Preparing data for multiparametric PET/MR imaging: Influence of PET point spread function modelling and EPI distortion correction on the spatial correlation of [18F]FDG-PET and diffusion-weighted MRI in head and neck cancer

Olin, Anders B.; Krogager, Louise; Rasmussen, Jacob; Andersen, Flemming; Specht, Lena; Beyer, Thomas; Kjær, Andreas; Fischer, Barbara; Hansen, Adam E.

doi:10.1016/j.ejmp.2019.04.006

Cited by 9 publications

(7 citation statements)

References 31 publications

(57 reference statements)

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“…The voxel-by-voxel analysis of parameter maps revealed weak correlations between RGD and FDG uptake, which varied strongly within the patient cohort, indicating that they provide different and potentially complementary information about the tumor. Our results demonstrated an average correlation coe cient of -0.7 between FDG uptake and ADC values, in line with earlier studies (26,43,44), while the correlation between ADC and RGD uptake was weaker.…”

Section: Discussionsupporting

confidence: 92%

Multi-parametric PET/MRI With FDG and RGD for Enhanced Tumor Characterization of Patients With Cervical Cancer

Ahangari

Andersen

Hansen

et al. 2022

Preprint

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Aim: The concept of personalized medicine has brought increased awareness to the importance of inter- and intra-tumor heterogeneity for cancer treatment. The aim of this study was to explore simultaneous multi-parametric PET/MRI prior to chemoradiotherapy for cervical cancer for characterization of tumors and tumor heterogeneity. Methods: Ten patients with histologically proven primary cervical cancer were examined with multi-parametric 68Ga-NODAGA-E[c(RGDyK)]2-PET/MRI for radiation treatment planning after diagnostic 18F-FDG-PET/CT. Standardized uptake values (SUV) of RGD and FDG, diffusion weighted MRI and the derived apparent diffusion coefficient (ADC), and pharmacokinetic maps obtained from dynamic contrast-enhanced MRI with the Tofts model (iAUC60, Ktrans, ve, and kep) were included in the analysis. The spatial relation between functional imaging parameters in tumors was examined by a correlation analysis and joint histograms at the voxel level. The ability of multi-parametric imaging to identify tumor tissue classes was explored using an unsupervised 3D Gaussian mixture model-based cluster analysis.Results: Functional MRI and PET of cervical cancers appeared heterogeneous both between patients and spatially within the tumors, and the relations between parameters varied strongly within the patient cohort. The strongest spatial correlation was observed between FDG uptake and ADC (median r=-0.7). There was moderate voxel-wise correlation between RGD and FDG uptake, and weak correlations between all other modalities. Distinct relations between the ADC and RGD uptake as well as the ADC and FDG uptake were apparent in joint histograms. A cluster analysis using the combination of ADC, FDG and RGD uptake suggested tissue classes which could potentially relate to tumor sub-volumes. Conclusion: A multi-parametric PET/MRI examination of patients with cervical cancer integrated with treatment planning and including estimation of angiogenesis and glucose metabolism as well as MRI diffusion and perfusion parameters is feasible. A combined analysis of functional imaging parameters indicates a potential of multi-parametric PET/MRI to contribute to a better characterization of tumor heterogeneity than the modalities alone. However, the study is based on small patient numbers and further studies are needed prior to the future design of individually adapted treatment approaches based on multi-parametric functional imaging.

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Section: Discussionsupporting

confidence: 92%

Multi-parametric PET/MRI With FDG and RGD for Enhanced Tumor Characterization of Patients With Cervical Cancer

Ahangari

Andersen

Hansen

et al. 2022

Preprint

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“…Other sequences, such as those for diffusion weighted MRI, are more prone to geometric distortions, but these can potentially also be corrected for. 43 One benefit of the presented deep learning network is that its input relies solely on the fast (19-second) Dixon sequence, which is acquired as a standard in all routine PET/MRI examinations, regardless of the anatomic site.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of Multiparametric Positron Emission Tomography/Magnetic Resonance Imaging as a One-Stop Shop for Radiation Therapy Planning for Patients with Head and Neck Cancer

