双源CT肠灌注碘成像诊断犬急性肠系膜上动脉栓塞的研究

目的 探讨双源CT(DSCT)肠灌注碘成像诊断犬实验性急性肠系膜上动脉(SMA)栓塞的可行性与准确性.方法 对8只犬行腹部DSCT双能量扫描后在DSA下建立6只犬SMA栓塞模型,对照组2只犬SMA内仅注入10 ml生理盐水;对两组犬于术后6～8h进行DSCT双能量扫描;最后,解剖6只模型犬,观察肠管大体病理改变,剪取部分坏死肠管进行病理检查.采用双能量评估软件将薄层重组数据进行灌注成像分析,将犬肠管自十二指肠至直肠分为9段进行观察,利用t检验分析梗死区术前、术后强化值与CT值差异,以病理结果为金标准,评价MSCT与DSCT肠灌注碘成像诊断肠梗死敏感性、特异性,Kappa分析其结果一致性.结果 栓后17种CT征象统计显示DSCT较MSCT有更好空间分辨率.灌注定量分析显示栓塞术前后正常肠管强化值分别是(107.23±12.27)、(110.33±17.78),两者比较差异无统计学意义(t=-0.491,P=0.635);缺血肠管栓塞前后CT值分别是(141.42±23.81)、(76.17±7.68),两者比较差异有统计学意义,(t=4.29,P=0.023);强化值分别是(108.43±8.82)、(36.40±6.67),两者比较差异有统计学意义(t=14.384,P=0).Kappa分析显示MSCT、DSCT肠灌注碘成像与病理结果具有很好一致性,DSCT的Kappa值高于MSCT.结论 DSCT肠灌注碘成像可用于检测急性SMA栓塞,其准确性与敏感性稍高于MSCT.     

基于双源CT双能量成像的犬无复流心肌活性实验研究

_目的：通过双源 CT（DSCT）心肌灌注扫描观察心肌缺血无复流动物模型的 CT 表现,初步探讨双能量心肌灌注扫描在评估无复流心肌中的应用价值。方法：通过球囊堵塞（60～90 min）加微粒明胶海绵栓塞犬前降支中远段,建立犬心肌缺血无复流模型（n＝6）,采用 DSCT 进行首过及3、5、10、15 min 多期延迟心肌灌注扫描,观察梗死区 CT 表现,完成检查后取犬心脏标本行氯化三苯基四氮唑（2,3,5-TTC）染色及 HE 染色,与 DSCT 检查结果进行对照。结果：2只犬在介入手术过程中死亡,4只犬完成模型建立。扫描过程中犬平均心率为135 bpm。DSCT 扫描均可见心肌梗死区 CT 值较正常心肌减低,首过及多期延迟扫描呈固定灌注减低表现,TTC 染色显示梗死区范围与 DSCT 所见相符,HE 染色梗死中心区和边缘区均可见心肌坏死。在不同能量的 DSCT 图像中,100 kV 灌注图像对心肌密度区分能力最强,140 kV 灌注图像噪声最低,而双能量融合灌注图像则在实现密度差异的前提下保证了较低的噪声。结论：DSCT 可以较好地在快心率状态下显示心肌,心肌灌注扫描显示固定灌注减低可能与心肌完全坏死有关。     

双源双能量CT成像评估猪急性心肌缺血再灌注损伤的实验研究

目的 评价双源双能量CT(DECT)成像诊断猪急性心肌缺血再灌注损伤的可行性和准确性.方法 8只猪通过开胸结扎冠状动脉左前降支(LAD)或第一对角支(D1)建立再灌注损伤模型,术后行DECT心肌灌注成像扫描.检查结束后立即处死动物,取出心脏,进行氯化三苯基四氮唑(TTC)染色,分析心肌缺血再灌注损伤范围.以病理结果为参照,测量损伤区、非损伤区的CT值以及损伤区面积.将左心室壁分为17个节段,确定DECT心肌灌注碘图、DECT(140、100和平均加权120 kV)3组图像和大体病理上心肌损伤的节段数.以病理结果为金标准分别评价DECT心肌灌注碘图、3组图像显示心肌损伤的敏感性、特异性和一致性.利用方差检验分析损伤区和非损伤心肌不同管电压条件的CT值、大体病理和DECT 3组图像所测量损伤区重量的差异.结果 8只猪DECT心肌灌注碘图见心尖前壁、心尖间隔灌注稀疏甚至缺损,DECT 3组图像中再灌注损伤区CT值均较正常心肌明显降低.与病理金标准对照,DECT心肌灌注碘图诊断再灌注损伤的敏感性、特异性分别为85.2％ (23/27)、86.2％ (94/109),Kappa值为0.62;DECT3组图像的敏感性、特异性和Kappa值:140 kV组分别为88.9％ (24/27)、92.7％ (101/109),0.76;100 kV组分别为85.2％ (23/27)、89.0％(97/109),0.67;平均加权120 kV组分别为88.9％ (24/27)、91.7％ (100/109),0.74.DECT 3组图像测量损伤心肌重量与大体病理所测值之间差异无统计学意义(F=0.419,P=0.741).结论 DECT心肌灌注成像可用于检测猪急性心肌缺血再灌注损伤,与病理诊断一致性较好.     

