SPECT心肌血流定量分析在冠状动脉微血管病变中应用的动物实验

Experimental study of SPECT myocardial blood flow quantitative analysis in animals with coronary microvascular disease

目的在冠状动脉微血管病变(CMVD)动物模型中比较SPECT与PET心肌血流定量指标,以明确SPECT定量分析的准确性及可行性。方法选取雌雄不拘、体质量(20±5)kg的萨能奶山羊7只,通过微球栓塞建立CMVD动物模型。分别在造模前和造模后第1天行一日法静息+ATP负荷99Tcm-甲氧基异丁基异腈(MIBI)SPECT动态心肌血流灌注显像(DMPI),并于造模后第2天行一日法静息+ATP负荷13N-氨水PET DMPI。对比造模后SPECT与PET显像的负荷心肌血流量(SMBF)、静息心肌血流量(RMBF)、心肌血流储备(MFR);并将造模后与造模前SPECT定量指标进行比较。采用配对t检验、Bland-Altman一致性检验分析数据。结果7只实验羊中4只显像完全。造模后SPECT和PET测得的实验羊左心室(整体)的RMBF(ml·g-1·min-1)、SMBF(ml·g-1·min-1)与MFR差异均无统计学意义(1.52±0.27和1.29±0.20;0.74±0.19和0.99±0.26;0.53±0.16和0.76±0.10;t值:3.121、1.195、1.930,均P>0.05);在左前降支(LAD)、左回旋支(LCX)、右冠状动脉(RCA)中,SPECT和PET测定的RMBF、SMBF和MFR差异也均无统计学意义(t值:0.182~2.734,均P>0.05)。Bland-Altman分析示SPECT与PET检测上述定量指标的一致性较好,2种方法测定RMBF最多相差0.63 ml·g-1·min-1,SMBF最多相差0.66 ml·g-1·min-1,所有点均在95%一致性界限以内;MFR最多相差0.56,有14/16的点在95%一致性界限以内。造模后与造模前SPECT所测左心室RMBF差异无统计学意义(1.52±0.27和1.57±0.36;t=0.166,P>0.05),而造模后左心室SMBF和MFR较造模前减低(0.74±0.19和2.34±0.89,0.53±0.16和1.39±0.31;t值:3.836、6.309,均P<0.05);SPECT测定的LAD、LCX及RCA造模前后相关指标比较结果也与上述类似(RMBF t值:0.191、0.235和0.195,均P>0.05;SMBF和MFR t值:0.411~19.911,均P<0.05)。结论SPECT DMPI与PET DMPI测定的CMVD动物模型RMBF、SMBF、MFR一致性好;SPECT心肌血流定量分析可以评估CMVD的血流灌注情况。

Objective To compare the quantitative parameters of myocardial blood flow based on SPECT imaging and those determined by PET imaging in coronary microvascular disease(CMVD)animal models,in order to clarify the accuracy and feasibility of SPECT quantitative analysis in CMVD.Methods Seven Saanen milk goats(either male or female;(20±5)kg),were selected for establishing CMVD animal models by microsphere embolization.Dynamic myocardial perfusion imaging(DMPI)with one-day method of resting+ATP stress 99Tcm-methoxyisobutylisonitrile(MIBI)SPECT was performed before and after the modeling,respectively.One-day method of resting+ATP stress 13N-ammonia PET DMPI was performed after the modeling.The quantitative parameters determined by SPECT and PET after the modeling,including stress myocardial blood flow(SMBF),resting myocardial blood flow(RMBF)and myocardial flow reserve(MFR),were compared by paired t test.Parameters based on SPECT after modeling were compared with those of baseline levels.Bland-Altman analysis was applied to access the agreement between SPECT and PET.Results Four of the seven experimental goats were fully imaged.The RMBF(ml·g-1·min-1;1.52±0.27 vs 1.29±0.20),SMBF(ml·g-1·min-1;0.74±0.19 vs 0.99±0.26),and MFR(0.53±0.16 vs 0.76±0.10)of the left ventricle(global)obtained by SPECT and PET in CMVD models were not significantly different(t values:3.121,1.195,1.930,all P>0.05).Among left anterior descending branch(LAD),left circumflex(LCX)and right coronary artery(RCA),the RMBF,SMBF and MFR values quantified by SPECT and PET were neither statistically significant(t values:0.182-2.734,all P>0.05).Bland-Altman analysis showed the quantitative parameters measured by SPECT and PET DMPI in left ventricle,LAD,LCX,RCA had a good consistency.The difference between the two methods for determining RMBF was up to 0.63 ml·g-1·min-1,and that of SMBF was up to 0.66 ml·g-1·min-1.All points are within the 95%confidence limit;MFR differs at most by 0.56,and 14/16 points were within 95%confidence limit.The RMBF(ml·g-1·min-1)of left ventricle measured by SPECT after modeling was not significantly different from that before modeling(1.52±0.27 vs 1.57±0.36;t=0.166,P>0.05);the SMBF(ml·g-1·min-1)and MFR after modeling were significantly lower than those before modeling(0.74±0.19 vs 2.34±0.89,0.53±0.16 vs 1.39±0.31,t values:3.836,6.309,both P<0.05).Similar results were found when comparing the parameters of LAD/LCX/RCA after modeling with those before modeling(RMBF t values:0.191,0.235,0.195,all P>0.05;SMBF/MFR t values:0.411-19.911,all P<0.05).Conclusion The blood flow quantitative parameters measured by SPECT imaging have a good consistency with those based on PET imaging,and the myocardial blood flow quantitative analysis of SPECT can evaluate the blood flow perfusion of CMVD.