Quantitative Tissue Velocity Imaging Combining With Low Dose Dobutamine Stress Experiment In Assessment Of Myocardial Viability

Aim To investigate the accuracy of quantitative tissue velocity imaging (QTVI) technology combining with low-dose dobutamine-stress echocardiography for the detection of myocardial viability, using nitroglycerine ⁹⁹Tc^m-MIBI SPECT (NTG-ECT) as a reference. Methods Twenty-seven patients with myocardial infarction underwent ⁹⁹Tc^m-MIBI SPECT myocardial perfusion imaging, low-dose dobutamine-stress echocardiography examination. Evaluation was performed using a sixteen-segment model in all patients. ⁹⁹Tc^m-MIBI SPECT imaging was done in two days, including rest and nitroglycerine imaging.The left ventricular wall segments including viable and non-viable myocardial were quantified and observed in baseline, 5μg.kg^-1.min^-1, 10μg.kg^-1.min^-1 stress stage and recovery stage using semiquantitative analysis methods and QTVI technology. The optimal index from Vs, Ve, Va, VTIs, VTIe, VTIa, M-Vs, M-VTIs was chosen and then the sensitivity , specificity and accuracy were calculated for identifying myocardial viability.Results 1.One hundred and eighty-nine segments were found abnormal perfusion by rest ⁹⁹Tc^m-MIBI SPECT imaging. Of which,thirteen segments showing normal motion in baseline echocardiography were excluded, one hundred and seventy-six segments were also found abnormal motion in baseline echocardiography. According to NTG-ECT, ninety-two segments were classified as viable segments (group A), eighty-two as non-viable segments (group B) . After the dose of dobutamine 10μg.kg^-1.min^-1, the sensitivity, specificity, accuracy for the prediction of myocardial viability using visual observation method were respectively 76.0%, 83.3%, 79.5%. 2.The results of QTVI analysis:(1) In group A, the index Vs, Ve, VTIs had a trend of improvement in every stress-stage compared with baseline stage,but only Vs and VTIs had statistical difference in both dobutamine dose of 5μg.kg^-1.min^-1 and 10μg.kg^-1.min^-1.(2) In group B,peak systolic velocity Vs in dose of dobutamine 10μg.kg^-1.min^-1 was greater than baseline (p<0.05).(3) In the baseline stage ,the index of Vs and VTIs were larger in group A than in group B,but had no statistical differences.In every stress-stage, the indexs of Vs and AVs% were greater in group A than in group B and had statistical differences.After the dose of dobutamine10μg.kg^-1.min^-1,group A: ΔVs% 60±42%, group B: 16±25%(p<0.05).(4) The index of M-Vs, M-VTIs of group A and group B had no statistical differences in the...