Initial experience in staging primary oesophageal/gastro-oesophageal cancer with 18F-FDG PET/MRI.

BACKGROUND 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) may improve cancer staging by combining sensitive cancer detection with high-contrast resolution and detail. We compared the diagnostic performance of 18F-FDG PET/MRI to 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for staging oesophageal/gastro-oesophageal cancer. Following ethical approval and informed consent, participants with newly diagnosed primary oesophageal/gastro-oesophageal cancer were enrolled. Exclusions included prior/concurrent malignancy. Following 324 ± 28 MBq 18F-FDG administration and 60-min uptake, PET/CT was performed, immediately followed by integrated PET/MRI from skull base to mid-thigh. PET/CT was interpreted by two dual-accredited nuclear medicine physicians and PET/MRI by a dual-accredited nuclear medicine physician/radiologist and cancer radiologist in consensus. Per-participant staging was compared with the tumour board consensus staging using the McNemar test, with statistical significance at 5%. RESULTS Out of 26 participants, 22 (20 males; mean ± SD age 68.8 ± 8.7 years) completed 18F-FDG PET/CT and PET/MRI. Compared to the tumour board, the primary tumour was staged concordantly in 55% (12/22) with PET/MRI and 36% (8/22) with PET/CT; the nodal stage was concordant in 45% (10/22) with PET/MRI and 50% (11/22) with PET/CT. There was no statistical difference in PET/CT and PET/MRI staging performance (p > 0.05, for T and N staging). The staging of distant metastases was concordant with the tumour board in 95% (21/22) with both PET/MRI and PET/CT. Of participants with distant metastatic disease, PET/MRI detected additional metastases in 30% (3/10). CONCLUSION In this preliminary study, compared to 18F-FDG PET/CT, 18F-FDG PET/MRI showed non-significant higher concordance with T-staging, but no difference with N or M-staging. Additional metastases detected by 18F-FDG PET/MRI may be of additive clinical value

Are staging F-18-FDG PET/MRI radiomic features associated with metastases in cancer of the gastro-esophageal junction?

Purpose: To identify quantitative imaging biomarkers at staging F-18-Fluorodeoxyglucose (FDG)-positron-emission-tomography/magnetic-resonance-imaging (PET/MRI) for predicting distant metastasis in patients with gastro-esophageal junction(GEJ) cancer. Materials and Methods: Following IRB approval and informed consent, 24 patients with histologically proven GEJ cancer were prospectively recruited; 4 patients were excluded for technical reasons. Finally, 19 male and 1 female (68.3\ub19.1 years) were considered. Patients were injected with 326\ub128 MBq FDG intravenously. Uptake time was 90 minutes. Two experienced radiologists and nuclear physicians reviewed the images in consensus. Maximum standardized uptake value (SUVmax) and tumor size were analyzed. First-order and second-order statistical texture features were computed on SUV values of the whole tumor volume. k-means clustering algorithm was used to assess the correlation of feature-pairs with the presence of distant metastases. Sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and accuracy (ACC) were calculated to quantify the discrimination ability of features. Results: Second-order entropy and maximum probability, linked to texture irregularity and homogeneity respectively, were the best feature-pair in discriminating patients with and without metastatic disease (SE=80%, SP=70%, PPV=73%, NPV=78%, ACC=75%). SUVmax (SE=80%, SP=30%, PPV=53%, NPV=60%, ACC=55%) and tumor size (SE=90%, SP=10%, PPV=50%, NPV=50%, ACC=50%) performed worse, particularly for specificity. Conclusions: These results confirm the common expectation that greater intra-tumor heterogeneity correlates with metastatic potential. The extraction of advanced quantitative PET imaging features from the primary lesion may help prognostication. Clinical Relevance statement: Radiomics may help in improving prognostication at staging

Exploratory radiomic features from integrated ¹⁸F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging are associated with contemporaneous metastases in oesophageal/gastroesophageal cancer

PURPOSE The purpose of this study was to determine if 18F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI) features are associated with contemporaneous metastases in patients with oesophageal/gastroesophageal cancer. METHODS Following IRB approval and informed consent, patients underwent a staging PET/MRI following 18F-FDG injection (326 ± 28 MBq) and 156 ± 23 min uptake time. First-order histogram and second-order grey level co-occurrence matrix features were computed for PET standardized uptake value (SUV) and MRI T1-W, T2-W, diffusion weighted (DWI) and apparent diffusion coefficient (ADC) images for the whole tumour volume. K-means clustering assessed the correlation of feature-pairs with metastases. Multivariate analysis of variance (MANOVA) was performed to assess the statistical separability of the groups identified by feature-pairs. Sensitivity (SN), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) were calculated for these features and compared with SUVmax, ADCmean and maximum diameter alone for predicting contemporaneous metastases. RESULTS Twenty patients (18 males, 2 female; median 67 years, range 52-86) comprised the final study cohort; ten patients had metastases. Lower second-order SUV entropy combined with higher second-order ADC entropy were the best feature-pair for discriminating metastatic patients, MANOVA p value <0.001 (SN = 80%, SP = 80%, PPV = 80%, NPV = 80%, ACC = 80%). SUVmax (SN = 30%, SP = 80%, PPV = 60%, NPV = 53%, ACC = 55%), ADCmean (SN = 20%, SP = 70%, PPV = 40%, NPV = 47%, ACC = 45%) and tumour maximum diameter (SN = 10%, SP = 90%, PPV = 50%, NPV = 50%, ACC = 50%) had poorer sensitivity and accuracy. CONCLUSION High ADC entropy combined with low SUV entropy is associated with a higher prevalence of metastases and a promising initial signature for future study

