^99Tc^m—MIBI与^18F-FDG双核素同时采集法心肌显像检测存活心肌

目的评价^99Tc^m-甲氧基异丁基异腈（MIBI）与^18F-脱氧葡萄糖（FDG）双核素同时采集法心肌显像（DISA SPECT）检测存活心肌的临床价值。方法21例经彩超检查证实存在左室壁节段运动障碍的冠心病患者,进行DISA SPECT、冠状动脉造影（CAG）及经皮冠状动脉介入治疗（PCI）,对所有狭窄病变行完全血运重建术。参照美国超声心动图学会16节段划分法获得心肌各运动异常节段DISA SPECT图像,并对心肌存活情况进行判定。DISA SPECT图像用目测半定量法分析。术后1,3和6个月时复查心脏超声,以冠状动脉血运重建后室壁节段收缩功能改善为判断存活心肌的“金标准”,根据诊断试验四格表评价DISA SPECT检测存活心肌的价值。结果21例冠心病患者共获得符合条件的室壁运动异常节段156个,根据“金标准”判断其中105个为存活心肌,51个为非存活心肌,DISA SPECT检测存活心肌的灵敏度、特异性、阳性预测值、阴性预测值、准确性分别是93．3％（98／105）、82．4％（42／51）、91．6％（98／107）、85．7％（42／49）、89．7％（140／156）。结论D1SA SPECT目测半定量法检测存活心肌有较高的临床价值。     

双核素心肌SPECT显像与PET显像检测存活心肌的对比研究

目的评价99Tcm-甲氧基异丁基异腈(MIBI)/18F-脱氧葡萄糖(FDG)双核素同时采集法(DISA)SPECT显像检测存活心肌的价值。方法对75例冠心病陈旧性心肌梗死患者进行了研究。采用双探头SPECT仪配备超高能准直器,行DISASPECT显像,同时行18F-FDGPET显像,用半定量法分析图像。结果75例患者中,99Tcm-MIBI心肌灌注显像有222个节段灌注减低,而DISA法FDG-SPECT显像有118个节段(53%)改善,FDG-PET显像有128个节段(58%)改善,即灌注/代谢不匹配,以存活心肌为主。DISA法FDG-SPECT有104个节段灌注/代谢匹配,FDG-PET显像有94个节段灌注/代谢匹配,为坏死心肌。FDG-SPECT与FDG-PET对存活心肌的检出率差异无显著性(χ2=0.863,P>0.05)。222个心肌灌注减低节段的FDG-SPECT与FDG-PET的得分符合率为91%。结论DISA法SPECT显像方法简便,费用较低,对检测存活心肌有重要价值。     

小剂量多巴酚丁胺负荷MRI与负荷超声心动图检测存活心肌的对比研究

目的对比小剂量多巴酚丁胺负荷MRI与负荷超声心动图检测存活心肌的价值。方法对30例陈旧心肌梗死患者(急性心肌梗死发作后3个月以上,具有静息期室壁运动异常)分别行静息和负荷(5、10μg.kg-1.min-1)MR及超声心动图检查。24例进行了血运重建,经皮穿刺冠状动脉成形术(PTCA)16例,冠状动脉旁路搭桥术(CABG)8例。血运重建术后3～6个月,10例患者进行静息MR检查以观察节段心肌运动恢复情况。心肌节段划分采用16节段分法,MRI存活心肌的定义为:≥2个相邻的静息期无运动及反向运动的节段,负荷后节段心肌收缩≥2mm;超声心动图心肌存活的定义为:≥2个相邻的静息期无运动及反向运动的心肌节段负荷后,室壁运动评分减少≥1分。结果30例患者108个心肌节段静息期运动异常,多巴酚丁胺负荷MRI阳性65个节段,阴性43个节段;负荷超声心动图阳性56个节段,阴性52个节段。2种方法一致性Kappa值为0.75,符合率为88%,具有高度一致性。10例患者38个心肌节段进行了复查,其中24个节段运动增加,14个节段无改善。MRI及超声心动图检测陈旧心肌梗死存活心肌的敏感度、特异度、准确度分别为95.8%和79.2%(P>0.05),85.7%和85.7%(P>0.05),92.1%和81.6%(P>0.05)。结论多巴酚丁胺负荷MRI与负荷超声心动图的诊断能力相当,MRI敏感度、准确度略高。     

