Assessment of contractile response to dobutamine stress by means of ECG-gated myocardial SPECT: comparison with myocardial perfusion and fatty acid metabolism.
The present study assessed left ventricular performance during dobutamine stress measured using gated SPECT, and compared the results to myocardial perfusion and fatty acid metabolism.


METHODS
Thirty-six patients with myocardial infarction given (99m)Tc-sestamibi or (99m)Tc-tetrofosmin were examined by gated SPECT at rest and during dobutamine stress (4-20 microg x kg(-1) x min(-1)). After acquiring data at the highest dose, 201TlCl was injected and dual-isotope SPECT was performed to assess myocardial ischemia. Thirty of 36 patients also underwent myocardial SPECT with 123I-BMIPP. Regional wall motion changes during dobutamine infusion were determined from the gated SPECT data and classified as: (1) Improvement, (2) Worsening, (3) No change, and (4) Biphasic response. For myocardial segments of each infarct area, stress 201Tl, rest (99m)Tc and (123)I-BMIPP uptakes were graded on a five-point scoring system of defects from 0 (normal) to 4 (grossly defective).


RESULTS
Rest 99mTc defect score index (DSI) in No change area was significantly higher than that in Biphasic area. The ADSI (stress 201Tl - rest (99m)Tc) in Biphasic area was significantly higher than those in Improvement and No change areas. The deltaDSI (BMIPP - (99m)Tc) in Worsening area tended to be higher than that in No Change area.


CONCLUSIONS
Regional contractile response to dobutamine stress analyzed by gated SPECT showed that the response in-myocardial infarct areas could be classified by rest and stress myocardial perfusion and BMIPP accumulation.
Kumita
Shin-ichiro
S
Department of Radiology, Nippon Medical School, 1-1-5 Sendagi, Bunkyoku, Tokyo 113-8603, Japan. s-kumita@nms.ac.jp
Cho
Keiichi
K
Nakajo
Hidenobu
H
Toba
Masahiro
M
Fukushima
Yoshimitsu
Y
Mizumura
Sunao
S
Sano
Junko
J
Takano
Teruo
T
Kumazaki
Tatsuo
T
D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004280:Dobutamine; D004562:Electrocardiography; D005080:Exercise Test / Q000379:methods; D005227:Fatty Acids / Q000097:blood*; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism*; D013223:Statistics as Topic; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000378:metabolism*
D005227:Fatty Acids; D004280:Dobutamine