Kluge R, Sattler B, Seese A, Knapp W H
Department of Nuclear Medicine, University of Leipzig, Germany.
Eur J Nucl Med. 1997 Sep;24(9):1107-14. doi: 10.1007/BF01254241.
Irregular photon attenuation may limit the diagnostic accuracy of myocardial single-photon emission tomography (SPET). The aim of this study was to quantify the potential benefit of attenuation correction by simultaneous emission and transmission imaging for the detection of coronary artery disease (CAD) of vessels supplying the inferoposterior wall segments. In 25 male patients with >/=50% stenoses of the right coronary artery and/or circumflex artery but without significant narrowing of the left anterior descending artery, stress studies using technetium-99m tetrofosmin (400 MBq) were carried out with and without attenuation correction. A dual-head camera with L-shaped detector positioning was equipped with two scanning gadolinium-153 line sources. Tomograms were reconstructed and quantified using circumferential count rate profiles of myocardial activity (two in each patient). The profiles were compared with the respective normal ranges obtained from a database of 25 male patients with a <10% likelihood of CAD. In patients without CAD, the maximal differences in count density of different wall segments were reduced from 29.0% in non-corrected (NC) studies to 9.5% in attenuation-corrected (AC) studies. In particular, the inferoposterior and septal wall segments were represented by significantly increased relative count densities after attenuation correction. The effects of attenuation correction proved independent of body mass. In patients with CAD, segmental count densities were abnormal in 84% of the NC studies and 100% of the AC studies. In single-vessel disease the stenotic vessel was identified in 66% of cases by NC studies and in 100% by AC studies. In AC studies, the extent and depth of defects exceeded those in NC studies. For the detection of CAD of the right coronary artery, the receiver operating characteristic (ROC) curves relating to the AC studies demonstrated improved discrimination capacity (P<0.05). ROC analysis of CAD detection yielded normalcy rates of 82% (NC) and 94% (AC) for the circumflex artery and 65% (NC) and 97% (AC) for the right coronary artery area at a sensitivity level of 95%. It is concluded that attenuation correction using the above system may enhance the diagnostic accuracy of myocardial SPET when inferoposterior wall segments are to be evaluated.
不规则的光子衰减可能会限制心肌单光子发射断层扫描（SPET）的诊断准确性。本研究的目的是通过同时进行发射和透射成像来量化衰减校正对检测供应下后壁节段血管的冠状动脉疾病（CAD）的潜在益处。在25例右冠状动脉和/或回旋支狭窄≥50%但左前降支无明显狭窄的男性患者中，使用锝-99m替曲膦（400MBq）进行了有无衰减校正的负荷研究。一台配备L形探测器定位的双头相机配备了两个扫描钆-153线源。使用心肌活性的圆周计数率曲线（每位患者两条）对断层图像进行重建和量化。将这些曲线与从CAD可能性<10%的25例男性患者数据库中获得的各自正常范围进行比较。在无CAD的患者中，不同壁节段计数密度的最大差异从未校正（NC）研究中的29.0%降至衰减校正（AC）研究中的9.5%。特别是，衰减校正后下后壁和间隔壁节段的相对计数密度显著增加。衰减校正的效果证明与体重无关。在有CAD的患者中，84%的NC研究和100%的AC研究中节段计数密度异常。在单支血管疾病中，NC研究在66%的病例中识别出狭窄血管，AC研究在100%的病例中识别出狭窄血管。在AC研究中，缺损的范围和深度超过了NC研究。对于右冠状动脉CAD的检测，与AC研究相关的受试者操作特征（ROC）曲线显示出更好的辨别能力（P<0.05）。在95%的敏感性水平下，CAD检测的ROC分析得出回旋支区域的正常率为82%（NC）和94%（AC），右冠状动脉区域为65%（NC）和97%（AC）。结论是，当要评估下后壁节段时，使用上述系统进行衰减校正可能会提高心肌SPET的诊断准确性。
