Farag Ayman A, Heo Jack, Tauxe Lindsey, Bhambhvani Pradeep, Germano Guido, Kavanagh Paul, Iskandrian Ami E, Hage Fadi G
Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Lyons Harrison Research building 306, 1900 University BLVD, Birmingham, AL, 35294, USA.
Division of Molecular Imaging and Therapeutics, Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, USA.
J Nucl Cardiol. 2019 Feb;26(1):266-271. doi: 10.1007/s12350-017-0954-4. Epub 2017 Jul 6.
In patients with right dominant coronary circulation, the right ventricular (RV) myocardium and the inferior region of the left ventricular (LV) myocardium share a common source of blood flow. We hypothesized that stress/rest SPECT myocardial perfusion imaging (MPI) could detect reversible perfusion defects in the RV in some patients with LV inferior wall perfusion abnormalities.
We identified 2 groups of patients with LV inferior wall perfusion defects (with or without defects in other regions of LV myocardium) from our database. Patients in group 1 (n = 17) had reversible perfusion defects in the RV free wall by visual analysis, while patients in group 2 (n = 17) did not. The images were processed with filtered back projection and, separately, with iterative reconstruction. The images were then re-processed using an automated quantitative software that is specifically designed to include the RV in the region of interest.
There were 76% men in group 1 and 94% in group 2 (P <0.05). The mean age was 65±20 in group 1 vs. 63±18 years in group 2 (P < 0.05). The stress type was exercise in 30% in group 1 and 35% in group 2, with the remaining patients studied with pharmacological stress testing (P = NS). The presence of RV reversible perfusion defects using filtered back projection was more evident in 13 patients (75%), while it was better seen with iterative reconstruction in 4 patients (25%). By automated analysis, the RV reversible perfusion defect size was 19 ± 14% of RV myocardium.
This proof-of-principle study demonstrates that reversible RV perfusion defects suggestive of ischemia can be detected by SPECT myocardial perfusion imaging in some patients with LV inferior ischemia by visual analysis and can be quantitated by automated programs. Further studies on the diagnostic and prognostic relevance of assessing RV ischemia on SPECT MPI are needed.
在右冠状动脉优势型循环的患者中，右心室（RV）心肌和左心室（LV）心肌下壁区域共享一个共同的血流来源。我们假设，静息/负荷单光子发射计算机断层扫描心肌灌注成像（MPI）可以在一些左心室下壁灌注异常的患者中检测到右心室的可逆性灌注缺损。
我们从数据库中识别出两组左心室下壁灌注缺损的患者（左心室心肌其他区域有无缺损）。第1组患者（n = 17）通过视觉分析在右心室游离壁有可逆性灌注缺损，而第2组患者（n = 17）则没有。图像分别采用滤波反投影法和迭代重建法进行处理。然后使用专门设计用于将右心室纳入感兴趣区域的自动定量软件对图像进行重新处理。
第1组男性占76%，第2组男性占94%（P <0.05）。第1组的平均年龄为65±20岁，第2组为63±18岁（P <0.05）。第1组30%的患者和第2组35%的患者采用运动负荷试验，其余患者采用药物负荷试验（P = 无显著性差异）。使用滤波反投影法时，13例患者（75%）右心室可逆性灌注缺损更明显，而采用迭代重建法时，4例患者（25%）更易观察到。通过自动分析，右心室可逆性灌注缺损大小为右心室心肌的19±14%。
这项原理验证研究表明，通过视觉分析，单光子发射计算机断层扫描心肌灌注成像可以在一些左心室下壁缺血的患者中检测到提示缺血的右心室可逆性灌注缺损，并且可以通过自动程序进行定量分析。需要进一步研究评估单光子发射计算机断层扫描心肌灌注成像上右心室缺血的诊断和预后相关性。
