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BACKGROUND: This study aimed to assess the impact of dedicated cardiac protocol (DCP) on diagnostic accuracy of state-of-the-art digital [18F]-FDG-PET/CT in infective endocarditis (IE) and the intra-individual comparison of the performance with that of conventional whole-body approach (WBA) and to analyze the effects of the expertise level of the investigators. METHODS: 44 patients suspected for IE underwent digital-FDG-PET/CT after overnight fasting. Each three consultants and trainees reread PET images blinded to the examination approach and clinical information. Visual and semiquantitative analyses were performed. RESULTS: Digital-FDG-PET/CT with DCP revealed sensitivity, specificity, and accuracy of 89%, 93%, and 91% for native valve endocarditis (NVE) and 93%, 86%, and 91% for prosthetic valve endocarditis. Compared to WBA, substantial improvement of the diagnostic performance for NVE in DCP was evident, especially in trainees, but not as high compared to consultants. Digital-FDG-PET/CT enabled 79.5% reclassification of modified-Duke-Clinical-Criteria (mDC) with 34.1% upgrading and 45.4% downgrading. CONCLUSIONS: This study provides new data using state-of-the-art digital-FDG-PET/CT with DCP improving the diagnostic accuracy in challenging cases of possible IE, particularly in NVE, provided that the investigators involved have the necessary expertise. These findings may have a significant impact on IE-related morbidity, mortality, and patient's management and might be meaningful for updates on the prevailing opinion regarding the value of FDG PET/CT in NVE.
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BACKGROUND: This work investigated the impact of different cardiac gating methods on the assessment of cardiac function by FDG-PET in a cross-validation PET/MR study. METHODS AND RESULTS: MR- and PET-based left ventricular end-diastolic, end-systolic volumes, and ejection fraction (EDV, ESV, and EF) were delineated in 30 patients with a PET/MR examination. Cardiac PET imaging was performed using three ECG gating methods: fixed number of gates per beat (STD), STD with a beat acceptance window (STD-BR), and fixed gate duration (FW). High MR-PET correlations were found in all the values. ESVs correlated better than EDVs and EFs: Pearson's r coefficient [0.92, 0.92, 0.92] in ESV vs [0.75, 0.81, 0.80] in EDV and [0.79, 0.91, 0.87] in EF, for each method [STD, STD-BR, FW]. Biases with respect to MRI for all the evaluated PET methods were less than 13% in EDV, 5% in ESV, and 14% in EF, but with wide limits of agreements, in the range (59-68)% in EDV, (65-70)% in ESV, and (49-71)% in EF. STD showed the strongest disagreement, while there were no marked differences between STD-BR and FW. CONCLUSION: Based on these findings, PET- and MR-based cardiac function parameters were highly correlated but in substantial disagreement with variabilities introduced by the selected PET ECG gating method. The most significant differences were associated with the ECG gating method susceptible to highly irregular beats, while similar performance was observed in the methods using uniform adjustment of gates width per beat with the beat acceptance window, and fixed gate width along all the beats. Thus, strict quality controls of R peak detection are needed to minimize its impact on the function assessment.
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Tomografia por Emissão de Pósitrons , Humanos , Eletrocardiografia/métodos , Imageamento por Ressonância Magnética , Tomografia por Emissão de Pósitrons/métodos , Reprodutibilidade dos Testes , Volume Sistólico , Função Ventricular EsquerdaRESUMO
PURPOSE: To evaluate the performance of combined PET and multiparametric MRI (mpMRI) radiomics for the group-wise prediction of postsurgical Gleason scores (psGSs) in primary prostate cancer (PCa) patients. METHODS: Patients with PCa, who underwent [68 Ga]Ga-PSMA-11 PET/MRI followed by radical prostatectomy, were included in this retrospective analysis (n = 101). Patients were grouped by psGS in three categories: ISUP grades 1-3, ISUP grade 4, and ISUP grade 5. mpMRI images included T1-weighted, T2-weighted, and apparent diffusion coefficient (ADC) map. Whole-prostate segmentations were performed on each modality, and image biomarker standardization initiative (IBSI)-compliant radiomic features were extracted. Nine support vector machine (SVM) models were trained: four single-modality radiomic models (PET, T1w, T2w, ADC); three PET + MRI double-modality models (PET + T1w, PET + T2w, PET + ADC), and two baseline models (one with patient data, one image-based) for comparison. A sixfold stratified cross-validation was performed, and balanced accuracies (bAcc) of the predictions of the best-performing models were reported and compared through Student's t-tests. The predictions of the best-performing model were compared against biopsy GS (bGS). RESULTS: All radiomic models outperformed the baseline models. The best-performing (mean ± stdv [%]) single-modality model was the ADC model (76 ± 6%), although not significantly better (p > 0.05) than other single-modality models (T1w: 72 ± 3%, T2w: 73 ± 2%; PET: 75 ± 5%). The overall best-performing model combined PET + ADC radiomics (82 ± 5%). It significantly outperformed most other double-modality (PET + T1w: 74 ± 5%, p = 0.026; PET + T2w: 71 ± 4%, p = 0.003) and single-modality models (PET: p = 0.042; T1w: p = 0.002; T2w: p = 0.003), except the ADC-only model (p = 0.138). In this initial cohort, the PET + ADC model outperformed bGS overall (82.5% vs 72.4%) in the prediction of psGS. CONCLUSION: All single- and double-modality models outperformed the baseline models, showing their potential in the prediction of GS, even with an unbalanced cohort. The best-performing model included PET + ADC radiomics, suggesting a complementary value of PSMA-PET and ADC radiomics.
