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.
Department of Nuclear Medicine, Hokkaido University Graduate School of Medicine, Kita-Ku, Kita 15 Nishi 7, Sapporo, 060-8638, Japan.
Keiichiro
K
Yoshinaga
Chietsugu
C
Katoh
Kazuyuki
K
Noriyasu
Satoshi
S
Yamada
Yoshinori
Y
Ito
Yuji
Y
Kuge
Yuko
Y
Kawai
Tetsuro
T
Kohya
Akira
A
Kitabatake
Nagara
N
Tamaki
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