心肌灌注/代谢显像评价干细胞移植后犬受损心肌的修复能力

目的 采用核素心肌灌注(MPI)/代谢(MMI)显像评价犬心肌梗死自体骨髓干细胞移植后受损心肌的修复能力.方法 选取杂种犬12条,按动物编号法随机分为移植组(单号)及对照组(双号)各6条.通过手术间断阻断左前降支(LAD)下1/3循环90 min,建立犬心肌梗死模型.将诱导分化的骨髓间质干细胞自体移植到移植组动物梗死区,通过核素MPI和MMI、组织病理、免疫组织化学等技术评价干细胞移植治疗后6周和10周的效果.采用SPSS 10.0软件进行统计学处理.结果 (1)3条犬死亡,其中对照组2条.其余9条犬结扎冠状动脉24-48 h后的心电图、9～12 h后静脉血清心肌酶谱、5～7 d后MPI符合心肌梗死改变.(2)细胞移植后5～7 d MPI/MMI发现对照组心肌梗死节段数及梗死区存活心肌节段数分别为20及8个节段,移植组分别为25及10个节段,2组差异无统计学意义(t=0.389,P＞0.05).(3)ANOVA分析结果示,移植组有存活心肌的节段数在细胞移植10周与移植后5～7 d MPI/MMI比较差异有统计学意义(F=5.879,P＜0.05);无存活心肌的节段数细胞移植6周及10周MPI/MMI差异均无统计学意义(F=0.376,P＞0.05).对照组细胞移植后5～7 d、6周和10周的MPI/MMI所示梗死心肌节段数差异无统计学意义(F=0.212,0.005,0.316,P均＞0.05).(4)细胞移植5～7 d及10周后对照组与移植组的MPI所示左心室射血分数(LVEF)的变化值分别为(5.50±2.69)%及(16.20±2.93)%,2组之间差异有统计学意义(t=13.563,P＜0.01).结论 MPI/MMI不仅可以确定心肌梗死的部位、范围、程度及梗死心肌是否存活,还可以反映骨髓干细胞移植后的细胞存活及生长状况.     

320层容积CT心肌灌注成像对心肌灌注缺损的诊断价值

目的 探讨320层容积CT心肌灌注成像(CT-MPI)的可行性及其对心肌灌注缺损的诊断价值.方法 对14例经SPECT心肌灌注成像(SPECT-MPI)阳性的已知或可疑冠心病患者行静息和腺苷负荷320层容积CT-MPI检查,使用专用心肌灌注软件对CT-MPI进行分析.以心肌16节段标准分段方法(心尖除外)分别分析核素和容积CT-MPI的固定或可逆性灌注缺损.以SPECT-MPI为参考标准评价CT-MPI对心肌灌注缺损诊断的敏感度、特异度.结果 所有患者均成功完成320层容积CT-MPI.SPECT-MPI显示14例患者中共有39段心肌出现固定或可逆性灌注缺损,CT-MPI正确显示了其中12例患者的34段心肌灌注缺损.320层容积CT-MPI诊断心肌灌注缺损的敏感度、特异度分别为87.2％( 34/39)和91.4％(169/185).结论 320层容积CT-MPI对诊断心肌灌注缺损有较高的敏感度和特异度.     