Olin

Hansen

Rasmussen

et al. 2020

International Journal of Radiation Oncology*Biology*Physics

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Purpose: Multiparametric positron emission tomography (PET)/magnetic resonance imaging (MRI) as a one-stop shop for radiation therapy (RT) planning has great potential but is technically challenging. We studied the feasibility of performing multiparametric PET/MRI of patients with head and neck cancer (HNC) in RT treatment position. As a step toward planning RT based solely on PET/MRI, a deep learning approach was employed to generate synthetic computed tomography (sCT) from MRI. This was subsequently evaluated for dose calculation and PET attenuation correction (AC). Methods and Materials: Eleven patients, including 3 pilot patients referred for RT of HNC, underwent PET/MRI in treatment position after a routine fluorodeoxyglucose-PET/CT planning scan. The PET/MRI scan protocol included multiparametric imaging. A convolutional neural network was trained in a leave-one-out process to predict sCT from the Dixon MRI. The clinical CT-based dose plans were recalculated on sCT, and the plans were compared in terms of relative differences in mean,

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“…Thanks to the information provided by PET, the improved TOF and the PFS, fewer MRI sequences are necessary in PET/MRI, therefore shortening the exploration time. Nevertheless, the examinations are still significantly longer and more uncomfortable than those of PET/CT [ 18 ]. This fact, added to the few PET/MRI pieces of equipment available, and their high cost, are its main drawbacks.…”

Section: Discussionmentioning

confidence: 99%

Same-day comparative protocol PET/CT-PET/MRI [68 Ga]Ga-DOTA-TOC in paragangliomas and pheochromocytomas: an approach to personalized medicine

et al. 2023

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Background PET/MRI is an emerging imaging modality which enables the evaluation and quantification of biochemical processes in tissues, complemented with accurate anatomical information and low radiation exposure. In the framework of theragnosis, PET/MRI is of special interest due to its ability to delineate small lesions, adequately quantify them, and therefore to plan targeted therapies. The aim of this study was to validate the diagnostic performance of [68 Ga]Ga-DOTA-TOC PET/MRI compared to PET/CT in advanced disease paragangliomas and pheochromocytomas (PGGLs) to assess in which clinical settings, PET/MRI may have a greater diagnostic yield. Methods We performed a same-day protocol with consecutive acquisition of a PET/CT and a PET/MRI after a single [68 Ga]Ga-DOTA-TOC injection in 25 patients. Intermodality agreement, Krenning Score (KS), SUVmax (Standard Uptake Value), target-to-liver-ratio (TLR), clinical setting, location, and size were assessed. Results The diagnostic accuracy with PET/MRI increased by 14.6% compared to PET/CT especially in bone and liver locations (mean size of new lesions was 3.73 mm). PET/MRI revealed a higher overall lesion uptake than PET/CT (TLR 4.12 vs 2.44) and implied an upward elevation of the KS in up to 60% of patients. The KS changed in 30.4% of the evaluated lesions (mean size 11.89 mm), in 18.4% of the lesions it increased from KS 2 on PET/CT to a KS ≥ 3 on PET/MRI and 24.96% of the lesions per patient with multifocal disease displayed a KS ≥ 3 on PET/MR, that were not detected or showed lower KS on PET/CT. In 12% of patients, PET/MRI modified clinical management. Conclusions PET/MRI showed minor advantages over conventional PET/CT in the detection of new lesions but increased the intensity of SSRs expression in a significant number of them, opening the door to select which patients and clinical settings can benefit from performing PET/MRI.

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Preparing data for multiparametric PET/MR imaging: Influence of PET point spread function modelling and EPI distortion correction on the spatial correlation of [18F]FDG-PET and diffusion-weighted MRI in head and neck cancer

Cited by 9 publications

References 31 publications

Multi-parametric PET/MRI With FDG and RGD for Enhanced Tumor Characterization of Patients With Cervical Cancer

Multi-parametric PET/MRI With FDG and RGD for Enhanced Tumor Characterization of Patients With Cervical Cancer

Feasibility of Multiparametric Positron Emission Tomography/Magnetic Resonance Imaging as a One-Stop Shop for Radiation Therapy Planning for Patients with Head and Neck Cancer

Same-day comparative protocol PET/CT-PET/MRI [68 Ga]Ga-DOTA-TOC in paragangliomas and pheochromocytomas: an approach to personalized medicine

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