Pub Date : 2024-01-30DOI: 10.1186/s13550-024-01072-y
Rajat Vashistha, Hamed Moradi, Amanda Hammond, Kieran O'Brien, Axel Rominger, Hasan Sari, Kuangyu Shi, Viktor Vegh, David Reutens
Background: The indirect method for generating parametric images in positron emission tomography (PET) involves the acquisition and reconstruction of dynamic images and temporal modelling of tissue activity given a measured arterial input function. This approach is not robust, as noise in each dynamic image leads to a degradation in parameter estimation. Direct methods incorporate into the image reconstruction step both the kinetic and noise models, leading to improved parametric images. These methods require extensive computational time and large computing resources. Machine learning methods have demonstrated significant potential in overcoming these challenges. But they are limited by the requirement of a paired training dataset. A further challenge within the existing framework is the use of state-of-the-art arterial input function estimation via temporal arterial blood sampling, which is an invasive procedure, or an additional magnetic resonance imaging (MRI) scan for selecting a region where arterial blood signal can be measured from the PET image. We propose a novel machine learning approach for reconstructing high-quality parametric brain images from histoimages produced from time-of-flight PET data without requiring invasive arterial sampling, an MRI scan, or paired training data from standard field-of-view scanners.
Result: The proposed is tested on a simulated phantom and five oncological subjects undergoing an 18F-FDG-PET scan of the brain using Siemens Biograph Vision Quadra. Kinetic parameters set in the brain phantom correlated strongly with the estimated parameters (K1, k2 and k3, Pearson correlation coefficient of 0.91, 0.92 and 0.93) and a mean squared error of less than 0.0004. In addition, our method significantly outperforms (p < 0.05, paired t-test) the conventional nonlinear least squares method in terms of contrast-to-noise ratio. At last, the proposed method was found to be 37% faster than the conventional method.
Conclusion: We proposed a direct non-invasive DL-based reconstruction method and produced high-quality parametric maps of the brain. The use of histoimages holds promising potential for enhancing the estimation of parametric images, an area that has not been extensively explored thus far. The proposed method can be applied to subject-specific dynamic PET data alone.
背景:正电子发射断层扫描(PET)中生成参数图像的间接方法涉及动态图像的采集和重建,以及根据测得的动脉输入函数对组织活动进行时间建模。这种方法并不稳健,因为每幅动态图像中的噪声都会导致参数估计的下降。直接方法将动力学模型和噪声模型纳入图像重建步骤,从而改进了参数图像。这些方法需要大量的计算时间和计算资源。机器学习方法在克服这些挑战方面已显示出巨大潜力。但这些方法受到配对训练数据集要求的限制。现有框架面临的另一个挑战是通过时间动脉血取样来估算最先进的动脉输入功能,这是一种侵入性程序,或者需要额外的磁共振成像(MRI)扫描,以便从 PET 图像中选择可以测量动脉血信号的区域。我们提出了一种新颖的机器学习方法,用于从飞行时间 PET 数据生成的组织图像重建高质量的参数脑图像,而无需侵入性动脉采样、核磁共振成像扫描或来自标准视场扫描仪的成对训练数据:使用西门子 Biograph Vision Quadra 对模拟模型和五名肿瘤受试者进行了脑部 18F-FDG-PET 扫描测试。在大脑模型中设定的动力学参数与估计参数(K1、k2 和 k3,皮尔逊相关系数分别为 0.91、0.92 和 0.93)密切相关,平均平方误差小于 0.0004。此外,我们的方法明显优于其他方法(p 结论:我们的方法是最有效的:我们提出了一种基于 DL 的直接无创重建方法,并绘制了高质量的大脑参数图。组织图像的使用在增强参数图像的估计方面具有广阔的前景,而这一领域迄今为止尚未得到广泛探索。所提出的方法可单独应用于特定受试者的动态 PET 数据。
{"title":"ParaPET: non-invasive deep learning method for direct parametric brain PET reconstruction using histoimages.","authors":"Rajat Vashistha, Hamed Moradi, Amanda Hammond, Kieran O'Brien, Axel Rominger, Hasan Sari, Kuangyu Shi, Viktor Vegh, David Reutens","doi":"10.1186/s13550-024-01072-y","DOIUrl":"10.1186/s13550-024-01072-y","url":null,"abstract":"<p><strong>Background: </strong>The indirect method for generating parametric images in positron emission tomography (PET) involves the acquisition and reconstruction of dynamic images and temporal modelling of tissue activity given a measured arterial input function. This approach is not robust, as noise in each dynamic image leads to a degradation in parameter estimation. Direct methods incorporate into the image reconstruction step both the kinetic and noise models, leading to improved parametric images. These methods require extensive computational time and large computing resources. Machine learning methods have demonstrated significant potential in overcoming these challenges. But they are limited by the requirement of a paired training dataset. A further challenge within the existing framework is the use of state-of-the-art arterial input function estimation via temporal arterial blood sampling, which is an invasive procedure, or an additional magnetic resonance imaging (MRI) scan for selecting a region where arterial blood signal can be measured from the PET image. We propose a novel machine learning approach for reconstructing high-quality parametric brain images from histoimages produced from time-of-flight PET data without requiring invasive arterial sampling, an MRI scan, or paired training data from standard field-of-view scanners.</p><p><strong>Result: </strong>The proposed is tested on a simulated phantom and five oncological subjects undergoing an 18F-FDG-PET scan of the brain using Siemens Biograph Vision Quadra. Kinetic parameters set in the brain phantom correlated strongly with the estimated parameters (K<sub>1</sub>, k<sub>2</sub> and k<sub>3</sub>, Pearson correlation coefficient of 0.91, 0.92 and 0.93) and a mean squared error of less than 0.0004. In addition, our method significantly outperforms (p < 0.05, paired t-test) the conventional nonlinear least squares method in terms of contrast-to-noise ratio. At last, the proposed method was found to be 37% faster than the conventional method.</p><p><strong>Conclusion: </strong>We proposed a direct non-invasive DL-based reconstruction method and produced high-quality parametric maps of the brain. The use of histoimages holds promising potential for enhancing the estimation of parametric images, an area that has not been extensively explored thus far. The proposed method can be applied to subject-specific dynamic PET data alone.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11374951/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139575374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-25DOI: 10.1186/s13550-024-01068-8
Sheng Bi, Shaozhen Yan, Zhigeng Chen, Bixiao Cui, Yi Shan, Hongwei Yang, Zhigang Qi, Zhilian Zhao, Ying Han, Jie Lu
Background: Developing biomarkers for early stage AD patients is crucial. Glucose metabolism measured by 18F-FDG PET is the most common biomarker for evaluating cellular energy metabolism to diagnose AD. Arterial spin labeling (ASL) MRI can potentially provide comparable diagnostic information to 18F-FDG PET in patients with neurodegenerative disorders. However, the conclusions about the diagnostic performance of AD are still controversial between 18F-FDG PET and ASL. This study aims to compare quantitative cerebral blood flow (CBF) and glucose metabolism measured by 18F-FDG PET diagnostic values in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) using integrated PET/MR.
