A Study Of The Correlation Between The Features Of MRI And Angiogenesis In Hepatocellular Carcinomas

Objective：The purpose of this study was to evaluate the correlation between thefeatures of magnetic resonance imaging （MRI） and angiogenesis inhepaocellular carcinomas （HCCs）.Materials and Methods：Preoperative liver MRI was performed in 46 patients with HCCs（confirmed by pathology） using the GE SIGNA EXCITE 1.5T MRI system.The conventional MRI scanning sequence had a gradient echo T1-weightedimage （GRE T₁WI）, a fast-recovery, fast-spin echo T₂-weighted image（FRFSE T₂WI） and a single-shot, fast-spin echo T₂-weighted image （SSFSET2WI）. Enhanced MRI scanning was performed by injecting an MR contrastagent （GD-DTPA） （GE） intravenously into the forearm with the help of amagnetic resonance dedicated dual-tube power injector （U.S. Medrad）. Thecontrast agent was injected at a concentration of 0.5mmol/ml and the rate of3.0ml/s for a total dose of 0.2mmol/Kg. Lesion features were measured onmagnetic resonance images, including tumor diameter, margin, necrosis andinvasion. The lesion-to-liver contrast-to-noise ratio （CNR） and the contrastenhancement index （CEI） were also calculated. The expression of vascularendothelial growth factor （VEGF） and the microvessel density （MVD） wereevaluated in tumor paraffin sections （including 14 adjacent tissues, controlgroup） using the Elivison immunohistochemical technique. The correlationbetween the MRI features and angiogenesis in HCCs was evaluated. SPSS 16.0 （SPSS Inc., Chicago, Illinois） was used to conduct the statistical analyses.The P value cutoff for statistical significance was set at 0.05.Results:1. In the 46 cases, VEGF expression was detected in 34 patients, and therate of positive VEGF expression was 73.9% （34/46）. The MVD valuesranged from 5.0 to 93.0, and the mean was 35.3±2.8. The MVD values were40.5±3.2 in VEGF-positive tumors and 20.7±3.1 in VEGF-negative tumors,which was a statistically significant result （p = 0.001）. In the control group（14 cases whose tumor paraffin sections contained adjacent tissues）, VEGFexpression was detected in 4 patients, and the VEGF-positive rate was 28.6%（4/14）. The MVD value ranged from 10.0 to 61.0, and the mean was 23.7±3.2. The MVD value and the VEGF-positive rate of the tumors were higherthan those of the adjacent tissues （p = 0.035 and p = 0.004）.2. The MVD in the group with a tumor diameter larger than 5.0 cm wasnot significantly different form that in the group with a diameter less than 5.0cm （p = 0.928）, but the VEGF-positive rate in patients with a tumor diameterlarger than 5.0 cm was higher than that with a tumor diameter less than 5.0cm （p = 0.017）. The MVD and the VEGF-positive rate were significantlydifferent between patients with central necrosis and patients without centralnecrosis （p = 0.000 and p = 0.011）. There was no statistically significantcorrelation between the VEGF-positive rate and the tumor margin （p = 0.113）.The MVD in the blurred-margin group was higher than that in the clearmargin group （p = 0.038）. There was no statistically significant correlationbetween the VEGF-positive rate and tumor invasion （p = 0.125）, but theMVD in the invasive tumor group was higher than that in the noninvasivetumor group （p = 0.004）. 3. The CNR difference in VEGF-positive group and the VEGF-negativegroup was significant （p = 0.004） on T1-weighted images, but did not differ onthe T2-weighted images （p = 0.122）. The CEI significantly differed betweenthe VEGF-positive group and the VEGF-negative group in the artery phaseand the portal venous phase （p = 0.000 and p = 0.001）, but it did not differ indelay phase （p = 0.765）.4. MVD and the CNR were not correlated on the T₁-weighted imagesand the T2-weighted images （p = 0.074 and p = 0.333）. The MVD positivelycorrelated with the CEI in the artery phase and the portal venous phase （r =0.316, p = 0.032 and r = 0.317, p = 0.032, respectively）, but it did notcorrelate with the CEI in the delay phase （p = 0.105）.Conclusion:1. The MVD value significantly different between the VEGF-positivegroup and the VEGF-negative group, indicating that VEGF protein, which isone of the vascular regulatory factors, plays an important role in HCCneovascularization. MVD and VEGF expression in tumors were higher thanthose in the adjacent tissues, which showed that the microvessels in tumorswere richer than those in normal tissues.2. VEGF expression and MVD were significantly related to the HCCMRI features, including tumor diameter, margin, necrosis and invasion,indicating that MVD and VEGF play an important role in tumor growth,aggressiveness and metastasis.3. The relationship between CNR and VEGF expression and MVD onT1-weighted and T2-weighted images requires further study. The CEI reflectsthe tumor blood supply,which will help to advance understanding of thesignificance of MRI features, determine the invasion and metastasis of HCC, and provide more biological characteristics for the diagnosis and treatment ofHCC.