Showing papers in "European Journal of Nuclear Medicine and Molecular Imaging in 2020"

Imaging and clinical features of patients with 2019 novel coronavirus SARS-CoV-2.

Abstract: The pneumonia caused by the 2019 novel coronavirus (SARS-CoV-2, also called 2019-nCoV) recently break out in Wuhan, China, and was named as COVID-19. With the spread of the disease, similar cases have also been confirmed in other regions of China. We aimed to report the imaging and clinical characteristics of these patients infected with SARS-CoV-2 in Guangzhou, China. All patients with laboratory-identified SARS-CoV-2 infection by real-time polymerase chain reaction (PCR) were collected between January 23, 2020, and February 4, 2020, in a designated hospital (Guangzhou Eighth People’s Hospital). This analysis included 90 patients (39 men and 51 women; median age, 50 years (age range, 18–86 years). All the included SARS-CoV-2-infected patients underwent non-contrast enhanced chest computed tomography (CT). We analyzed the clinical characteristics of the patients, as well as the distribution characteristics, pattern, morphology, and accompanying manifestations of lung lesions. In addition, after 1–6 days (mean 3.5 days), follow-up chest CT images were evaluated to assess radiological evolution. The majority of infected patients had a history of exposure in Wuhan or to infected patients and mostly presented with fever and cough. More than half of the patients presented bilateral, multifocal lung lesions, with peripheral distribution, and 53 (59%) patients had more than two lobes involved. Of all included patients, COVID-19 pneumonia presented with ground glass opacities in 65 (72%), consolidation in 12 (13%), crazy paving pattern in 11 (12%), interlobular thickening in 33 (37%), adjacent pleura thickening in 50 (56%), and linear opacities combined in 55 (61%). Pleural effusion, pericardial effusion, and lymphadenopathy were uncommon findings. In addition, baseline chest CT did not show any abnormalities in 21 patients (23%), but 3 patients presented bilateral ground glass opacities on the second CT after 3–4 days. SARS-CoV-2 infection can be confirmed based on the patient’s history, clinical manifestations, imaging characteristics, and laboratory tests. Chest CT examination plays an important role in the initial diagnosis of the novel coronavirus pneumonia. Multiple patchy ground glass opacities in bilateral multiple lobular with periphery distribution are typical chest CT imaging features of the COVID-19 pneumonia.

Comparison of [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer.

Abstract: We evaluated the potential usefulness of [68Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT) for the diagnosis of primary and metastatic lesions in various types of cancer, compared with [18F] FDG PET/CT. A total of 75 patients with various types of cancer underwent contemporaneous [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT either for an initial assessment or for recurrence detection. Tumour uptake was quantified by the maximum standard uptake value (SUVmax). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of [18F] FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT were calculated and compared to evaluate the diagnostic efficacy. The study cohort consisted of 75 patients (47 males and 28 females; median age, 61.5 years; age range, 32–85 years). Fifty-four patients with 12 different tumour entities underwent paired [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT for initial assessment, while the other 21 patients underwent paired scans for recurrence detection. [68Ga]Ga-DOTA-FAPI-04 PET/CT was able to clearly identify 12 types of malignant tumours with favourable tumour-to-background contrast, which resulted in a higher detection rate of primary tumours than did [18F] FDG PET/CT (98.2% vs. 82.1%, P = 0.021). Meanwhile, [68Ga]Ga-DOTA-FAPI-04 PET/CT showed a better sensitivity than [18F] FDG PET/CT in the detection of lymph nodes (86.4% vs. 45.5%, P = 0.004) and bone and visceral metastases (83.8% vs. 59.5%, P = 0.004). [68Ga]Ga-DOTA-FAPI-04 PET/CT showed a superior diagnostic efficacy than [18F] FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer, especially in identifying liver metastases, peritoneal carcinomatosis, and brain tumours.