第二代双源CT冠状动脉成像结合双能量心肌灌注评价猪急性心肌梗死的实验研究

目的：通过建立猪急性心肌梗死模型,以组织病理学和冠状动脉造影（CAG）结果为金标准,评价第二代双源CT双能量“一站式”冠状动脉CT血管造影（CCTA）结合心肌灌注成像（MPI）检测急性心肌梗死的准确率。方法7只健康小型猪,采用导管介入冠状动脉明胶海绵栓塞方法制作急性心肌梗死模型,分别在造模前20 min、心肌梗死后即刻、心肌梗死后24 h行CAG及双能量模式CCTA和MPI。采用心肌17节段法评价心肌碘图灌注缺损。双盲法由2名放射科医师对图像进行评价,以病理和CAG结果为金标准,计算双能量CCTA结合心肌灌注碘图诊断心肌灌注缺损节段的灵敏度和特异度。结果双能量碘图显示45个梗死节段和40个非梗死节段。以病理和CAG结果为金标准,基于节段分析得出灵敏度、特异度、阳性预测值、阴性预测值分别为93%、95%、95%、93%;基于血管分布区域分析,双能量CT心肌灌注检测心肌梗死的灵敏度、特异度、阳性预测值、阴性预测值分别为100%、86%、89%、100%。单次双能量扫描平均有效射线剂量为（3．07±0．85）mSv（2．21～4．49 mSv）。结论以病理和CAG结果为金标准,第二代双源CT双能量“一站式”CCTA结合心肌灌注碘图检测急性心肌梗死准确率较高,CCTA的图像质量好。     

多层螺旋CT冠状动脉成像与SPECT心肌灌注显像的相关性研究

目的 通过同时行多层螺旋CT冠状动脉成像(CTCA)和单光子发射计算机断层(SPECT)心肌灌注显像检查,分析不同程度、类型、部位的冠状动脉狭窄的病理解剖学改变与心肌灌注缺损的病理生理学变化之间的相互关系.探讨冠状动脉粥样硬化性心脏病诊断的检查流程.资料与方法 应用Toshiba Aquilion 16层螺旋CT及Siemens e.cam+双探头SPECT,对51例行CTCA检查及SPECT心肌灌注显像.结果 51例患者共计冠状动脉左前降支(LAD)、左回旋支(LCX)、右冠状动脉(RCA)153支,其中正常45支,冠状动脉狭窄108支.狭窄<25%者24支、26%～50%者30支、51%～75%者33支、>75%者21支.SPECT心肌灌注显像51例,按照LAD、LCX、RCA三支动脉所供血范围统计,灌注正常73支;灌注减低80支.轻度减低34支、中度减低36支、严重减低10支.结论 冠状动脉狭窄与心肌灌注缺损存在正相关性.     

心肌SPECT显像观察卡托普利对犬心肌梗死后左心室重构的作用

目的 应用心肌SPECT显像观察卡托普利对实验犬急性心肌梗死后早期左心室重构的预防作用.材料与方法 34只杂种犬采用完全随机分组方法分为对照组(n=23)和治疗组(n=11).开胸结扎所有犬的左前降支制作心肌梗死模型.治疗组术前3d 口服卡托普利20mg,每天2次.术后6h行SPECT心肌显像,观察两组术前与术后左心室舒张末期容积( EDV)、收缩末期容积(ESV)、射血分数(EF)的变化.结果 ①对照组与治疗组分别有16只犬和6只犬成功建立模型并纳入实验.②对照组术前左心室EDV、ESV与术后比较,差异有统计学意义(t =2.81、2.83,P＜0.05);术前EF与术后比较,差异无统计学意义(t=0.06,P＞ 0.05).治疗组术前EDV、ESV、EF与术后比较,差异均无统计学意义(t=0.76、0.56、1.20,P＜0.05);两组术前EDV、ESV差异无统计学意义(t=0.08、0.94,P＞ 0.05),术后EDV、ESV差异有统计学意义(t=6.12、9.91,P＜0.05),EF差异无统计学意义(t=0.79,P＞0.05).结论 急性心肌梗死前预防性使用卡托普利可阻止早期左心室重构;心肌SPECT显像对评价预防性使用卡托普利控制急性心肌梗死后早期左心室重构有重要价值.     