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Imageamento por Ressonância Magnética Multiparamétrica , Neoplasias da Próstata , Humanos , Masculino , Gradação de Tumores , Prostatectomia , Neoplasias da Próstata/patologia , Estudos RetrospectivosRESUMO
Here, we present a case with a pacemaker due to an atrioventricular (AV) block 2 Mobitz type, in whom a gating failure resulted in a relevant underestimation of cardiac function in myocardial perfusion scintigraphy. A set of quality control steps for gating errors is proposed.
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Bloqueio Atrioventricular , Marca-Passo Artificial , Humanos , Imagem de Perfusão , Tomografia Computadorizada por Raios XRESUMO
Our previous study has demonstrated the feasibility of noninvasive imaging of fibroblast activation protein (FAP)-expression after myocardial infarction (MI) in MI-territory in a rat model with 68Ga-FAPI-04-PET. In the current extended clinical case, we sought to delineate cardiac uptake of 68Ga-FAPI-04 in a patient after MI with clinical indication for the evidence of fibroblast activation. Carcinoma patients without cardiac disease underwent 68Ga-FAPI-04-PET/CT as control. The patient with one-vessel disease underwent dynamic 68Ga-FAPI-04-cardiac-PET/CMR for 60 minutes. Correlation of cardiac 68Ga-FAPI-04 uptake with clinical findings, ECG, echocardiography, coronary-arteriography and enhanced cardiac-MRI with T1 MOLLI and ECV mapping were performed. No uptake was found in normal myocardium and in mature scar. A focal intense 68Ga-FAPI-04 uptake with continuous wash-out in the infarct territory of coronary occlusion correlating with T1 and ECV mapping was observed. The uptake of 68Ga-FAPI-04 extends beyond the actual infarcted area and overestimates the infarct size as confirmed by follow-up CMR.
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Radioisótopos de Gálio , Infarto do Miocárdio , Animais , Fibroblastos/metabolismo , Fibroblastos/patologia , Proteínas de Membrana/metabolismo , Infarto do Miocárdio/diagnóstico por imagem , Infarto do Miocárdio/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Quinolinas , RatosRESUMO
BACKGROUND: In patients with increasing PSA and suspicion for prostate cancer, but previous negative biopsies, PET/MRI is used to test for tumours and target potential following biopsy. We aimed to determine different PSMA PET timing effects on signal kinetics and test its correlation with the patients' PSA and Gleason scores (GS). METHODS: A total of 100 patients were examined for 900 s using PET/MRI approximately 1-2 h p.i. depending on the tracer used (68Ga-PSMA-11, 18F-PSMA-1007 or 18F-rhPSMA7). The scans were reconstructed in static and dynamic mode (6 equal frames capturing "late" PSMA dynamics). TACs were computed for detected lesions as well as linear regression plots against time for static (SUV) and dynamic (SUV, SUL, and percent injected dose per gram) parameters. All computed trends were tested for correlation with PSA and GS. RESULTS: Static and dynamic scans allowed unchanged lesion detection despite the difference in statistics. For all tracers, the lesions in the pelvic lymph nodes and bones had a mostly negative activity concentration trend (78% and 68%, resp.), while a mostly positive, stronger trend was found for the lesions in the prostate and prostatic fossa following RPE (84% and 83%, resp.). In case of 68Ga-PSMA-11, a strong negative (Rmin = - 0.62, Rmax = - 0.73) correlation was found between the dynamic parameters and the PSA. 18F-PSMA-1007 dynamic data showed no correlation with PSA, while for 18F-rhPSMA7 dynamic data, it was consistently low positive (Rmin = 0.29, Rmax = 0.33). All tracers showed only moderate correlation against GS (Rmin = 0.41, Rmax = 0.48). The static parameters showed weak correlation with PSA (Rmin = 0.24, Rmax = 0.36) and no correlation with GS. CONCLUSION: "Late" dynamic PSMA data provided additional insight into the PSMA kinetics. While a stable moderate correlation was found between the PSMA kinetics in pelvic lesions and GS, a significantly variable correlation with the PSA values was shown depending on the radiotracer used, the highest being consistently for 68Ga-PSMA-11. We reason that with such late dynamics, the PSMA kinetics are relatively stable and imaging could even take place at earlier time points as is now in the clinical routine.
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When this article was written, it coincided with the 11th anniversary of the installation of our PET/MR device in Munich. In fact, this was the first fully integrated device to be in clinical use. During this time, we have observed many interesting behaviors, to put it kindly. However, it is more critical that in this process, our understanding of the system also improved - including the advantages and limitations from a technical, logistical, and medical perspective. The last decade of PET/MRI research has certainly been characterized by most sites looking for a "key application." There were many ideas in this context and before and after the devices became available, some of which were based on the earlier work with integrating data from single devices. These involved validating classical PET methods with MRI (eg, perfusion or oncology diagnostics). More important, however, were the scenarios where intermodal synergies could be expected. In this review, we look back on this decade-long journey, at the challenges overcome and those still to come.