Results: Analyses revealed overlapping between decreased regional rCBF and 18F-FDG PET SUVR in patients with AD compared with NC participants in the bilateral parietotemporal regions, frontal cortex, and cingulate cortex. Compared with NC participants, patients with aMCI exclusively demonstrated lower 18F-FDG PET SUVR in the bilateral temporal cortex, insula cortex, and inferior frontal cortex. Comparison of the rCBF in patients with aMCI and NC participants revealed no significant difference (P > 0.05). The ROC analysis of rCBF in the meta-ROI could diagnose patients with AD (AUC, 0.87) but not aMCI (AUC, 0.61). The specificity of diagnosing aMCI has been improved to 75.56% when combining rCBF and 18F-FDG PET SUVR.
Conclusion: ASL could detect similar aberrant patterns of abnormalities compared to 18F-FDG PET in patients with AD compared with NC participants but not in aMCI. The diagnostic efficiency of 18F-FDG-PET for AD and aMCI patients remained higher to ASL. Our findings support that applying 18F-FDG PET may be preferable for diagnosing AD and aMCI.
背景:为早期注意力缺失症患者开发生物标志物至关重要。18F-FDG PET 测量的葡萄糖代谢是评估细胞能量代谢的最常见生物标记物,可用于诊断注意力缺失症。动脉自旋标记(ASL)核磁共振成像可为神经退行性疾病患者提供与 18F-FDG PET 相当的诊断信息。然而,18F-FDG PET 和 ASL 对 AD 诊断性能的结论仍存在争议。本研究旨在比较 18F-FDG PET 对阿尔茨海默病(AD)和失智性轻度认知障碍(aMCI)患者的定量脑血流(CBF)和葡萄糖代谢的诊断价值:分析显示,与NC参与者相比,AD患者双侧顶颞区、额叶皮层和扣带皮层的区域rCBF和18F-FDG PET SUVR下降有重叠。与 NC 参与者相比,aMCI 患者的双侧颞叶皮质、岛叶皮质和下额叶皮质的 18F-FDG PET SUVR 均较低。对 aMCI 患者和 NC 参与者的 rCBF 进行比较后发现,两者没有显著差异(P > 0.05)。在元ROI中,rCBF的ROC分析可以诊断出AD患者(AUC,0.87),但不能诊断出aMCI患者(AUC,0.61)。结合 rCBF 和 18F-FDG PET SUVR,诊断 aMCI 的特异性提高到 75.56%:结论:与 18F-FDG PET 相比,ASL 能检测出 AD 患者与 NC 参与者相似的异常模式,但不能检测出 aMCI。18F-FDG-PET对AD和aMCI患者的诊断效率仍然高于ASL。我们的研究结果支持应用18F-FDG PET诊断AD和aMCI。
{"title":"Comparison of <sup>18</sup>F-FDG PET and arterial spin labeling MRI in evaluating Alzheimer's disease and amnestic mild cognitive impairment using integrated PET/MR.","authors":"Sheng Bi, Shaozhen Yan, Zhigeng Chen, Bixiao Cui, Yi Shan, Hongwei Yang, Zhigang Qi, Zhilian Zhao, Ying Han, Jie Lu","doi":"10.1186/s13550-024-01068-8","DOIUrl":"10.1186/s13550-024-01068-8","url":null,"abstract":"<p><strong>Background: </strong>Developing biomarkers for early stage AD patients is crucial. Glucose metabolism measured by <sup>18</sup>F-FDG PET is the most common biomarker for evaluating cellular energy metabolism to diagnose AD. Arterial spin labeling (ASL) MRI can potentially provide comparable diagnostic information to <sup>18</sup>F-FDG PET in patients with neurodegenerative disorders. However, the conclusions about the diagnostic performance of AD are still controversial between <sup>18</sup>F-FDG PET and ASL. This study aims to compare quantitative cerebral blood flow (CBF) and glucose metabolism measured by <sup>18</sup>F-FDG PET diagnostic values in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) using integrated PET/MR.</p><p><strong>Results: </strong>Analyses revealed overlapping between decreased regional rCBF and <sup>18</sup>F-FDG PET SUVR in patients with AD compared with NC participants in the bilateral parietotemporal regions, frontal cortex, and cingulate cortex. Compared with NC participants, patients with aMCI exclusively demonstrated lower <sup>18</sup>F-FDG PET SUVR in the bilateral temporal cortex, insula cortex, and inferior frontal cortex. Comparison of the rCBF in patients with aMCI and NC participants revealed no significant difference (P > 0.05). The ROC analysis of rCBF in the meta-ROI could diagnose patients with AD (AUC, 0.87) but not aMCI (AUC, 0.61). The specificity of diagnosing aMCI has been improved to 75.56% when combining rCBF and <sup>18</sup>F-FDG PET SUVR.</p><p><strong>Conclusion: </strong>ASL could detect similar aberrant patterns of abnormalities compared to <sup>18</sup>F-FDG PET in patients with AD compared with NC participants but not in aMCI. The diagnostic efficiency of <sup>18</sup>F-FDG-PET for AD and aMCI patients remained higher to ASL. Our findings support that applying <sup>18</sup>F-FDG PET may be preferable for diagnosing AD and aMCI.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10811308/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139546078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.1186/s13550-024-01067-9
Yong-Il Kim, Seung Hak Lee, Jin Hwa Jung, Seog-Young Kim, Nare Ko, Sang Ju Lee, Seung Jun Oh, Jin-Sook Ryu, Dabin Ko, Won Kim, Kyunggon Kim
Background: The increased expression of the nicotinic acetylcholine receptor (nAChR) in muscle denervation is thought to be associated with electrophysiological acetylcholine supersensitivity after nerve injury. Hence, we investigated the utility of the 18F-ASEM alpha7-nAChR targeting radiotracer as a new diagnostic method by visualizing skeletal muscle denervation in mouse models of sciatic nerve injury.
