[DWI MAGNETIC RESONANCE IN CHARACTERIZATION OF FOCAL LIVER LESIONS].

The aim of this study was to examine the possibilities of measuring ADC/DWI values with the ROI method for precise differentiation of focal liver lesions from normal liver parenchyma. The study included 100 liver lesions sized ≥1 cm, previously detected in patients by ultrasound and computed tomography. It is done by measuring the diffusion coefficient ADC folder (MRI 3T), setting the ROI on the periphery of hepatic lesions, on the liver parenchyma around the focal hepatic lesions and on liver parenchyma that is distant to hepatic lesions. In our study, difference between the average ADC value of focal liver lesions (1.24 x10(-3) mm(2)/s) and normal liver parenchyma around focal liver lesions (1.001x10(-3) mm(2)/s) was statistically confirmed. There was statistically proven difference in the average ADC values between normal liver parenchyma around focal lesions and liver parenchyma located distant from focal lesions of (1.003x10-3 mm2/s). Wilcoxon rank test yielded differences in the average (median) ADC values between total lesions in patients and liver parenchyma directly around focal lesions (p<0.0005). Wilcoxon rank test showed no differences in the average (median) ADC between liver parenchyma directly around focal lesions and distant of focal hepatic lesions (p<0.0005). The results obtained for each focal liver lesion were compared with histopathology findings obtained by puncture or surgery, and for cystic lesions radiological follow up was sufficient. For all liver lesions, the resulting overall DWI/ADC sensitivity was 92% and specificity 77%. Kendall’s tau-b coefficient of concordance showed a statistically significant correlation between our DWI diagnosis and histopathology verification for all liver lesions (p<0.0005). He mangiomas and cysts showed greatest difference in ADC values as compared with healthy liver. ADC values of hepatocellular carcinoma (HCC) and the surrounding normal liver parenchyma were not statistically different, which can be explained by similarities in their cell structure. Related articles conclude that DWI has inadequate sensitivity in detecting HCC, explaining this minimal difference in cellularity of well differentiated HCC and liver parenchyma. DWI/ADC has the potential to differentiate and reliably define the limits of focal lesions of the normal liver parenchyma. ADC delimitation of focal lesions of the liver parenchyma is most reliable for hemangiomas and cysts, while ADC delimitation of HCC can pose diagnostic difficulties.