Daou D, Delahaye N, Lebtahi R, Vilain D, Peker C, Faraggi M, Le Guludec D
Nuclear Medicine Department, Bichat University Hospital, Paris, France.
J Nucl Med. 2000 Apr;41(4):567-74.
Exercise lung 201 TI uptake calculated with planar imaging has an important diagnostic and prognostic value in patients with coronary artery disease (CAD). However, its value with SPECT imaging raises methodological concerns and is controversial. We studied its value for the discrimination between extensive (E) and limited (L) angiographic CAD with exercise SPECT.
Four methods of lung-to-heart ratio quantification were calculated in patients with a low likelihood (< 5%) of CAD (n = 62). Their dependent variables were defined, and corresponding correction equations were derived. Receiver operating characteristic (ROC) analysis was performed in a pilot group (L-CAD, n = 49; E-CAD, n = 126) to define the optimal method of calculation of the lung-to-heart ratio. Its best threshold providing the best sensitivity for a specificity of 90% was defined. After correction for dependent variables, the 4 methods were also compared by ROC analysis and the optimal corrected method was compared with the optimal uncorrected method using ROC analysis and the best threshold. The consistency of these results in the validation group (L-CAD, n = 41; E-CAD, n = 122) and of the results of visual analysis of lung 201TI uptake were then verified.
On ROC analysis in the pilot group, the optimal method of calculation of the lung-to-heart ratio was the mean activity in a region of interest drawn at the base of the lungs to the mean activity over the heart (Lb/H). For the best threshold, Lb/H presented a sensitivity of 34%. Corrected Lb/H still remained the best method of calculation on ROC analysis compared with the other corrected methods. On ROC analysis, there was no difference between corrected and uncorrected Lb/H. For the best threshold, corrected Lb/H presented a similar sensitivity of 37% compared with uncorrected Lb/H. When applied to the validation group (L-CAD, n = 41; E-CAD, n = 122), the best-defined threshold in the pilot group for corrected Lb/H presented a diagnostic value similar to that in the pilot group (sensitivity, 41%; specificity, 90%), but uncorrected Lb/H presented a higher sensitivity (47%; P < 0.04) and a slightly lower specificity (80%). Results of lung 201TI uptake visual analysis were inconsistent between pilot and validation groups (42% versus 58% sensitivity, P = 0.012; 86% versus 66% specificity, P = 0.023).
For evaluation of E-CAD versus L-CAD, quantification of the exercise lung-to-heart 201TI uptake ratio with SPECT is feasible, reproducible, more discriminate than simple visual analysis, and best calculated as Lb/H. It presents an intrinsic diagnostic value even after correction for other clinically valuable dependent variables.
采用平面显像计算的运动时肺201铊摄取量在冠心病（CAD）患者中具有重要的诊断和预后价值。然而，其在单光子发射计算机断层显像（SPECT）成像中的价值引发了方法学上的关注且存在争议。我们研究了运动SPECT对广泛（E）和局限性（L）血管造影CAD的鉴别价值。
在CAD可能性低（<5%）的患者（n = 62）中计算了四种肺心比定量方法。定义了它们的因变量，并推导了相应的校正方程。在一个试验组（L-CAD，n = 49；E-CAD，n = 126）中进行了受试者操作特征（ROC）分析，以确定计算肺心比的最佳方法。定义了其在特异性为90%时提供最佳敏感性的最佳阈值。在校正因变量后，还通过ROC分析比较了这四种方法，并使用ROC分析和最佳阈值将最佳校正方法与最佳未校正方法进行比较。然后在验证组（L-CAD，n = 41；E-CAD，n = 122）中验证了这些结果的一致性以及肺201铊摄取视觉分析结果的一致性。
在试验组的ROC分析中，计算肺心比的最佳方法是在肺底部绘制的感兴趣区域的平均活性与心脏平均活性之比（Lb/H）。对于最佳阈值，Lb/H的敏感性为34%。与其他校正方法相比，校正后的Lb/H在ROC分析中仍是最佳计算方法。在ROC分析中，校正和未校正的Lb/H之间没有差异。对于最佳阈值，校正后的Lb/H与未校正的Lb/H相比，敏感性相似，为37%。当应用于验证组（L-CAD，n = 41；E-CAD，n = 122）时，试验组中校正后Lb/H的最佳定义阈值显示出与试验组相似的诊断价值（敏感性，41%；特异性，90%），但未校正的Lb/H具有更高的敏感性（47%；P < 0.04）和略低的特异性（80%）。试验组和验证组之间肺201铊摄取视觉分析结果不一致（敏感性分别为42%对58%，P = 0.012；特异性分别为86%对66%，P = 0.023）。
对于评估E-CAD与L-CAD，采用SPECT定量运动时肺心201铊摄取比是可行的、可重复的，比简单的视觉分析更具鉴别力，并且以Lb/H计算最佳。即使在校正因其他具有临床价值的因变量后，它仍具有内在的诊断价值。