门控心肌灌注显像局部室壁运动异常判断冠状动脉狭窄程度的价值

目的 探讨_99mTc-甲氧基异丁基异腈(_99mTc-MIBI)门控心肌灌注显像出现的可逆性局部室壁运动异常(RWMA)在判断冠状动脉狭窄程度中的价值。方法 入选90例疑似冠心病患者,在门控心肌灌注显像的前后2周内进行冠状动脉造影检查。门控心肌SPECT检查应用9节段5分制进行室壁运动及增厚率评分。结果 心肌显像上可逆性RWMA判断≥75%的冠状动脉狭窄的灵敏度为64%,特异度为95%;用可逆性RWMA来区别严重冠状动脉狭窄(≥75%)和不严重的冠状动脉狭窄(<75%)有很高的阳性预测值(97%)。可逆性RWMA和濒危冠状动脉评分之间有良好的相关性。多因素分析显示,负荷室壁负荷总积分、室壁负荷差分值和心电图负荷试验阳性是濒危冠状动脉积分的独立危险因子。结论 根据_99mTc-MIBI门控心肌灌注显像上可逆性RWMA判断严重冠状动脉狭窄具有高度的特异性和阳性预测值。潘生丁负荷后及可逆性RWMA增强了心肌灌注显像对冠状动脉狭窄程度的评估。     

衰减校正处理对提高99Tcm-MIBI心肌显像准确性的价值

目的　探讨衰减校正(AC)处理对提高99Tcm-甲氧基异丁基异腈(MIBI)心肌显像诊断冠心病和判断存活心肌准确性的作用。方法　16例正常对照者和25例经冠状动脉造影证实的冠心病患者进行了99Tcm-MIBI心肌断层显像,分别应用AC和非衰减校正(NC)处理,其中9例冠心病患者在显像后1周内接受了经皮冠状动脉腔内成形术(PTCA)治疗。将左心室分成9个心肌节段,心肌各节段相对放射性分布值以左室心肌最高计数的百分率表达。结果　在正常对照组中,NC显示的心肌各节段放射性分布呈显著的不均匀性,后基底部与前壁的左室峰计数百分率(LVP%)相差26.9%;而在AC图中,左心室心肌放射性分布的均匀性明显改善,后基底部与前壁的LVP%相差仅5.6%。在冠心病的定位诊断中,经AC处理后,99Tcm-MIBI心肌显像对左前降支(LAD)和左回旋支(LX)检测的灵敏度可由常规NC显像的77%和58%分别提高到91%和89%(P<0.05),右冠状动脉(RCA)定位的特异性由NC的67%提高到88%(P<0.05)。在缺血区存活心肌判断中,当心肌节段的99Tcm-MIBI相对分布值小于30%,AC与NC结果相似;节段放射性分布值在30%～75%范围内,以PTCA术后心室壁活动改善为标准,AC对存活心肌检测的准确性明显高于NC,AC改善存活心肌判断的部位主要是下壁、后基底部和间隔部。结论　99Tcm-MIBI心肌显像的AC处理能明显改善整个心肌显像的图像质量,并在提高冠心病早期诊断与存活心肌判断中有独特价值。     

小剂量多巴酚丁胺负荷试验对急性心肌梗塞早期心肌存活性的检测

目的 :探讨小剂量多巴酚丁胺负荷超声心动图 (LDDSE)检测急性心肌梗塞 (AMI)心肌存活的可靠性和安全性。材料和方法 :对 2 5例AMI后两周患者 ,在接受冠状动脉成形术治疗前后应用LDDSE检测 ,比较分析其室壁节段性运动异常的改变 ,以判断心肌存活性。结果 :在冠状动脉血运重建术前对室壁节段收缩功能的恢复预测准确率为 80 .2 % ,检测中并发症发生率极低 ( 4 % )。结论 :LDDSE对AMI早期可以较准确预测术后缺血心肌功能的恢复部位 ,安全性好。     