用99Tcm-MIBI心肌显像评价犬急性心肌梗死后早期左室重构

目的 使用99Tcm-甲氧基异丁基异腈(MIBI)心肌显像观察犬实验性急性心肌梗死(AMI)后6 h内左心室形态、功能等早期重构变化.方法 杂种犬24条,分为手术组16条,假手术组8条.手术组犬在麻醉下开胸打开心包,结扎冠状动脉左前降支(LAD)主干建成AMI模型.即刻按体重静脉注射99Tcm-MIBI 37～55.5 MBq/kg.结扎LAD后[21.87±11.03(14～48)]min开始行首次显像,并连续采集6 h.假手术组手术过程同上,但不结扎冠状动脉LAD.仪器为ADAC VertexDual-head SPECT仪.结果 结扎后首次显像即可观察到左心室前壁、心尖部放射性缺损或明显减低,左室整体扩张变形、梗死区膨胀无室壁运动.QGS软件计算手术组舒张末期容积(EDV)、收缩末期容积(ESV)分别为(48.73±12.74)、(32.57±8.10)ml,与假手术组[分别为(36.88±11.12)、(24.93±7.25)ml]相比差异有显著性(t=5.24、3.50,P＜0.01);左室射血分数(LVEF)为(33.64±6.05)%与假手术组[(32.40±9.20)%]比较差异无显著性(t=0.95,P＞0.05).结扎LAD后6 h内EDV、ESV仍增大,而LVEF无明显变化.结论 99Tcm-MIBI心肌显像可在AMI后早期(最早14min)就观察到左心形态、大小及功能改变等早期左室重构的发生,并可随时间进展了解AMI后心功能受损情况,是研究AMI后左室重构的有用方法.     

CT心肌灌注成像新进展

随着对心血管疾病研究的深入,越来越多的证据表明冠脉解剖狭窄与心肌功能并不呈正比。在典型的缺血级联反应中,血流灌注异常最先出现,然后才出现代谢改变、室壁运动异常、心电图改变和临床症状。CT心肌灌注成像技术可评估心肌血流灌注的生理学信息,对临床决策的制订及远期预后的评估至关重要。近年来,CT心肌灌注成像技术发展较快,在技术方面,低剂量、双能量扫描及人工智能的应用是主要关注话题;在诊断方面,与CT-血流储备分数(FFR)的对比、心肌病的诊断及预后预测是主要研究方向。本文对心肌灌注成像的扫描方案及相关技术和其在诊断方面的临床应用进展进行了总结和分析。     

99Tcm-NOET门控心肌灌注SPECT评价冠心病的价值

目的评价99Tcm--双（N-乙氧基,N-乙基-二硫代氨基甲酸酯）氮化锝（99Tcm-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925MBq 99Tcm-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99Tcm-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=42．60：4,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）％1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99Tcm-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?     

~(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.     

128层CT对心肌梗死综合评估及预后判断的价值

目的:探讨MSCT对急性心肌梗死介入治疗早期综合评估及6个月左心室重构的预测价值。方法:选择36例急性心肌梗死介入治疗患者,均于介入治疗后1周及6个月行MSCT和经胸超声心动图检查,并根据MSCT延迟扫描将患者分为A、B、C组,分析不同组别的图像特点。结果:36例患者中,早期扫描检出早期灌注缺损(early defect,ED)34例,经冠脉造影证实32例,30例表现为心内膜下,2例为透壁性,ED区域CT值(45.32±15.32)HU,明显低于正常心肌。延迟扫描检出孤立性心内膜下晚期增强(late enhancement,LE)18例,心内膜下残余灌注缺损(residual defect,RD)和心外膜下LE 4例,单纯心内膜下RD 12例;LE区域CT值(105.85±16.23)HU,明显高于正常心肌;RD区域CT值(39.24±8.36)HU,明显低于正常心肌。A组ST回落程度(63.2±7.1)%明显高于B、C组,C组(44.3±3.5)%明显高于B组;B组CT梗死容积(13.2±4.1)%明显高于A、C组;B组左心室舒张末容积(41.2±7.2)mm3明显高于A、C组。结论:介入治疗后急性心肌梗死患者MSCT双期扫描图像表现出不同的强化方式,具有一定的特征性,对急性心肌梗死6个月左心室重构有较好的预测价值。     

