Attenuation-corrected 99mTc-tetrofosmin single-photon emission computed tomography in the detection of viable myocardium: comparison with positron emission tomography using 18F-fluorodeoxyglucose.
OBJECTIVE
The purpose of this study was to assess the efficacy of attenuation-corrected (AC) technetium-99m (99mTc)-tetrofosmin single-photon emission computed tomography (SPECT) in detecting viable myocardium compared to 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET).


BACKGROUND
The role of 99mTc-labeled perfusion tracers in the assessment of myocardial viability remains controversial. Attenuation artifacts affect the diagnostic accuracy of SPECT images.


METHODS
Twenty-four patients with coronary artery disease (mean left ventricular ejection fraction 30%) underwent resting 99mTc-tetrofosmin SPECT and FDG PET imaging. Both AC and non-attenuation-corrected (NC) SPECT images were generated.


RESULTS
Using a 50% threshold for viability by FDG PET, the percentage of concordant segments of viability between 99mTc-tetrofosmin and FDG on the patient basis increased from 79.8%+/-14.0% (mean+/-SD) on the NC images to 90.8%+/-10.6% on the AC images (p=0.002). The percentage of 99mTc-tetrofosmin defect segments within PET-viable segments, an estimate for the degree of underestimation of viability, decreased from 19.8%+/-15.2% on the NC images to 9.7%+/-12.6% on the AC images (p=0.01). Similar results were obtained when a 60% threshold was used to define viability by FDG PET. When the anterior-lateral and inferior-septal regions were separately analyzed, the effect of attenuation correction was significant only in the inferior-septal region.


CONCLUSIONS
The results indicate that AC 99mTc-tetrofosmin SPECT improves the detection of viable myocardium mainly by decreasing the underestimation of viability particularly in the inferior-septal region, although some underestimation/overestimation of viability may still occur even with attenuation correction.
Nuklearmedizinische Klinik und Poliklinik der Technischen Universität München, Klinikum rechts der Isar, Munich, Germany.
I
I
Matsunari
G
G
Böning
S I
SI
Ziegler
S G
SG
Nekolla
J C
JC
Stollfuss
I
I
Kosa
E P
EP
Ficaro
M
M
Schwaiger
D000368:Aged; D000369:Aged, 80 and over; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C078700:technetium tc-99m tetrofosmin