Impact of point spread function modelling and time of flight on FDG uptake measurements in lung lesions using alternative filtering strategies.
Impact of point spread function modelling and time of flight on FDG uptake measurements in lung lesions using alternative filtering strategies.
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DOI：
10.1186/s40658-014-0099-3
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发表时间：
2014-12
期刊：
影响因子：
4
通讯作者：
Matthews JC
中科院分区：
文献类型：
--
作者：
Armstrong IS;Kelly MD;Williams HA;Matthews JC
最大标准化摄取值（SUVmax）的使用在肿瘤学正电子发射断层扫描（PET）中很常见。点扩散函数（PSF）建模和飞行时间（TOF）重建对SUVmax有重大影响，这对具有基于SUVmax阈值的病变分类定义协议的中心提出了挑战。这可能导致了这些重建的缓慢采用。本研究评估了两种不同后过滤方案下PSF和/或TOF重建对SUVmax、SUVpeak和总病灶糖酵解（TLG）的影响。使用NEMA NU-2模体确定匹配体素方差或SUVmax的后滤镜。采用标准迭代算法和TOF对68例连续肺癌患者的图像进行重建；PSF建模-西门子HD·PET (HD)；并结合PSF建模和TOF - Siemens超高清·PET （UHD）与两组后滤波器。每组重建74个病灶，测量其SUVmax、SUVpeak、TLG和肿瘤相对于肝脏的信噪比（SNR(T-L)）。计算摄取措施的相对差异，并使用已发表的指南和当地实践评估任何变化的临床影响。当匹配体素方差时，SUVmax显著增加（HD和UHD分别平均增加+32%和+49%），这可能影响大多数患者的预后。SUVpeak的增加不那么显著（HD和UHD分别平均增加17%和23%）。两种方法单独使用TOF的增幅都要小得多。两组后滤镜的所有算法对TLG的平均变化均<10%。在使用两种后滤波集的所有重建中，信噪比（T-L）大于有序子集期望最大化（OSEM）。将图像体素方差与PSF和/或TOF重建相匹配，特别是与PSF建模和小病变相匹配，会导致SUVmax显著增加，从而抑制了基于SUVmax的病变分类的定义方案的使用。然而，减少部分体积效应可能会增加病变的可检出性。在幻影中匹配SUVmax很好地转化为PSF重建的患者研究，但在TOF中不太好，在患者图像中观察到小的正偏倚。匹配SUVmax显著降低了体素方差和潜在的变化性。最后，与SUVmax或SUVpeak相比，TLG可能对重建方法不太敏感。本文的在线版本（doi:10.1186/s40658-014-0099-3）包含补充材料，可供授权用户使用。
The use of maximum standardised uptake value (SUVmax) is commonplace in oncology positron emission tomography (PET). Point spread function (PSF) modelling and time-of-flight (TOF) reconstructions have a significant impact on SUVmax, presenting a challenge for centres with defined protocols for lesion classification based on SUVmax thresholds. This has perhaps led to the slow adoption of these reconstructions. This work evaluated the impact of PSF and/or TOF reconstructions on SUVmax, SUVpeak and total lesion glycolysis (TLG) under two different schemes of post-filtering. Post-filters to match voxel variance or SUVmax were determined using a NEMA NU-2 phantom. Images from 68 consecutive lung cancer patients were reconstructed with the standard iterative algorithm along with TOF; PSF modelling - Siemens HD·PET (HD); and combined PSF modelling and TOF - Siemens ultraHD·PET (UHD) with the two post-filter sets. SUVmax, SUVpeak, TLG and signal-to-noise ratio of tumour relative to liver (SNR(T-L)) were measured in 74 lesions for each reconstruction. Relative differences in uptake measures were calculated, and the clinical impact of any changes was assessed using published guidelines and local practice. When matching voxel variance, SUVmax increased substantially (mean increase +32% and +49% for HD and UHD, respectively), potentially impacting outcome in the majority of patients. Increases in SUVpeak were less notable (mean increase +17% and +23% for HD and UHD, respectively). Increases with TOF alone were far less for both measures. Mean changes to TLG were <10% for all algorithms for either set of post-filters. SNR(T-L) were greater than ordered subset expectation maximisation (OSEM) in all reconstructions using both post-filtering sets. Matching image voxel variance with PSF and/or TOF reconstructions, particularly with PSF modelling and in small lesions, resulted in considerable increases in SUVmax, inhibiting the use of defined protocols for lesion classification based on SUVmax. However, reduced partial volume effects may increase lesion detectability. Matching SUVmax in phantoms translated well to patient studies for PSF reconstruction but less well with TOF, where a small positive bias was observed in patient images. Matching SUVmax significantly reduced voxel variance and potential variability of uptake measures. Finally, TLG may be less sensitive to reconstruction methods compared with either SUVmax or SUVpeak. The online version of this article (doi:10.1186/s40658-014-0099-3) contains supplementary material, which is available to authorized users.