Right Ventricular Volume And Function Measurement Using Cardiac Magnetic Resonance Imaging In Diagnosis Of Pulmonary Hypertension

Part 1:Right ventricular volume and function measurements by short axial orientation paralleled to the tricuspid valve using magnetic resonance imagingPurpose:Right ventricular volume and function parameters are very important to patients with respiratory and cardiovascular system diseases which could lead to the right ventricle damage, and magnetic resonance imaging is considered to be the most accurate method to evaluate right ventricular volume and function. This study is to measure right ventricular volume and function using short axial cine magnetic resonance imaging paralleled to the tricuspid valve.Materials and Methods:30 normal volunteers (15 males and 15 females, mean age 41.5 years, age range 21-60 years) with no past medical history and normal blood pressure were recruited. Exclusion criteria were contraindications to MRI scanning, arrhythmia, age under 20 or over 60, and pregnancy. Right ventricular volumes from data sets acquired in short axial orientation paralleled to the tricuspid valve were compared with normal Chinese reference value.Results:30 volunteers right ventricular end-systolic volume and right ventricular end-diastolic volume were according to the normal distribution. There was no significant difference in the right ventricular end-diastolic volumes, end-systolic volumes and ejection fraction between normal Chinese reference value and data from short axial orientation paralleled to the tricuspid valve.Conclusion:The short axial orientation paralleled to the tricuspid valve is feasible to measure the right ventricular volumes and function.Part 2:Comparison of right ventricular volume measurements between short axial paralleled to the tricuspid valve and left ventricle short axis orientation using magnetic resonance imagingPurpose:To compare right ventricular volume measurements and their reproducibility between short axial paralleled to the tricuspid valve and left ventricle short axis orientation acquisition techniques.Materials and Methods:30 normal volunteers (15 male and 15 female, mean age 41.5years, age range 21-60 years) with no past medical history and normal blood pressure were recruited. Exclusion criteria were contraindications to MRI scanning, arrhythmia, age under 20 or over 60, and pregnancy. Measurements of right ventricular volumes from data sets acquired in short axial paralleled to the tricuspid valve and left ventricle short axis orientations were compared in 30 normal subjects. The observer variabilities were assessed and the left ventricle and right ventricular stroke volumes were compared.Results:There were significant difference in the right ventricular end-diastolic volumes(117.4±23.8ml,125.6±25.2ml), end-systolic volumes (60.4±14.4ml,66.8 ±15.8ml), right ventricular stroke volume (57.1±12.7ml,58.8±12.8ml) and ejection fraction (48.7±4.9%,46.9±4.8%) between left ventricle short axis and short axial paralleled to the tricuspid valve methods. The latter method resulted in larger volumes. The short axial orientation paralleled to the tricuspid valve method had lower intra-and inter-observer variability than the left ventricle short axis method. There was no significant difference between right ventricular stroke volume acquired from short axial orientation method paralleled to the tricuspid valve and left ventricular stroke volume acquired from left ventricle short axial orientation method. 97%(29/30) of the points were in the limits of agreement The standard deviation of the difference and the limits of agreement were consistently lower for the short axial paralleled to the tricuspid valve method.Conclusion:There is a significant systematic difference between volumes measured using the two different orientations. The short axial orientation acquisition techniques paralleled to the tricuspid valve result in better inter-and intra-observer reproducibility.Part 3:Value of measurement of right ventricular volume and function in pulmonary hypertension using cardiac magnetic resonance imagingPurpose:Pulmonary hypertension is a state of hemodynamics and pathophysiotogy, and is visible in a variety of clinical disease. Accurate, noninvasive monitoring of pulmonary hypertension in patients with right ventricular function change is particularly important This study aims to explore the value of volume and function measurement using cardiac magnetic resonance imaging in diagnosis of pulmonary hypertensionMaterials and Methods:Cardiac catheterization and cardiac magnetic resonance imaging examination were performed in 39 patients suspected diagnosis of pulmonary hypertension, and two examinations interval time were less than one