Methods: Ten-week-old C57BL/6 male mice were utilized. The mice were anesthetized, and the left sciatic nerve was resected after splitting the gluteal muscle. One week (n = 11) and three weeks (n = 6) after the denervation, 18F-ASEM positron emission tomography/magnetic resonance imaging (PET/MRI) was acquired. Maximum standardized uptake values (SUVmax) of the tibialis anterior muscle were measured for the denervated side and the control side. Autoradiographic evaluation was performed to measure the mean counts of the denervated and control tibialis anterior muscles at one week. In addition, immunohistochemistry was used to identify alpha7-nAChR-positive areas in denervated and control tibialis anterior muscles at one week (n = 6). Furthermore, a blocking study was conducted with methyllycaconitine (MLA, n = 5).
Results: 18F-ASEM PET/MRI showed significantly increased 18F-ASEM uptake in the denervated tibialis anterior muscle relative to the control side one week and three weeks post-denervation. SUVmax of the denervated muscles at one week and three weeks showed significantly higher uptake than the control (P = 0.0033 and 0.0277, respectively). The relative uptake by autoradiography for the denervated muscle was significantly higher than in the control, and immunohistochemistry revealed significantly greater alpha7-nAChR expression in the denervated muscle (P = 0.0277). In addition, the blocking study showed no significant 18F-ASEM uptake in the denervated side when compared to the control (P = 0.0796).
Conclusions: Our results suggest that nAChR imaging with 18F-ASEM has potential as a noninvasive diagnostic method for peripheral nervous system disorders.
{"title":"<sup>18</sup>F-ASEM PET/MRI targeting alpha7-nicotinic acetylcholine receptor can reveal skeletal muscle denervation.","authors":"Yong-Il Kim, Seung Hak Lee, Jin Hwa Jung, Seog-Young Kim, Nare Ko, Sang Ju Lee, Seung Jun Oh, Jin-Sook Ryu, Dabin Ko, Won Kim, Kyunggon Kim","doi":"10.1186/s13550-024-01067-9","DOIUrl":"10.1186/s13550-024-01067-9","url":null,"abstract":"<p><strong>Background: </strong>The increased expression of the nicotinic acetylcholine receptor (nAChR) in muscle denervation is thought to be associated with electrophysiological acetylcholine supersensitivity after nerve injury. Hence, we investigated the utility of the <sup>18</sup>F-ASEM alpha7-nAChR targeting radiotracer as a new diagnostic method by visualizing skeletal muscle denervation in mouse models of sciatic nerve injury.</p><p><strong>Methods: </strong>Ten-week-old C57BL/6 male mice were utilized. The mice were anesthetized, and the left sciatic nerve was resected after splitting the gluteal muscle. One week (n = 11) and three weeks (n = 6) after the denervation, <sup>18</sup>F-ASEM positron emission tomography/magnetic resonance imaging (PET/MRI) was acquired. Maximum standardized uptake values (SUVmax) of the tibialis anterior muscle were measured for the denervated side and the control side. Autoradiographic evaluation was performed to measure the mean counts of the denervated and control tibialis anterior muscles at one week. In addition, immunohistochemistry was used to identify alpha7-nAChR-positive areas in denervated and control tibialis anterior muscles at one week (n = 6). Furthermore, a blocking study was conducted with methyllycaconitine (MLA, n = 5).</p><p><strong>Results: </strong><sup>18</sup>F-ASEM PET/MRI showed significantly increased <sup>18</sup>F-ASEM uptake in the denervated tibialis anterior muscle relative to the control side one week and three weeks post-denervation. SUVmax of the denervated muscles at one week and three weeks showed significantly higher uptake than the control (P = 0.0033 and 0.0277, respectively). The relative uptake by autoradiography for the denervated muscle was significantly higher than in the control, and immunohistochemistry revealed significantly greater alpha7-nAChR expression in the denervated muscle (P = 0.0277). In addition, the blocking study showed no significant <sup>18</sup>F-ASEM uptake in the denervated side when compared to the control (P = 0.0796).</p><p><strong>Conclusions: </strong>Our results suggest that nAChR imaging with <sup>18</sup>F-ASEM has potential as a noninvasive diagnostic method for peripheral nervous system disorders.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10803689/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139511516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-11DOI: 10.1186/s13550-023-01058-2
Victoria J M Reid, Wesley K X McLoughlin, Kalyani Pandya, Holly Stott, Monika Iškauskienė, Algirdas Šačkus, Judit A Marti, Dominic Kurian, Thomas M Wishart, Christophe Lucatelli, Dan Peters, Gillian A Gray, Andrew H Baker, David E Newby, Patrick W F Hadoke, Adriana A S Tavares, Mark G MacAskill
Background: Cardiac repair and remodeling following myocardial infarction (MI) is a multifactorial process involving pro-reparative inflammation, angiogenesis and fibrosis. Noninvasive imaging using a radiotracer targeting these processes could be used to elucidate cardiac wound healing mechanisms. The alpha7 nicotinic acetylcholine receptor (ɑ7nAChR) stimulates pro-reparative macrophage activity and angiogenesis, making it a potential imaging biomarker in this context. We investigated this by assessing in vitro cellular expression of ɑ7nAChR, and by using a tritiated version of the PET radiotracer [18F]NS14490 in tissue autoradiography studies.