99锝m N-2-巯基吡啶-N-氧化物与99锝m-甲氧基异丁基异腈对犬急性心肌梗死模型的对照研究

目的 在正常和心肌梗死犬模型上,研究99TcmN-2-巯基吡啶-N-氧化物(99TcmN-MPO)的药物代谢动力学特征、生物学分布特征和对急性心肌梗死的诊断能力,并与传统示踪剂99锝m-甲氧基异丁基异腈(99Tcm-MIBI)进行对比研究.方法 正常杂种犬12只.静脉注射99TcmN-MPO,于不同时间点(30 s及1、2、3、4、5、10、20、30、40、60和90 min)静脉分别采血1 ml,经γ探测器测量其放射活性;注药后10、20、30、60、90及120 min行全身SPECT显像,并于不同器官上各取同样大小的ROI,测量其放射性计数进行定量研究.每只犬均注射相同剂量的99TcmMIBI,进行相同的实验作为对照.介入学方法构建犬急性心肌梗死模型,24 h后,静脉注入99TcmN-MPO(5只)和99Tcm-MIBI(5只),并于注药后30、60min进行心肌SPECT显像.结果 在静脉注射90 min内,99TcmN-MPO和99Tcm-MIBI均表现为快速的血液清除.两种示踪剂的初始注射剂量均为370 MBq.注射后1 min,每毫克血浆的放射活性小于初始注射剂量的50%[99TcmN-MPO为(35.77±6.31)%ID/mg;99Tcm-MIBI为(34.46±6.83)%ID/mg],30 min时＜5%[99TcmN-MPO:(3.11±1.44)%ID/mg;99Tcm-MIBI:(2.93±0.39)%ID/mg].99TcmN-MPO在心脏的浓聚明显,且存留时间很长,由于其在肝脏清除的速度较快,因此可获得良好的心/肝摄取比值,注射后10 min为0.54±0.06,30 min为1.02±0.06,60 min上升到1.38±0.06.相比之下,99Tcm-MIBI的心/肝摄取比值上升较为缓慢(注射后10 min为0.46±0.03,30 min为0.63±0.03,60 min为0.62±0.12).犬心肌梗死后SPECT心肌断层扫描显示,在注射99TcmN-MPO 30 min后,心脏与肝脏分界清楚,可清楚显示心肌缺血、梗死灌注缺损区域、范围和程度;而99Tcm-MIBI注射后60 min,心脏和肝脏的分界依然不清,尤其是肝脏的高放射性对心脏下壁和左心室壁的影响很大,对心脏左心室壁的心肌梗死灌注缺损区域的显示不佳.结论 99TcmN-MPO具有心肌摄取量较高,肝脏代谢快的特点,是一种具有广阔临床应用前景的SPECT心肌灌注成像显像剂.

Abstract：

Objective The purpose of the present study is to compare the pharmacokinetic and biodistribution properties of 99Tcm N-mercaptopyridine-N-oxide (99 Tcm N-MPO) with 99 Tcm-sestamibi (99 Tcm-MIBI) in normal dogs, and to investigate the potential of 99TcmN-MPO as a myocardial perfusion agent in canines with acute myocardial infarction. Methods Twelve healthy mongrel dogs were injected intravenously with 99TcmN-MPO (n = 6) or 99Tcm-MIBI (n = 6). Tracer kinetics in body fluids were determined by collecting blood of 1 ml via a femoral vein catheter at 30 s, 1,2,3,4,5, 10, 20, 30, 40, 60and 90 min post-injection (p. i.). The collected blood samples were weighed and counted for radioactivity in a γ-counter. Anterior and posterior planar γ-camera images were collected at 10, 20, 30, 60, 90, and 120 min after injection, with organ uptake quantified by region-of-interest (ROIs) analysis. For comparison, 99Tcm-MIBI was also evaluated in the same twelve dogs. Canine infarct models were set up by micro-invasive interventional embolization. SPECT images in the canine infarct model were collected 24 hours after myocardial infarction at 30 min and 60 min after the administration of 99Tcm N-MPO (n = 5) or 99Tcm-MIBI (n = 5). Results Both of 99Tcm N-MPO and 99Tcm-M1BI had a rapid blood clearance with less than 50% of initial radioactivity remaining at 1 min [99TcmN-MPO: (35. 77 ± 6. 31)% ID/mg ,99Tcm-MIBI (34. 46 ± 6. 83) % ID/mg] and less than 5% at 30 min p. i. [99Tcm N-MPO(3. 11 ± 1.44) % ID/mg,99Tcm-MIBI (2.93 ±0. 39)% ID/mg] . After injection, 99TcmN-MPO showed significant accumulation in the myocardium and prolonged retention. This rapid liver clearance of 99TcmN-MPO led to favorable heart-to-liver ratios, reaching values of 0. 54 ±0. 06 at 10 min, 1.02 ±0. 06 at 30 min, and 1.38 ±0. 06 at 60 min p. i.In contrast, the heart/liver ratio of 99Tcm-MIBI remained low at all time points (0. 46 ± 0. 03 at 10 min,0. 63 ±0. 03 at 30 min, and 0. 62 ± 0. 12 at 60 min p. i.). SPECT imaging studies in canines with acute myocardial infarction indicated that good visualization of the left ventricular wall and perfusion defects could be achieved at 30 min after administration of 99TcmN-MPO, but not 99Tcm-MIBI. Conclusion The combination of high heart uptake and rapid liver clearance makes 99TcmN-MPO a promising new radiotracer for myocardial perfusion imaging.     

