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随着SPECT/CT被广泛应用,CT衰减校正(CT attenuation correction,CTAC)技术也受到了众多临床工作者的关注,但其诊断的准确性存有争议。Shibutani等[1]发现,CTAC后可明显提高左心室下壁的放射性摄取率10%~15%。卫华等[2]研究结果表明,CTAC能够有效地鉴别心肌灌注显像(myocardial perfusion imaging,MPI)中左心室下后壁的伪影,但在心尖和前壁可引起新伪影的出现。
智能(intelligence quotient, IQ)-SPECT/CT采集技术是使用心脏专用多焦点准直器(SMART-ZOOM准直器)进行图像采集,具有灵敏度及空间分辨率高、扫描时间短、注射显像剂剂量少及辐射剂量低等优点[3]。李珺奇等[4]研究结果显示,IQ-SPECT/CT CTAC后,受检者左心室下壁和间壁的放射性摄取值明显升高,心尖部则显著降低。本研究中,我们对31例MPI确诊或可疑的冠心病患者同日分别行IQ-SPECT/CT和低能高分辨率(low energy high resolution,LEHR)-SPECT/CT,然后进行图像采集以及CTAC,通过量化血流灌注SPECT(quantitative perfusion SPECT,QPS)分析软件计算出心肌节段的放射性摄取值(%),比较经CTAC后IQ-SPECT/CT与LEHR-SPECT/CT MPI图像的变化,评价CTAC对两种采集方式所得图像的影响。
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CTAC前,IQ-SPECT/CT MPI图像正常者10名、异常者21例;LEHR-SPECT/CT MPI图像正常者13名、异常者18例,两组各心肌节段MPI图像正常者、异常者的比较均无明显差异,且具有很高的一致性(Kappa值=0.795,P<0.001)。IQ-SPECT/CT、LEHR-SPECT/CT CTAC前有3例患者左心室下壁的放射性分布不一致,在IQ-SPECT/CT中放射性分布略稀疏,而在LEHR-SPECT/CT中放射性分布基本正常。
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IQ-SPECT/CT CTAC后有17例患者(55%,17/31)的左心室间壁放射性分布明显稀疏(图1),7例患者(23%,7/31)的左心室前壁明显稀疏;LEHR-SPECT/CT CTAC后有7例患者(23%,7/31)的左心室心尖放射性分布明显稀疏,14例患者(45%,14/31)的左心室下壁放射性得到补偿。两种方法比较,IQ-SPECT/CT CTAC后心肌节段出现明显稀疏的比例(77%,24/31)显著高于LEHR-SPECT/CT CTAC后(23%,7/31),且差异有统计学意义(χ2=16.52,P<0.001)(表1)。
显像方法 心尖 前壁 侧壁 下壁 间壁 合计(稀疏) IQ-SPECT/CT CTAC后 0 7(稀疏) 0 0 17(稀疏) 24 a LEHR-SPECT/CT CTAC后 7(稀疏) 0 0 14(补偿) 0 7 IQ-SPECT/CT CTAC手动配位后 5(稀疏) 0 0 15(补偿) 2(补偿) 5 注:表中,a: 与LEHR-SPECT/CT CTAC后相比,差异有统计学意义(χ 2=16.52,P<0.001)。IQ:智能;SPECT:单光子发射计算机体层摄影术;CT:计算机体层摄影术;AC:衰减校正;LEHR:低能高分辨率 表 1 IQ-SPECT/CT 、LEHR-SPECT/CT CTAC后和IQ-SPECT/CT CTAC手动配位后左心室各室壁的放射性分布情况(例)
Table 1. The radioactivity distribution of left ventricular wall after intelligence quotient-SPECT/CT, low energy high resolution-SPECT/CT CT attenuation correction and intelligence quotient-SPECT/CT CT attenuation correction manual coordination (case)
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由表1可知,IQ-SPECT/CT CTAC后心肌节段出现明显稀疏的比例较高(24/31,77%),对其原始图像分析后发现,31例患者(31/31,100%)均存在不同程度的配位不准。而在LEHR-SPECT/CT 中,分析31例患者(31/31,100%)的原始图像后,发现配位良好。将IQ-SPECT/CT MPI与CT图像进行手动重新配位后发现,5例患者(16%,5/31)心尖放射性分布稀疏、15例患者(48%,15/31)下壁放射性得到补偿、2例患者(6%,2/31)间壁放射性得到补偿。配位后与LEHR-SPECT/CT (23%,7/31)比较,差异无统计学意义(χ2=0.103,P=0.748)。
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由表2可知,IQ-SPECT/CT CTAC后左心室心尖、前壁、间壁的放射性摄取值明显低于CTAC前(t=4.014、4.232、5.473,均P<0.05);左心室下壁的放射性摄取值高于CTAC前;IQ-SPECT/CT CTAC配位后与CTAC前比较,左心室心尖的放射性摄取值降低(t=3.439,P=0.002);前壁、侧壁、下壁和间壁的放射性摄取值均增高,且差异均有统计学意义(t=−2.497,P=0.018;t=−2.672,P=0.012;t=−7.632, P<0.001;t=−3.557,P <0.001)。由表3可知,LEHR-SPECT/CT CTAC后左心室前壁、下壁及间壁的放射性摄取值明显高于CTAC前,且差异均有统计学意义。
