[Study of apparent diffusion coefficient value and histopathological differentiation of hepatocellular carcinoma]

To determine the relationship between apparent diffusion coefficient (ADC) and histopathological differentiation of hepatocellular carcinoma (HCC).

Magnetic resonance examinations of magnetic resonance imaging (MRI) plain scan, LAVA dynamic enhanced scan and diffusion weighted imaging (DWI)(1.5 T, b values: 0 and 600 s/mm²) were retrospectively reviewed for 229 surgically resected HCCs. Histopathology revealed 34 well, 170 moderately and 25 poorly-differentiated HCCs. The incidence of each ADC value was measured. The relationship between ADC and histopathological differentiation was also evaluated.

The ADC value of well-differentiated HCCs (1.68 ± 0.13 × 10⁻³ mm²/s) was significantly higher those of moderately HCCs (1.31 ± 0.16 × 10⁻³ mm²/s) (P < 0.05) and poorly-differentiated HCCs (1.08 ± 0.11 × 10⁻³ mm²/s) (P < 0.05). There was a significant positive correlation between ADC value and differentiation of HCCs (r = 0.693, P < 0.05). ROC analysis showed that the optimal cutoff point of ADC value was 1.500 × 10⁻³ mm²/s in diagnosing well-differentiated HCCs. A cutoff ADC value equal to or under 1.5 × 10⁻³ mm²/s was used to differentiate well-differentiated HCC from moderately and poorly-differentiated ones with a sensitivity of 100% and a specificity of 94.36%. ROC analysis showed that the optimal cutoff point of ADC value was 1.235 × 10⁻³ mm²/s in diagnosing poorly-differentiated HCCs. A cutoff ADC value equal to or above 1.235 × 10⁻³ mm²/s was used for differentiating poorly-differentiated HCC from well and moderately-differentiated ones with a sensitivity of 73.5% and a specificity of 96%.

In clinical practice, ADC value is important for predicting histopathological differentiation of HCC and improving its diagnostic accuracy.