtained with a single-shot, echo-planar imaging sequence in the axial plane (b values: 0 and 1,000 sec/mm(2)). On DWIs, the ADC value of the HCCs was measured by one radiologist, who was kept 'blinded' to the histological findings. Histopathologically, the differentiation was classified into well (n = 9), moderate (n = 9) and poor (n = 9). The expression of VEGF was semiquantitatively graded as grade 0 (n = 8), grade 1 (n = 9) and grade 2 (n = 10). We analyzed whether the histopathological differentiation and the expression of VEGF of the HCC showed correlation with the ADC value on DWI.

RESULTS

The mean ADC value of the poorly-differentiated HCCs (0.9 +/- 0.13x10(-3) mm(2)/s) was lower than those of the well-differentiated HCCs (1.2 +/- 0.22x10(-3) mm(2)/s) (p = 0.031) and moderately-differentiated HCCs (1.1 +/- 0.01x10(-3) mm(2)/s) (p = 0.013). There was a significant correlation between the differentiation and the ADC value of the HCCs (r = -0.51, p = 0.012). The mean ADC of the HCCs with a VEGF expression grade of 0, 1 and 2 was 1.1 +/- 0.17, 1.1 +/- 0.21 and 1.1 +/- 0.18x10(-3) mm(2)/s, respectively. The VEGF expression did not show correlation with the ADC value of the HCCs (r = 0.07, p = 0.74).

CONCLUSION

The histopathological differentiation of HCC shows inverse correlation with the ADC value. Therefore, DWI with ADC measurement may be a valuable tool for noninvasively predicting the differentiation of HCC.