显像方法 心尖 前壁 侧壁 下壁 间壁 IQ-SPECT/CT CTAC前 65.71±25.69 204.23±43.24 355.81±46.79 191.58±33.06 316.19±47.43 IQ-SPECT/CT CTAC后 58.68±20.39a 184.66±41.22a 351.58±49.27 203.26±30.18 270.03±65.33a IQ-SPECT/CT CTAC手动配位后 59.65±19.08a 212.06±33.59a 372.84±39.37a 219.13±25.10a 335.00±36.84a 注:表中,a: 与IQ-SPECT/CT CTAC前相比,差异有统计学意义(t=−7.632~5.473, P<0.05)。IQ:智能;SPECT:单光子发射计算机体层摄影术;CT:计算机体层摄影术;AC:衰减校正 表 2 IQ-SPECT/CT CTAC前后及手动配位后左心室各室壁的放射性摄取值比较(%,
±s)$\bar x$ Table 2. Comparison of left ventricular wall radioactive uptake value before and after intelligence quotient-SPECT/CT CT attenuation correction and after manual coordination (%,
±s)$\bar x $ 显像方法 心尖 前壁 侧壁 下壁 间壁 LEHR-SPECT/CT CTAC前 63.10±21.60 204.68±41.14 360.97±38.87 185.48±31.06 319.13±44.90 LEHR-SPECT/CT CTAC后 63.10±19.08 211.81±35.04 363.96±38.49 228.67±29.45 350.87±44.24 t值 0.947 −2.471 −0.593 −11.311 −5.968 P值 0.351 0.019 0.558 <0.001 <0.001 注:表中,LEHR:低能高分辨率;SPECT:单光子发射计算机体层摄影术;CT:计算机体层摄影术;AC:衰减校正 表 3 LEHR-SPECT/CT CTAC前后左心室各室壁的放射性摄取值比较(%,
±s)$ \bar x $ Table 3. Comparison of left ventricular wall radioactive uptake values before and after low energy high resolution-SPECT/CT CT attenuation correction(%,
±s)$ \bar x $
CT衰减校正对IQ-SPECT/CT和LEHR-SPECT/CT心肌灌注显像的影响
Effect of CT attenuation correction on IQ-SPECT/CT and LEHR-SPECT/CT myocardial perfusion imaging
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摘要:
目的 探讨CT衰减校正(CTAC)对智能(IQ)-SPECT/CT和低能高分辨率(LEHR)-SPECT/CT心肌血流灌注显像(MPI)图像的影响。 方法 收集2018年5月至10月在山西医科大学第一医院行静息心肌灌注显像(MPI)的31例确诊或者可疑的冠心病患者,其中男性21例、女性10例,年龄(49.4±12.01)岁。所有患者同日分别行IQ-SPECT/CT+CTAC及LEHR-SPECT/CT+CTAC。视觉分析IQ-SPECT/CT CTAC前后图像及手动配位后图像、LEHR-SPECT/CT CTAC前后断层图像;同时比较左心室各个室壁(心尖、前壁、侧壁、间壁、下壁)IQ-SPECT/CT和LEHR-SPECT/CT CTAC前后与重新配位后的放射性摄取值(%)。两组间比较采用配对t检验,率的比较采用卡方检验,一致性分析采用Kappa检验。 结果 ①视觉分析:IQ-SPECT/CT与LEHR-SPECT/CT CTAC前图像比较,具有很高的一致性(Kappa值=0.795,P<0.001)。IQ-SPECT/CT CTAC后心肌节段出现放射性分布明显稀疏的比例为77%(24/31),远高于LEHR- SPECT/CT CTAC后的23%(7/31),差异有统计学意义(χ2=16.52,P<0.001)。将MPI与CT图像手动重新配位后,IQ-SPECT/CT左心室心尖的放射性分布为16%(5/31),与LEHR-SPECT/CT的23%(7/31)相比,差异无统计学意义(χ2=0.103,P=0.748)。②放射性摄取值(%):IQ-SPECT/CT CTAC前后比较,左心室心尖[(65.71±25.69)%对(58.68±20.39)%]、前壁[(204.23±43.24)%对(184.66±41.22)%]及间壁[(316.19±47.43)%对(270.03±65.33)% ] 的放射性摄取值明显降低,且差异均有统计学意义(t=4.014、4.232、5.473,均P<0.05);LEHR-SPECT/CT CTAC前后比较,左心室前壁[(204.68±41.14)%对[(211.81±35.04)%]、间壁[(319.13±44.90)%对(350.87±44.24)%]及下壁[(185.48±31.06)%对(228.67±29.45)% ]的放射性摄取值显著增高,且差异均有统计学意义(t=−2.471,P =0.019;t=−5.968,P<0.001;t=−11.311,P<0.001)。IQ-SPECT/CT CTAC配位后与IQ-SPECT/CT CTAC前比较,左心室前壁[(212.06±33.59)%对(204.23±43.24)% ]、侧壁[(372.84±39.37)%对(355.81±46.79)%]、下壁[(219.13±25.10)%对(191.58±33.06)%]和间壁[(335.00±36.84)%对(316.19±47.43)%]的放射性摄取值均明显增高,且差异均有统计学意义(t=−2.497,P=0.018;t=−2.672,P=0.012;t=−7.632,P<0.001;t=−3.557,P<0.001) 。 结论 LEHR-SPECT/CT CTAC后左心室间壁及下壁的放射性分布得到补偿;而IQ-SPECT/CT CTAC后左心室心尖、前壁及间壁的放射性分布却更加稀疏。在IQ-SPECT/CT采集模式下,CTAC后容易出现矫枉过正,重新手动配位后这种情况将得到明显改善。 -
