Akamatsu Go, Ikari Yasuhiko, Nishio Tomoyuki, Nishida Hiroyuki, Ohnishi Akihito, Aita Kazuki, Sasaki Masahiro, Sasaki Masayuki, Senda Michio
Division of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2, Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan.
Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
Ann Nucl Med. 2016 Jan;30(1):18-28. doi: 10.1007/s12149-015-1024-0. Epub 2015 Sep 4.
The purpose of this study was to optimize image reconstruction conditions for brain (18)F-FDG, (11)C-PiB, (18)F-florbetapir and (18)F-flutemetamol PET imaging with Discovery-690 PET/CT for diagnosis and research on Alzheimer's disease (AD) based on the standard imaging protocols and phantom test procedures and criteria published by the Japanese society of nuclear medicine (JSNM).
A Hoffman 3D brain phantom and a cylindrical pool phantom were scanned according to the JSNM procedure, and the reconstruction conditions (iteration, subset, post-filter) were optimized so that the images satisfy the JSNM criteria regarding spatial resolution (FWHM ≤ 8 mm) and gray/white matter contrast (%contrast ≥ 55%) on the Hoffman phantom and uniformity (SD of small ROIs ≤ 0.0249) and image noise (coefficient of variation ≤ 15 %) on the pool phantom. Human images were acquired with (18)F-FDG (15-min scan starting at 30 min post-injection [p.i.] of 185 MBq), (11)C-PiB (20-min scan starting at 50 min p.i. of 555 MBq), (18)F-florbetapir (10-min scan starting at 50 min p.i. of 370 MBq) and (18)F-flutemetamol (30-min scan starting at 90 min p.i. of 185 MBq) on 1 or 2 subjects for each tracer and reconstructed with thus determined conditions to evaluate the image quality visually. The effect of reconstruction parameters on the standardized uptake value ratio (SUVR) was also evaluated on 5 amyloid-positive and 5 amyloid-negative PiB images.
A sufficient image quality was obtained at an iterative update (product of iteration and subset) of 64 for (18)F-FDG. The same reconstruction parameters with an additional Gaussian filter of 5 mm FWHM was optimal for (11)C-PiB, (18)F-florbetapir and (18)F-flutemetamol to achieve the phantom criteria. Those optimal reconstruction conditions were confirmed with human images. The SUVR value was stable over a wide range of iterative updates around the optimal parameters both for positive and negative amyloid images.
Optimal image reconstruction conditions were determined for brain (18)F-FDG and amyloid PET imaging with Discovery-690 PET/CT for diagnosis and research on AD based on the JSNM phantom criteria. This supports feasibility of the phantom criteria for standardization and harmonization of brain (18)F-FDG and amyloid PET for multicenter studies.
本研究旨在基于日本核医学协会（JSNM）发布的标准成像方案、体模测试程序及标准，优化Discovery - 690 PET/CT对脑部（18）F - FDG、（11）C - PiB、（18）F - florbetapir和（18）F - flutemetamol进行PET成像的图像重建条件，用于阿尔茨海默病（AD）的诊断与研究。
根据JSNM程序对Hoffman 3D脑体模和圆柱形水池体模进行扫描，并优化重建条件（迭代次数、子集数、后置滤波），以使图像满足关于Hoffman体模的空间分辨率（半高宽≤8 mm）和灰质/白质对比度（对比度%≥55%）以及关于水池体模的均匀性（小感兴趣区的标准差≤0.0249）和图像噪声（变异系数≤15%）的JSNM标准。对1或2名受试者分别使用（18）F - FDG（注射185 MBq后30分钟开始进行15分钟扫描）、（11）C - PiB（注射555 MBq后50分钟开始进行20分钟扫描）、（18）F - florbetapir（注射370 MBq后50分钟开始进行10分钟扫描）和（18）F - flutemetamol（注射185 MBq后90分钟开始进行30分钟扫描）采集人体图像，并使用确定的条件进行重建，以视觉方式评估图像质量。还对5例淀粉样蛋白阳性和5例淀粉样蛋白阴性的PiB图像评估了重建参数对标准化摄取值比率（SUVR）的影响。
对于（18）F - FDG，在迭代更新次数（迭代次数与子集数的乘积）为64时可获得足够的图像质量。对于（11）C - PiB、（18）F - florbetapir和（18）F - flutemetamol，相同的重建参数外加5 mm半高宽的高斯滤波器是达到体模标准的最佳选择。这些最佳重建条件在人体图像中得到了证实。对于阳性和阴性淀粉样蛋白图像，在最佳参数周围的广泛迭代更新范围内，SUVR值均稳定。
基于JSNM体模标准，确定了Discovery - 690 PET/CT对脑部（18）F - FDG和淀粉样蛋白PET成像用于AD诊断与研究的最佳图像重建条件。这支持了体模标准在多中心研究中对脑部（18）F - FDG和淀粉样蛋白PET进行标准化和协调的可行性。