Results: ɑ7nAChR expression in human monocyte-derived macrophages and vascular cells showed the highest relative expression was within macrophages, but only endothelial cells exhibited a proliferation and hypoxia-driven increase in expression. Using a mouse model of inflammatory angiogenesis following sponge implantation, specific binding of [3H]NS14490 increased from 3.6 ± 0.2 µCi/g at day 3 post-implantation to 4.9 ± 0.2 µCi/g at day 7 (n = 4, P < 0.01), followed by a reduction at days 14 and 21. This peak matched the onset of vessel formation, macrophage infiltration and sponge fibrovascular encapsulation. In a rat MI model, specific binding of [3H]NS14490 was low in sham and remote MI myocardium. Specific binding within the infarct increased from day 14 post-MI (33.8 ± 14.1 µCi/g, P ≤ 0.01 versus sham), peaking at day 28 (48.9 ± 5.1 µCi/g, P ≤ 0.0001 versus sham). Histological and proteomic profiling of ɑ7nAChR positive tissue revealed strong associations between ɑ7nAChR and extracellular matrix deposition, and rat cardiac fibroblasts expressed ɑ7nAChR protein under normoxic and hypoxic conditions.
Conclusion: ɑ7nAChR is highly expressed in human macrophages and showed proliferation and hypoxia-driven expression in human endothelial cells. While NS14490 imaging displays a pattern that coincides with vessel formation, macrophage infiltration and fibrovascular encapsulation in the sponge model, this is not the case in the MI model where the ɑ7nAChR imaging signal was strongly associated with extracellular matrix deposition which could be explained by ɑ7nAChR expression in fibroblasts. Overall, these findings support the involvement of ɑ7nAChR across several processes central to cardiac repair, with fibrosis most closely associated with ɑ7nAChR following MI.
{"title":"Assessment of the alpha 7 nicotinic acetylcholine receptor as an imaging marker of cardiac repair-associated processes using NS14490.","authors":"Victoria J M Reid, Wesley K X McLoughlin, Kalyani Pandya, Holly Stott, Monika Iškauskienė, Algirdas Šačkus, Judit A Marti, Dominic Kurian, Thomas M Wishart, Christophe Lucatelli, Dan Peters, Gillian A Gray, Andrew H Baker, David E Newby, Patrick W F Hadoke, Adriana A S Tavares, Mark G MacAskill","doi":"10.1186/s13550-023-01058-2","DOIUrl":"10.1186/s13550-023-01058-2","url":null,"abstract":"<p><strong>Background: </strong>Cardiac repair and remodeling following myocardial infarction (MI) is a multifactorial process involving pro-reparative inflammation, angiogenesis and fibrosis. Noninvasive imaging using a radiotracer targeting these processes could be used to elucidate cardiac wound healing mechanisms. The alpha7 nicotinic acetylcholine receptor (ɑ7nAChR) stimulates pro-reparative macrophage activity and angiogenesis, making it a potential imaging biomarker in this context. We investigated this by assessing in vitro cellular expression of ɑ7nAChR, and by using a tritiated version of the PET radiotracer [<sup>18</sup>F]NS14490 in tissue autoradiography studies.</p><p><strong>Results: </strong>ɑ7nAChR expression in human monocyte-derived macrophages and vascular cells showed the highest relative expression was within macrophages, but only endothelial cells exhibited a proliferation and hypoxia-driven increase in expression. Using a mouse model of inflammatory angiogenesis following sponge implantation, specific binding of [<sup>3</sup>H]NS14490 increased from 3.6 ± 0.2 µCi/g at day 3 post-implantation to 4.9 ± 0.2 µCi/g at day 7 (n = 4, P < 0.01), followed by a reduction at days 14 and 21. This peak matched the onset of vessel formation, macrophage infiltration and sponge fibrovascular encapsulation. In a rat MI model, specific binding of [<sup>3</sup>H]NS14490 was low in sham and remote MI myocardium. Specific binding within the infarct increased from day 14 post-MI (33.8 ± 14.1 µCi/g, P ≤ 0.01 versus sham), peaking at day 28 (48.9 ± 5.1 µCi/g, P ≤ 0.0001 versus sham). Histological and proteomic profiling of ɑ7nAChR positive tissue revealed strong associations between ɑ7nAChR and extracellular matrix deposition, and rat cardiac fibroblasts expressed ɑ7nAChR protein under normoxic and hypoxic conditions.</p><p><strong>Conclusion: </strong>ɑ7nAChR is highly expressed in human macrophages and showed proliferation and hypoxia-driven expression in human endothelial cells. While NS14490 imaging displays a pattern that coincides with vessel formation, macrophage infiltration and fibrovascular encapsulation in the sponge model, this is not the case in the MI model where the ɑ7nAChR imaging signal was strongly associated with extracellular matrix deposition which could be explained by ɑ7nAChR expression in fibroblasts. Overall, these findings support the involvement of ɑ7nAChR across several processes central to cardiac repair, with fibrosis most closely associated with ɑ7nAChR following MI.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10784260/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139416590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-10DOI: 10.1186/s13550-023-01066-2
Nathaniel J Smith, Mark A Green, Clinton D Bahler, Mark Tann, Wendy Territo, Anne M Smith, Gary D Hutchins
Background: 68Ga-PSMA-11 positron emission tomography enables the detection of primary, recurrent, and metastatic prostate cancer. Regional radiopharmaceutical uptake is generally evaluated in static images and quantified as standard uptake values (SUVs) for clinical decision-making. However, analysis of dynamic images characterizing both tracer uptake and pharmacokinetics may offer added insights into the underlying tissue pathophysiology. This study was undertaken to evaluate the suitability of various kinetic models for 68Ga-PSMA-11 PET analysis. Twenty-three lesions in 18 patients were included in a retrospective kinetic evaluation of 55-min dynamic 68Ga-PSMA-11 pre-prostatectomy PET scans from patients with biopsy-demonstrated intermediate- to high-risk prostate cancer. Three kinetic models-a reversible one-tissue compartment model, an irreversible two-tissue compartment model, and a reversible two-tissue compartment model, were evaluated for their goodness of fit to lesion and normal reference prostate time-activity curves. Kinetic parameters obtained through graphical analysis and tracer kinetic modeling techniques were compared for reference prostate tissue and lesion regions of interest.
