Myocardial Contractile Reserve and Perfusion Defect Severity with Rest and Stress Dobutamine 99mTc-Sestamibi SPECT in Canine Stunning and Subendocardial Infarction

Journal of Nuclear Medicine

Dara L. Kraitchman¹  Giuseppe Esposito¹  Bennett B. Chin¹ 

关键词: myocardial infarction;    myocardial stunning;    ^99mTc-sestamibi;    contractile reserve;    myocardial viability;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

Myocardial contractile reserve and resting perfusion scintigraphy provide independent information to assess myocardial viability. The purpose of this study was to simultaneously evaluate both with 99mTc-sestamibi SPECT and low-dose dobutamine in canine stunning and subendocardial infarction (SEMI). Methods: Eighteen dogs were included in the study: 7 normal, 7 stunned, and 4 with SEMI. Closed-chest stunning and SEMI were produced by angioplasty balloon occlusion of the left anterior descending artery (20 and 90 min, respectively). Subsequent radiolabeled mircospheres confirmed reflow, and 99mTc-sestamibi was then administered at rest. Gated SPECT and MRI tagging were performed at rest and during low-dose dobutamine infusion (5 μg/kg/min). SPECT systolic wall thickening index (SWI) and MRI radial strain quantified myocardial contraction. Postmortem 2,3,5-triphenyltetrazolium chloride staining quantified SEMI. Results: Defect severity by SPECT in the anterior wall was mild and was not statistically different for the stunned versus SEMI groups (P = not significant). At rest, anterior wall SPECT SWI was significantly higher in the normal versus stunned groups (21.1 ± 3.1 vs. 10.1 ± 9.0; P = 0.0002) and the normal versus SEMI groups (21.1 ± 3.1 vs. 2.6 ± 6.0; P = 0.000002). With low-dose dobutamine, SWI increased significantly compared with rest for the stunned group (29.1 ± 10.4 vs. 10.1 ± 9.0; P = 0.000007) but did not increase significantly for the SEMI group (11.0 ± 11.3 vs. 2.6 ± 6.0; P = 0.09); SWI during low-dose dobutamine infusion for the stunned group was comparable to that for the normal group (29.1 ± 10.4 vs. 28.2 ± 7.0; P = 0.80). SWI also showed correlation with MRI radial strain (r = 0.42; P = 0.00015). Conclusion: Defect severity for stunned myocardium and SEMI was mild and was not significantly different. Contractile reserve was significantly different in stunned myocardium and SEMI. 99mTc-Sestamibi SPECT at rest and with low-dose dobutamine is a promising new technique to simultaneously assess myocardial perfusion and contractile reserve.

【 授权许可】

Unknown