心肌灌注SPECT显像采用X线CT衰减校正的临床应用

The value of X-ray attenuation correction for myocardial perfusion imaging

目的:评价SPECT/CT复合成像装置采用CTX线对心肌灌注显像衰减校正的临床应用价值。方法:受检者65例,35例经临床病史、心电图、超声心动图等检查排除冠心病患者;30例临床诊断明确的冠心病患者。均行^(99m)Tc-甲氧基异丁基异晴(^(99m)Tc-MIBI)常规心肌断层显像及X线衰减校正显像,并与冠状动脉造影结果进行对比分析。结果:①非冠心病组和冠心病组下壁和后壁放射性摄取率由未采用X线CT衰减校正方法的(77.0±4.77)%和(76.0±5.7)%、(31±4.3)%和(35±5.5)%增至采用X线衰减校正方法的(85.0±4.5)%和(83.0±5.2)%、(38±5.1)%和(42±5.5)%,两组校正后均P<0.001。②35例非冠心病患者经目测定性分析,衰减校正后,原下后壁放射性减低明显改善者82.8%,中度改善14.3%;30例冠心病患者经X线衰减校正后有改善者73.7%。③非冠心病35例和30例冠心病患者与冠状动脉造影结果对比,经X线衰减较正后心肌灌注显像符合率分别提高了8.6%和15.4%。结论:SPECT/CT复合显像装置对心肌灌注显像行X线衰减校正技术,方法简便,可以使大多数由于γ射线在组织中的衰减造成的放射性计数减低得到校正,尤其对左室下后壁的衰减校正更明显。经衰减校正后提高了心肌灌注图像质量,在临床诊断中减少了假阳性的发生,使诊断符合率提高。

Objective： To evaluate the clinical value of X-ray attenuation correction for myocardial imaging in SPECT/CT. Methods： Total 65 cases, 35 cases （Group 1）, with no coronary artery disease by clinical history, ECG, ultrasound and other necessary clinical examinations; 30 patients （Group 2） with coronary artery disease. All underwent ^99mTc-MIBI myocardial perfusion tomography imaging and X-ray attenuation correction and were compared with their angiograms. Results： ①The uptake ratios of inferior and posterior wall in Group 1 and Group 2 increased from （77.0±4.77）% and （76.0±5.7）%, （31±4.3）% and （35±5.5）% without X-ray attenuation correction to （85.0±4.5）% and （83.0±5.2）%, （38±5.1）% and （42±5.5）% with X-ray attenu- ation correction （P0.001）, respectively. ②With qualitative analysis, Group 1： 82.8% subjects showed obvious improvement in the defects in inferior and posterior wall; 14.3% subjects with medium-level improvement. Group 2： 73.7% subjects showed improvement. ③The coherence of myocardial perfusion angiographic images of Group 1 and Group 2 after X-ray attenuation correction improved to 8.6%, 15.4% separately. Conclusion： X-ray attenuation correction in SPECT/CT is a simple and valid method. It corrects most of the attenuation artifacts in myocardial perfusion imaging, especially in the inferior and posterior wall. It helps to avoid the false positive diagnosis and improve the diagnostic confidence of nuclear cardiologists. It is important for coronary artery disease especially with myocardial perfusion images.