Results: Supported by goodness of fit and information loss criteria, the irreversible two-tissue compartment model optimally fit the time-activity curves. Lesions exhibited significant differences in kinetic rate constants (K1, k2, k3, Ki) and semiquantitative measures (SUV and %ID/kg) when compared with reference prostatic tissue. The two-tissue irreversible tracer kinetic model was consistently appropriate across prostatic zones.
Conclusions: An irreversible tracer kinetic model is appropriate for dynamic analysis of 68Ga-PSMA-11 PET images. Kinetic parameters estimated by Patlak graphical analysis or full compartmental analysis can distinguish tumor from normal prostate tissue.
背景:68Ga-PSMA-11 正电子发射断层扫描可检测原发性、复发性和转移性前列腺癌。区域放射性药物摄取一般在静态图像中进行评估,并量化为标准摄取值(SUV),供临床决策使用。然而,分析示踪剂摄取和药代动力学特征的动态图像可为了解潜在的组织病理生理学提供更多信息。本研究旨在评估各种动力学模型在 68Ga-PSMA-11 PET 分析中的适用性。对活检证实为中高危前列腺癌患者的前列腺切除术前 55 分钟动态 68Ga-PSMA-11 PET 扫描进行了回顾性动力学评估,共纳入了 18 名患者的 23 个病灶。评估了三种动力学模型--可逆的单组织区室模型、不可逆的双组织区室模型和可逆的双组织区室模型--与病变和正常参考前列腺时间-活动曲线的拟合度。比较了通过图形分析和示踪剂动力学建模技术获得的参考前列腺组织和病变区域的动力学参数:结果:在拟合优度和信息丢失标准的支持下,不可逆的双组织区室模型对时间活动曲线进行了最佳拟合。与参考前列腺组织相比,病变区域在动力学速率常数(K1、k2、k3、Ki)和半定量指标(SUV 和 %ID/kg)方面存在明显差异。双组织不可逆示踪剂动力学模型在各前列腺区始终是合适的:结论:不可逆示踪剂动力学模型适用于 68Ga-PSMA-11 PET 图像的动态分析。通过 Patlak 图形分析或全分区分析估计的动力学参数可以区分肿瘤和正常前列腺组织。
{"title":"Comparison of tracer kinetic models for <sup>68</sup>Ga-PSMA-11 PET in intermediate-risk primary prostate cancer patients.","authors":"Nathaniel J Smith, Mark A Green, Clinton D Bahler, Mark Tann, Wendy Territo, Anne M Smith, Gary D Hutchins","doi":"10.1186/s13550-023-01066-2","DOIUrl":"10.1186/s13550-023-01066-2","url":null,"abstract":"<p><strong>Background: </strong><sup>68</sup>Ga-PSMA-11 positron emission tomography enables the detection of primary, recurrent, and metastatic prostate cancer. Regional radiopharmaceutical uptake is generally evaluated in static images and quantified as standard uptake values (SUVs) for clinical decision-making. However, analysis of dynamic images characterizing both tracer uptake and pharmacokinetics may offer added insights into the underlying tissue pathophysiology. This study was undertaken to evaluate the suitability of various kinetic models for <sup>68</sup>Ga-PSMA-11 PET analysis. Twenty-three lesions in 18 patients were included in a retrospective kinetic evaluation of 55-min dynamic <sup>68</sup>Ga-PSMA-11 pre-prostatectomy PET scans from patients with biopsy-demonstrated intermediate- to high-risk prostate cancer. Three kinetic models-a reversible one-tissue compartment model, an irreversible two-tissue compartment model, and a reversible two-tissue compartment model, were evaluated for their goodness of fit to lesion and normal reference prostate time-activity curves. Kinetic parameters obtained through graphical analysis and tracer kinetic modeling techniques were compared for reference prostate tissue and lesion regions of interest.</p><p><strong>Results: </strong>Supported by goodness of fit and information loss criteria, the irreversible two-tissue compartment model optimally fit the time-activity curves. Lesions exhibited significant differences in kinetic rate constants (K<sub>1</sub>, k<sub>2</sub>, k<sub>3</sub>, K<sub>i</sub>) and semiquantitative measures (SUV and %ID/kg) when compared with reference prostatic tissue. The two-tissue irreversible tracer kinetic model was consistently appropriate across prostatic zones.</p><p><strong>Conclusions: </strong>An irreversible tracer kinetic model is appropriate for dynamic analysis of <sup>68</sup>Ga-PSMA-11 PET images. Kinetic parameters estimated by Patlak graphical analysis or full compartmental analysis can distinguish tumor from normal prostate tissue.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10781928/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139402372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.1186/s13550-023-01062-6
Xiaoyu Fan, Hans W Nijman, Marco de Bruyn, Philip H Elsinga
Background: Immune checkpoint inhibitors (ICIs) have made significant progress in oncotherapy improving survival of patients. However, the benefits are limited to only a small subgroup of patients who could achieve durable responses. Early prediction of response may enable treatment optimization and patient stratification. Therefore, developing appropriate biomarkers is critical to monitoring efficacy and assessing patient response to ICIs.
Main body: Herein, we first introduce a new potential biomarker, CD103, expressed on tissue-resident memory T cells, and discuss the potential application of CD103 PET imaging in predicting immune checkpoint inhibitor treatment. In addition, we describe the current targets of ImmunoPET and compare these targets with CD103. To assess the benefit of PET imaging, a comparative analysis between ImmunoPET and other imaging techniques commonly employed for tumor diagnosis was performed. Additionally, we compare ImmunoPET and immunohistochemistry (IHC), a widely utilized clinical method for biomarker identification with respect to visualizing the immune targets.
Conclusion: CD103 ImmunoPET is a promising method for determining tumor-infiltrating lymphocytes (TILs) load and response to ICIs, thereby addressing the lack of reliable biomarkers in cancer immunotherapy. Compared to general T cell markers, CD103 is a specific marker for tissue-resident memory T cells, which number increases during successful ICI therapy. ImmunoPET offers noninvasive, dynamic imaging of specific markers, complemented by detailed molecular information from immunohistochemistry (IHC). Radiomics can extract quantitative features from traditional imaging methods, while near-infrared fluorescence (NIRF) imaging aids tumor detection during surgery. In the era of precision medicine, combining such methods will offer a more comprehensive approach to cancer diagnosis and treatment.