18F-FDG PET/MRI versus PET/CT in staging Gastro-Esophageal Junction cancer

Purpose: To compare F-18-Flurodeoxyglucose(FDG)-positron-emission-tomography/magnetic-resonance-imaging(PET/MRI) and PET/computed-tomography(PET/CT) in staging of gastro-esophageal junction(GEJ) cancer. Materials and Methods: Following IRB approval and informed consent, 24 patients with histologically proven GEJ cancer were prospectively recruited; 4 patients were excluded for technical reasons (19 male, 1 female; mean 68.3 +/- 9.1 years). Patients were injected with 326+/-28 MBq F-18-FDG intravenously for the clinical PET/CT. Uptake time was 60 minutes. PET/MRI was acquired directly after the PET/CT. 2 experienced radiologists and nuclear physicians reviewed the images and defined the PET/MRI-TNM stage in consensus. PET/CT NM-stage was defined clinically. They were compared to the multidisciplinary team meeting(MDT) stage, which was defined by contrast enhanced CT+/-endoscopic ultrasonography(EUS). Sensitivity(SE), Specificity(SP), positive predictive value(PPV), negative predictive value(NPV) and accuracy(AC) were calculated. McNemar test was performed to assess differences between different modalities. Results: For PET/MRI T-stage was concurred with MDT stage in 14 (70%) of 20 patients. Differences in T-stages between PET/MRI and MDT were statistically significant (p=0.03) (Table1). In our cohort, PET/MRI upstaged three T3 primary lesions as T4 and correctly assigned two T4 lesions. Both PET/MRI and PET/CT agreed in N-and M-staging in all patients. Differences in N-stage between hybrid modalities and MDT were significant (p=0.03) (6 of 20 patients) (Table2). SE, SP, PPV, NPV and AC for detection of lymph node metastases were 94%, 100%, 100%, 67% and 95% for both imaging modalities. Conclusions: PET/MRI and PET/CT performed similarly in N and M staging. PET/MRI has advantages over PET/CT in providing additional T-stage. Clinical Relevance statement: PET/MRI might be used for staging of patients with cancer of GOJ in the future. Table 1: Differences in T-stage. PET/MRI MDT 3 4 4 3 2 3 4 3 4 3 2 3 4 4 Table 2: Differences in N-stage. PET/MRI PET/MRI MDT 2 2 1 0 0 1 2 2 1 2 2 3 2 2 3 1 1

Reliability and reproducibility of pseudo-continuous arterial spin labeling (pCASL) derived measurements of cerebral blood flow: a replication study

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Simultaneous PET-MR-EEG to detect dopamine release during absence seizures

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Non-rigid Motion-compensated 3D Whole-heart T2 mapping in a hybrid 3T PET-MR system

PURPOSE: Simultaneous PET-MRI improves inflammatory cardiac disease diagnosis. However, challenges persist in respiratory motion and mis-registration between free-breathing 3D PET and 2D breath-held MR images. We propose a free-breathing non-rigid motion-compensated 3D T 2 -mapping sequence enabling whole-heart myocardial tissue characterization in a hybrid 3T PET-MR system and provides non-rigid respiratory motion fields to correct also simultaneously acquired PET data. METHODS: Free-breathing 3D whole-heart T 2 -mapping was implemented on a hybrid 3T PET-MRI system. Three datasets were acquired with different T 2 -preparation modules (0, 28, 55 ms) using 3-fold undersampled variable-density Cartesian trajectory. Respiratory motion was estimated via virtual 3D image navigators, enabling multi-contrast non-rigid motion-corrected MR reconstruction. T 2 -maps were computed using dictionary-matching. Approach was tested in phantom, 8 healthy subjects, 14 MR only and 2 PET-MR patients with suspected cardiac disease and compared with spin echo reference (phantom) and clinical 2D T 2 -mapping (in-vivo). RESULTS: Phantom results show a high correlation (R 2  = 0.996) between proposed approach and gold standard 2D T 2 mapping. In-vivo 3D T 2 -mapping average values in healthy subjects (39.0 ± 1.4 ms) and patients (healthy tissue) (39.1 ± 1.4 ms) agree with conventional 2D T 2 -mapping (healthy = 38.6 ± 1.2 ms, patients = 40.3 ± 1.7 ms). Bland-Altman analysis reveals bias of 1.8 ms and 95% limits of agreement (LOA) of -2.4-6 ms for healthy subjects, and bias of 1.3 ms and 95% LOA of -1.9 to 4.6 ms for patients. CONCLUSION: Validated efficient 3D whole-heart T 2 -mapping at hybrid 3T PET-MRI provides myocardial inflammation characterization and non-rigid respiratory motion fields for simultaneous PET data correction. Comparable T 2 values were achieved with both 3D and 2D methods. Improved image quality was observed in the PET images after MR-based motion correction. </p

Single Breath-Hold 3-Dimensional Magnetic Resonance Elastography Depicts Liver Fibrosis and Inflammation in Obese Patients

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