Einstein Andrew J, Johnson Lynne L, DeLuca Albert J, Kontak Andrew C, Groves Daniel W, Stant Jennifer, Pozniakoff Ted, Cheng Bin, Rabbani LeRoy E, Bokhari Sabahat
Cardiology Division, Department of Medicine, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York; and
Cardiology Division, Department of Medicine, Columbia University Medical Center and New York-Presbyterian Hospital, New York, New York.
J Nucl Med. 2015 Apr;56(4):545-51. doi: 10.2967/jnumed.114.150664. Epub 2015 Mar 5.
Although SPECT myocardial perfusion imaging (MPI) provides valuable information about patients with chest pain, there is growing concern regarding its radiation burden and lengthy duration. New high-efficiency (HE) cameras and stress-first protocols both offer the potential to markedly reduce radiation. No previous study has assessed outcomes and radiation doses of patients undergoing MPI on an HE-SPECT camera using an ultra-low-dose stress-first protocol.
One hundred patients presenting to the emergency department with chest pain who were candidates for stress-first MPI underwent injection of approximately 185 MBq (5 mCi) of (99m)Tc-tetrofosmin at peak stress, followed by supine and prone imaging on an HE-SPECT camera. Same-day rest imaging was performed on patients with any abnormality on imaging after stress. Radiation effective dose was calculated from administered and residual activities. Patients were contacted 3 mo after discharge, and electronic records were accessed to evaluate the need for reevaluation for chest pain, additional imaging, or cardiac events.
Stress-only imaging was performed in 69 patients, for whom radiation effective dose averaged 0.99 mSv and study duration, 117 min. Radiation dose averaged 2.22 mSv over all patients. At 3 mo, 96 patients were free of major adverse cardiac events, repeat hospital chest pain evaluation, and repeat imaging or stress testing. One year after MPI and hospital discharge, all patients were living and without acute coronary syndrome.
HE-SPECT stress-only imaging can be performed in more than two thirds of chest pain patients without a high pretest probability of a stress perfusion defect, with excellent prognosis, a radiation dose averaging 1 mSv, and a test duration of less than 2 h.
尽管单光子发射计算机断层扫描心肌灌注成像（MPI）可为胸痛患者提供有价值的信息，但人们对其辐射负担和检查时间过长越来越担忧。新型高效（HE）相机和先负荷方案都有可能显著降低辐射剂量。此前尚无研究评估使用超低剂量先负荷方案在HE-SPECT相机上进行MPI检查的患者的检查结果和辐射剂量。
100例因胸痛就诊于急诊科且适合先负荷MPI检查的患者，在负荷高峰时注射约185MBq（5mCi）的（99m）锝-替曲膦，随后在HE-SPECT相机上进行仰卧位和俯卧位成像。负荷成像后有任何异常的患者于同日进行静息成像。根据注入和残留活度计算辐射有效剂量。患者出院后3个月进行随访，并查阅电子记录以评估是否需要因胸痛进行重新评估、额外成像或心脏事件。
69例患者仅进行了负荷成像，其辐射有效剂量平均为0.99mSv，检查时长为117分钟。所有患者的辐射剂量平均为2.22mSv。3个月时，96例患者无重大不良心脏事件、无需重复进行医院胸痛评估以及重复成像或负荷试验。MPI检查及出院后1年，所有患者均存活且无急性冠状动脉综合征。
超过三分之二的胸痛患者可进行HE-SPECT仅负荷成像，这些患者负荷灌注缺损的预检概率不高，预后良好，辐射剂量平均为1mSv，检查时长小于2小时。