硝酸甘油介入99Tcm-MIBI SPECT心肌显像对PTCA决策的影响

目的评价硝酸甘油(NTG)介入99Tcm-甲氧基异丁基异腈(MIBI) SPECT心肌显像对心肌梗死患者行经皮冠状动脉腔内成形术(PTCA)决策的影响.方法 51例心肌梗死患者PTCA前1周内行99Tcm-MIBI静息和NTG介入心肌显像,术后2～3个月内复查静息心肌显像,并进行对比分析.结果 51例患者共141个心肌灌注异常节段,其中术后74个节段心肌血流灌注改善,治疗有效率为52.48%.术前NTG介入显像表现为可逆性缺损79个节段,术后84.81%(67个)节段心肌灌注改善,其中有明显填充的58个节段,术后全部灌注改善.NTG介入显像表现为不可逆性缺损的62个节段,有11.29 %(7个)节段术后心肌灌注改善.NTG介入显像检测心肌存活的准确性为86.52%.结论 NTG介入99Tcm-MIBI SPECT心肌显像对患者行PTCA起重要的决策作用.     

~(99)Tc~m-NOET门控心肌灌注SPECT评价冠心病的价值

目的 评价~(99)Tc~m-双(N-乙氧基,N-乙基-二硫代氨基甲酸酯)氮化锝(~(99)Tc~m-NOET)静息门控断层心肌灌注显像对冠心病患者的诊断价值.方法 疑诊为冠心病的45例患者注射925 MBq~(99)Tc~m-NOET后1h用SPECT行静息门控心肌灌注显像,获得舒张未期容积(EDV)、收缩未期容积(ESV)、左室射血分数(LVEF)等心功能参数和舒张末期容积灌注、局部射血分数、局部室壁活动和室壁增厚度4个靶心图.所有患者在1周内行冠状动脉造影,将冠状动脉狭窄≥50%定为病变血管.根据冠状动脉造影结果将其分为心肌梗死组、心肌缺血组和对照组三组.结果 ~(99)Tc~m-NOET静息门控SPECT诊断冠心病的灵敏度和特异度分别为68.42%和83.33%.心肌梗死组的心功能参数[EDV=(129.32±9.14)ml,ESV=(80.97±9.49)ml,LVEF=(40.15±3.28)%]与对照组[EDV=(80.91±3.12)ml,ESV=(30.12±1.79)ml,LVEF=(63.51±1.04)%]相比,统计学差异有显著性(EDV:F=22.103,ESV:F=32.277,LVEF:F=42.604,均为P＜0.01),心肌缺血组的心功能参数[(EDV=(70.83±3.46)ml,ESV=(25.13±2.85)ml,LVEF=(65.55±2.62)%]与对照组相比,统计学差异无显著性意义.心肌梗死组左室心肌共分为460个节段,其中209个节段局部灌注、局部射血分数、局部室壁活动和室壁增厚度4个靶心图均异常.局部灌注异常的节段共328个节段.伴有局部射血分数、局部室壁活动和室壁增厚度异常分别有250个、240个和276个节段.局部灌注异常的节段与局部射血分数、局部室壁活动和室壁增厚度异常的节段不完全匹配.结论 ~(99)Tc~m-NOET静息门控心肌灌注显像对冠心病的诊断有较大临床应用价值,所获得的整体心室功能参数在心肌梗死的评价中有优越性,但对心肌缺血的诊断价值不大.心肌梗死中存在有不少的局部灌注与心肌室壁功能异常节段的不匹配,对心肌存活的评价有帮助.     

双源CT双能量冠状动脉CTA在冠心病诊疗中的应用

目的探讨双源CT双能量冠状动脉CT血管造影(简称DE-CTA)联合心肌灌注显像(简称DE-CTP)在冠心病诊疗中的应用价值。方法对35例拟诊冠心病患者行DE-CTA检查,运用DE-CTA扫描数据获取DE-CTP图像,并以心导管造影(CAG)、SPECT为金标准,分别评价DE-CTA、DE-CTP以及DE-CTA联合DE-CTP诊断冠心病的敏感性、特异性、阳性预测值、阴性预测值及准确率。结果 30例患者DE-CTA显示42支冠状动脉血管狭窄≥50%,诊断的敏感性、特异性、阳性预测值、阴性预测值及准确率分别为84.8%(39/46),95.2%(59/62),92.9%(39/42),89.4%(59/66),90.7%(98/108);DE-CTP显示45支冠状动脉供血区域心肌灌注减低或缺损,诊断敏感性、特异性、阳性预测值、阴性预测值及准确率分别为78.3%(36/46),85.7%(54/63),80.0%(36/45),84.4%(54/64),83.3%(90/108);DE-CTA联合DE-CTP诊断52支冠状动脉狭窄≥50%,诊断冠状动脉狭窄的敏感性、特异性、阳性预测值和阴性预测值及准确率分别为95.7%(45/47)、89.2%(58/65)、86.5%(45/52)、96.7%(58/60)、92.0%(103/112)。结论双源CT双能量冠状动脉CTA一次检查即可获得冠状动脉解剖学和心肌血流灌注信息,可以提高冠心病诊断的准确率,有效指导冠状动脉支架植入的选择。     

