An Evaluation Study of Myocardium Viability Using MR Perfusion Imaging

• Main Authors: Yu-Shu Wu, 吳玉書
• Other Authors: Liang-Yu Shyu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/56633159252294656609

碩士 === 中原大學 === 醫學工程研究所 === 95 === In recent years, the incident rate of coronary artery disease (CAD) is significantly increasing in Taiwan. It has been greatly improved in diagnosis of CAD in past decade; however, it is not easy to identify with template-damaged of myocardium. The efficiency of treatment for damaged-myocardium may not easy to evaluate due to insufficient of information in this tissue. The damaged-region and damaged-volume of myocardium were not clearly to identify in the past; in recent years, however, the information can be obtained by examining with MRI myocardial perfusion. Since MRI myocardial perfusion is a noninvasive and radiation-free exam, the health of patient can not be affected after received the exams. The purpose of this study is to analyze the cardiac function of patients with CAD after treatment by using MRI myocardial perfusion. All the subjects included in this study were suspected with CAD. The exams of MRI myocardial perfusion and digital subtraction angiography (DSA) were taken within one week for the same patient. The images of MRI myocardial perfusion were acquired with a Siemens 1.5T MRI scanner. The technique of ECG trigger was employed in this work. All the patients were injected with GD-DTPA contrast medium with 0.07 mmol per kilogram. The images along short axis of heart were acquired with perfusion scan of first-pass with contrast medium injection rate of 3 ml/s. The images along short axis and long (both horizontal and vertical) axis of heart were acquired with delayed enhancement scan after 10 minutes later by injecting of contrast medium with injection rate of 3 ml/s. All the patients were examined with DSA to quantify the level of stenosis of artery, abnormal perfusion region and volume of myocardium. The golden standard in this work is DSA. To investigate the detection efficiency for patient examined with MRI myocardial perfusion, the sensitivity, specificity and accuracy of MRI were calculated. Total of 33 patients were included in this study. The sensitivity, specificity and accuracy of MRI were 90%, 94% and 96%, respectively. The positive predictive value and negative predictive value were respect to 90% and 100%. The signal intensity of ischemic region of myocardium is significantly lower than that of normal region for patient with CAD. However, the signals were enhanced for infracted myocardium in the delay phase. The difference of myocardium activity and heart function before and after treatment were evaluated in 14 patients within 3 months after treatment. A significant difference of signal intensity at first phase of MRI myocardial perfusion was observed before and after treatment. The increased slops of signal of myocardium before and after treatment were 0.93±0.16 and 1.67±0.35 (p<0.03), respectively. The peak signal of myocardium before and after treatment were 30.84±5.93 and 53±11.35 (p<0.02), respectively. The wall thickness of left ventricle was improved from 1.54±0.83 to 2.51±0.54 before and after treatment. The increasing percentages of wall thickness were 25.9±10.13 (p<0.2) and 35.26±1.70 (p<0.3), which no significantly difference was observed before and after treatment. The image of MR Cine can evaluate the contraction function of whole left ventricle and the function of segmental myocardium for patients with CAD. Moreover, the diagnosis of stenosis level of coronary artery and the myocardium activity are significantly improved by using perfusion MRI.