18 F-FDG PET/CT findings of COVID-19: a series of four highly suspected cases.

Abstract: The aim of this case series is to illustrate the 18F-FDG PET/CT findings of patients with acute respiratory disease caused by COVID-19 in Wuhan, Hubei province of China. We describe the 18F-FDG PET/CT results from four patients who were admitted to the hospital with respiratory symptoms and fever between January 13 and January 20, 2020, when the COVID-19 outbreak was still unrecognized and the virus infectivity was unknown. A retrospective review of the patients’ medical history, clinical and laboratory data, as well as imaging findings strongly suggested a diagnosis of COVID-19. All patients had peripheral ground-glass opacities and/or lung consolidations in more than two pulmonary lobes. Lung lesions were characterized by a high 18F-FDG uptake and there was evidence of lymph node involvement. Conversely, disseminated disease was absent, a finding suggesting that COVID-19 has pulmonary tropism. Although 18F-FDG PET/CT cannot be routinely used in an emergency setting and is generally not recommended for infectious diseases, our pilot data shed light on the potential clinical utility of this imaging technique in the differential diagnosis of complex cases.

Value of pre-therapy 18F-FDG PET/CT radiomics in predicting EGFR mutation status in patients with non-small cell lung cancer.

Abstract: To assess the predictive power of pre-therapy 18F-FDG PET/CT-based radiomic features for epidermal growth factor receptor (EGFR) mutation status in non-small cell lung cancer. Two hundred and forty-eight lung cancer patients underwent pre-therapy diagnostic 18F-FDG PET/CT scans and were tested for genetic mutations. The LIFEx package was used to extract 47 PET and 45 CT radiomic features reflecting tumor heterogeneity and phenotype. The least absolute shrinkage and selection operator (LASSO) algorithm was used to select radiomic features and develop a radiomics signature. We compared the predictive performance of models established by radiomics signature, clinical variables, and their combinations using receiver operating curves (ROCs). In addition, a nomogram based on the radiomics signature score (rad-score) and clinical variables was developed. The patients were divided into a training set (n = 175) and a validation set (n = 73). Ten radiomic features were selected to build the radiomics signature model. The model showed a significant ability to discriminate between EGFR mutation and EGFR wild type, with area under the ROC curve (AUC) equal to 0.79 in the training set, and 0.85 in the validation set, compared with 0.75 and 0.69 for the clinical model. When clinical variables and radiomics signature were combined, the AUC increased to 0.86 (95% CI [0.80–0.91]) in the training set and 0.87 (95% CI [0.79–0.95]) in the validation set, thus showing better performance in the prediction of EGFR mutations. The PET/CT-based radiomic features showed good performance in predicting EGFR mutation in non-small cell lung cancer, providing a useful method for the choice of targeted therapy in a clinical setting.

EANM Practice Guideline/SNMMI Procedure Standard for Dopaminergic Imaging in Parkinsonian Syndromes 1.0

Abstract: This joint practice guideline or procedure standard was developed collaboratively by the European Association of Nuclear Medicine (EANM) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI). The goal of this guideline is to assist nuclear medicine practitioners in recommending, performing, interpreting, and reporting the results of dopaminergic imaging in parkinsonian syndromes. Currently nuclear medicine investigations can assess both presynaptic and postsynaptic function of dopaminergic synapses. To date both EANM and SNMMI have published procedural guidelines for dopamine transporter imaging with single photon emission computed tomography (SPECT) (in 2009 and 2011, respectively). An EANM guideline for D2 SPECT imaging is also available (2009). Since the publication of these previous guidelines, new lines of evidence have been made available on semiquantification, harmonization, comparison with normal datasets, and longitudinal analyses of dopamine transporter imaging with SPECT. Similarly, details on acquisition protocols and simplified quantification methods are now available for dopamine transporter imaging with PET, including recently developed fluorinated tracers. Finally, [18F]fluorodopa PET is now used in some centers for the differential diagnosis of parkinsonism, although procedural guidelines aiming to define standard procedures for [18F]fluorodopa imaging in this setting are still lacking. All these emerging issues are addressed in the present procedural guidelines for dopaminergic imaging in parkinsonian syndromes.

Fibroblast activation protein inhibitor (FAPI) PET for diagnostics and advanced targeted radiotherapy in head and neck cancers.