心肌声学造影和二维斑点追踪成像在冠心病诊断中的应用价值

目的 分析对比冠心病患者的心肌声学造影(MCE)、二维斑点追踪成像技术(2D-STI)与冠状动脉血管造影术的结果，评价左心室心肌声学造影及2D-STI在冠心病节段室壁血流灌注异常中的应用价值。方法 选取本院50例临床初诊为冠心病患者的心肌声学造影及2D-STI,将其分别与冠状动脉造影结果进行对照分析，评估其在室壁节段血流灌注异常的准确性与一致性。结果 50例冠心病患者经冠状动脉造影纳入血管共150支，其中40例患者经冠状动脉造影证实有单支或多支冠状动脉狭窄>50%,病变血管56支，左前降支30支，左旋支12支，右冠状动脉14支。单支病变22例，多支病变18例，冠状动脉造影正常10例。按照冠状动脉的供血范围与左心室壁17节段相对应关系入选的心肌节段共850个，冠状动脉狭窄0%～49%的心肌节段共672个，冠状动脉狭窄50%～75%的心肌节段共65个，冠状动脉狭窄76%～99%的心肌节段共103个，冠状动脉完全闭塞的心肌节段10个。MCE检出心肌灌注异常与冠状动脉狭窄≥50%的一致性为89%,2D-STI检出节段室壁运动异常与相应供血支冠状动脉狭窄≥50%的一致性为87%;以冠状动脉...     

Low-dose dobutamine electrocardiograph-gated myocardial SPECT for identifying viable myocardium: comparison with dobutamine stress echocardiography and PET.

The identification of severely dysfunctional but viable myocardium is of particular importance for the selection of patients with depressed left ventricular function who will benefit from coronary revascularization. Assessment of inotropic reserve with dobutamine has recently been used for this purpose. This study compared the accuracy of low-dose dobutamine stress gated myocardial SPECT (DS SPECT) with the accuracy of dobutamine stress echocardiography (DSE) and resting perfusion SPECT for the identification of viable myocardium in patients with previous myocardial infarction. METHODS: Resting and low-dose dobutamine (7.5 microg/kg/min) gated (99m)Tc-tetrofosmin SPECT and echocardiography and resting (18)F-FDG PET were prospectively studied in 23 patients with previous myocardial infarction and severely depressed regional function. Twenty-one of them were successfully studied with each technique. The left ventricular wall was divided into 14 segments to assess wall motion using a 5-point scale. PET viability was defined as FDG uptake >/= 50% of the maximum uptake in a region with normal wall motion. For DS SPECT and DSE studies, viable myocardium was defined as hypokinetic areas with > or = 1 point improvement in wall motion. For resting perfusion SPECT, viable myocardium was defined as hypokinetic areas with a relative uptake > or = 50% of the maximum uptake. RESULTS: Of a total of 294 segments, 55 had severe resting dyskinesis. Thirty-four segments were identified as viable on FDG PET, and 21 segments were identified as nonviable. Eleven segments were inadequately visualized with DSE, including 5 segments in the apex. Sensitivities (78% vs. 76%) and specificities (94% vs. 100%) were similar for DSE and DS SPECT, with a concordance of 86% (kappa = 0.72). DS SPECT and perfusion SPECT did not significantly differ with respect to sensitivities (76% vs. 85%, respectively). However, specificity was significantly higher for DS SPECT than for perfusion SPECT (100% vs. 52%, respectively, P < 0.05). CONCLUSION: This study indicated that DS SPECT correlates well with DSE in the assessment of viability. In addition, gated SPECT can evaluate regional wall motion, even in areas inadequately assessed by echocardiography. DS SPECT may also provide additional information for identifying viable myocardium, which is often overestimated by routine perfusion scans.     

