European Journal of Nuclear Medicine and Molecular Imaging最新文献

Purpose: A hypometabolic profile involving the limbic areas, brainstem and cerebellum has been identified in long COVID patients using [¹⁸F]fluorodeoxyglucose (FDG)-PET. This study was conducted to evaluate possible recovery of brain metabolism during the follow-up of patients with prolonged symptoms.

Methods: Fifty-six adults with long COVID who underwent two brain [¹⁸F]FDG-PET scans in our department between May 2020 and October 2022 were retrospectively analysed, and compared to 51 healthy subjects. On average, PET1 was performed 7 months (range 3-17) after acute COVID-19 infection, and PET2 was performed 16 months (range 8-32) after acute infection, because of persistent severe or disabling symptoms, without significant clinical recovery. Whole-brain voxel-based analysis compared PET1 and PET2 from long COVID patients to scans from healthy subjects (p-voxel < 0.001 uncorrected, p-cluster < 0.05 FWE-corrected) and PET1 to PET2 (with the same threshold, and secondarily with a less constrained threshold of p-voxel < 0.005 uncorrected, p-cluster < 0.05 uncorrected). Additionally, a region-of-interest (ROI) semiquantitative anatomical approach was performed for the same comparisons (p < 0.05, corrected).

Results: PET1 and PET2 revealed voxel-based hypometabolisms consistent with the previously reported profile in the literature. This between-group analysis comparing PET1 and PET2 showed minor improvements in the pons and cerebellum (8.4 and 5.2%, respectively, only significant under the less constrained uncorrected p-threshold); for the pons, this improvement was correlated with the PET1-PET2 interval (r = 0.21, p < 0.05). Of the 14,068 hypometabolic voxels identified on PET1, 6,503 were also hypometabolic on PET2 (46%). Of the 7,732 hypometabolic voxels identified on PET2, 6,094 were also hypometabolic on PET1 (78%). The anatomical ROI analysis confirmed the brain hypometabolism involving limbic region, the pons and cerebellum at PET1 and PET2, without significant changes between PET1 and PET2.

Conclusion: Subjects with persistent symptoms of long COVID exhibit durable deficits in brain metabolism, without progressive worsening.

Purpose

This study aimed to evaluate a novel technique for cell tracking by visualising the activity of the human sodium/iodide symporter (hNIS) after transplantation of hNIS-expressing multilayered cell sheets in a rat model of chronic myocardial infarction.

Methods

Triple-layered cell sheets were generated from mouse embryonic fibroblasts (MEFs) derived from mice overexpressing hNIS (hNIS-Tg). Myocardial infarction was induced by permanent ligation of the left anterior descending coronary artery in F344 athymic rats, and a triple-layered MEFs sheets were transplanted to the infarcted area two weeks after surgery. To validate the temporal tracking and kinetic analysis of the transplanted MEFs sheets, sequential cardiac single-photon emission computed tomography (SPECT) examinations with a ^99mTcO₄^– injection were performed. The cell sheets generated using MEFs of wild-type mice (WT) served as controls.

Results

A significantly higher amount of ^99mTcO₄^– was taken into the hNIS-Tg MEFs than into WT MEFs (146.1 ± 30.9-fold). The obvious accumulation of ^99mTcO₄^– was observed in agreement with the region where hNIS-Tg MEFs were transplanted, and these radioactivities peaked 40–60 min after ^99mTcO₄^– administration. The volume of distribution of the hNIS-Tg MEF sheets declined gradually after transplantation, implying cellular malfunction and a loss in the number of transplanted cells.

Conclusion

The reporter gene imaging with hNIS enables the serial tracking and quantitative kinetic analysis of cell sheets transplanted to infarcted hearts.

We provide updated guidance and standards for the indication, acquisition, and interpretation of [¹⁸F]FDG PET/CT for plasma cell disorders. Procedures and characteristics are reported and different scenarios for the clinical use of [¹⁸F]FDG PET/CT are discussed. This document provides clinicians and technicians with the best available evidence to support the implementation of [¹⁸F]FDG PET/CT imaging in routine practice and future research.

Purpose

to assess the utility of response monitoring to enzalutamide by using [⁶⁸Ga]Ga-PSMA PET in mCRPC patients treated with enzalutamide as first-line therapy.

Methods

patients underwent [⁶⁸Ga]Ga-PSMA PET less than 8 weeks before and 3 months after starting enzalutamide. On the basis of EAU/EANM criteria, patients were categorized as PSMA responders (PET-R) or PSMA non-responders (PET-NR), whilst, based on PSA, they were classified as biochemical responders (PSA-R) or non-responders (PSA-NR). Survival analysis was performed using the Cox regression hazard model and the Kaplan-Meier method.

Results

69 patients were considered fully evaluable. We observed 47.8% of concordance between [68Ga]Ga-PSMA PET and PSA monitoring at 3 months after starting enzalutamide. For discordant cases, the PSA reduction has a weak impact on PFS and a significant impact on OS in PET-NR patients, whilst this change has no impact either for PFS and OS in PET-R ones.

Conclusions

[⁶⁸Ga]Ga-PSMA PET could be a useful imaging tool for monitoring response to enzalutamide in mCRPC patients, being more informative than PSA in this setting, and possibly better guiding clinicians in therapeutic decisions.

