Bayesian penalised likelihood (BPL) reconstruction, which incorporates point-spread-function (PSF) correction, provides higher signal-to-noise ratios and more accurate quantitation than conventional ordered subset expectation maximization (OSEM) reconstruction. However, applying PSF correction to brain PET imaging is controversial due to Gibbs artefacts that manifest as unpredicted cortical uptake enhancement. The present study aimed to validate whether BPL without PSF would be useful for amyloid PET imaging. Images were acquired from Hoffman 3D brain and cylindrical phantoms for phantom study and 71 patients administered with [18F]flutemetamol in clinical study using a Discovery MI. All images were reconstructed using OSEM, BPL with PSF correction, and BPL without PSF correction. Count profile, %contrast, recovery coefficients (RCs), and image noise were calculated from the images acquired from the phantoms. Amyloid β deposition in patients was visually assessed by two physicians and quantified based on the standardised uptake value ratio (SUVR). The overestimated radioactivity in profile curves was eliminated using BPL without PSF correction. The %contrast and image noise decreased with increasing β values in phantom images. Image quality and RCs were better using BPL with, than without PSF correction or OSEM. An optimal β value of 600 was determined for BPL without PSF correction. Visual evaluation almost agreed perfectly (κ = 0.91–0.97), without depending on reconstruction methods. Composite SUVRs did not significantly differ between reconstruction methods. Gibbs artefacts disappeared from phantom images using the BPL without PSF correction. Visual and quantitative evaluation of [18F]flutemetamol imaging was independent of the reconstruction method. The BPL without PSF correction could be the standard reconstruction method for amyloid PET imaging, despite being qualitatively inferior to BPL with PSF correction for [18F]flutemetamol amyloid PET imaging.

中文翻译：

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淀粉样蛋白 PET 图像中未经 PSF 校正的贝叶斯惩罚似然重建算法 Q.Clear 的模型和临床评估

贝叶斯惩罚似然 (BPL) 重建结合了点扩散函数 (PSF) 校正，与传统的有序子集期望最大化 (OSEM) 重建相比，可提供更高的信噪比和更准确的定量。然而，由于吉布斯伪影表现为不可预测的皮质摄取增强，因此将 PSF 校正应用于大脑 PET 成像存在争议。本研究旨在验证不含 PSF 的 BPL 是否可用于淀粉样蛋白 PET 成像。从 Hoffman 3D 大脑和圆柱形模型获取图像以进行模型研究，并使用 Discovery MI 在临床研究中对 71 名患者施用 [18F]flutemetamol。所有图像均使用 OSEM、带 PSF 校正的 BPL 和不带 PSF 校正的 BPL 重建。根据从体模获取的图像计算计数概况、对比度百分比、恢复系数 (RC) 和图像噪声。两名医生对患者的β淀粉样蛋白沉积进行目视评估，并根据标准化摄取值比（SUVR）进行量化。使用 BPL 消除了剖面曲线中高估的放射性，无需 PSF 校正。随着幻影图像中 β 值的增加，%对比度和图像噪声降低。使用带有 PSF 校正或 OSEM 的 BPL 比不使用 PSF 校正或 OSEM 时的图像质量和 RC 更好。对于没有 PSF 校正的 BPL，确定最佳 β 值为 600。视觉评估几乎完全一致（κ = 0.91–0.97），不依赖于重建方法。复合 SUVR 在重建方法之间没有显着差异。使用未经 PSF 校正的 BPL，吉布斯伪影从幻影图像中消失。 [18F]氟替他莫成像的视觉和定量评估独立于重建方法。不带 PSF 校正的 BPL 可能是淀粉样蛋白 PET 成像的标准重建方法，尽管 [18F]氟替他莫淀粉样蛋白 PET 成像的质量不如带 PSF 校正的 BPL。