Pulsed Doppler tissue imaging for the assessment of myocardial viability: comparison with 99mTc sestamibi perfusion imaging

The aim of the present study was to examine whether Doppler tissue imaging demonstrated comparable diagnostic performance for the detection of viable myocardium compared to myocardial perfusion imaging with Tc hexakis-2-methoxyisobutylisonitrile (MIBI). We studied 30 patients with old myocardial infarction who underwent percutaneous transluminal coronary angioplasty (PTCA). Myocardial single photon emission computed tomography (SPECT) with Tc-MIBI and two-dimensional echocardiography were carried out within 7 days before PTCA. We measured regional Tc-MIBI uptake for each myocardial segment from SPECT and peak systolic velocity and a ratio of regional pre-ejection period to regional ejection time (PEP/ET) from pulsed Doppler tissue imaging. Biplane left ventriculography was performed before interventional procedures and repeated 3 months after PTCA. Myocardial viability was determined when wall motion was improved at least one grade after PTCA. The peak systolic velocity was positively correlated with regional Tc-MIBI uptake (R =0.59, P<0.01). The PEP/ET demonstrated inverse correlation with Tc-MIBI uptake ( R=-0.59, P<0.01). Peak systolic velocity of viable segments was higher than that of non-viable segments ( P<0.05). The PEP/ET was lower in viable segments than in non-viable segments ( P<0.05). Peak systolic velocity and PEP/ET demonstrated high diagnostic accuracy for detecting viable myocardium compared with Tc-MIBI perfusion imaging (80% and 79% vs 90%). These data indicate that measurements of regional peak systolic velocity and PEP/ET by Doppler tissue imaging are useful for evaluating myocardial viability quantitatively and provide helpful information for a clinical judgment in an interventional strategy.     

Selective intracoronary injection of sestamibi to detect myocardial viability: Prediction of perfusion and contractile recovery after percutaneous transluminal coronary angioplasty

BACKGROUND: The main limitation of myocardial single photon emission computed tomography (SPECT) in detecting hibernating myocardium is the poor delivery of radiotracers in hypoperfused areas supplied by severely stenotic coronary arteries. Increasing local availability of radiotracers by intracoronary injection might represent an attractive solution. The hypothesis that the intracoronary administration of sestamibi could improve myocardial SPECT accuracy in detecting hibernating myocardium was addressed in this pilot study. METHODS AND RESULTS: Seven patients with prior myocardial infarction and severe stenosis of the infarct-related artery underwent myocardial SPECT after intracoronary injection of technetium 99m sestamibi immediately before percutaneous transluminal coronary angioplasty (PTCA). Wall motion and perfusion were evaluated, before and 1 month after PTCA, by 2-dimensional echocardiography and rest-redistribution thallium 201 SPECT. A "low-flow area" was identified on the pre-PTCA Tl-201 SPECT image as the area with less than 50% of maximum radiotracer uptake. Changes in wall motion and perfusion in the low-flow area were compared with results of intracoronary sestamibi imaging. On a pixel-by-pixel analysis, intracoronary sestamibi predicted perfusion recovery within the low-flow area with a 91% sensitivity, a 78% specificity, and an 82% overall accuracy. Only in the 5 patients with an extent of sestamibi uptake greater than one third of the low-flow area was an improved regional and global left ventricular wall motion observed after PTCA (wall motion score index decreased from 1.95 +/- 0.28 to 1.60 +/- 0.34, P =.007; left ventricular ejection fraction increased from 42% +/- 7% to 49% +/- 7%, P =.001; asynergic segments in the low-flow area decreased from 3.6 +/- 0.9 to 1.8 +/- 1.5, P =.021). CONCLUSIONS: In patients with prior myocardial infarction and severe stenosis of the infarct-related artery, sestamibi uptake after intracoronary administration identified viable myocardium that was undetected after rest-redistribution thallium SPECT but capable of clinically significant contractile improvement after revascularization.     

Detecting myocardial salvage after primary PTCA: early myocardial contrast echocardiography versus delayed sestamibi perfusion imaging.