Purpose

In metastatic castration-resistant prostate cancer (mCRPC), some patients show low/absent PSMA expression in tumour lesions on positron emission tomography (PET) scans, indicating heterogeneity and heightened risk of non-response to PSMA-RLT (radioligand therapy). Imaging cancer-associated fibroblasts and glucose uptake may further characterise tumour heterogeneity in mCRPC patients. Here, we aimed to evaluate tumour heterogeneity and its potential implications for management in mCRPC patients assessed for PSMA-RLT using [⁶⁸Ga]Ga-FAPI-46, 2-[¹⁸F]FDG and [⁶⁸Ga]Ga-/[¹⁸F]F-PSMA-11/-1007 PET.

Material and Methods

Patients with advanced, progressive mCRPC underwent clinical [⁶⁸Ga]Ga-/[¹⁸F]F-PSMA-11/-1007, 2-[¹⁸F]FDG and [⁶⁸Ga]Ga-FAPI-46 PET/CT to evaluate treatment with PSMA-directed RLT. Tumour detection/semiquantitative parameters were compared on a per-lesion/-region basis. Two phenotypes were defined: Criteria for the mixed phenotype were: (a) PSMA-negative findings for lymph node metastases ≥ 2.5 cm, any solid organ metastases ≥ 1.0 cm, or bone metastases with soft tissue component ≥ 1.0 cm, (b) low [⁶⁸Ga]Ga-/[¹⁸F]F-PSMA-11/-1007 uptake and/or (c) balanced tumour uptake of all radioligands. The PSMA-dominant phenotype was assigned if the criteria were not met.

Results

In ten patients, 472 lesions were detected on all imaging modalities (miTNM regions: M1b: 327 (69.3%), M1a: 95 (20.1%), N1: 26 (5.5%), M1c: 18 (3.8%), T: 5 (1.1%) and Tr: 1 (0.2%). [⁶⁸Ga]Ga-/[¹⁸F]F-PSMA-11/-1007 (n = 453 (96.0%)) demonstrates the highest detection rate, followed by [⁶⁸Ga]Ga-FAPI-46 (n = 268 (56.8%))/2-[¹⁸F]FDG (n = 241 (51.1%)). Semiquantitative uptake was highest for [⁶⁸Ga]Ga-/[¹⁸F]F-PSMA-11/-1007 (mean SUV_max (interquartile range): 22.7 (22.5), vs. [⁶⁸Ga]Ga-FAPI-46 (7.7 (3.7)) and 2-[¹⁸F]FDG (6.8 (4.7)). Seven/three patients were retrospectively assigned to the PSMA-dominant/mixed phenotype. Median overall survival was significantly longer for patients who underwent [¹⁷⁷Lu]Lu-PSMA-617 RLT and were retrospectively assigned to the PSMA-dominant phenotype (19.7 vs. 9.3 months).

Conclusion

Through whole-body imaging, we identify considerable inter- and intra-patient heterogeneity of mCRPC and potential imaging phenotypes. Regarding uptake and tumour detection, [⁶⁸Ga]Ga-/[¹⁸F]F-PSMA-11/-1007 was superior to [⁶⁸Ga]Ga-FAPI-46 and 2-[¹⁸F]FDG, while the latter two were comparable. Patients who underwent [¹⁷⁷Lu]Lu-PSMA-617 RLT based on clinical-decision making had a longer overall survival and could be assigned to

Purpose: [¹⁸F]SynVesT-1 is a novel radiopharmaceutical for assessing synaptic density in vivo. This study aims to investigate the potential of [¹⁸F]SynVesT-1 positron emission tomography (PET) in evaluating neurological recovery in the rat model of ischemic stroke, and to compare its performance with [¹⁸F]FDG PET.

Methods: Sprague-Dawley rats were subjected to photothrombotic cerebral infarction, and safinamide was administered intraperitoneally from day 3 to day 14 post-stroke to alleviate neurological deficits. Cylinder test and forelimb placing test were performed to assess the neurological function. MRI, [¹⁸F]SynVesT-1 PET/CT and [¹⁸F]FDG PET/CT imaging were used to evaluate infarct volume, synaptic density, and cerebral glucose metabolism pre- and post-treatment. [¹⁸F]SynVesT-1 and [¹⁸F]FDG PET images were compared using Statistical Parametric Mapping (SPM) and region of interest (ROI)-based analysis. Post-mortem histological analysis was performed to validate PET images.

Results: Safinamide treatment improved behavioral outcomes in stroke-damaged rats. Both [¹⁸F]SynVesT-1 and [¹⁸F]FDG PET detected stroke-induced injury, with the injured region being significantly larger in [¹⁸F]FDG PET than in [¹⁸F]SynVesT-1 PET. Compared with the saline group, radiotracer uptake in the injured area significantly increased in [¹⁸F]SynVesT-1 PET after safinamide treatment, whereas no notable change was observed in [¹⁸F]FDG PET. Additionally, [¹⁸F]SynVesT-1 PET imaging showed a better correlation with neurological function recovery than [¹⁸F]FDG PET. Post-mortem analysis revealed increased neuronal numbers, synaptic density, and synaptic neuroplasticity, as well as decreased glia activation in the stroke-injured area after treatment.

Conclusion: [¹⁸F]SynVesT-1 PET effectively quantified spatiotemporal dynamics of synaptic density in the rat model of stroke, and showed different capabilities in detecting stroke injury and neurological recovery compared with [¹⁸F]FDG PET. The utilization of [¹⁸F]SynVesT-1 PET holds promise as a potential non-invasive biomarker for evaluating ischemic stroke in conjunction with [¹⁸F]FDG PET.