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Purpose: New generation of receptor tyrosine kinase inhibitors (RTKIs) have shown to improve survival in many solid tumors. However, an imaging biomarker is needed for patient selection and prediction of treatment response. This study evaluates the use of quantitative changes of HER3 on 68 Ga-NOTA-HER3P1 PET/MRI for prediction of early response to pan-RTKIs in gastric cancer (GCa).Procedures: GCa cell lines were evaluated for expression of RTKs, and downstream signaling pathways (AKT and MAPK). Cell viability was assessed following 24-72 h of treatment with 0.01-1 µmol/L of afatinib, a pan-RTKI. HER3-expressing afatinib-sensitive (NCI-N87) and resistant cells (SNU16) were selected for evaluation of changes in RTKs expression and downstream pathways, with 24-72 h of 0.1 µmol/L afatinib treatment. 68 Ga-NOTA-HER3P1 PET/MRI was performed in subcutaneous NCI-N87 and SNU16 xenografts (nu:nu, n = 12/group) at baseline and 4 days after afatinib treatment (10 mg/kg, PO, daily). Temporal changes in PET measures were correlated to HER3 expression in tumors, tumor growth rate, and treatment response.Results: With afatinib therapy, NCI-N87 cells showed increased total HER3 expression, and reduction of other RTKs and downstream nodes within 72 h, while SNU16 cells showed no significant change in total HER3 and downstream nodes. 68 Ga-HER3P1 PET/MRI showed increased uptake in NCI-N87 and no significant change in SNU16 tumors (day 4 vs. baseline SUVmean: 3.8 ± 0.7 vs. 1.6 ± 0.6, p < 0.05 in NCI-N87, and 1.5 ± 0.7 vs. 1.7 ± 0.7, p > 0.05 in SNU16). These findings were in concordance with HER3 expression in histopathological analyses and tumor growth over 3 weeks of treatment (mean tumor volume in treated vs. control: 11 ± 17 mm3 vs. 293 ± 79 mm3, p < 0.001 in NCI-N87, and 238 ± 91 mm3 vs. 282 ± 35 mm3, p > 0.05 in SNU16).Conclusions: Quantitative changes in HER3 PET could be used to predict response to pan-RTKI within few days after initiation of treatment and can help with personalizing GCa management. [ABSTRACT FROM AUTHOR]

Purpose : To evaluate the correlation of radiomic features in pelvic [2-deoxy-2-18F]fluoro-d-glucose positron emission tomography/magnetic resonance imaging and computed tomography ([18F]FDG PET/MRI and [18F]FDG PET/CT) in patients with primary cervical cancer (CCa). Procedures: Nineteen patients with histologically confirmed primary squamous cell carcinoma of the cervix underwent same-day [18F]FDG PET/MRI and PET/CT. Two nuclear medicine physicians performed a consensus reading in random order. Free-hand regions of interest covering the primary cervical tumors were drawn on PET, contrast-enhanced pelvic CT, and pelvic MR (T2 weighted and ADC) images. Several basic imaging features, standard uptake values (SUVmean, SUVmax, and SUVpeak), total lesion glycolysis (TLG), metabolic tumor volume (MTV), and more advanced texture analysis features were calculated. Pearson's correlation test was used to assess the correlation between each pair of features. Features were compared between local and metastatic tumors, and their role in predicting metastasis was evaluated by receiver operating characteristic curves. Results: For a total of 101 extracted features, 1104/5050 pairs of features showed a significant correlation (ρ ≥ 0.70, p < 0.05). There was a strong correlation between 190/484 PET pairs of features from PET/MRI and PET/CT, 91/418 pairs of CT and PET from PET/CT, 79/418 pairs of T2 and PET from PET/MRI, and 50/418 pairs of ADC and PET from PET/MRI. Significant difference was seen between eight features in local and metastatic tumors including MTV, TLG, and entropy on PET from PET/CT; MTV and TLG on PET from PET/MRI; compactness and entropy on T2; and entropy on ADC images. Conclusions: We demonstrated strong correlation of many extracted radiomic features between PET/MRI and PET/CT. Eight radiomic features calculated on PET/CT and PET/MRI were significantly different between local and metastatic CCa. This study paves the way for future studies to evaluate the diagnostic and predictive potential of radiomics that could guide clinicians toward personalized patients care. [ABSTRACT FROM AUTHOR]

Purpose: Imaging is central to the diagnosis and management of Pancreatic Ductal Adenocarcinoma (PDAC). This study evaluated if positron emission tomography (PET)/magnetic resonance imaging (MRI) elicited treatment modifications in PDAC when compared to standard of care imaging (SCI). Procedures: This retrospective study included consecutive patients with PDAC who underwent 2-deoxy-2-[18F]fluoro-d-glucose ([18F]F-FDG) PET/MRI and SCI from May 2017 to January 2019. SCI included abdominal computed tomography (CT), MRI, and/or PET/CT. For patients who had more than one pair of PET/MRI and SCI, each management decision was independently evaluated. Treatment strategies based on each modality were extracted from electronic medical records. Follow-up was evaluated until January 2020. Results: Twenty-five patients underwent 37 PET/MRI's, mean age was 65 ± 9 years and 13 (13/25, 52 %) were men. 49 % (18/37, 95 % CI 33–64 %) of the PET/MRI scans changed clinical management. Whether the SCI included a PET/CT or not did not significantly modify the probability of management change (OR = 0.9, 95 % CI 0.2–4, p = 1). One hundred percent (33/33) of the available follow-up data confirmed PET/MRI findings. Conclusions: PET/MRI significantly changed PDAC management, consistently across the different SCI modalities it was compared to. These findings suggest a role for PET/MRI in the management of PDAC. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to explore possible correlations among different imaging features from 2-deoxy-2-[18F]fluoro-D-Glucose positron emission tomography/magnetic resonance imaging (PET/MRI) in rectal cancer (RC). Procedures: RC patients who underwent PET/MRI were enrolled. A region of interest (ROI) was drawn around each primary RC on PET/MRI images (PET, pelvic axial T2w, and apparent diffusion coefficient maps (ADC)). Multiple imaging features were assessed, and Pearson's correlation was used to explore possible correlations among them. Results: A total of 13 patients were included, mean age 56.1 years old, 6 females. A strong inverse correlation was observed between SUVpeak and ADCmean values, MTV and T2 sphericity, MTV and ADC sphericity, MTV and T2 entropy, and TLG and ADC sphericity. There was also strong direct correlation between PET entropy and ADC sphericity. Conclusions: In conclusion, several clinically relevant correlations were observed between PET and MRI imaging features. These findings show how the use of both modalities provides complementary information. [ABSTRACT FROM AUTHOR]

Publisher Correction to: PET/MRI and PET/CT Radiomics in Primary Cervical Cancer: A Pilot Study on the Correlation of Pelvic PET, MRI, and CT Derived Image Features B Correction to: Molecular Imaging and Biology b https://doi.org/10.1007/s11307-021-01658-1 This article was updated to include the statement "Shadi A. Esfahani and Angel Torrado-Carvajal contributed equally to this manuscript." Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. [Extracted from the article]