Baer F M, Smolarz K, Theissen P, Voth E, Schicha H, Sechtem U
Klinik III für Innere Medizin, Universität zu Köln, Germany.
Eur Heart J. 1994 Jan;15(1):97-107. doi: 10.1093/oxfordjournals.eurheartj.a060386.
It is not yet clear whether 99mTc-methoxyisobutyl-isonitrile (MIBI)-uptake is a reliable indicator of myocardial viability, and a threshold value, differentiating viable from scarred myocardium, in comparison to a morphological and functional standard of reference has not been defined. MIBI-uptake was quantified in 800 segments from 55 patients with angiographically proven coronary artery disease with and without a history of myocardial infarction. Viable myocardium was defined from gradient-echo magnetic resonance images (MRI) as regions with systolic wall thickening or an end-diastolic wall thickness above the mean value -2.5 SD of a healthy control group (n = 21). Scar was defined as end-diastolic wall thickness > 2.5 SD below the normal mean value and absent systolic wall thickening or wall thinning. Mean MIBI-uptake of viable (n = 676; 79 +/- 14%) and scar segments by MRI (n = 124; 31 +/- 16%) was significantly different (P < 0.001). Segmental MIBI-uptake vs end-diastolic wall thickness (r = 0.7) and systolic wall thickening (r = 0.71) yielded a fair correlation. The highest values as regards sensitivity and specificity of MIBI-uptake in predicting the presence of scar were 89% and 96% respectively for MIBI-uptake < or = 50%. However, of the 136 segments with MIBI-uptake < or = 50%, 26 (19%) were viable by MRI, resulting in a positive predictive accuracy for scar tissue of 81%. Of the 26 segments diagnosed as scarred by MIBI-SPECT but viable by MRI, 25 (96%) were located in the inferoseptal region. MIBI-SPECT seems useful in the detection of viable myocardium after anterior myocardial infarcts, but over-estimates scar in the inferoseptal regions. Perfusion defects in these regions could be confirmed or denied by additional evaluation of myocardial morphology and function by MRI or tissue metabolism by positron emission tomography (PET).
目前尚不清楚99mTc-甲氧基异丁基异腈（MIBI）摄取是否是心肌存活的可靠指标，且与形态学和功能参考标准相比，区分存活心肌和瘢痕心肌的阈值尚未确定。对55例经血管造影证实患有冠状动脉疾病且有或无心肌梗死病史患者的800个节段进行了MIBI摄取定量分析。通过梯度回波磁共振成像（MRI）将存活心肌定义为收缩期室壁增厚或舒张末期室壁厚度高于健康对照组（n = 21）平均值-2.5标准差的区域。瘢痕定义为舒张末期室壁厚度低于正常平均值2.5标准差以上且无收缩期室壁增厚或室壁变薄。通过MRI显示存活节段（n = 676；79±14%）和瘢痕节段（n = 124；31±16%）的平均MIBI摄取有显著差异（P < 0.001）。节段性MIBI摄取与舒张末期室壁厚度（r = 0.7）和收缩期室壁增厚（r = 0.71）有较好的相关性。MIBI摄取≤50%时，预测瘢痕存在的敏感性和特异性最高值分别为89%和96%。然而，在136个MIBI摄取≤50%的节段中，26个（19%）通过MRI显示为存活，导致瘢痕组织的阳性预测准确率为81%。在26个经MIBI-SPECT诊断为瘢痕但通过MRI显示为存活的节段中，25个（96%）位于下间隔区域。MIBI-SPECT似乎有助于检测前壁心肌梗死后的存活心肌，但高估了下间隔区域的瘢痕。这些区域的灌注缺损可通过MRI对心肌形态和功能的进一步评估或正电子发射断层扫描（PET）对组织代谢的评估来证实或排除。