Abstract: Cancer-associated fibroblasts (CAFs) expressing fibroblast activation protein (FAP) have been associated with the aggressive nature of head and neck cancers (HNCs). These tumours grow diffusely, leading to extremely challenging differentiation between tumour and healthy tissue. This analysis aims to introduce a novel approach of tumour detection, contouring and targeted radiotherapy of HNCs using visualisation of CAFs: PET-CT with 68Ga-radiolabeled inhibitors of FAP (FAPI). FAPI PET-CT was performed without complications prior to radiotherapy in addition to contrast enhanced CT (CE-CT) and MRI on 14 patients with HNC. First, for tissue biodistribution analysis, volumes of interest were defined to quantify SUVmean and SUVmax in tumour and healthy parenchyma. Secondly, using four thresholds of three-, five-, seven- and tenfold increase of FAPI enhancement in the tumour as compared with normal tissue, four different gross tumour volumes (FAPI-GTV) were created automatically. These were compared with GTVs created conventionally with CE-CT and MRI (CT-GTV). The biodistribution analysis revealed high FAPI avidity within tumorous lesions (e.g. primary tumours, SUVmax 14.62 ± 4.44; SUVmean 7.41 ± 2.39). In contrast, low background uptake was measured in healthy tissues of the head and neck region (e.g. salivary glands: SUVmax 1.76 ± 0.31; SUVmean 1.23 ± 0.28). Considering radiation planning, CT-GTV was of 27.3 ml, whereas contouring with FAPI resulted in significantly different GTVs of 67.7 ml (FAPI × 3, p = 0.0134), 22.1 ml (FAPI × 5, p = 0.0419), 7.6 ml (FAPI × 7, p = 0.0001) and 2.3 ml (FAPI × 10, p = 0.0001). Taking these significant disparities between the GTVs into consideration, we merged FAPI-GTVs with CT-GTVs. This resulted in median volumes, that were, as compared to CT-GTVs, significantly larger with FAPI × 3 (54.7 ml, + 200.5% relative increase, p = 0.0005) and FAPI × 5 (15.0 ml, + 54.9%, p = 0.0122). Furthermore, FAPI-GTVs were not covered by CE-CT-based planning target volumes (CT-PTVs) in several cases. We present first evidence of diagnostic and therapeutic potential of FAPI ligands in head and neck cancer. Larger studies with histopathological correlation are required to validate our findings.

225 Ac-PSMA-617/ 177 Lu-PSMA-617 tandem therapy of metastatic castration-resistant prostate cancer: pilot experience

Abstract: Up to 30% of patients with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer (mCRPC) never respond or develop resistance to 177Lu-labeled PSMA-targeted radioligand monotherapy. Single-agent PSMA-targeted radioligand therapy (PRLT) with the alpha-emitter 225Ac showed promise against mCRPC but may cause severe and/or persistent xerostomia, which may substantially impair patients’ quality-of-life. We hypothesized that when 177Lu-PSMA ligand alone is ineffective, tandem therapy with low-activity 225Ac-PSMA ligand plus full activity of the beta emitter may enhance efficacy while minimizing xerostomia severity. We retrospectively analyzed pilot experience with 1 course of 225Ac-PSMA-617/177Lu-PSMA-617 tandem therapy in our first 20 patients with mCRPC receiving this intervention after insufficiently responding to 177Lu-PSMA-617 monotherapy. This cohort had late-stage/end-stage disease with high baseline prostate-specific antigen (PSA) concentration (median 215 ng/mL), heavy pre-treatment (abiraterone and/or enzalutamide, and 177Lu-PRLT [median cumulative activity, 26.3 GBq] in 20/20 patients, 100%; docetaxel and/or cabazitaxel in 13/20 patients, 65%), and frequent Eastern Cooperative Oncology Group performance status of 2 (8/20 patients, 40%). Median (minimum–maximum) administered activities were 225Ac-PSMA-617, 5.3 (1.5–7.9) MBq, and 177Lu-PSMA-617, 6.9 (5.0–11.6) GBq. Significant responders to tandem therapy received 177Lu-PSMA-617 monotherapy as maintenance (median [minimum–maximum]: 1 [0–5] cycle). After a median (minimum–maximum) 22 (14–63) weeks’ follow-up, 13/20 patients (65%) had as best biochemical response a PSA decline > 50%. Median (95% confidence interval) progression-free survival was 19 (12–26) weeks, and overall survival was 48 (4–92) weeks post-tandem therapy administration. Xerostomia was reported as grade 1 (very mild) in 8/20 patients (40%), grade 2 (mild) in 5/20 (25%), and grade 3/4 in 0/20. Our results suggest that a single course of tandem therapy with low-activity 225Ac-PSMA-617/full-activity 177Lu-PSMA-617 may safely enhance response to PRLT in men with late-stage/end-stage mCRPC while minimizing xerostomia severity. Formal study of this combination is warranted.

