Lupi Andrea, Zaroccolo Marta, Salgarello Matteo, Malfatti Veronica, Zanco Pierluigi
Division of Nuclear Medicine, Ospedale "S. Bortolo,", Via M. Rodolfi, 36100 Vicenza, Italy.
Ann Nucl Med. 2009 Feb;23(2):191-6. doi: 10.1007/s12149-008-0225-1. Epub 2009 Feb 19.
Respiratory gated PET/CT (positron emission tomography/computed tomography) of the lung is expected to increase the accuracy of quantitative determinations in lesional activities, regardless of the gating method used; reasonably, respiratory gating should increase standard uptake value (SUV; and possibly decrease lesional size), on the basis of the reduction of the "smearing effect." However, literature data are very limited, particularly for in vivo studies. The objective of this article is to test the SUV variations in a large group of lung lesion studies.
A group of 26 consecutive positive studies (21 men, 5 women, age 36-84, mean 68), performed on patients referred to our institution for known or suspected lung cancer, are examined. All studies were performed both with conventional PET/CT total body scan and with Real-Time Position Management (RPM) triggered selective gated study of the thorax. Four studies were considered technically unsatisfactory and were discarded; the remaining 22 studies are the object of this work. Max lesional SUVs were evaluated in both settings by semi-automated algorithms; for the gated studies, both values of the bin that showed more relevant variations from the clinical routinary study ("best bin") and an average value that was calculated over all bins were determined. Results were compared on a one-to-one basis.
In conventional, SUV showed a mean +/- standard deviation (SD) value of 9.2 +/- 6.9 (range 0.9-26). In the averaged gated studies, the mean +/- SD value was 13.4 +/- 11.7 (range 1.4-47); in the "best bin" dataset the mean +/- SD was 14.9 +/- 12.9, ranging from 1.6 to 53.1. In general, the use of respiratory trigger induced rather variable but overall consistent increases in SUV. If the percentage variations in the average trigger dataset are considered, there is an average increase of +60%, SD +/- 97 (P < 0.05). Similar results are found in the "best bin" dataset, the average percentage increase in SUV values being +77.2% (SD +/- 04.6).
In lung cancer, triggering procedures increase the signal to noise ratio. The increase in SUV determined by gating is very variable, but generally relevant. This could lead to an SUV values cut-off revision, and may have an impact on smaller lesions detection.
无论采用何种门控方法，肺部呼吸门控正电子发射断层扫描/计算机断层扫描（PET/CT）有望提高病变活动定量测定的准确性；合理地讲，基于“涂抹效应”的减少，呼吸门控应会增加标准摄取值（SUV），并可能减小病变大小。然而，文献数据非常有限，尤其是关于体内研究的。本文的目的是在一大组肺部病变研究中测试SUV的变化情况。
对一组连续的26项阳性研究（21名男性，5名女性，年龄36 - 84岁，平均68岁）进行检查，这些研究是针对因已知或疑似肺癌转诊至本机构的患者进行的。所有研究均进行了常规PET/CT全身扫描以及实时位置管理（RPM）触发的胸部选择性门控研究。4项研究在技术上被认为不满意而被舍弃；其余22项研究是本工作的对象。通过半自动算法在两种情况下评估最大病变SUV；对于门控研究，确定了与临床常规研究相比显示出更显著变化的区间的值（“最佳区间”）以及所有区间计算出的平均值。结果进行一对一比较。
在常规扫描中，SUV的均值±标准差（SD）为9.2±6.9（范围0.9 - 26）。在平均门控研究中，均值±SD为13.4±11.7（范围1.4 - 47）；在“最佳区间”数据集中，均值±SD为14.9±12.9，范围为1.6至53.1。总体而言，呼吸触发的使用导致SUV有相当大的变化但总体上是一致的增加。如果考虑平均触发数据集中的百分比变化，SUV平均增加60%，标准差±97（P < 0.05）。在“最佳区间”数据集中也发现了类似结果，SUV值的平均百分比增加为77.2%（标准差±04.6）。
在肺癌中，触发程序提高了信噪比。门控确定的SUV增加非常多变，但通常较为显著。这可能导致SUV值截断值的修订，并可能对较小病变的检测产生影响。
