| Objective: Chronic liver disease causes aberrant formation of fibrous tissue that impedes normal liver function,ultimately resulting in liver cirrhosis.Cirrhosis of liver is the advanced stage of the development of chronic liver disease,and is characterized by liver cell degeneration,necrosis,nodular hyperplasia and hyperplasia of fibrous tissue and liver structure disorder in pathology.It is a common chronic,progressive,diffuse liver disease.Approximately 45% of cirrhotic nodules have selective deposition of iron.Iron uptake can occur within the hepatic parenchyma or within the various nodules that form in a cirrhotic liver,termed siderotic nodules(SN).Susceptibility-weighted imaging is a new magnetic resonance imaging technology which is based on T2*,and it is very sensitive to the blood and its metabolites,vein,calcification,iron etc.SWI imaging is currently the most sensitive method in detection of SN.We aimed to investigate the diagnostic performance of susceptibility weighted imaging(SWI)for detection of SN in patients with liver cirrhosis,and to compare SWI with T1 WI,T2WI and T2*WI,and to evaluate the potential of SN numbers for assessing liver function.By two abdominal imaging diagnostician common evaluation,Methods: According to the Child-Pugh classification of liver function,each level selected 20 cases of patients with liver cirrhosis.The Child-Pugh classification was assessed based on the following five factors;hepatic encephalopathy,ascites,total bilirubin,prothrombin time,and albumin concentrations(class A: 5-6 points;class B:7-9 points;class C:10-15 points).And selected 20 healthy volunteers matched for age and sex;They underwent MRI scan,the scanning sequences included T1-,T2-,T2*-weighted imaging and SWI at a 3.0T MR system.The liver parenchyma with focal low signal is defined as SN,Less than 3 millimeter is defined as a small SN;Calculating the total number of SN and small SN.The conspicuity of siderotic nodules was assessed using a scale from 1 to 3(1,weak;2,moderate;3,prominent).Calculating and comparing the detection rate of SN in the four kinds of images.According to the clinical data of the patients,recording the score of the patients with cirrhosis based on Child-Pugh classification of liver function.According Couinaud liver segment division method,liver was divided into left lobe and right lobe of liver,and in five leaves,which left half liver include: caudate lobe,left lateral lobe and left internal lobe,right half liver include: right anterior lobe and right posterior lobe.In the SWI image calculating the number of SN in left half liver?right liver and total hepatic respectively.Carrying on the correlation research between the score and the number of SN in left half liver?right half liver and total hepatic respectively.Results:1 The detection rate of SN with T1WI?T2WI?T2*WI and SWI is 13.33%(8/60)?25%(15/60)?43.33%(26/60)and 66.67%(40/60)respectively.The detection rate of SN with SWI is higher than that with MR T1WI(?2=35.56,P<0.05)?T2WI(?2=20.98,P<0.05)and T2*WI(?2=6.60,P<0.05);The normal control group showed no detectable SN.2 Quantitative analysis of the total number of SN which is counted manually from four kinds of acquisition mode were detected: T1 WI: N=39(4.88±2.90);T2 WI: N=144(9.60±5.22);T2*WI:N=376(14.46±6.31);SWI:N= 1121(28.03±6.36).SWI detected the higher number of SN than T1-,T2-,T2*-weighted imaging;The difference was statistically significant(P<0.05).3 T1-,T2-,T2*-weighted imaging and SWI can detect the distribution of SN,SWI can show more diffuse SN than T1-,T2-,T2*-weighted imaging.SWI detected 220 SN which is less than 3.0mm.T2*-weighted imaging detected 96 SN which is less than 3.0mm.4 The display degree of SN detected in T1-,T2-,T2*-weighted imaging and SWI is different,the display degree of SN is worst in T1-weighted imaging and best in the SWI image.SN displayed better in the SWI image than those in T2*-weighted imaging,the boundary of SN is sharp in the SWI image and had better contrast degree.There are 87.5%(35/40)patients whose SN visibility performance into three level in the SWI image,There are 30.77%(8/26)patients whose SN visibility performance into three level in T2*-weighted imaging,so SWI images have obvious advantages.5 The number of patients from Child-Pugh classification A,B and C whose SN is showed in the SWI imaging were 11 cases,15 cases,14 cases respectively.In the SWI image calculating the number of SN in left half liver?right liver and total hepatic respectively.Carrying on the correlation research between the score and the number of SN in left half liver?right liver and total hepatic respectively.And calculating the corresponding Child-Pugh score.Spearman correlation analysis on the score and the number of SN in left half liver,the correlation coefficient is-0.17,P=0.30,by P=0.05 level,there is no correlation between the two.Spearman correlation analysis on the score and the number of SN in right half liver,the correlation coefficient is-0.50,P=0.76,by P=0.05 level,there is no correlation between the two.Spearman correlation analysis on the score and the number of SN in total hepatic,the correlation coefficient is-0.11,P=0.49,by P=0.05 level,there is no correlation between the two.Conducting paired-samples t-test between the number of SN in left half liver and the number of SN in right half liver.The statistic t=1.81,bilateral inspection P=0.08,by P=0.05 level,there is no difference between the two.Conclusions: The results of our study suggest that the SWI procedure provides contrast images that are superior to the conventional T1,T2 and T2* weighted images.The detection rate for SN on SWI is higher than T1,T2 and T2* weighted images.SWI sequences can provide detailed information of hepatic SN.SWI appears to provide the most sensitive method to detect SN in cirrhotic liver.It is a valuable complement to conventional liver MRI.However,Spearman correlation analysis on the score and the number of SN in the SWI imaging,there is no correlation between the two.Therefore the number of SN was determined not to be a predictor for the severity of cirrhosis and prognosis.In summary,SWI is expected to become a new noninvasive method for hepatic iron overload evaluation. |
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