Radiomics of 18F-FDG PET/CT images predicts clinical benefit of advanced NSCLC patients to checkpoint blockade immunotherapy.

Abstract: Immunotherapy has improved outcomes for patients with non-small cell lung cancer (NSCLC), yet durable clinical benefit (DCB) is experienced in only a fraction of patients. Here, we test the hypothesis that radiomics features from baseline pretreatment 18F-FDG PET/CT scans can predict clinical outcomes of NSCLC patients treated with checkpoint blockade immunotherapy. This study included 194 patients with histologically confirmed stage IIIB-IV NSCLC with pretreatment PET/CT images. Radiomics features were extracted from PET, CT, and PET+CT fusion images based on minimum Kullback–Leibler divergence (KLD) criteria. The radiomics features from 99 retrospective patients were used to train a multiparametric radiomics signature (mpRS) to predict DCB using an improved least absolute shrinkage and selection operator (LASSO) method, which was subsequently validated in both retrospective (N = 47) and prospective test cohorts (N = 48). Using these cohorts, the mpRS was also used to predict progression-free survival (PFS) and overall survival (OS) by training nomogram models using multivariable Cox regression analyses with additional clinical characteristics incorporated. The mpRS could predict patients who will receive DCB, with areas under receiver operating characteristic curves (AUCs) of 0.86 (95%CI 0.79–0.94), 0.83 (95%CI 0.71–0.94), and 0.81 (95%CI 0.68–0.92) in the training, retrospective test, and prospective test cohorts, respectively. In the same three cohorts, respectively, nomogram models achieved C-indices of 0.74 (95%CI 0.68–0.80), 0.74 (95%CI 0.66–0.82), and 0.77 (95%CI 0.69–0.84) to predict PFS and C-indices of 0.83 (95%CI 0.77–0.88), 0.83 (95%CI 0.71–0.94), and 0.80 (95%CI 0.69–0.91) to predict OS. PET/CT-based signature can be used prior to initiation of immunotherapy to identify NSCLC patients most likely to benefit from immunotherapy. As such, these data may be leveraged to improve more precise and individualized decision support in the treatment of patients with advanced NSCLC.

Broadening horizons with 225 Ac-DOTATATE targeted alpha therapy for gastroenteropancreatic neuroendocrine tumour patients stable or refractory to 177 Lu-DOTATATE PRRT: first clinical experience on the efficacy and safety

Abstract: The objective of this study was to investigate and present the early results on the efficacy, safety, and quality of life of 225Ac-DOTATATE targeted alpha therapy (TAT) in patients with advanced, progressive, 177Lu-DOTATATE refractory, and somatostatin receptor (SSTR) expressing metastatic GEP-NETs. In this prospective study, we recruited patients with metastatic GEP-NETs who were stable or progressive disease on 177Lu-DOTATATE therapy. Systemic TAT using 225Ac-DOTATATE was performed in all the patients with 225Ac-DOTATATE (100 kBq/kg body weight) at an interval of 8 weeks. The primary end point was to assess the objective response (measured by RECIST 1.1 and functional M.D. Anderson criteria). The secondary end points included biochemical response assessment as per the Italian Trials in Medical Oncology (ITMO), adverse event profile as per CTCAE v5.0, and clinical response assessment by the quality of life (assessed with EORTC QLQ-GI.NET21 patient-based questionnaire). Between April 2018 and March 2019, 32 patients (17 females, 15 males, mean age 52 ± 9.2 years, 35–72 years) with either stable disease after completing 177Lu-DOTATATE therapy (14, 44%) or progressive disease on 177Lu-DOTATATE therapy (18, 56%) were included in the study. The morphological response was assessed in 24/32 patients that revealed partial remission in 15 and stable disease in 9. There was no documented disease progression or deaths in the median follow-up of 8 months (range 2–13 months). There was a significant decrease in the plasma chromogranin level post-225Ac-DOTATATE therapy (P < 0.0001). Our short-term clinical results indicate 225Ac-DOTATATE TAT as a promising treatment option which adds a new dimension in patients who are refractory to 177Lu-DOTATATE therapy or have reached the maximum prescribed cycles of 177Lu-DOTATATE therapy.