关键词:
- 体层摄影术,发射型计算机,单光子 /
- 体层摄影术,X线计算机 /
- 衰减校正 /
- 心肌灌注显像
Abstract:Objective To evaluate the impact of CT attenuation correction (CTAC) on intelligence quotient (IQ)-SPECT/CT and low energy high resolution (LEHR)- SPECT/CT myocardial perfusion imaging (MPI). Methods Thirty-one patients (21 males and 10 females, aged 49.4 ± 12.01 years) with confirmed or suspected coronary heart disease were subjected to resting MPI from May 2018 to Octorber 2018 in the First Hospital of Shanxi Medical University. All patients were subjected to IQ-SPECT/CT+CTAC and LEHR-SPECT/CT+CTAC on the same day. The visual analysis and myocardial uptake of five myocardial segments (apical, anterior, lateral, inferior, and septal walls) were compared before and after IQ-SPECT/CT CTAC and after manual coordination, as well as before and after LEHR-SPECT/CT CTAC. Paired t test was used for comparison between the two groups. Chi-square test was used to compare the rate. Kappa test was used for consistency analysis. Results (1) Visual analysis results were as follows. The IQ group was compared with the LEHR group without CTAC. Two nuclear medicine physicians were double blind and had high agreement (Kappa value = 0.795, P<0.001). The sparse rate of myocardial segments of the IQ group was 77% (24/31), which was much higher than that of the LEHR group by 23% (7/31) ( χ2=16.52, P<0.001). Owing to the high sparse rate myocardial segments of IQ, the original image and manual reregistration the MPI and CT images were analyzed. After re-coordination, the distribution of apical in the IQ group was found to be sparse (16%, 5/31), and the difference between the LEHR group (23%, 7/31) was not statistically significant (χ2=0.103, P=0.748). (2) Results of myocardial uptake were as follows. Compared with the previous IQ-CTAC, the myocardial uptake values of the apical wall [(65.71±25.69)% vs.(58.68±20.39)%], anterior wall[ (204.23±43.24)% vs.(184.66±41.22)%], and septal wall [ (316.19±47.43)% vs. (270.03±65.33)% ] significantly decreased after CTAC(t=4.014, 4.232, and 5.473, respectively; all P<0.05). Meanwhile, myocardial uptake increased in anterior wall [ (204.68±41.14) % vs. (211.81±35.04)%], septal wall[ (319.13±44.90)% vs.( 350.87±44.24)%], and inferior wall [(185.48±31.06)% vs.