Serial assessment of left ventricular function during dobutamine stress by means of electrocardiographygated myocardial SPECT: Combination with dual-isotope myocardial perfusion SPECT for detection of ischemic heart disease

BACKGROUND: Technetium-labeled myocardial perfusion tracers allow simultaneous assessment of myocardial perfusion and left ventricular function by electrocardiography (ECG)-gated myocardial single photon emission computed tomography (SPECT). The purpose of this study was to evaluate left ventricular performance during dobutamine stress by means of ECG-gated myocardial perfusion SPECT with short-time data collection. METHODS AND RESULTS: After administration of Tc-99m sestamibi or tetrofosmin (600-740 MBq), 67 patients with ischemic heart disease, including 35 with prior myocardial infarction, were examined by ECG-gated myocardial perfusion SPECT at rest and during dobutamine stress (at dosages of 4, 8, 12, 16, and 20 microg/kg/min, with increments every 8 minutes). The ECG-gated data collection time was 5 minutes for each dobutamine dosage. After acquisition of gated SPECT data at the highest dose, thallium 201 chloride (111 MBq) was injected, and dual-isotope SPECT was also performed to assess the myocardial ischemia. In 32 patients without prior myocardial infarction, the sensitivity of individual stenosed-vessel detection with dual-isotope perfusion SPECT, with wall motion abnormality obtained from gated SPECT, and with the combined method was 55.9%, 52.9%, and 73.5%, respectively, based on coronary angiography. ECG-gated SPECT during dobutamine infusion revealed regional wall motion abnormalities (worsening or biphasic response) in 19 (57.6%) of 33 infarcted areas with culprit coronary arterial stenosis. The prevalence of reversible perfusion defects on dual-isotope SPECT was higher in segments with wall motion abnormalities than in segments with normal wall motion response (89.5% vs 42.9%, P <.02). CONCLUSIONS: Myocardial perfusion and left ventricular function during dobutamine infusion were analyzed in a single examination by means of the combined method. This procedure has the potential to provide comprehensive information with which to evaluate patients with ischemic heart disease.     

201Tl定量门控心肌灌注体层显像与99mTc-红细胞门控心血池显像测定左心室射血分数的对比研究

目的 探讨201Tl定量门控心肌灌注体层显像与99mTc-红细胞门控心血池显像测量左心室射血分数(LVEF)的相关性.方法 72例受检者接受201Tl静息门控心肌灌注体层显像,用AUTOQUANT 4.21软件测量LVEF,并与24 h内的静息99mTc-红细胞平衡法门控心血池显像结果进行比较.结果 ①门控心肌灌注体层显像与门控心血池显像测量LVEF值的结果呈明显正相关(r=0.554,P=-0.000),两种方法无统计学差别(t=1.194,P＞0.05).②不同疾病组之间两种测量方法无统计学差异(P值均大于0.05).③门控心肌灌注体层显像及门控心血池显像测量的LVEF值分别为(64.68±10.77)%和(62.46±8.99)%,门控心肌灌注体层显像测量的LVEF值要比门控心血池显像高出3.55%.结论 201Tl门控心肌灌注体层显像与99mTc-红细胞门控心血池显像测量LVEF值的相关性好且结果准确,但门控心肌灌注体层显像的LVEF测量值要稍高于门控心血池显像.     

Dual Energy CT lung perfusion imaging--correlation with SPECT/CT

Objective

Aims were (1) to determine the diagnostic accuracy of Dual Energy CT (DECT) in the detection of perfusion defects and (2) to evaluate the potential of DECT to improve the sensitivity for PE.

