Comparison Study of Myocardial contrast Echocardiography and Tc99m MIBI SPECT in Assessing Myocardial Perfusion

Song, Woo Hyuk; Shim, Wan Joo; Rha, Seung Woon; Lee, Sang Chil; Lim, Do Sun; Kim, Young Hoon; Jin, Dong Gyu; Park, Chang Gyu; Oh, Dong Joo; Ro, Young Moo

Abstract

BACKGROUND
The radionuclide scintigraphy with Thallium201 or Tc99m sestamibi(MIBI) is the most commonly used method in assessing myocardial perfusion in the clinic. Recently myocardial contrast echocardiography(MCE) has been reported as a new method to evaluate the status of myocardial perfusion, But the objectivity of the MCE was not verified completely. Thus this study was undertaken to evalute the usefulness of MCE by comparing the myocardial opacification grades of MCE and scintigraphic perfusion grades using Tc99m MIBI. METHOD: MCE and MIBI scintigraphy was carried out 2 weeks after acute myocardial infarction with a mean time interval of 2 days in 15 patients(M : F=13 : 2, mean age : 59 yrs). Scintigraphic myocardial tomographic image at short axis, vertical and horizontal long axis were obtained after 15 mCi of Tc99m MIBI injection in resting state. MCE was done in the catheterization laboratory on the completion of coronary angiography by injecting sonicated Hexabrix(4cc to left and 3cc to right coronary artery) in parasternal short, apical 4 and 2 chamber view. To anaylaze the MCE images and SPECT images, the left ventricle in 3 views were divided into 20 segments and the myocardial opacification and MIBI perfusion grades were scored in each segment. The myocardial segments were classified into 3 coronary artery territoris and opacification indexes and MIBI perfusion indexes were calculated in each coronary artery territories. The comparison of myocardial opacification indexes and MIBI perfusion indexes was done in the whole patients and by location of infarction site. RESULT: The total number of analyzed mocardial segments was 289. THe correlation of myocardial opacification indexes and MIBI perfusion indexes was r=0.63(p < 0.01). The correlation between MCE index and MIBI index was higher in left anterior descending artery territory(r=0.73, p < 0.01) than left circumplex artery territory(r=0.49, p=0.06) and right coronary artery territory(r=0.65, p < 0.01). The correlations between MCE index and MIBI index as not influenced by infarction site(r=0.66, p < 0.01 in anterior wall infarction, r=0.60, p < 0.01 in inferior wall infarction). MCE had a better correlation with the degree of regional wall motion abnormality than MIBI myocardial scintigraphy.
CONCLUSION
Because myocardial opacification grade by MCE shows good correlation with MIBI perfusion grades, MCE can be used as an objective method in evaluating myocardial perfusion of ischemic heart.