Ultrasonography Study Of Peritoneal Lesions

IntroductionPeritoneum is the largest and most widely distributed serous membrane.The omentum,mesenterium and ligaments composed by peritoneum connect and fix the organs.They are also doors of the blood vessels,nerves and lymph vessels and the dissemination path of diseases.Peritoneum is composed of mesothelium and deep connective tissues.Mesothelium is monolayer squamous epithelium and free surface of peritoneum.If epithelium was damaged or deleted,connective tissue would form conglutination and if peritoneum was involved by disease,peritoneum would become thick,edema and forming nodules.Rich capillary network is located in deep peritoneum.Growth factor can produce new blood vessels and make the foci of disease grow more easily.The production of vessels is in control in normal healthy body,because two-ways regulation of growth and inhibition balance the production and apoptosis of blood cells.But chronic inflammation and malignant tumor can up-regulate the level of vascular growth factor and make production and inhibition out of control.Our study reviewed the sonography of peritoneal lesions of 231 cases,discussed their sonography characters and evaluated the effect of ultrasound-guided peritoneal biopsy in differentiating benign and malignant peritoneal lesions.We used color Doppler flow imaging,contrast pulsing sequence contrast imaging and time-intensity curve to analyze the perfusion of thickened peritoneum in 32 cases and western blot to test the activity of vascular endothelial growth factor(VEGF) and angiopoietin 2(Ang-2) in peritoneal lesions and try to understand the angiogenesis and dynamic changes in peritoneal tissues.Materials and Methods1.The sonograms of 231 patients who underwent peritoneal biopsy in our hospital from April 2001 to August 2008 were reviewed,including the distribution of thickened peritoneum,internal echoes,contour,thickness,degree of CDFI blood flow and the existence of nodules.The sonography characters of peritoneal lesions were analyzed and the accuracy of peritoneal biopsy under the guidance of ultrasound in differentiating benign and malignant peritoneal lesions was evaluated.2.32 patients admitted in our hospital with unclear ascites and scheduled to have peritoneal biopsy from April 2007 to February 2009 were chosen in this study.Color Doppler ultrasonic diagnostic apparatus PHILIP IU22 and Simens Sequoia 512 were used to perfume the examination and the contrast agent was Sonovue.Contrast-enhanced ultrasound was performed after routine ultrasound examination and time-intensity curve was used to analyze the difference of parameters and the correlation between perfusion parameters and degree of CDFI blood flow.After the peritoneum biopsy under the guidance of ultrasound,Western blot was used to test the activity of VEGF and Ang-2 in peritoneal tissues and the correlation between perfusion parameters and the activity of the protein were analyzed.Results1.The peritoneums involved by malignant lesions were significantly thicker than those involved by benign lesions(P＜0.001).97.00%of benign peritoneal lesions were tuberculous peritonitis inwhich 34 cases were hyperechoic and 97 cases showed high echo interlaced with irregular hypoechoic or heterogenous strip area and we defined this appearance as "cerebral fissure" sign.The 4 cases of chronic peritoneal inflammation were all hyperechoic.89.20%of malignant peritoneal lesions were peritoneal metastatic carcinoma which appeared like cake.Malignant mesothelioma was hypoechoic and peritoneal pseudomyxoma was usually echogenic.In all the positive diagnoses,40 cases were found having hypoechoic nodules in peritoneum by high-frequency probe in which 12 cases were benign and 28 cases were malignant.The benign nodules were usually round with clear contour and malignant nodules were irregular with heterogenous echo.The positive predictive value of nodules in indicating malignant lesions was 70.00%,negative predictive value was 69.10%.Blood signals could be seen in both benign and malignant peritoneal lesions,but there was no difference in degree of CDFI blood flow between these two groups.Blood signal was found in none of benign nodules and in 8 cases of malignant nodules.218 cases were definitely diagnosed after peritoneal biopsy and the successful biopsy rate was 94.37%.Peritoneal biopsy under the guidance of ultrasound failed in 13 cases.Complications happened in 5 cases in which 3 cases of abdominal wall edema, 1 case of abdominal wall hematoma and 1 case of needle implantation.The 13 failed cases had experimental treatment of tuberculosis and 7 cases were cured and diagnosed tuberculous peritonitis at last.The sonograms showed "cerebral fissure" sign in five of them and two were echogenic.The other 6 cases didn't react to the treatment and 3 cases died one year later because of multiple organs failure and 3 cases spontaneously cured.The sensitivity and specificity of peritoneal biopsy in indicating malignant peritoneal lesions were respectively 96.51%and 93.10%.The "cerebral fissure" sign only appeared in tuberculous peritonitis and its sensitivity and specificity in indicating this disease were respectively 74.05%and 100%.If the "cerebral fissure" sign was combined with biopsy results,the sensitivity and specificity in indicating malignant peritoneal lesions would be raised up to 96.70% and 96.43%.2.32 cases were all definitely diagnosed after biopsy and the successful rate was 100%.There were 11 cases of tuberculous peritonitis and 21 cases of peritoneal metastatic carcinoma.There were 1 case of tubeculous nodule and 3 cases of metastatic nodules.In tubeculous peritonitis,6 cases were echogenic and 4 cases showed "cerebral fissure" sign and 1 case showed nodule.The peritoneal metastatic carcinoma was significantly thicker than tuberculous peritonitis in which 14 cases were heterogenous echogenic and 7 cases were hypoechoic.The degree of CDFI blood flow had no significantly difference between these two groups.The enhancment patterns of tuberculous peritonitis and peritoneal carcinoma were similar.In the 3 metastatic nodules,2 showed slow in and fast out and 1 showed fast in and fast out.The enhancement pattern of tuberculous nodule was the same with peripheral tissue.In the TIC parameters,only amplitude intensity had group difference (P＜0.05).The activity of VEGF and Ang-2 in peritoneal metastatic carcinoma was significantly higher than that of tuberculous peritonitis(P＜0.01).Pearson correlation analysis showed the degree of CDFI blood flow and the activity of VEGF and Ang-2 in peritoneal lesions had significant positive correlation with peak intensity and amplitude intensity.Conclusions1.The "cerebral fissure" sign is characteristic sonograms of tuberculous peritonitis.2.Nodules in peritoneum have good indication for malignant peritoneal carcinoma.3.Peritoneal biopsy under the guidance of ultrasound has great clinical effect in differentiating malignant and benign peritoneal lesions.4.Contrast-enhanced ultrasound can clearly show the contour of peritoneal lesions. The enhancment patterns of tuberculous peritonitis and peritoneal carcinoma are similar.5.Contrast-enhanced ultrasound can show the perfusion changes of nodules.6.Contrast-enhanced ultrasound is more sensitive than CDFI in displaying micro-vessels.7.In the TIC parameters,only amplitude intensity has group difference,indicating that the effect of contrast-enhanced ultrasound in differentiating malignant and benign peritoneal lesions is limited.8.VEGF and Ang-2 are involved in the angiogenesis of peritoneal lesions.The degree of angiogenesis in peritoneal metastatic carcinoma is higher than tuberculous peritonitis.The activity of VEGF and Ang-2 has significant positive correlation with perfusion parameters and indicates that contrast-enhanced ultrasound can reflect the angiogenesis in peritoneum.