背景:免疫检查点抑制剂(ICIs免疫检查点抑制剂(ICIs)在肿瘤治疗中取得了重大进展,提高了患者的生存率。然而,这种益处仅限于一小部分可获得持久应答的患者。早期预测反应可以优化治疗并对患者进行分层。因此,开发适当的生物标志物对于监测疗效和评估患者对 ICIs 的反应至关重要:在本文中,我们首先介绍了一种新的潜在生物标志物--CD103,它表达于组织驻留记忆T细胞上,并讨论了CD103 PET成像在预测免疫检查点抑制剂治疗中的潜在应用。此外,我们还介绍了目前免疫PET的靶点,并将这些靶点与CD103进行了比较。为了评估 PET 成像的益处,我们对免疫PET 和其他常用于肿瘤诊断的成像技术进行了比较分析。此外,我们还比较了免疫PET和免疫组织化学(IHC),后者是临床上广泛使用的一种生物标记物鉴定方法,可将免疫靶标显现出来:CD103免疫PET是确定肿瘤浸润淋巴细胞(TILs)负荷和对ICIs反应的一种有前途的方法,从而解决了癌症免疫疗法缺乏可靠生物标记物的问题。与一般的 T 细胞标记物相比,CD103 是组织驻留记忆 T 细胞的特异性标记物,在 ICI 治疗成功时,这种细胞的数量会增加。免疫发射计算机断层显像(ImmunoPET)可对特异性标记物进行无创、动态成像,并辅以免疫组化(IHC)提供的详细分子信息。放射组学可从传统成像方法中提取定量特征,而近红外荧光(NIRF)成像则有助于手术中的肿瘤检测。在精准医疗时代,结合这些方法将为癌症诊断和治疗提供更全面的方法。
{"title":"ImmunoPET provides a novel way to visualize the CD103<sup>+</sup> tissue-resident memory T cell to predict the response of immune checkpoint inhibitors.","authors":"Xiaoyu Fan, Hans W Nijman, Marco de Bruyn, Philip H Elsinga","doi":"10.1186/s13550-023-01062-6","DOIUrl":"10.1186/s13550-023-01062-6","url":null,"abstract":"<p><strong>Background: </strong>Immune checkpoint inhibitors (ICIs) have made significant progress in oncotherapy improving survival of patients. However, the benefits are limited to only a small subgroup of patients who could achieve durable responses. Early prediction of response may enable treatment optimization and patient stratification. Therefore, developing appropriate biomarkers is critical to monitoring efficacy and assessing patient response to ICIs.</p><p><strong>Main body: </strong>Herein, we first introduce a new potential biomarker, CD103, expressed on tissue-resident memory T cells, and discuss the potential application of CD103 PET imaging in predicting immune checkpoint inhibitor treatment. In addition, we describe the current targets of ImmunoPET and compare these targets with CD103. To assess the benefit of PET imaging, a comparative analysis between ImmunoPET and other imaging techniques commonly employed for tumor diagnosis was performed. Additionally, we compare ImmunoPET and immunohistochemistry (IHC), a widely utilized clinical method for biomarker identification with respect to visualizing the immune targets.</p><p><strong>Conclusion: </strong>CD103 ImmunoPET is a promising method for determining tumor-infiltrating lymphocytes (TILs) load and response to ICIs, thereby addressing the lack of reliable biomarkers in cancer immunotherapy. Compared to general T cell markers, CD103 is a specific marker for tissue-resident memory T cells, which number increases during successful ICI therapy. ImmunoPET offers noninvasive, dynamic imaging of specific markers, complemented by detailed molecular information from immunohistochemistry (IHC). Radiomics can extract quantitative features from traditional imaging methods, while near-infrared fluorescence (NIRF) imaging aids tumor detection during surgery. In the era of precision medicine, combining such methods will offer a more comprehensive approach to cancer diagnosis and treatment.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10769965/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139106029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-05DOI: 10.1186/s13550-023-01065-3
Fabian Schmitz-Peiffer, Mathias Lukas, Ajay-Mohan Mohan, Jakob Albrecht, Jörg R Aschenbach, Winfried Brenner, Nicola Beindorff
Background: The influence of anaesthetic depth and the potential influence of different anaesthetic beds and thus different handling procedures were investigated in 86 severe combined immunodeficient (SCID) mice using semi-stationary dynamic single photon emission computed tomography (SPECT) for kidney scintigraphy. Therefore, isoflurane concentrations were adjusted using respiratory rate for low (80-90 breath/min) and deep anaesthesia (40-45 breath/min). At low anaesthesia, we additionally tested the influence of single bed versus 3-mouse bed hotel; the hotel mice were anaesthetized consecutively at ~ 30, 20, and 10 min before tracer injections for positions 1, 2, and 3, respectively. Intravenous [99mTc]Tc-MAG3 injection of ~ 28 MBq was performed after SPECT start. Time-activity curves were used to calculate time-to-peak (Tmax), T50 (50% clearance) and T25 (75% clearance).
Results: Low and deep anaesthesia corresponded to median isoflurane concentrations of 1.3% and 1.5%, respectively, with no significant differences in heart rate (p = 0.74). Low anaesthesia resulted in shorter aortic blood clearance half-life (p = 0.091) and increased relative renal tracer influx rate (p = 0.018). A tendency toward earlier Tmax occurred under low anaesthesia (p = 0.063) with no differences in T50 (p = 0.40) and T25 (p = 0.24). Variance increased with deep anaesthesia. Compared to single mouse scans, hotel mice in position 1 showed a delayed Tmax, T50, and T25 (p < 0.05 each). Furthermore, hotel mice in position 1 showed delayed Tmax versus position 3, and delayed T50 and T25 versus position 2 and 3 (p < 0.05 each). No difference occurred between single bed and positions 2 (p = 1.0) and 3 (p = 1.0).
Conclusions: Deep anaesthesia and prolonged low anaesthesia should be avoided during renal scintigraphy because they result in prolonged blood clearance half-life, delayed renal influx and/or later Tmax. Vice versa, low anaesthesia with high respiratory rates of 80-90 rpm and short duration (≤ 20 min) should be preferred to obtain representative data with low variance.
