Intravoxel incoherent motion imaging of focal hepatic lesions

To compare diffusivity values between malignant and benign focal hepatic lesions using the intravoxel incoherent motion model.

This study included 84 focal hepatic lesions in 84 patients. Final diagnoses were as follows: hepatocellular carcinoma (n = 45), cholangiocarcinoma (n = 6), metastatic liver tumor (n = 3), cyst (n = 20), hemangioma (n = 5), inflammatory pseudotumor (n = 2), abscess (n = 2), and focal nodular hyperplasia (n = 1). Diffusion-weighted images at 12 b-values were used to obtain the diffusion coefficient of pure molecular diffusion (D), diffusion coefficient of microcirculation or perfusion-related diffusion (D*), and perfusion-related diffusion fraction (f). Parameters of malignant and benign focal hepatic lesions were compared using the Wilcoxon test. The diagnostic performance for distinguishing between malignant and benign hepatic lesions was also analyzed.

Both the D value (1.15 ± 0.21 × 10(-3) mm(2) /s [mean ± standard deviation]) and D* value (62.7 ± 12.7 × 10(-3) mm(2) /s) in malignant lesions was significantly lower than that in benign lesions (D value [2.46 ± 0.45× 10(-3) mm(2) /s], P < 0.0001; D* value [87.6 ± 35.3 × 10(-3) mm(2) /s], P = 0.0008). The f value did not differ significantly between malignant (25.0 15.1 ± 15.1%) and benign lesions (30.1 ± 16.3%).

D* and D values were suppressed in malignant lesions. However, the D value was more reliable for distinguishing between malignant and benign focal hepatic lesions.