Baseline metabolic tumor burden on FDG PET/CT scans predicts outcome in advanced NSCLC patients treated with immune checkpoint inhibitors.

Abstract: We aimed to evaluate if imaging biomarkers on FDG PET are associated with clinical outcomes in patients with advanced non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs). In this retrospective monocentric study, we included 109 patients with advanced NSCLC who underwent baseline FDG PET/CT before ICI initiation between July 2013 and September 2018. Clinical, biological (including dNLR = neutrophils/[leukocytes minus neutrophils]), pathological and PET parameters (tumor SUVmax, total metabolic tumor volume [TMTV]) were evaluated. A multivariate prediction model was developed using Cox models for progression-free survival (PFS) and overall survival (OS). The association between biomarkers on FDG PET/CT and disease clinical benefit (DCB) was tested using logistic regression. Eighty patients were eligible. Median follow-up was 11.6 months (95%CI 7.7–15.5). Sixty-four and 52 patients experienced progression and death, respectively. DCB was 40%. In multivariate analyses, TMTV > 75 cm3 and dNLR > 3 were associated with shorter OS (HR 2.5, 95%CI 1.3–4.7 and HR 3.3, 95%CI 1.6–6.4) and absence of DCB (OR 0.3, 95%CI 0.1–0.9 and OR 0.4, 95%CI 0.2–0.9). Unlike TMTV, dNLR was a significant prognostic factor for PFS (HR 1.9, 95%CI 1.1–3.3) along with anemia (HR 1.9, 95%CI 1.2–3.8). No association was observed between tumor SUVmax and PFS or OS. Baseline tumor burden (TMTV) on FDG PET/CT scans and inflammatory status (dNLR) were associated with poor OS and absence of DCB for ICI treatment in advanced NSCLC patients, unlike tumor SUVmax, and may be used together to improve the selection of appropriate candidates.

PET/MRI versus PET/CT in oncology: a prospective single-center study of 330 examinations focusing on implications for patient management and cost considerations

Abstract: PET/MRI has recently been introduced into clinical practice. We prospectively investigated the clinical impact of PET/MRI compared with PET/CT, in a mixed population of cancer patients, and performed an economic evaluation of PET/MRI. Cancer patients referred for routine staging or follow-up by PET/CT underwent consecutive PET/CT and PET/MRI, using single applications of [18F]FDG, [68Ga]Ga-DOTANOC, or [18F]FDOPA, depending on tumor histology. PET/MRI and PET/CT were rated separately, and lesions were assessed per anatomic region; based on regions, per-examination and per-patient accuracies were determined. A simulated, multidisciplinary team meeting served as reference standard and determined whether differences between PET/CT and PET/MRI affected patient management. The McNemar tests were used to compare accuracies, and incremental cost-effectiveness ratios (ICERs) for PET/MRI were calculated. Two hundred sixty-three patients (330 same-day PET/CT and PET/MRI examinations) were included. PET/MRI was accurate in 319/330 examinations and PET/CT in 277/330 examinations; the respective accuracies of 97.3% and 83.9% differed significantly (P < 0.001). The additional findings on PET/MRI—mainly liver and brain metastases—had implications for patient management in 21/263 patients (8.0%). The per-examination cost was 596.97 EUR for PET/MRI and 405.95 EUR for PET/CT. ICERs for PET/MRI were 14.26 EUR per percent of diagnostic accuracy and 23.88 EUR per percent of correctly managed patients. PET/MRI enables more appropriate management than PET/CT in a nonnegligible fraction of cancer patients. Since the per-examination cost is about 50% higher for PET/MRI than for PET/CT, a histology-based triage of patients to either PET/MRI or PET/CT may be meaningful.

Prognostic biomarkers in men with metastatic castration-resistant prostate cancer receiving [177Lu]-PSMA-617.