{"title":"Effects of isoflurane anaesthesia depth and duration on renal function measured with [<sup>99m</sup>Tc]Tc-mercaptoacetyltriglycine SPECT in mice.","authors":"Fabian Schmitz-Peiffer, Mathias Lukas, Ajay-Mohan Mohan, Jakob Albrecht, Jörg R Aschenbach, Winfried Brenner, Nicola Beindorff","doi":"10.1186/s13550-023-01065-3","DOIUrl":"10.1186/s13550-023-01065-3","url":null,"abstract":"<p><strong>Background: </strong>The influence of anaesthetic depth and the potential influence of different anaesthetic beds and thus different handling procedures were investigated in 86 severe combined immunodeficient (SCID) mice using semi-stationary dynamic single photon emission computed tomography (SPECT) for kidney scintigraphy. Therefore, isoflurane concentrations were adjusted using respiratory rate for low (80-90 breath/min) and deep anaesthesia (40-45 breath/min). At low anaesthesia, we additionally tested the influence of single bed versus 3-mouse bed hotel; the hotel mice were anaesthetized consecutively at ~ 30, 20, and 10 min before tracer injections for positions 1, 2, and 3, respectively. Intravenous [<sup>99m</sup>Tc]Tc-MAG3 injection of ~ 28 MBq was performed after SPECT start. Time-activity curves were used to calculate time-to-peak (Tmax), T50 (50% clearance) and T25 (75% clearance).</p><p><strong>Results: </strong>Low and deep anaesthesia corresponded to median isoflurane concentrations of 1.3% and 1.5%, respectively, with no significant differences in heart rate (p = 0.74). Low anaesthesia resulted in shorter aortic blood clearance half-life (p = 0.091) and increased relative renal tracer influx rate (p = 0.018). A tendency toward earlier Tmax occurred under low anaesthesia (p = 0.063) with no differences in T50 (p = 0.40) and T25 (p = 0.24). Variance increased with deep anaesthesia. Compared to single mouse scans, hotel mice in position 1 showed a delayed Tmax, T50, and T25 (p < 0.05 each). Furthermore, hotel mice in position 1 showed delayed Tmax versus position 3, and delayed T50 and T25 versus position 2 and 3 (p < 0.05 each). No difference occurred between single bed and positions 2 (p = 1.0) and 3 (p = 1.0).</p><p><strong>Conclusions: </strong>Deep anaesthesia and prolonged low anaesthesia should be avoided during renal scintigraphy because they result in prolonged blood clearance half-life, delayed renal influx and/or later Tmax. Vice versa, low anaesthesia with high respiratory rates of 80-90 rpm and short duration (≤ 20 min) should be preferred to obtain representative data with low variance.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10769950/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139097606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.1186/s13550-023-01063-5
Marin Simunic, Jay T Joshi, Helen Merkens, Nadine Colpo, Hsiou-Ting Kuo, Julian J Lum, François Bénard
{"title":"PSMA imaging as a non-invasive tool to monitor inducible gene expression in vivo.","authors":"Marin Simunic, Jay T Joshi, Helen Merkens, Nadine Colpo, Hsiou-Ting Kuo, Julian J Lum, François Bénard","doi":"10.1186/s13550-023-01063-5","DOIUrl":"10.1186/s13550-023-01063-5","url":null,"abstract":"","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10767034/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139097607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-04DOI: 10.1186/s13550-023-01064-4
Qingqing Pan, Huaxia Yang, Ziyue Zhou, Min Li, Xu Jiang, Fang Li, Yaping Luo, Mengtao Li
Background: The identification of biomarkers predicting the treatment response of rheumatoid arthritis (RA) is important. [68 Ga]Ga-FAPI-04 showed markedly increased uptake in the joints of patients with RA. The purpose of this study is to investigate whether [68 Ga]Ga-FAPI-04 PET/CT can be a predictor of treatment response in RA.
Results: Nineteen patients diagnosed with RA in the prospective cohort study were finally enrolled. Both total synovitis uptake (TSU) and metabolic synovitis volume (MSV) in [68 Ga]Ga-FAPI-04 and [18F]FDG PET/CT of the responders were significantly higher than those in non-responders according to Clinical Disease Activity Index (CDAI) and Simplified Disease Activity Index (SDAI) response criteria at 3-months' follow-up (P < 0.05). The PET joint count (PJC) detected in [68 Ga]Ga-FAPI-04 and [18F]FDG PET/CT were also significantly higher in CDAI responders than non-responders (P = 0.016 and 0.045, respectively). The clinical characteristics of disease activity at baseline did not show significant difference between the responders and non-responders, except CRP (P = 0.035 and 0.033 in CDAI and SDAI response criteria, respectively). The baseline PJCFAPI, TSUFAPI and MSVFAPI > cutoff values in [68 Ga]Ga-FAPI-04 PET/CT successfully discriminated CDAI and SDAI responders and non-responders at 3-months' follow-up.
Conclusion: [68 Ga]Ga-FAPI-04 uptake at baseline were significantly higher in early responders than those in non-responders. Trial registration ClinicalTrials. NCT04514614. Registered 13 August 2020, https://register.