The extent of myocardial salvage after primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI) is variable and cannot be predicted on the basis of either vessel patency or early regional wall motion assessment. The aim of this study was to evaluate the reliability of microvascular integrity, as shown by myocardial contrast echocardiography (MCE), as an indicator of tissue salvage and a predictor of late functional recovery, and to compare MCE with the quantification of tracer activity in sestamibi perfusion imaging. METHODS: Twenty-six patients with AMI who received successful treatment with primary PTCA were examined with MCE during cardiac catheterization immediately before and after vessel recanalization. Myocardial contrast effect was scored as 0 (absent), 0.5 (partial) or 1 (normal). Wall motion was assessed by two-dimensional echocardiography on admission and 1 mo later with a 16-segment model and 4-point score. Resting sestamibi SPECT was collected within 1 wk after AMI. The risk area was defined by MCE as the sum of the segments with no perfusion (score 0) before PTCA. Myocardial viability was defined by MCE as an increase in contrast score in the same segments after PTCA and by sestamibi SPECT as a preserved tracer activity (>60% of peak activity). The functional recovery after 1 mo detected by two-dimensional echocardiography was the reference standard for viability. RESULTS: A total of 50 segments showed perfusion defects before PTCA (risk area). Immediately after PTCA, the MCE score increased in 44 of 50 segments, whereas sestamibi SPECT showed preserved activity in 22 of 50 segments. After 1 mo, the wall motion score decreased in 22 of 50 segments (viable segments) and was unchanged in the remaining 28 segments. Thus, MCE showed a sensitivity of 91% and a specificity of 14% in detecting viable myocardium, whereas sestamibi SPECT showed a lower sensitivity (68%) but a significantly higher specificity (75%; P < 0.00001). The positive predictive values were 45% and 68% for MCE and SPECT (P < 0.005), respectively, and the negative predictive values were 67% and 71%, respectively. On a patient basis, SPECT was more specific (79% versus 21%; P < 0.01) and showed a higher overall predictive accuracy (88% versus 50%; P < 0.01) than MCE. CONCLUSION: The demonstration of microvascular integrity by MCE performed immediately after primary PTCA has a limited diagnostic value in predicting salvaged myocardium. Conversely, tracer activity quantification in resting sestamibi SPECT performed in a later stage is confirmed to be a reliable approach for recognizing myocardial stunning and predicting functional recovery.     

Fatty acid imaging with 123I-15-(p-iodophenyl)-9-R,S-methylpentadecanoic acid in acute coronary syndrome.

123I-15-(p-iodophenyl)-9-R,S-methylpentadecanoic acid (9-MPA) has recently been developed as a tracer for myocardial fatty acid uptake. The aim of this study, which was performed as part of a phase III clinical trial of 9-MPA, was to test the usefulness of 9-MPA for the assessment of myocardial viability in patients with acute coronary syndrome (ACS). METHODS: Fifteen patients with ACS who had undergone direct percutaneous transluminal coronary angioplasty were examined. Myocardial SPECT with 9-MPA and 99mTc-sestamibi and low-dose dobutamine echocardiography were performed within 2 wk after onset. The 9-MPA images were obtained 10 and 60 min after tracer administration, and sestamibi imaging was begun 60 min after the injection. The left ventricle was divided into 9 segments, and 9-MPA and sestamibi uptake were scored from 0 (normal) to 3 (no activity) in each segment. Lower uptake of 9-MPA than of sestamibi was defined as a mismatch. Myocardial segments showing improvement in wall motion during low-dose dobutamine infusion (5-10 microg/kg/ min) were considered viable. RESULTS: The 9-MPA images were of high quality for all patients. Myocardial uptake of 9-MPA was lower in ischemic myocardium than in nonischemic myocardium (58.2%+/-14.2% versus 91.9%+/-6.5%, P<0.0001). Clearance of 9-MPA from ischemic myocardium was slower than that from nonischemic myocardium (10.2%+/-11.7% versus 19.1%+/-5.9%, P<0.01). A mismatch was seen in 10 of 15 patients, and 18 of 20 (90%) mismatched segments were defined as viable by dobutamine echocardiography. Conversely, 18 of 20 (90%) matched segments did not show any improvement in function during dobutamine stimulation (P<0.0001). Uptake of 9-MPA in nonviable segments was lower than that in dysfunctional but viable segments (P<0.05), and 9-MPA clearance from nonviable segments was slower than that from viable segments (P<0.05). CONCLUSION: The imaging characteristics of 9-MPA for SPECT are excellent, allowing noninvasive assessment of myocardial fatty acid uptake. Myocardial imaging with 9-MPA may reveal impaired fatty acid uptake in dysfunctional but viable myocardium and thus provide useful information for clinical decision making in ACS.     

