99mTc-tetrofosmin SPECT for prediction of functional recovery defined by MRI in patients with severe left ventricular dysfunction: additional value of gated SPECT.
This study was designed to evaluate gated 99mTc-tetrofosmin SPECT for prediction of functional recovery proven by sequential MRI. 99mTc-labeled tetrofosmin is a recently introduced tracer for myocardial perfusion. However, its role for viability assessment is still under investigation.


METHODS
99mTc-tetrofosmin uptake in 19 patients with coronary artery disease and severe left ventricular dysfunction was correlated to regional wall thickening before and 4.5 +/- 0.8 mo after successful coronary artery bypass grafting, as derived from corresponding gated short-axis MRI. Preoperative wall thickening determined by gated SPECT was used as an additional parameter for prediction of functional outcome. Optimal threshold cutoffs to separate reversible from irreversible dysfunction were determined by receiver operator characteristic (ROC) analysis.


RESULTS
The sensitivity and specificity of regional 99mTc-tetrofosmin for prediction of functional recovery was 87% and 42%, respectively (cutoff: 50% of maximum tracer retention). The area under ROC curves for prediction of functional recovery measured 0.66 +/- 0.01. Segments with > or =50% uptake and impaired but detectable wall thickening determined by gated SPECT had a significantly higher likelihood for functional improvement compared with segments with absent wall thickening (P < 0.05). There was no difference in segments with <50% tracer retention. There was good agreement for ejection fraction measurements by MRI and gated SPECT (mean ejection fraction 32 +/- 12 versus 34 +/- 11; r = 0.71, P < 0.001).


CONCLUSIONS
Regional 99mTc-tetrofosmin uptake provided high sensitivity but limited specificity for prediction of functional recovery after revascularization, leading to fair overall accuracy. Wall thickening assessment derived from gated SPECT may improve the specificity of 99mTc-tetrofosmin uptake for prediction of functional recovery but not the sensitivity in low-flow areas. In addition to the assessment of global function, gated data acquisition can be helpful to improve the overall accuracy of 99mTc-tetrofosmin SPECT for prediction of functional recovery after bypass surgery.
Stollfuss
J C
JC
Department of Nuclear Medicine, Technische Universität München, Munich, Germany.
Haas
F
F
Matsunari
I
I
Neverve
J
J
Nekolla
S
S
Ziegler
S
S
Schwaiger
M
M
D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000175:diagnosis / Q000601:surgery; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011237:Predictive Value of Tests; D012372:ROC Curve; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000000981:diagnostic imaging*
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C078700:technetium tc-99m tetrofosmin