Methods

15 patients underwent Dual Energy pulmonary CT angiography (DE CTPA) and a combination of lung perfusion SPECT/CT and ventilation scintigraphy. CTPA and DE iodine distribution maps as well as perfusion SPECT/CT and inhalation scintigrams were reviewed for pulmonary embolism (PE) diagnosis. DECT and SPECT perfusion images were assessed regarding localization and extent of perfusion defects. Diagnostic accuracy of DE iodine (perfusion) maps was determined with reference to SPECT/CT. Diagnostic accuracies for PE detection of DECT and of SPECT/CT with ventilation scintigraphy were calculated with reference to the consensus reading of all modalities.

Results

DE CTPA had a sensitivity/specificity of 100%/100% for acute PE, while the combination of SPECT/CT and ventilation scintigraphy had a sensitivity/specificity of 85.7%/87.5%. For perfusion defects, DECT iodine maps had a sensitivity/specificity of 76.7% and 98.2%.

Conclusion

DECT is able to identify pulmonary perfusion defects with good accuracy. This technique may potentially enhance the diagnostic accuracy in the assessment of PE.     

Quantified dual energy computed tomography perfusion imaging using myocardial iodine concentration: Validation using CT derived myocardial blood flow and invasive fractional flow reserve in a porcine model

BackgroundMyocardial CT perfusion imaging with dual energy (DE-CTP) can produce myocardial iodine perfusion maps. This study evaluated the accuracy of first pass myocardial iodine concentration in DE-CTP compared to CT derived dynamic myocardial blood flow (MBF) to determine regional myocardial ischemia in an animal model of coronary stenosis using invasive Fractional Flow Reserve (FFR).MethodsSeven anaesthetised pigs (mean weight 51 ± 4 kg) had a graded coronary artery stenosis produced in six vessels (plus one control animal) using a methacrylate plug with FFR recorded in the target artery (ischemia = FFR<0.80). During adenosine vasodilation, dynamic myocardial CTP and DE-CTP imaging was performed. Using vendor supplied applications, matching regions of interest (ROIs) were drawn in myocardial segments supplied by the target coronary artery to compare the two techniques.ResultsFFR correlated strongly to MBF (r = 0.81) and modestly to myocardial iodine concentration (r = 0.65) and myocardial CT attenuation (r = 0.62) (p < 0.0001 each). The correlation to FFR was stronger using relative ratios (absolute value/reference value of normal segments) than absolute values for MBF (r = 0.86), myocardial iodine concentration (r = 0.80) and CT number (r = 0.79) (p < 0.0001 each). Comparing normal and ischaemic territories there were significant differences in MBF (96 ± 14 vs. 27 ± 18 ml/100 ml of tissue/min, p < 0.0001), myocardial iodine concentration (3.5 ± 1 vs. 1.0 ± 0.7 mg/ml, p < 0.0001) and myocardial CT number (89 ± 9 vs. 73 ± 14 HU, p = 0.002). Myocardial iodine concentration had 91% sensitivity and 98% specificity for detecting FFR <0.8.ConclusionQuantified myocardial iodine content from first pass DE-CTP correlates with CT derived myocardial blood flow and FFR and accurately discriminates ischemic territories in a porcine model. The accuracy and utility of myocardial iodine content in DE-CTP warrants further investigation in a clinical population with FFR as a reference standard.     

双源CT双能量心肌灌注对诊断心肌梗塞及其罪犯血管关系的研究

目的 探讨双源CT双能量心肌灌注对心肌梗塞的诊断价值及其与罪犯血管的关系.方法 用双源CT双能量灌注成像方法对42例临床疑诊或确诊为冠心病的患者进行扫描.分析心肌灌注情况与罪犯冠脉狭窄程度的关系;对19例临床确诊为陈旧性心梗患者的心电图与心肌灌注情况进行了对比分析.结果 42例患者的心肌灌注改变与冠脉狭窄程度存在线性变化趋势(P＞0.05),11例冠脉轻及中度狭窄患者心肌灌注未见异常,31例重度及完全闭塞患者,26例可见心肌灌注减低;19例临床确诊为陈旧性心梗患者心电图均见病理性Q波、心肌灌注均有缺损.结论 双源CT双能量心肌灌注成像.可一站式评价冠心病心肌缺血或梗死情况及其与罪犯血管的关系,对冠心病的诊断、治疗及预后评估具有重要指导意义.