A review of harmonization strategies for quantitative PET

Akamatsu, Go; Tsutsui, Yuji; Daisaki, Hiromitsu; Mitsumoto, Katsuhiko; Baba, Shingo; Sasaki, Masayuki

doi:10.1007/s12149-022-01820-x

Cited by 7 publications

(4 citation statements)

References 131 publications

(134 reference statements)

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“…Although SUVmax is the most widely used semiquantitative PET/CT parameter, variations across PET/CT scanners, protocols, and patient factors make it hard to generalize results. [ 22 , 23 ] As an alternative parameter, TLR may show lower interscan variability because of the reference normalization (usually using normal liver uptake), which results in better reproducibility than SUVmax. [ 24 , 25 ] In this regard, our study results imply that TLR could be widely applied.…”

Section: Discussionmentioning

confidence: 99%

Characterization of sacral chordoma and differential diagnosis from other sacral malignancy using [18F]FDG PET/CT

Lee,

Kim,

Ryu

et al. 2024

Medicine

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2-Deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET)/computed tomography (CT) is known to be a helpful imaging modality for sacral chordoma, but its detailed characteristics have not been fully described. The purpose of our study was to identify the [18F]FDG PET/CT imaging characteristics of sacral chordoma and compare them with other sacral malignancy. This retrospective study included patients who underwent [18F]FDG PET/CT because of a mass involving the sacrum. Investigated visual findings included visual score and distribution, and semiquantitative parameters measured included standardized uptake values (SUVmax, SUVpeak, SUVmean), tumor-to-liver ratio (TLR), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and tumor size. Comparison studies and receiver operating characteristics (ROC) curve analysis were performed to differentiate between sacral chordoma and other sacral malignancy. Ten patients with sacral chordoma were finally included (M:F = 6:4, median age = 67 yr). On [18F]FDG PET/CT, sacral chordomas presented as a mass with minimal–moderate uptake with a usually heterogenous distribution. Compared with 12 patients with other sacral malignancies (M:F = 4:8, median age 42 yr), sacral chordoma showed a significantly lower TLR (median value 2.1 vs 6.3, P = .021). In ROC curve analysis, TLR showed the largest area under the curve (AUC) of 0.79 (cutoff ≤ 4.0; sensitivity 100.0%, specificity 58.3%; P = .004), and SUVmax showed the second largest AUC of 0.73 (cutoff ≤ 6.9; sensitivity 80.0%, specificity 66.7%; P = .034). [18F]FDG PET/CT of sacral chordoma showed minimal–moderate uptake. The TLR of [18F]FDG PET/CT was significantly lower than that of other sacral malignancy and was the most useful parameter for differentiating sacral chordoma, with the largest AUC. SUVmax could be another helpful semiquantitative parameter.

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Section: Discussionmentioning

confidence: 99%

Characterization of sacral chordoma and differential diagnosis from other sacral malignancy using [18F]FDG PET/CT

Lee,

Kim,

Ryu

et al. 2024

Medicine

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“…This is described in the following steps of DWI harmonization, and PET normalization. We distinguish PET normalization from harmonization, as true harmonization in PET data can be only achieved by the scans of standardized phantom which were not available at the centers acquiring the data ( Akamatsu et al. 2023 ), while DWI harmonization can be achieved computationally.…”

Section: Methodsmentioning

confidence: 99%

Prediction of misfolded proteins spreading in Alzheimer’s disease using machine learning and spreading models

Gherardini,

Zajdel,

Pini

et al. 2023

Cerebral Cortex

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The pervasive impact of Alzheimer’s disease on aging society represents one of the main challenges at this time. Current investigations highlight 2 specific misfolded proteins in its development: Amyloid-$\beta$ and tau. Previous studies focused on spreading for misfolded proteins exploited simulations, which required several parameters to be empirically estimated. Here, we provide an alternative view based on 2 machine learning approaches which we compare with known simulation models. The first approach applies an autoregressive model constrained by structural connectivity, while the second is based on graph convolutional networks. The aim is to predict concentrations of Amyloid-$\beta$ 2 yr after a provided baseline. We also evaluate its real-world effectiveness and suitability by providing a web service for physicians and researchers. In experiments, the autoregressive model generally outperformed state-of-the-art models resulting in lower prediction errors. While it is important to note that a comprehensive prognostic plan cannot solely rely on amyloid beta concentrations, their prediction, achieved by the discussed approaches, can be valuable for planning therapies and other cures, especially when dealing with asymptomatic patients for whom novel therapies could prove effective.

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“…Several studies have investigated harmonization measures of accurate SUV quanti cation for oncological [ 18 F]FDG and neurological studies. Akamatsu et al list several investigations of the latest PET harmonization strategies [11]. For example, SUV harmonization can be based on the image uniformity and spatial resolution with tracer-speci c phantoms [12].…”

Section: Introductionmentioning

confidence: 99%

Preliminary Protocol for Measuring the Reproducibility and Accuracy of Flow values on Digital PET/CT Systems in [15O]H2O Myocardial Perfusion Imaging Using a Flow Phantom

Siekkinen,

Partanen,

Kukola

et al. 2023

Preprint

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Background: Several factors may decrease the accuracy of quantitative PET myocardial perfusion imaging (MPI). It is therefore essential to ensure that myocardial blood flow (MBF) values are reproducible and accurate, and to design systematic protocols for assessing this. Until now, no systematic phantom protocols have been available to assess the technical factors affecting measurement accuracy and reproducibility in MPI. Materials and Methods: We implemented a standard measurement protocol, which applies a flow phantom in order to compare image-derived flow values with respect to a ground truth flow value with [15O]H2O MPI performed on both a Discovery MI (DMI-20, GE Healthcare) and a Biograph Vision 600 (Vision-600, Siemens Healthineers) system. Both systems have automatic [15O]H2O radio water generators (Hidex Oy) individually installed, allowing us to also study the differences occurring due to two different bolus delivery systems. To investigate the technical factors contributing to the modelled flow values, we extracted the [15O]H2O bolus profiles, the flow values from the kinetic modeling (Qin and Qout), and finally calculated their differences between test-retest measurements on both systems. Results: The input time activity curves (TAC) showed dependency on the bolus injection curves. The measurements performed on the DMI-20 system produced Qin and Qout values equal to each other as well as to the reference flow value across all test-retest measurements. Also, all DMI-20 repeatability differences were below 15 %. The measurements performed on the Vision-600 system showed more variation between Qin and Qout values across test-retest measurements and exceeded the 15 % difference in half (6/12) of the measurements. Conclusions: This preliminary study proposes a protocol for measuring the accuracy and reproducibility of flow between different injector and PET systems. Our results suggest that flow values can be reproduced on DMI-20 or Vision-600 systems and with two different injector systems, with less than 15 % error. The most significant factor contributing to the variation was the injected bolus, which directly affects the phantom input TAC. In order to extend the protocol to a multi-center setting, a standardized and repeatable bolus injection protocol needs to be designed.

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A review of harmonization strategies for quantitative PET

Cited by 7 publications

References 131 publications

Characterization of sacral chordoma and differential diagnosis from other sacral malignancy using [18F]FDG PET/CT

Characterization of sacral chordoma and differential diagnosis from other sacral malignancy using [18F]FDG PET/CT

Prediction of misfolded proteins spreading in Alzheimer’s disease using machine learning and spreading models

Preliminary Protocol for Measuring the Reproducibility and Accuracy of Flow values on Digital PET/CT Systems in [15O]H2O Myocardial Perfusion Imaging Using a Flow Phantom

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