Abstract: We analysed quantitative biomarkers derived from both baseline whole-body imaging and blood serum to identify prognostic markers in patients treated within the lutetium-177 prostate-specific membrane antigen (LuPSMA) phase 2 trial. PET image analysis was carried out using whole-body segmentation quantifying molecular tumour volume (SUV > 3 threshold for PSMA, SUV > liver+2sd for fluorodeoxyglucose (FDG) including SUVmax and SUVmean. For baseline bone scans, EXINI bone scan index (BSI) was used to calculate the percentage of involved bone. Baseline alkaline phosphatase (ALP), lactate dehydrogenase (LDH), prostate specific antigen (PSA) and PSA doubling time were also used in this analysis. We used univariate cox regression analysis and log-rank comparison with optimised cut-offs to find suitable biomarkers prognostic of overall survival from time of enrolment. This analysis identified FDG-positive tumour volume (FDGvol; HR 2.6; 95% CI, 1.4–4.8), mean intensity of PSMA-avid tumour uptake (PSMAmean; HR 0.89; 95% CI, 0.8–0.98), bone scan index (BSI; HR 2.3; 95% CI, 1.2–4.4), ALP (HR 1.1; 95% CI, 1–1.2) and LDH (HR 1.2; 95% CI, 1–1.5) as biomarkers prognostic of overall survival. In addition to established biomarkers, both FDG and PSMA PET/CT parameters have prognostic significance for survival in men undergoing LuPSMA therapy.

COVID-19 pandemic: guidance for nuclear medicine departments.

Abstract: Coronaviruses are non-segmented, enveloped positive-sense ribonucleic acid viruses from the Coronaviridae family. There are six types of the coronavirus known to infect humans. Four of them cause mild respiratory symptoms, while two of them, the Middle East respiratory syndrome coronavirus (MERS) and the severe acute respiratory syndrome (SARS), have caused epidemics with high mortality rates [1, 2]. In December 2019, a new type of coronavirus 2019-nCoV/ SARS-CoV-2, causing COVID-19 disease, was extracted and identified from the lower respiratory tract samples of several patients in Wuhan, China [3]. These patients presented with symptoms of severe pneumonia, including fever, fatigue, dry cough, and respiratory distress. The coronavirus disease 19 (COVID-19) is a highly transmittable and pathogenic viral infection. It is believed to be transmitted via respiratory droplets and fomites during close unprotected contact between an infector and an infectee. The coronaviruses mainly infect epithelial cells in the lung, but SARS-CoV-2 has been detected in respiratory, fecal, and blood specimens of patients infected with the virus [4]. On February 3, 2020, the World Health Organization declared a public health emergency of international concern, and on March 11, declared COVID-19 a pandemic [5]. The total number of confirmed cases, deaths associated with COVID19, and affected countries and territories continues to grow; detailed statistics can be found at the WHO–Coronavirus disease (COVID-19) Pandemic site [5] or the John Hopkins Coronavirus Resource Centre. [6]. Health care providers around the world are facing challenging decisions. They are rapidly adjusting their standard operating procedures (SOPs) to cope with the pandemic cases and deliver their services. This is done in line with local guidance, resources available, and the advice of the World Health Organization (WHO) Minimum Requirements for infection prevention and control (IPC) programmes [7]. This publication was prepared based on the systematic review of available literature on the subject and the contribution of a panel of international experts during the webinar entitled

Automated detection and quantification of COVID-19 pneumonia: CT imaging analysis by a deep learning-based software.

Abstract: The novel coronavirus disease 2019 (COVID-19) is an emerging worldwide threat to public health. While chest computed tomography (CT) plays an indispensable role in its diagnosis, the quantification and localization of lesions cannot be accurately assessed manually. We employed deep learning-based software to aid in detection, localization and quantification of COVID-19 pneumonia. A total of 2460 RT-PCR tested SARS-CoV-2-positive patients (1250 men and 1210 women; mean age, 57.7 ± 14.0 years (age range, 11–93 years) were retrospectively identified from Huoshenshan Hospital in Wuhan from February 11 to March 16, 2020. Basic clinical characteristics were reviewed. The uAI Intelligent Assistant Analysis System was used to assess the CT scans. CT scans of 2215 patients (90%) showed multiple lesions of which 36 (1%) and 50 patients (2%) had left and right lung infections, respectively (> 50% of each affected lung’s volume), while 27 (1%) had total lung infection (> 50% of the total volume of both lungs). Overall, 298 (12%), 778 (32%) and 1300 (53%) patients exhibited pure ground glass opacities (GGOs), GGOs with sub-solid lesions and GGOs with both sub-solid and solid lesions, respectively. Moreover, 2305 (94%) and 71 (3%) patients presented primarily with GGOs and sub-solid lesions, respectively. Elderly patients (≥ 60 years) were more likely to exhibit sub-solid lesions. The generalized linear mixed model showed that the dorsal segment of the right lower lobe was the favoured site of COVID-19 pneumonia. Chest CT combined with analysis by the uAI Intelligent Assistant Analysis System can accurately evaluate pneumonia in COVID-19 patients.

