Bisi G, Podio V, Sciagrà R
Department of Internal Medicine, University of Turin, Italy.
Q J Nucl Med. 1996 Mar;40(1):68-75.
Detection of myocardial viability is an important clinical issue in the time course of acute myocardial infarction and in chronic coronary artery disease. The wide availability of myocardial revascularization procedures requires a refinement of specific indications for revascularization whenever left ventricular failure is the most prominent feature of coronary artery disease. In this instance the risk/benefit ratio has to be attentively evaluated with diagnostic tests able to predict favourable changes in regional and global left ventricular function, symptoms, life quality, risk of adverse events and ultimately prognosis. 201Tl has been shown to provide clinically televant information regarding the presence of myocardial viability in patients with extensive regional or global ventricular dysfunction. However, the increasing use of 99mTc labeled myocardial perfusion agents requires a careful evaluation of diagnostic and predictive accuracy of these agents also for the issue of myocardial viability. The widely accepted opinion of a lower predictive accuracy of these agents compared to 201Tl could be no longer true. The available clinical and experimental data indicate, at least for 99mTc-sestamibi, a comparable accuracy when independent and clinically relevant gold standard of viability like post-revascularization functional recovery is considered. Preliminary data indicate that protocols, like nitrate administration, slow infusion or delayed imaging, and accurate quantitation of 99mTc-sestamibi SPECT studies could enhance the predictive accuracy to a level comparable or even better than that of 201Tl and similar to the more demanding PET technology.
检测心肌存活性是急性心肌梗死病程及慢性冠状动脉疾病中的一个重要临床问题。心肌血运重建术的广泛应用要求在左心室衰竭为冠状动脉疾病最突出特征时，进一步明确血运重建的具体指征。在这种情况下，必须通过能够预测局部和整体左心室功能、症状、生活质量、不良事件风险及最终预后的诊断测试，仔细评估风险/获益比。已证实，201Tl能为存在广泛局部或整体心室功能障碍的患者提供有关心肌存活性的临床相关信息。然而，随着99mTc标记的心肌灌注剂使用的增加，对于这些药物在心肌存活性问题上的诊断和预测准确性也需要仔细评估。与201Tl相比，这些药物预测准确性较低这一广泛接受的观点可能不再成立。现有的临床和实验数据表明，至少对于99mTc-甲氧基异丁基异腈来说，当考虑像血运重建后功能恢复这样独立且临床相关的存活性金标准时，其准确性相当。初步数据表明，诸如给予硝酸盐、缓慢注射或延迟显像等方案，以及对99mTc-甲氧基异丁基异腈SPECT研究进行准确量化，可将预测准确性提高到与201Tl相当甚至更好的水平，且类似于更复杂的PET技术。
