Interpretation of ²⁰¹Tl Myocardial Scan in Ischemic Heart Disease

This study was performed to evaluate the method of quantification of exercise thallium-201(²⁰¹Tl) myocardial perfusion imaginges(M.P.I.) for the detection of coronary artery disease. Exercise 201 Tl MPI were interpreted objectively, reproducibly, quantitatively and easily by a computer assisted technique-Circumferential profile method.

Exercise ²⁰¹Tl MPI and redistribution images were taken in 32 patients(9 cases of post infarction angina, 13 cases of angina pectoris, 8 cases of atypical chest pain, 1 case of arrhythmial and 1 case of caridac neurosis).

The results obtained were as follows:

1) Exercise ²⁰¹Tl MPI of 3 cases of angina pectoris demonstrated transient perfusion defect in 5 cases, persistent perfusion defect in 2 cases, transient and persistent perfusion defect in 1 cases and no perfusion defect in 5 cases. Exercise ²⁰¹Tl MPI of 9 case of post-infarction angina revealed persistent perfusion defect in 7 cases and transient and persistent perfusion defect in 2 cases. ²⁰¹Tl MPI of 8 cases of atypical chest pain showed transient perfusion defect in 1 case and no perfusion defect in 7 cases. There was no perfusion defect in 1 case of arrhythmia and another case of cardiac neurosis.

2) The location of persistent perfusion defects in several views of ²⁰¹Tl MPI in 9 case of postinfarction angina were consistent with those of infarction area in the electrocardiogram.

3) While visual analysis interpreted three cases to have no perfusion defect and one case to have transient perfusion defect respectively, objective analysis revealed that one of them had transient perfusion defect, another of them had persistent perfusion defect and the other had transient and persistent perfusion defect.

²⁰¹Tl MPI of three cases could be done easily by circumferential profile method, which were difficult to interprete by subjective visual analysis. The results indicate that Exercise ²⁰¹Tl MPI interpreted by circumferential profile analysis would be an objective, quantitative and noninvasive method for the detection of ischemic change and location in coronary artery disease.