Lyon Morgan C, Foster Courtney, Ding Xinhong, Dorbala Sharmila, Spence Don, Bhattacharya Manojeet, Vija A Hans, DiCarli Marcelo F, Moore Stephen C
Division of Nuclear Medicine, Department of Radiology, Brigham and Women's Hospital, Boston, MA, USA.
Department of Radiology, Harvard Medical School, Boston, MA, USA.
J Nucl Cardiol. 2016 Aug;23(4):657-67. doi: 10.1007/s12350-016-0471-x. Epub 2016 Mar 31.
Recent technological advances in myocardial perfusion imaging may warrant the use of lower injected activity. We evaluated whether quantitative measures of stress myocardial perfusion defects using Tc-99m sestamibi and low-energy high-resolution (LEHR) collimators are equivalent to lower dose SPECT-CT with cardiac multifocal collimators and software (IQ·SPECT).
93 patients underwent one-day rest-stress gated SPECT-CT. Following conventional rest imaging, 925-1100 MBq (25-30 mCi) of Tc-99m sestamibi was injected during stress testing. Stress SPECT-CT images were acquired two ways: with LEHR (13 minutes) and IQ·SPECT (7 minutes). Low-dose IQ·SPECT stress was simulated by subsampling the full-dose data to half-, quarter-, and eighth-count levels. Abnormalities were quantified using the total perfusion deficit (TPD) score and dose-specific databases.
The mean ± SD of the differences between LEHR and IQ·SPECT TPD scores were -1.01 ± 5.36%, -0.10 ± 5.81%, 1.78 ± 4.81%, and 1.75 ± 6.05% at full, half, quarter, and eighth doses, respectively. Differences were statistically significant for quarter and eighth doses. Correlation between LEHR and IQ·SPECT was excellent at all doses (R ≥ 0.93). Bland-Altman plots demonstrated minimal bias.
With IQ·SPECT, quantitative stress SPECT-CT imaging is possible with half of the standard injected activity in half the time.
心肌灌注成像的最新技术进展可能使较低的注射活度成为可能。我们评估了使用锝-99m 甲氧基异丁基异腈和低能高分辨率（LEHR）准直器对负荷心肌灌注缺损进行定量测量是否等同于使用心脏多焦点准直器和软件（IQ·SPECT）的低剂量 SPECT-CT。
93 例患者接受了一日静息-负荷门控 SPECT-CT 检查。在常规静息成像后，负荷试验期间注射 925 - 1100 MBq（25 - 30 mCi）的锝-99m 甲氧基异丁基异腈。负荷 SPECT-CT 图像通过两种方式采集：使用 LEHR（13 分钟）和 IQ·SPECT（7 分钟）。通过将全剂量数据下采样到半计数、四分之一计数和八分之一计数水平来模拟低剂量 IQ·SPECT 负荷。使用总灌注缺损（TPD）评分和特定剂量数据库对异常进行定量。
LEHR 和 IQ·SPECT 的 TPD 评分差异的均值±标准差在全剂量、半剂量、四分之一剂量和八分之一剂量时分别为 -1.01±5.36%、-0.10±5.81%、1.78±4.81%和 1.75±6.05%。四分之一剂量和八分之一剂量时差异具有统计学意义。所有剂量下 LEHR 和 IQ·SPECT 之间的相关性都非常好（R≥0.93）。Bland-Altman 图显示偏差极小。
使用 IQ·SPECT，在一半的时间内用一半的标准注射活度即可进行定量负荷 SPECT-CT 成像。