week. We called for 30 healthy volunteers (15 men and 15 women, average age of 41.5 years, range in age from 21 years to 60 years), which served as controls. Cardiac magnetic resonance imaging scan sequence included horizontal long axis, vertical long axis, left ventricular short axis of a real steady precession fast imaging, black blood sequence and short axis parallel to the tricuspid valve of real steady precession fast imaging cine sequence. The continuous short axis cine images were imported to Siemens post-processing software to calculate the right ventricular and left ventricular end-diastolic volume, end systolic volume, stroke volume, and ejection fraction. The above data were correced by body surface area except the ejection fraction. Left and right ventricular volume data of pulmonary hypertension group and control group were compared by independent t test or rank test. The relationship between right ventricular volume data and pulmonary artery pressure, the main pulmonary artery blood oxygen saturation, lung resistance, and the WHO classification were tested by the linear correlation analysis or Kendall correlation analysis(standard for P< 0.05)Results:Abnormal cardiac magnetic resonance performance of pulmonary hypertension group included 29 cases of right ventricular expansion,15 cases of right atrium expansion,6 cases of the left ventricle expansion and 10 cases of the left atrium expansion,33 cases of right ventricle wall thickening or trabecular bulky,18 cases of t noncompaction of ventricular myocardium,11 cases of flat ventricular septal or convex to left ventricle,35 cases of pulmonary artery enlargeing,13 cased of tricuspid regurgitation,10 cases of pulmonary valve regurgitation, and 6 cases of ventricular septal defect,11 cases of atrial septum defect,3 cases of patent ductus arteriosus,1 cases of aortic straddles, dry forever artery in 1 case,1 case of double outlet of right ventricular, endocardial cushion defect in 1 case.35 cases diagnosed with pulmonary hypertension group by cardiac catheterization. The right ventricular end diastolic volume, end systolic volume, stroke volume, end diastolic volume index, end systolic volume index, stroke volume index of pulmonary hypertension group were significantly greater than those of the control group (P< 0.05). No significant difference was found in right ventricular ejection fraction between pulmonary hypertension group and control group. There were no significant difference in left ventricular end diastolic volume, end systolic volume, stroke volume, ejection fraction, end diastolic volume index, end systolic volume index, stroke volume index between pulmonary hypertension group and control group (P> 0.05). There were no correlation between the right ventricular end diastolic volume, end systolic volume, stroke volume, ejection fraction, end diastolic volume index, end systolic volume index, stroke volume index of pulmonary hypertension group and systolic pulmonary artery pressure, diastolic pulmonary artery pressure, mean pulmonary artery pressure (P>0.05). There were weak correlations between pulmonary artery trunk diameter and systolic pulmonary artery pressure, mean pulmonary artery pressure (P<0.05), while there were weak correlations between pulmonary artery trunk diameter/ascending aorta diameter and systolic pulmonary artery pressure, diastolic pulmonary artery pressure, mean pulmonary artery pressure (P< 0.05). There were weak correlations between the main pulmonary artery oxygen saturation and the right ventricular stroke volume, stroke volume index, ejection fraction in cardiac atheterization group, and were no correlations between the main pulmonary artery oxygen saturation and the right ventricualr end diastolic volume, end systolic volume, end diastolic volume index, end systolic volume index. There was no correlation between total pulmonary resistance, pulmonary vascular resistance, pulmonary vascular resistance index and right ventricular end diastolic volume, end systolic volume, stroke volume, ejection fraction, end diastolic volume index, end systolic volume index, stroke volume index in cardiac atheterization group. There were positive correlations between right ventricular end diastolic volume, end systolic volume, ejection fraction, end diastolic volume index, end systolic volume index, stroke volume index in cardiac atheterization group and the WHO heart function classification (P< 0.05), of which the end diastolic volume index, end systolic volume index's relevance were the larger.Conclusion:Cardiac magnetic resonance imaging can measure the right ventricular volume, function in patients with pulmonary hypertension, and is helpful for more accurate classification of grading diagnosis and prognosis judgement.