改良的迭代图像重建法在单光子发射计算机断层心肌灌注显像的临床应用研究

Clinical Investigation of an Improved Iterative Reconstruction Algorithm in SPECT Myocardial Perfusion Imaging

目的:以滤波反投影重建法(FBP)为标准,评价改良的迭代图像重建方法(Astonish,AS),在单光子发射计算机断层(SPECT)心肌灌注显像的临床应用研究。方法:100例疑诊或确诊冠心病患者行SPECT心肌显像。根据注射显像剂的用量,分为全剂量组(n=54)和半剂量组(n=46)。全剂量组:两日法门控运动+静息心肌灌注显像,运动和静息显像均先行半时间采集,随后全时间采集,半时间用AS重建,全时间用FBP重建;半剂量组:一日法门控运动+静息心肌灌注显像,运动时注射99m锝—甲氧基异丁基异腈[99mTc-MIBI(5.2±0.6)mCi,标准一日法剂量的一半],先行全时间采集,随后双倍时间采集,全时间用AS重建,双倍时间用FBP重建;如果运动显像异常,于当日行静息显像(与全剂量组静息显像完全相同)。用4分法对图像质量进行半定量评分(1:差,2:一般,3:好,4:非常好)。图像诊断结果采用5分类法(正常,心肌梗死,心肌缺血,心肌缺血+心肌梗死,模棱两可)。结果:两组中图像质量评分AS图像均高于FBP图像(P<0.001)。诊断结果按照5分类法,AS图像与FBP图像之间有高度的诊断一致性(Kappa=0.922,P<0.001)。结论:经AS重建的半时间采集或半剂量注射的心肌灌注图像,其质量优于全时间和全剂量标准的FBP重建的图像,但不影响对诊断结果的判断。

Objective：Based on fihered back projection （FBP）reconstruction, we evaluated an improved iterative Astonish（AS） reconstruction for SPECT myocardial perfusion imaging in clinical practice. Methods ： A total of 100 patients were randomly divided into2 groups according to the dosage of contrast. Full-dose group, n = 54,the patients underwent a 2-day gated stress/rest protocol. Half-time and full-time acquisitions were performed in both stress and rest SPECT. Half-time raw data was reconstructed by AS, and full-time raw data was reconstructed with FBP. Half-dose group, n = 46, the patients underwent a 1-day gated stress/rest protocol and received a mean dose of（5.2 ± 0. 6）mCi of 99mTc-MIBI in stress. Full-time and double-time acquisition were performed in stress SPECT. Full-time raw data was reconstructed by AS, and double-time raw data was reconstructed with FBP. If stress image predicted a defect, the patients would undergo the same rest SPECT as Full-dose group in the same day. The quality of imaging was interpreted by a 4-point scales： 1 = poor,2 = fair, 3 = good,4 = excellent. The diagnosis included 5 categories ： normal, infarction, ischemia, infarction ＋ ischemia and equivocal. Resuhs ：The quality scores of AS imaging were higher than FBP imaging,P〈0. 001. The diagnosis agreement of AS and FBP was very high,Kappa=0. 922,P〈0. 001. Conclusion ： AS reconstruction imaging with half-time or half-dose acquisition had better quality than FBP reconstruction ima- ging with full-time or full-dose acquisition, but not influence the diagnosis accuracy in SPECT myocardial perfusion imaging.