The potential added value of FDG PET/CT for COVID-19 pneumonia.

Abstract: Dear Sir, By February 27, 2020, COVID-19 had infected about 82,163 people and killed 2800 in about 37 countries and regions [1]. The coronavirus, like SARS-CoV-2 and MERSCoV, belongs to the coronavirus family [2]. Most infections are followed by fever, cough, and other non-specific symptoms. Mild symptoms were similar to the common cold, mortality was lower in relatively healthy and younger patients, and most patients without complications survived the infection and fully recovered. Due to the progression of pneumonia and a pathologic disease characterized by diffuse alveolar damage, severe cases are most likely leading to adult respiratory distress syndrome (ARDS) [3]. Nucleic acid testing (RT-PCR) is the gold standard for the diagnosis of COVID-19 infection, but with a high false negative rate, which is easy to miss the diagnosis and cause the spread of the epidemic [4]. Chest high-resolution CT is the routine-preferred method for screening, diagnosis, course severity assessment, and efficacy monitoring of COVID-19 pneumonia. CT findings of COVID-19 pneumonia have been widely reported [5–7]. In the early stage, single or multiple plaques, masses, nodules, or segmental ground glass density lesions were found in the lung. As the disease progressed, the lesions increased and spread to the center. The inflammatory exudation, consolidation, and density increased, accompanied by pulmonary vascular shadow thickening, air bronchi sign, paving stone sign, interlobular septal thickening, pleural effusion, and other signs. The images are similar to those seen in viral pneumonia such asMERS-CoVand SARS-CoV-2 [8]. As for the FDG PET/CT imaging results after COVID-19 infection, there are only four patients with highly suspected COVID-19 infection having been reported so far by Qin et al. [9]. They found lung lesions characterized by increased FDG uptake and evidence of lymph node involvement. In fact, as a non-invasive imaging method, FDG PET/CT plays an important role in evaluating inflammatory and infectious pulmonary diseases, monitoring disease progression and treatment effect, and improving patient management [10]. When the virus infects the body, the cascade of reactions activates inflammatory cells such as neutrophils, monocytes, and effector T cells by releasing local chemokines. In acute inflammation or chest infection, activated neutrophils are heavily dependent on anaerobic glycolysis, requiring increased glucose and resulting in high FDG uptake [11]. Granulocytes and macrophages also facilitate glucose transport under chronic conditions. Before FDG uptake was observed in patients with COVID-19 infection by Qin et al. [9], Das et al. also observed significant FDG uptake in patients with MERS-CoV infection which progressed to pneumonia [12]. Chefer et al. used FDG PET/ CT to observe the rhesus macaques model and to simulate the host response after MERS-CoV infection [13]. In their model, increased FDG uptake was observed in mediastinal and axillary lymph nodes, and the uptake variation constant was associated with increased monocytes percentage. It is not hard to see the reason. Increased monocytes in lymphoid tissue used the immune system to fight off viral infections, andmonocytes contributed to increase uptake of FDG. As for lymph node enlargement, it has been manifested in pneumonia caused by parainfluenza virus and adenovirus. Although lymph node enlargement on CT is rare, lymphadenopathy is present in more than 1% of patients [14]. Considering that CT is less sensitive to host reactions than FDG PET/CT, the actual percentage of lymph node involvement may be higher. FDG uptake is often thought of as non-specific inflammatory or immune activation that fails to reflect the host response produced by specific cells. Depending on the stages of the This article is part of the Topical Collection on Infection and inflammation

Advances in CNS PET: the state-of-the-art for new imaging targets for pathophysiology and drug development.