{"title":"[<sup>68</sup> Ga]Ga-FAPI-04 PET/CT may be a predictor for early treatment response in rheumatoid arthritis.","authors":"Qingqing Pan, Huaxia Yang, Ziyue Zhou, Min Li, Xu Jiang, Fang Li, Yaping Luo, Mengtao Li","doi":"10.1186/s13550-023-01064-4","DOIUrl":"10.1186/s13550-023-01064-4","url":null,"abstract":"<p><strong>Background: </strong>The identification of biomarkers predicting the treatment response of rheumatoid arthritis (RA) is important. [<sup>68</sup> Ga]Ga-FAPI-04 showed markedly increased uptake in the joints of patients with RA. The purpose of this study is to investigate whether [<sup>68</sup> Ga]Ga-FAPI-04 PET/CT can be a predictor of treatment response in RA.</p><p><strong>Results: </strong>Nineteen patients diagnosed with RA in the prospective cohort study were finally enrolled. Both total synovitis uptake (TSU) and metabolic synovitis volume (MSV) in [<sup>68</sup> Ga]Ga-FAPI-04 and [<sup>18</sup>F]FDG PET/CT of the responders were significantly higher than those in non-responders according to Clinical Disease Activity Index (CDAI) and Simplified Disease Activity Index (SDAI) response criteria at 3-months' follow-up (P < 0.05). The PET joint count (PJC) detected in [<sup>68</sup> Ga]Ga-FAPI-04 and [<sup>18</sup>F]FDG PET/CT were also significantly higher in CDAI responders than non-responders (P = 0.016 and 0.045, respectively). The clinical characteristics of disease activity at baseline did not show significant difference between the responders and non-responders, except CRP (P = 0.035 and 0.033 in CDAI and SDAI response criteria, respectively). The baseline PJC<sub>FAPI</sub>, TSU<sub>FAPI</sub> and MSV<sub>FAPI</sub> > cutoff values in [<sup>68</sup> Ga]Ga-FAPI-04 PET/CT successfully discriminated CDAI and SDAI responders and non-responders at 3-months' follow-up.</p><p><strong>Conclusion: </strong>[<sup>68</sup> Ga]Ga-FAPI-04 uptake at baseline were significantly higher in early responders than those in non-responders. Trial registration ClinicalTrials. NCT04514614. Registered 13 August 2020, https://register.</p><p><strong>Clinicaltrials: </strong>gov/prs/app/action/SelectProtocol?sid=S000A4PN&selectaction=Edit&uid=U0001JRW&ts=2&cx=-x9t7cp.</p>","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10766931/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139086385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-02DOI: 10.1186/s13550-023-01061-7
Hamed Moradi, Rajat Vashistha, Kieran O’Brien, Amanda Hammond, Viktor Vegh, David Reutens
In parametric PET, kinetic parameters are extracted from dynamic PET images. It is not commonly used in clinical practice because of long scan times and the requirement for an arterial input function (AIF). To address these limitations, we designed an 18F-fluorodeoxyglucose (18F-FDG) triple injection dynamic PET protocol for brain imaging with a standard field of view PET scanner using a 24-min imaging window and an input function modeled using measurements from a region of interest placed over the left ventricle. To test the protocol in 6 healthy participants, we examined the quality of voxel-based maps of kinetic parameters in the brain generated using the two-tissue compartment model and compared estimated parameter values with previously published values. We also utilized data from a 36-min validation imaging window to compare (1) the modeled AIF against the input function measured in the validation window; and (2) the net influx rate ( $$K_{i}$$ ) computed using parameter estimates from the short imaging window against the net influx rate obtained using Patlak analysis in the validation window. Compared to the AIF measured in the validation window, the input function estimated from the short imaging window achieved a mean area under the curve error of 9%. The voxel-wise Pearson’s correlation between $$K_{i}$$ estimates from the short imaging window and the validation imaging window exceeded 0.95. The proposed 24-min triple injection protocol enables parametric 18F-FDG neuroimaging with noninvasive estimation of the AIF from cardiac images using a standard field of view PET scanner.
在参数 PET 中,动力学参数是从动态 PET 图像中提取的。由于扫描时间长且需要动脉输入函数(AIF),这种方法在临床实践中并不常用。为了解决这些局限性,我们设计了一种 18F- 氟脱氧葡萄糖(18F-FDG)三重注射动态 PET 方案,使用标准视野 PET 扫描仪进行脑成像,使用 24 分钟成像窗口,并使用左心室上方感兴趣区的测量结果模拟输入函数。为了在 6 名健康参与者中测试该方案,我们检查了使用双组织室模型生成的基于体素的大脑动力学参数图的质量,并将估计参数值与之前公布的值进行了比较。我们还利用 36 分钟验证成像窗口的数据,比较了(1)建模的 AIF 与验证窗口中测量的输入函数;以及(2)使用短成像窗口中的参数估算值计算的净流入率($$K_{i}$$)与验证窗口中使用 Patlak 分析获得的净流入率。与验证窗口测得的 AIF 相比,短成像窗口估计的输入函数的平均曲线下面积误差为 9%。短成像窗口和验证成像窗口估计的 $$K_{i}$ 之间的体素相关性超过 0.95。所提出的 24 分钟三重注射方案可实现参数化 18F-FDG 神经成像,并使用标准视野 PET 扫描仪从心脏图像无创估计 AIF。
{"title":"A short 18F-FDG imaging window triple injection neuroimaging protocol for parametric mapping in PET","authors":"Hamed Moradi, Rajat Vashistha, Kieran O’Brien, Amanda Hammond, Viktor Vegh, David Reutens","doi":"10.1186/s13550-023-01061-7","DOIUrl":"https://doi.org/10.1186/s13550-023-01061-7","url":null,"abstract":"In parametric PET, kinetic parameters are extracted from dynamic PET images. It is not commonly used in clinical practice because of long scan times and the requirement for an arterial input function (AIF). To address these limitations, we designed an 18F-fluorodeoxyglucose (18F-FDG) triple injection dynamic PET protocol for brain imaging with a standard field of view PET scanner using a 24-min imaging window and an input function modeled using measurements from a region of interest placed over the left ventricle. To test the protocol in 6 healthy participants, we examined the quality of voxel-based maps of kinetic parameters in the brain generated using the two-tissue compartment model and compared estimated parameter values with previously published values. We also utilized data from a 36-min validation imaging window to compare (1) the modeled AIF against the input function measured in the validation window; and (2) the net influx rate ( $$K_{i}$$ ) computed using parameter estimates from the short imaging window against the net influx rate obtained using Patlak analysis in the validation window. Compared to the AIF measured in the validation window, the input function estimated from the short imaging window achieved a mean area under the curve error of 9%. The voxel-wise Pearson’s correlation between $$K_{i}$$ estimates from the short imaging window and the validation imaging window exceeded 0.95. The proposed 24-min triple injection protocol enables parametric 18F-FDG neuroimaging with noninvasive estimation of the AIF from cardiac images using a standard field of view PET scanner.","PeriodicalId":11611,"journal":{"name":"EJNMMI Research","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139084058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}