药物负荷试验核素心肌断层显像识别存活心肌

Dobutamine combined with nitrate stress single photon emission computed tomography for assessment of myocardial viability

目的探讨药物多巴酚丁胺、硝酸异山梨酯负荷试验核素锝[99mTc]甲氧异丁异腈(technetium[99mTc]methoxyisobutylisonitrile,99mTc-MIBI)心肌断层显像识别存活心肌的价值。方法对48例陈旧性心肌梗死伴左心室收缩功能受损患者进行静息心肌99mTc-MIBI心肌断层显像和多巴酚丁胺、硝酸异山梨酯负荷试验99mTc-MIBI心肌断层显像,用半定量的方法将99mTc-MIBI摄取进行评分,区分存活心肌和非存活心肌。结果99mTc-MIBI显像判定,经皮冠状动脉介入术前存活心肌节段有279个,非存活心肌节段235个;经多巴酚丁胺加硝酸异山梨酯负荷后,心肌显像改善:轻度稀疏节段9个、中度稀疏节段24个、严重稀疏或缺损节段10个,共计43个节段显像改善,评分减少1分以上,存活心肌节段313个,非存活心肌节段201个。两组差异有统计学意义(P<0.05)。经皮冠状动脉介入术后6个月,随访多巴酚丁胺加硝酸异山梨酯负荷后,心肌显像改善的32个节段发现,静息99mTc-MIBI显像改善,另有8个受损节段正常化。多巴酚丁胺加硝酸异山梨酯负荷后心肌显像无变化的389个节段在经皮冠状动脉介入术后346个节段无变化。多巴酚丁胺加硝酸异山梨酯负荷心肌显像检测存活心肌的阳性预测值93%,阴性预测值89%。结论多巴酚丁胺加硝酸异山梨酯负荷后心肌显像对存活心肌的识别能够提高存活心肌的检出率,其阳性预测值和阴性预测值较好。

Objectives To investigate the value of dobutamine combined with nitrate stress （ DNS ） technetium [99m] methoxy isobutyl isonitrile （^99mTc-MIBI） single photon emission computed tomography （SPECT） for assessment of myocardial viability. Methods 48 patients with old myocardial infarction （OMI） and postischemic heart failure （ejection fraction,35% ±8.1%） were studied. All patients underwent ^99mTc-MIBI SPECT at rest and DNS before percutaneous coronary intervention （PCI） and after six months. The semiquantitative scoring system was used for both images to assess the myocardial viability, which was defined as an improvement of at least ≥ 1 grade in at least two contiguous segments at rest 2DE after PCI. Results In a total of 514 segments, rest SPECT showed reversible perfusion defects in 279 regions and irreversible perfusion defects in 235 regions obtained from the 48 patients. On the other hand, DNS-SPECT showed reversible perfusion defects in 313 regions and irreversible perfusion defects in 201 regions. The viable segments detecting rate with DNSSPECT was 60.1% （313/514）, which was significantly higher than that in the rest group（P〈 0.05）. Among 43 hypoperfused segments, 40 segments were defined as viable and only 3 segments described as nonviable after six months of rcvascularization. The specificity and sensitivity of DNS-SPECT for the assessment of myocardial viability were 93% and 89%, respectively. Conclusions In identifying myocardial viability in patients with OMI and severe left ventricular dysfunction, the DNS ^99mTc-MIBI SPECT has higher specificity and sensitivity.