A comparison between 99mTc-MIBI and 201TlCl in the distribution of myocardial perfusion

A newly-developed 99mTc-MIBI was studied regarding its detectability and assessment of myocardial blood flow maldistribution in comparison with 201TlCl in 9 patients with an ischemic heart disease and one patient with IIIdeg AV block. Using the polar mapping display generated from the exercise or resting SPECT image data, visual estimation of traces distribution (normal (N), reduced-uptake (R) and defect (D)) were done segmentally. In 10 cases (120 segments), the coincidence of the estimation (N, R and D) between 99mTc-MIBI and 201TlCl images was 92.5%. Moreover, mean and cumulative counts in 99mTc-MIBI images were highly comparable in each segment with those in 201TlCl images, although 1 out of 10 cases showed significantly lower values of the segmental mean and cumulative counts in 99mTc-MIBI images than in the 201TlCl images. In conclusion, 201TlCl and 99mTc-MIBI yielded comparable data in both the visual and quantitative evaluation in 9 of the 10 cases, suggesting that 99mTc-MIBI allows to assess regional myocardial blood flow distribution almost equally to 201TlCl. (author)