( 228.67±29.45)% ] of the LEHR group after CTAC(t=−2.471, P=0.019; t=−5.968, P<0.001; and t=−11.311, P<0.001, respectively). After IQ registration, compared with previous CTAC, the myocardial uptake values of anterior wall [(212.06±33.59)% vs. (204.23±43.24)%], lateral wall [(372.84±39.37)% vs. (355.81±46.79)%], inferior wall [(219.13±25.10)% vs. (191.58±33.06)%], and septal wall [(335.00±36.84)% vs. (316.19±47.43)%] obviously increased (t=−2.497, P=0.018; t=2.672, P=0.012; t=−7.632, P<0.001 and t=−3.557, P<0.001, respectively). Conclusions The distribution of inferior and inferior walls of LEHR-SPECT/CT CTAC was compensated, whereas the distribution of apical, anterior, and septal walls became sparse after IQ-SPECT/CT CTAC. In the IQ-SPECT/CT acquisition mode, overcorrection likely occurred after CTAC, and this situation was significantly improved after re-coordination. -
表 1 IQ-SPECT/CT 、LEHR-SPECT/CT CTAC后和IQ-SPECT/CT CTAC手动配位后左心室各室壁的放射性分布情况(例)
Table 1. The radioactivity distribution of left ventricular wall after intelligence quotient-SPECT/CT, low energy high resolution-SPECT/CT CT attenuation correction and intelligence quotient-SPECT/CT CT attenuation correction manual coordination (case)
显像方法 心尖 前壁 侧壁 下壁 间壁 合计(稀疏) IQ-SPECT/CT CTAC后 0 7(稀疏) 0 0 17(稀疏) 24 a LEHR-SPECT/CT CTAC后 7(稀疏) 0 0 14(补偿) 0 7 IQ-SPECT/CT CTAC手动配位后 5(稀疏) 0 0 15(补偿) 2(补偿) 5 注:表中,a: 与LEHR-SPECT/CT CTAC后相比,差异有统计学意义(χ 2=16.52,P<0.001)。IQ:智能;SPECT:单光子发射计算机体层摄影术;CT:计算机体层摄影术;AC:衰减校正;LEHR:低能高分辨率 表 2 IQ-SPECT/CT CTAC前后及手动配位后左心室各室壁的放射性摄取值比较(%,
±s)$\bar x$ Table 2. Comparison of left ventricular wall radioactive uptake value before and after intelligence quotient-SPECT/CT CT attenuation correction and after manual coordination (%,
±s)$\bar x $ 显像方法 心尖 前壁 侧壁 下壁 间壁 IQ-SPECT/CT CTAC前 65.71±25.69 204.23±43.24 355.81±46.79 191.58±33.06 316.19±47.43 IQ-SPECT/CT CTAC后 58.68±20.39a 184.66±41.22a 351.58±49.27 203.26±30.18 270.03±65.33a IQ-SPECT/CT CTAC手动配位后 59.65±19.08a 212.06±33.59a 372.84±39.37a 219.13±25.10a 335.00±36.84a 注:表中,a: 与IQ-SPECT/CT CTAC前相比,差异有统计学意义(t=−7.632~5.473, P<0.05)。IQ:智能;SPECT:单光子发射计算机体层摄影术;CT:计算机体层摄影术;AC:衰减校正 表 3 LEHR-SPECT/CT CTAC前后左心室各室壁的放射性摄取值比较(%,
±s)$ \bar x $ Table 3. Comparison of left ventricular wall radioactive uptake values before and after low energy high resolution-SPECT/CT CT attenuation correction(%,
±s)$ \bar x $ 显像方法 心尖 前壁 侧壁 下壁 间壁 LEHR-SPECT/CT CTAC前 63.10±21.60 204.68±41.14 360.97±38.87 185.48±31.06 319.13±44.90 LEHR-SPECT/CT CTAC后 63.10±19.08 211.81±35.04 363.96±38.49 228.67±29.45 350.87±44.24 t值 0.947 −2.471 −0.593 −11.311 −5.968 P值 0.351 0.019 0.558 <0.001 <0.001 注:表中,LEHR:低能高分辨率;SPECT:单光子发射计算机体层摄影术;CT:计算机体层摄影术;AC:衰减校正 -
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