F18-fluorodeoxyglucose single-photon emission computed tomography predicts functional outcome of dyssynergic myocardium after surgical revascularization

Background  Prediction of functional recovery after revascularization is possible with positron emission tomography and F18-fluorodeoxyglucose (FDG). Recently, the use of FDG in combination with single-photon emission computed tomography (SPECT), with 511 keV collimators, has been proposed to allow more widespread use of FDG. In the current study we aimed to predict improvement of regional left ventricular function after surgical revascularization with FDG and SPECT. Methods and Results  Twenty-seven patients with regional wall motion abnormalities (on echocardiography) underwent early thallium-201 (TI-201) SPECT to assess perfusion and FDG SPECT to assess regional glucose uptake. The left ventricular myocardium was divided into 13 segments. For each segment, tracer uptake was evaluated visually (with the use of a 4-point scoring system) by consensus of two observers. Myocardial viability was determined in dyssynergic segments on echocardiography and defined as normal perfusion or increased FDG uptake in a perfusion defect (mismatch). Absence of viability was defined as a perfusion defect without increased FDG uptake (match). Improvement of regional, wall motion was assessed 3 months after revascularization. In the group of segments that were viable on FDG/TI-201 SPECT (n=64), the segmental wall motion score decreased from 1.4±0.5 to 0.6±0.7 (p<0.01), whereas the segmental wall motion score remained unchanged in nonviable segments (n=72): 1.6±0.5 versus 1.5±0.6 (not significant). Forty-six (72%) of the 64 segments that were viable on FDG/TI-201 SPECT demonstrated improved contractile function after coronary revascularization. In contrast, only 7 (10%) of 72 nonviable segments on FDG/TI-201 SPECT showed improvement in function after revascularization (p<0.01 versus viable segments). The sensitivity, specificity, and positive and negative predictive values were 87%, 78%, 72%, and 90%, respectively. Conclusion  This study shows that FDG/TI-201 SPECT can identify patients who improve in regional ventricular function after revascularization.     

Detection of coronary artery disease: Comparison between technetium 99m-labeled sestamibi single-photon emission computed tomography and two-dimensional echocardiography with dipyridamole low-level exercise-stress

Background

Myocardial perfusion imaging in conjunction with dipyridamole low-level exercise stress has proved its value in the evaluation of patients with coronary artery disease (CAD). Simultaneous wall motion analysis by two-dimensional (2D) echocardiography may provide additional information beyond that obtained by myocardial perfusion imaging alone. The purpose of this study was to compare ^99mTc-labeled sestamibi single-photon emission computed tomography (SPECT) and 2D echocardiography for the evaluation of CAD according to a dipyridamole low-level bicycle exercise stress protocol.

Methods and Results

We studied 35 consecutive patients referred for the evaluation of chest pain who had undergone coronary arteriography. ^99mTc-labeled sestamibi SPECT and 2D echocardiography agreed in 27 patients (80%) studied for overall detection of CAD. On a segmental basis, agreement was found between SPECT and 2D echocardiography in 124 (73%) of 170 segments (Cohen’s kappa=0.43). The accuracy of the combined assessment of myocardial perfusion and echocardiographic wall motion in detecting CAD was 86%, which was not different from the accuracy of SPECT alone (80%; difference not significant) but significantly higher than for 2D echocardiography alone (71%; p=0.03). In the detection of individual coronary artery stenoses, SPECT had a significantly higher accuracy for detecting left anterior descending coronary artery lesions than had 2D echocardiography (80% vs 60%; p<0.01); combining the two methods did not improve the accuracy (80%). The combined assessment slightly improved the accuracy for detecting left circumflex coronary artery stenoses from 71% to 83% (p=0.05).

