Application Of MR Diffusion-Weighted Imaging In Diagnosing Small Hepatic Lesion

It is very important to detect and diagnosis the local lesion in the earlier stage,which will help the patients to be cured in time and improve their prognosis.MRI is one of the best methods to evaluate the local liver diseases, but it is hard to detect the subtle lesion.MR dynamic enhancement examination could improve the level of detection to the subtle lesion greatly, but only 70%of liver cancers can be detect in arterial phase because of their affluent arterial blood supply,30%of liver cancerr will be missed diagnosis because of their absence of arterial blood supply.DWI is the only method to detect the series state of the heat movement of molecules in vivo,and it can reflect the function and construction features of tissues through activity or diffusion of these molecules.ObjectiveComparing the the rates of detection between MR diffusion-weighted imaging and dynamic enhancement examination.Judging whether it is benign or malignant with the help of ADC.MethodThe researching object including 31 healthy volunteer and 48 patients who had liver focal disease(DA≤3 cm),scaning the patient's liver by routine MRI,DWI and dynamic enhancement scanning with siemens Mgagnetom Avanto 1.5T magnetic resonance imaging machine,adopting SE-EPI-DWI array,exerting breathe gating technique and space force-saturation technique. Counting DWI and the number of tumor nodals' pieces(DA≤3 cm) separately detected by routine MRI,and counting the apparent diffusion coefficient(ADC)according to formula:ADC=[In(S low S/high)]/(b high —b low)Calculating ADC,select ROI and get the value of ADC.Judging whether it is benign or malignant by statistics.Result(1)The detecting rate of malignant focus(93.8%)by the DWI when b=500s/mm~2 is higher than CE(83.8%)(x2=4.01,p＜0.05)。(2)ADC of normal hepatic tissue is(1.42±0.08)×10-3mm~2/s。ADC of hepatic cyst,hemangiomas of liver,hepatic cell hepatoma,hepar metastatic tumor,Hepar cholangiocellular carcinoma is(4.04±0.51)×10-3mm~2/s,(2.33±0.22)×10-3mm~2/s,(1.23±0.17)×10-3mm~2/s,(1.39±0.13)×10-3mm~2/s,(1.33±0.17)×10-3mm~2/s,there are statistics difference between each group(p＜0.05).ConclusionComparing with CE,DWI can detect subtle focus of liver.Through the analysis of DWI and the value of ADC,the value of ADC of hepar malignant occupying lesion is generally lower than benign lesion,it is helpful for differentiating the malignant lesion and benign lesion and it will improve the detecting rate of sbutle focal lesion.DWI is a useful technique in the diagnosis and differential diagnosis of focal liver lesions.In a word,it is useful to filter benign or malignant subtle lesion of the liver combining the examination of DWI and AFP and dynamicenhancement.