Intravoxel incoherent motion imaging of focal hepatic lesions

Purpose: To compare diffusivity values between malignant and benign focal hepatic lesions using the intravoxel incoherent motion model. Materials and Methods: 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. Results: Both the D value (1.15 +/- 0.21 x 103 mm2/s [mean +/- standard deviation]) and D* value (62.7 +/- 12.7 x 103 mm2/s) in malignant lesions was significantly lower than that in benign lesions (D value [2.46 +/- 0.45x 103 mm2/s], P < 0.0001; D* value [87.6 +/- 35.3 x 103 mm2/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%). Conclusion: 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. J. Magn. Reson. Imaging 2013;37:13711376. (c) 2012 Wiley Periodicals, Inc.