Conclusion

The combined simultaneous assessment of myocardial perfusion by ^99mTc-labeled sestamibi SPECT and wall motion by 2D echocardiography did not significantly improve overall accuracy over that obtained by ^99mTc-labeled sestamibi SPECT alone. Therefore ^99mTc-labeled sestamibi SPECT with dipyridamole low-level exercise stress appears the preferred imaging modality for the evaluation of patients with CAD.     

Usefulness and limitations of ECG-gated myocardial single-photon emission computed tomography with 99mTc-methoxy-isobutyl-isonitrile (MIBI) in patients with prior myocardial infarction]

To evaluate the relationship between regional wall motion and 99mTc-methoxy-isobutyl-isonitrile (MIBI) uptake, ECG-gated single-photon emission computed tomography (SPECT) with 99mTc-MIBI was performed in 20 patients with prior myocardial infarction. The left ventricular images at end-diastole (ED) and end-systole (ES) were divided into 39 segments, respectively. Based on circumferential profile analysis, relative uptake (%EDc, %ESc), percent count increase (% delta C), and normalized percent count increase (% delta Cn) were analyzed in each segment and compared with regional wall motion indices assessed by echocardiography and left ventriculography. ECG-gated SPECT with 99mTc-MIBI provided high contrast tomograms of the left ventricular myocardium. %EDc and %ESc showed good correlations with regional wall motion indices. % delta C and % delta Cn, however, showed lower correlations compared with %EDc and %ESc. In conclusion, high-quality left ventricular images were obtained with 99mTc-MIBI ECG-gated SPECT, but quantitative analysis based on only percent count increase (% delta C) have limitations for evaluation of regional wall motion.     

MR多技术扫描检测活性心肌及其影像学对比的实验研究

目的 评估各种影像学方法检测活性心肌的价值。材料与方法 建立慢性心肌缺血模型猪10头,分别于制作模型前和后1～2月进行磁共振多技术扫描及小剂量多巴酚丁胺负荷超声心动图（LDDSE）、^201TI单光子发射计算机体层显像（^201TI SPECT）、正电子发射体层显像（^18F-PET）检查,判断心肌缺血区和坏死区的大小,并与病理结果对照了解各种方法的敏感性、特异性。结果 7头动物顺利完成所有检查,负荷磁共振电影扫描见10个（8．93％）节段为梗死心肌,6个（5．36％）节段为缺血心肌;心肌灌注扫描见34个（30．35％）节段缺血,心肌活性扫描见12个（10．71％）节段坏死。LDDSE检查见8个（7．14％）节段为梗死心肌,9个（8．04％）节段为缺血心肌。SPECT检查见9个（8．04％）节段为梗死心肌。PET检查见17个（15．18％）节段为梗死心肌。TTC染色见14个（12．50％）节段为梗死区。MR电影检出的坏死节段比TTC染色显示的节段少并有统计学意义（P=0．0455,Kappa=0．8100）;MR活性扫描检出的坏死节段比TTC染色显示的坏死节段略少但无统计学意义（P=0．1573,Kappa=0．9130）。LDDSE检出的坏死节段较TTC染色显示的节段少并有统计学意义（P=0．0140,Kappa=0．7000）;PET检出的坏死节段多于磁共振活性扫描（P=0．0253,Kappa=0．8028）和MR电影扫描（P=0．0082,Kappa=0．7079）并有统计学意义;亦多于TTC染色显示的坏死节段（P=0．0833,Kappa=0．8879）,但无统计学意义;SPECT检出的坏死节段比TTC染色显示的节段少并有统计学意义（P=0．0253,Kappa=0．7590）。以TTC染色结果为金标准,MRI电影、MRI活性扫描、LDDSE、SPECT、PET检出无活性心肌的敏感性、特异性分别为71．43％、100％;85．71％、100％;57．10％、100％;64．29％、100％;100％、96．94％。结论 MR多技术扫描可结合形态、功能及灌注多种方法检测活性心肌．清晰显示心肌梗死的位置、程度,并可对左窒室壁运动进行直观显示,且价格相对PET便宜;磁共振和PET、病理结果均有较高一致性。PET高估心肌坏死范围,且不能判断心肌梗死的透壁程度。SPECT和LDDSE低估心肌活性。而且亦不能显示心肌梗死的透壁程度。