[Clinical significance of the role of left ventricular cavitation ratio in the assessment of coronary artery disease with 99mTc-tetrofosmin].
This study was aimed at assessing the increase in left ventricular cavity volume in patients with induced stress ischemia, by the quantitative analysis of myocardial SPECT perfusion images obtained 30-45 min after 99mTc-Tetrofosmin injection.


METHODS
31 consecutive patients with suspected CAD (group A) and 16 low risk CAD subjects (group B) underwent the study. Global (GMPR) and regional myocardial perfusion reserve indices were assessed superimposing a 17 ROI mask on stress and rest bull's eye images. Ventricular cavitation index (VCI) was calculated manually, outlining the left ventricular cavity on stress and rest midventricular SPECT slices. L/H ratio was determined on anterior SPECT images.


RESULTS
On the basis of perfusion patterns, group A was divided into two subgroups: subgroup 1 included the patients with reversible perfusion defects (n = 20) and subgroup B those with irreversible perfusion defects (n = 11). Average stress CI was significantly higher in group A than in group B (p < 0.01) and in subgroup 1 than in group B (p < 0.005). Rest CVI, GMPR and L/H ratio showed no significant intergroup differences. The stress VCI to rest VCI ratio (VCI ratio) was higher in subgroup 1 than group B (p < 0.0001) and in subgroup 1 than in subgroup 2 (p < 0.01). Moreover, VCI ratio was higher in group A than in group B.


CONCLUSIONS
These preliminary data show that, in ischemic patients, left ventricular cavity volume increases after stress also in 99mTc-Tetrofosmin images. Since our images were acquired 30-45 min after stress, when the dilatation due to ventricular dysfunction is usually resolved, the volume increase may be caused by a cavitation effect due to reduced intracardiac blood flow.
Bestetti
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A
Cattedra di Medicina Nuclear, Università degli Studi di Milano.
Chiapparino
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Tarolo
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D000368:Aged; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D016277:Ventricular Function, Left
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin