[New trials for improving diagnostic accuracy of stress technetium-99m-tetrofosmin single photon emission computed tomography].
OBJECTIVE
This study evaluated the influence of extra-cardiac accumulation in technetium-99m-tetrofosmin myocardial single photon emission computed tomography (SPECT) imaging.


METHODS
Technetium-99m-tetrofosmin myocardial SPECT was performed in 247 patients from 1997 to 1999. To evaluate the sensitivity, 42 patients with inferior infarction were selected. To evaluate the specificity, 32 patients with no significant perfusion defect and low pretest likelihood (< 15%) of coronary artery disease and 13 patients with normal coronary angiography were selected. Firstly, the SPECT raw data were evaluated according to the effects of diaphragm and breast, the position and the degree of accumulation of the liver, gall bladder and intestine. Then, the myocardial tracer uptake was scored semiquantitatively from 0 (normal) to 4 (perfusion defect) in the 13 segments of the left ventricle.


RESULTS
The specificity was 86.7% and the sensitivity was 92.8%. Perfusion abnormality of the inferior wall was observed in 6 of 45 patients with a low pretest likelihood of coronary artery disease. These 6 patients were classified into the false positive group, and the other 39 patients were classified into the true negative group. The liver position and the liver accumulation on the stress images were significantly higher in the false positive group than in the true negative group (p < 0.001), but only the liver position on the rest images was significantly higher in the false positive group (p < 0.001). By estimating the defect 1 point lower for the high-positioned liver patients, specificity improved from 86.7% to 100% and sensitivity did not change.


CONCLUSIONS
Inferior perfusion defect on technetium-99m-tetrofosmin myocardial SPECT of high-positioned liver patients needs to be evaluated with special caution.
Sasaki
Ryu
R
Department of Cardiology, Fujisawa City Hospital, Fujisawa 2-6-1, Fujisawa, Kanagawa 251-8550.
Mitani
Isao
I
Kitamura
Yutaka
Y
Nemoto
Toyoji
T
Tsukahara
Kengo
K
Tanaka
Yutaka
Y
Higuma
Kikuhiko
K
D000368:Aged; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin