Low-dose dobutamine stress gated SPET for identification of viable myocardium: comparison with stress-rest perfusion SPET and PET.
The detection of viable myocardium is important for the prediction of functional recovery after revascularisation. However, a fixed perfusion defect often includes viable myocardium, and perfusion imaging then underestimates myocardial viability. We previously reported that low-dose dobutamine stress gated single-photon emission tomography (SPET) provides similar findings to dobutamine stress echocardiography in the assessment of myocardial viability. The present study investigated whether low-dose dobutamine stress gated SPET is of additional value as compared with stress-rest technetium-99m tetrofosmin SPET for the detection of myocardial viability. Standard stress-rest perfusion SPET, low-dose dobutamine stress gated SPET and fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) were studied in 23 patients (mean age 67+/-7.6 years) with previous myocardial infarction. Twenty-one of them were successfully studied with each technique. FDG PET viability (FDG uptake >/=50%) was employed as the gold standard. One-day stress-rest (99m)Tc-tetrofosmin myocardial SPET was performed. After the resting study, gated SPET was acquired following infusion of 7.5 microg kg(-1) min(-1) of dobutamine. Left ventricular wall motion in 16 segments was assessed by cine mode display using a four-point scale. Myocardial viability was considered present when there was improvement by one point. Of a total of 336 segments analysed, 53 had persistent defects on stress-rest perfusion SPET. FDG viability was seen in 16 of 17 dobutamine-responsive segments, but in only 11 of 36 dobutamine non-responsive segments ( P<0.01). Thus, in the segments with persistent defects, viability findings on low-dose dobutamine stress gated SPET were concordant with those on FDG PET in 77% of segments (kappa value =0.55). For the detection of FDG-viable myocardium, the combination of stress-rest perfusion SPET and low-dose dobutamine stress gated SPET achieved a better sensitivity than stress-rest perfusion SPET alone (35/46, 76% vs 19/46, 41.3%, P<0.001), with a similar specificity (25/29, 86% vs 26/29, 90%, P=NS). We conclude that in the identification of viable myocardium, low-dose dobutamine stress gated SPET may provide additional information missed on a routine stress-rest perfusion scan. Dobutamine stress gated SPET may provide new insights into myocardial viability on the basis of ischaemia and contractile reserve.
Yoshinaga
Keiichiro
K
Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-Ku, Kita 15 Nishi 7, Sapporo, 060-8638, Japan.
Katoh
Chietsugu
C
Noriyasu
Kazuyuki
K
Yamada
Satoshi
S
Ito
Yoshinori
Y
Kuge
Yuji
Y
Kawai
Yuko
Y
Kohya
Tetsuro
T
Kitabatake
Akira
A
Tamaki
Nagara
N
D000368:Aged; D004280:Dobutamine / Q000008:administration & dosage; D005080:Exercise Test; D005260:Female; D019788:Fluorodeoxyglucose F18; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006321:Heart / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014463:Ultrasonography
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D004280:Dobutamine; C078700:technetium tc-99m tetrofosmin