BACKGROUND/AIMS

Our purpose is to investigate whether the diffusion-weighted imaging (DWI) can be used as an initial and decisive sequence to shorten liver magnetic resonance imaging (MRI) study, rather than being complementary to conventional sequences especially in patients without known malignancy.

MATERIAL and METHODS

The MRI characteristics of 105 focal liver lesions (FLLs) were classified as benign or malignant by visually assessing the DWI features, and the lesions were compared with a complete liver MRI protocol. Hyperintensity or isointensity of a lesion in apparent diffusion coefficient map by visual assessment was accepted as unrestricted diffusion and benignity, while hypointensity in any part of a lesion was accepted as restricted diffusion and malignancy. Specificity, sensitivity, positive predictive value, negative predictive value, and accuracy of DWI were calculated.

RESULTS

The visual assessment of DWI alone had 74.29% sensitivity, 94.29% specificity, 86.67% positive predictive value, 88.00% negative predictive value, and 87.62% accuracy in differentiating malignant lesions from the benign ones. In 28 of 32 patients without malignancy, DWI results were in concordance with the final diagnosis of benign lesions. The misinterpreted lesions in these patients were three abscesses and a hemorrhagic adenoma.

CONCLUSION

Visual DWI characteristics of FLLs in patients without known malignancy can accurately classify the lesions as benign or malignant. In appropriately selected patients, a liver MRI examination can be completed with only DWI, resulting decrease in time and cost related to intravenous contrast media usage.

Keywords: MRI, diffusion-weighted imaging, liver, tumor, intravenous contrast, abdomen