This paper proposes a new method based on principal component analysis to find the direction of an object in any pose.Experiments show that this method is fast,can be applied to objects with any pixel distribution and keep the original properties of objects invariant.It is a new application of PCA in image analysis. u001acardial infarction and yet normal coronary artery angiography$$$$ WANG Yuetao *,LU Cunzhi,WANG Li. *Cardiovascular Institute of Xuzhou City , Xuzhou 221009, China Abstract Objective To evaluate the clinical value of 99 Tc m MIBI myocardial perfusion imaging in patients with myocardial infarction(MI) and normal coronary artery angiography(CAG). Methods Five cases were included in this study. Four patients were diagnosed with acute MI according to the clinical work up, ECG and enzymatic evidence. One patient was with indeterminate abnormal Q wave in ECG. CAG was normal in all five patients. Seven to ten days after CAG, all patients underwent 99 Tc m MIBI myocardial perfusion imaging. Results The perfusion imaging showed fixed defects in four patients and normal in one patient.The patient with abnormal Q wave was diagnosed with MI by 99 Tc m MIBI myocardial perfusion imaging. The perfusion defects demonstrated with perfusion imaging were larger than those showed in ECG in four patients. One patient showed transmural MI in ECG and yet normal in perfusion imaging.During the follow up, one patient underwent aneurysmectomy. Conclusion 99 Tc m MIBI myocardial perfusion imaging is of help to work up in patients with MI but normal CAG. This paper proposes a new method based on principal component analysis to find the direction of an object in any pose. Experiments show that this method is fast, can be applied to objects with any pixel distribution and keep the original properties of objects invariant. It is a new application of PCA in image analysis. u001acardial infarction and yet normal coronary artery angiography $$$$ WANG Yuetao *, LU Cunzhi, WANG Li. * Cardiovascular Institute of Xuzhou City, Xuzhou 221009, China Abstract Objective To evaluate the clinical value of 99 Tc m MIBI myocardial perfusion imaging in patients with myocardial infarction (MI) and normal coronary artery angiography (CAG). Methods Five cases were included in this study. Four patients were diagnosed with acute MI according to the clinical work up, ECG and enzymatic evidence. One patient was with indeterminate abnormal Q wave in ECG. CAG was normal in all five patients. Seven to ten days after CAG, all patients underwent 99 Tc m MIBI myocardial perfusion imaging. Results The perfusion imaging showed fixed defects in four patients and normal in one patient. The patient with abnormal Q wave was diagnosed with MI by 99 Tc m MIBI myocardial perfusion imaging. The perfusion defect demonstrated with perfusion imaging were larger than those showed in ECG in four patients. One patient showed transmural MI in ECG and yet normal in perfusion imaging. Drawing the follow up, one patient underwent aneurysmectomy. Conclusion 99 Tc m MIBI myocardial perfusion imaging is of help to work up in patients with MI but normal CAG.