| Purpose: To quantitatively analyse the value of apparent diffusion coefficient (ADC) of diffusion weighted MR imaging (DWI) in the diagnosis of focal liver masses .Materials and methods : Fifty-three patients suspected of having hepatic lesions were examined with diffusion weighted single-shot echoplanar imaging using multiple b values (100s/mm2, 500s/mm2, 1000s/mm2) . ADCs were measured in all hepatic masses (hepatic carcinoma 11 , metastasis 18 , hemangioma 32 , hepatic cyst 11) and correlation analysis (t test)was used to determine the relation among the lesions .Moreover, T2 value was also measured in all hepatic masses ,then the accuracy of malignant lesions was compared between T2 and ADC valueResults : (1) The average apparent diffusion coefficient of hepatic carcinoma, metastasis, hemangioma and cyst were (1.32±0.17)× 10-3mm2/s, (1.40 ± 0.19) ×10-3 mm2/s, (2.31 ±0.23) × 10-3 mm2/s and (3.45±0.27)× 10-3 mm2/s. The average apparent diffusion coeffecient of malignant masses(1.33 × 10-3 mm2/s)was significantly lower than that of hemangioma and cys (P<0.01), and no statistically significant difference in ADC was foundin hepatic carcinoma and metastasis (P>0.2) .(2) The greater difference in b value resulted in different ADC value, and accurate ADCs come from larger b value .(3) T2 relaxation time of malignant lesions was significantly shorter than that of benign lesions(P<0.05),but the accuracy of differentiating benign with malignant lesions was lower than that of DWI as a large number of T2 value in the two groups was overlapped with each other.Conclusions: Diffusion weighted MR imaging could give quantitative information, ADC value was surely of value in differentiating malignant lesions from benign ones, and it can be accepted as a new method in the characterization of focal liver lesions . |
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