ABSTRACT
<p><b>BACKGROUND</b>Intravascular microbubble-enhanced acoustic cavitation is capable of disrupting the vascular walls of capillaries and small vessels. This study was designed to investigate the impact of microbubble-enhanced, pulsed and focused ultrasound (MEUS) on the blood perfusion of subcutaneous VX2 tumors in rabbits.</p><p><b>METHODS</b>Subcutaneous VX2 cancers in twenty New Zealand rabbits were treated by combining high-pressure amplitude, pulsed and focused therapeutic ultrasound (TUS) and intravenous microbubble injections. The TUS transducer was operated with a peak negative pressure of 4.6 MPa and a duty cycle of 0.41%. Controls were subcutaneous VX2 cancers treated with TUS or microbubbles only. Contrast-enhanced ultrasound (CEUS) and intravenous Evans Blue (EB) perfusion were performed to assess the tumor circulation. The tumor microvascular disruption was assessed by histological examination.</p><p><b>RESULTS</b>CEUS showed that the tumor circulation almost vanished after MEUS treatment. The average peak grayscale value (GSV) of tumor CEUS dropped significantly from 84.1±22.4 to 15.8±10.8 in the MEUS-treated tumors but no significant GSV changes were found in tumors in the two control groups. The mean tumor EB content of the MEUS-treated tumors was significantly lower than that of the controls. Histological examination found scattered tumor microvascular disruption with intercellular edema after MEUS treatment.</p><p><b>CONCLUSION</b>The tumor circulation of VX2 cancers can be arrested or significantly reduced by MEUS due to microvascular disruption.</p>
Subject(s)
Animals , Rabbits , Contrast Media , High-Intensity Focused Ultrasound Ablation , Liver Neoplasms , Therapeutics , Microbubbles , Ultrasonic TherapyABSTRACT
Objective To investigate the relationship betwee n tricuspid insufficiency (TI) and the function of the right ventricle, degree o f pulmonary vascular pathological change in patients with rheumatic heart diseas e so as to provide the indication of operation for treating TI. Methods 41 cases of rheumatic heart disease with TI accompanying with bicuspid pathological changes were reviewed. Correlation analysis was done between the s everity of TI and the right ventricular size(RVS), pulmonary artery pressure(PAP ), pulmonary artery resistance(PAR) etc. Results It was found t hat the size of the right ventricle, PAP, PAR were positively correlated to th e degree of TI. Tricuspid annuloplasty should be carried out in patients with RV D>40 mm, PAR >48 kPa*s/L, PAP>8 kPa. Conclusion TI resulted ma inly from insufficient function of the right ventricle and marked patholog ical changes of the pulmonary blood vessels. Doppler echocardiography evaluation for the function of right ventricle and pathological condition of pulmonary blo od vessels might be of significant in deciding whether tricuspid annuloplasty sh ould be performed simutaneously in patients of bicuspid valve replacement.
ABSTRACT
Objective To investigate the relationship betwee n tricuspid insufficiency (TI) and the function of the right ventricle, degree o f pulmonary vascular pathological change in patients with rheumatic heart diseas e so as to provide the indication of operation for treating TI. Methods 41 cases of rheumatic heart disease with TI accompanying with bicuspid pathological changes were reviewed. Correlation analysis was done between the s everity of TI and the right ventricular size(RVS), pulmonary artery pressure(PAP ), pulmonary artery resistance(PAR) etc. Results It was found t hat the size of the right ventricle, PAP, PAR were positively correlated to th e degree of TI. Tricuspid annuloplasty should be carried out in patients with RV D>40 mm, PAR >48 kPa*s/L, PAP>8 kPa. Conclusion TI resulted ma inly from insufficient function of the right ventricle and marked patholog ical changes of the pulmonary blood vessels. Doppler echocardiography evaluation for the function of right ventricle and pathological condition of pulmonary blo od vessels might be of significant in deciding whether tricuspid annuloplasty sh ould be performed simutaneously in patients of bicuspid valve replacement.