Nakaya Koji, Onoguchi Masahisa, Nishimura Yoshihiro, Kiso Keisuke, Otsuka Hideki, Nouno Yoshifumi, Shibutani Takayuki, Yasuda Eisuke
aDepartment of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa bDepartment of Radiological Technology, Faculty of Health Science, Suzuka University of Medical Science, Suzuka City cDepartment of Radiology and Nuclear Medicine, National Cerebral and Cardiovascular Center Hospital, Suita dDepartment of Medical Imaging/Nuclear Medicine, Tokushima University Graduate School, Tokushima, Japan.
Nucl Med Commun. 2017 Sep;38(9):748-755. doi: 10.1097/MNM.0000000000000713.
Myocardial perfusion single-photon emission computed tomography (SPECT) is occasionally suspected to generate images that represent either ischemia or infarction for the inferior wall [right coronary artery (RCA) disease] or attenuation artifacts because of the diaphragm. We often encounter this. The application of prone imaging is advantageous in the differentiation of RCA disease because of attenuation artifacts. If decreased accumulation of radioisotopes is observed at the site with either RCA disease or attenuation artifacts, then a criterion that enables the addition of prone imaging should be implemented. Then, we evaluated sites where RCA disease and attenuation artifacts would likely appear and investigated the threshold of decreased accumulation that enables utilization of prone imaging.
The patients in this study were divided into two groups: group A (20 patients) suspected to have attenuation artifacts because of the diaphragm and group B (14 patients) with RCA disease. Additional evaluation by prone imaging was performed in all patients. We utilized a 20-segment quantitative perfusion SPECT polar map in the supine and prone positions to compare the percentage increase in Thallium chloride (Tl) in both groups. We then investigated the percent uptake (%uptake) value of decreased accumulation in the inferior wall for the addition of prone imaging.
The highest %uptake was present in segments 3, 4, 5, and 10 in group A after the prone imaging. Detection of attenuation artifacts from the diaphragm was easy in segments 3, 4, 5, and 10, and we set the %uptake threshold at 62, 61, 71, and 76%, respectively, in the supine position for the addition of prone imaging.
A decrease of the %uptake in segments 3, 4, 5, and 10 after supine imaging is presumed to result from attenuation artifact or RCA disease. We established evaluation criteria for the addition of prone imaging in patients with decreased accumulation in the inferior wall during supine imaging.
心肌灌注单光子发射计算机断层扫描（SPECT）偶尔会被怀疑生成代表下壁（右冠状动脉病变）缺血或梗死的图像，或者由于膈肌导致衰减伪影。我们经常遇到这种情况。俯卧位成像的应用在鉴别因衰减伪影导致的右冠状动脉病变方面具有优势。如果在右冠状动脉病变或衰减伪影部位观察到放射性同位素积聚减少，那么应该实施一个能够增加俯卧位成像的标准。然后，我们评估了右冠状动脉病变和衰减伪影可能出现的部位，并研究了能够利用俯卧位成像的放射性同位素积聚减少的阈值。
本研究中的患者分为两组：A组（20例患者）怀疑因膈肌导致衰减伪影，B组（14例患者）患有右冠状动脉病变。所有患者均进行了俯卧位成像的额外评估。我们使用仰卧位和俯卧位的20节段定量灌注SPECT极坐标图来比较两组中氯化铊（Tl）的增加百分比。然后，我们研究了下壁放射性同位素积聚减少时用于增加俯卧位成像的摄取百分比（%摄取）值。
A组在俯卧位成像后，第3、4、5和10节段的%摄取最高。在第3、4、5和10节段很容易检测到来自膈肌的衰减伪影，对于增加俯卧位成像，我们在仰卧位分别将%摄取阈值设定为62%、61%、71%和76%。
仰卧位成像后第3、4、5和10节段%摄取的降低被认为是由衰减伪影或右冠状动脉病变导致的。我们为仰卧位成像时下壁放射性同位素积聚减少的患者建立了增加俯卧位成像的评估标准。