Abstract: A limit on developing new treatments for a number of central nervous system (CNS) disorders has been the inadequate understanding of the in vivo pathophysiology underlying neurological and psychiatric disorders and the lack of in vivo tools to determine brain penetrance, target engagement, and relevant molecular activity of novel drugs. Molecular neuroimaging provides the tools to address this. This article aims to provide a state-of-the-art review of new PET tracers for CNS targets, focusing on developments in the last 5 years for targets recently available for in-human imaging. We provide an overview of the criteria used to evaluate PET tracers. We then used the National Institute of Mental Health Research Priorities list to identify the key CNS targets. We conducted a PubMed search (search period 1st of January 2013 to 31st of December 2018), which yielded 40 new PET tracers across 16 CNS targets which met our selectivity criteria. For each tracer, we summarised the evidence of its properties and potential for use in studies of CNS pathophysiology and drug evaluation, including its target selectivity and affinity, inter and intra-subject variability, and pharmacokinetic parameters. We also consider its potential limitations and missing characterisation data, but not specific applications in drug development. Where multiple tracers were present for a target, we provide a comparison of their properties. Our review shows that multiple new tracers have been developed for proteinopathy targets, particularly tau, as well as the purinoceptor P2X7, phosphodiesterase enzyme PDE10A, and synaptic vesicle glycoprotein 2A (SV2A), amongst others. Some of the most promising of these include 18F-MK-6240 for tau imaging, 11C-UCB-J for imaging SV2A, 11C-CURB and 11C-MK-3168 for characterisation of fatty acid amide hydrolase, 18F-FIMX for metabotropic glutamate receptor 1, and 18F-MNI-444 for imaging adenosine 2A. Our review also identifies recurrent issues within the field. Many of the tracers discussed lack in vivo blocking data, reducing confidence in selectivity. Additionally, late-stage identification of substantial off-target sites for multiple tracers highlights incomplete pre-clinical characterisation prior to translation, as well as human disease state studies carried out without confirmation of test-retest reproducibility.

In vivo imaging of synaptic loss in Alzheimer’s disease with [18F]UCB-H positron emission tomography

Abstract: Loss of brain synapses is an early pathological feature of Alzheimer’s disease. The current study assessed synaptic loss in vivo with positron emission tomography and an 18F-labelled radiotracer of the synaptic vesicle protein 2A, [18F]UCB-H. Twenty-four patients with mild cognitive impairment or Alzheimer’s disease and positive [18F]Flutemetamol amyloid-PET were compared to 19 healthy controls. [18F]UCB-H brain uptake was quantified with Logan graphical analysis using an image-derived blood input function. SPM12 and regions-of-interest (ROI) analyses were used for group comparisons of regional brain distribution volumes and for correlation with cognitive measures. A significant decrease of [18F]UCB-H uptake was observed in several cortical areas (11 to 18% difference) and in the thalamus (16% difference), with the largest effect size in the hippocampus (31% difference). Reduced hippocampal uptake was related to patients’ cognitive decline (ROI analysis) and unawareness of memory problems (SPM and ROI analyses). The findings thus highlight predominant synaptic loss in the hippocampus, confirming previous autopsy-based studies and a recent PET study with an 11C-labelled SV2A radiotracer. [18F]UCB-H PET allows to image in vivo synaptic changes in Alzheimer’s disease and to relate them to patients’ cognitive impairment.

Non-invasive tumor decoding and phenotyping of cerebral gliomas utilizing multiparametric 18 F-FET PET-MRI and MR Fingerprinting

Abstract: The introduction of the 2016 WHO classification of CNS tumors has made the combined molecular and histopathological characterization of tumors a pivotal part of glioma patient management. Recent publications on radiogenomics-based prediction of the mutational status have demonstrated the predictive potential of imaging-based, non-invasive tissue characterization algorithms. Hence, the aim of this study was to assess the potential of multiparametric 18F-FET PET-MRI including MR fingerprinting accelerated with machine learning and radiomic algorithms to predict tumor grading and mutational status of patients with cerebral gliomas. 42 patients with suspected primary brain tumor without prior surgical or systemic treatment or biopsy underwent an 18F-FET PET-MRI examination. To differentiate the mutational status and the WHO grade of the cerebral tumors, support vector machine and random forest were trained with the radiomics signature of the multiparametric PET-MRI data including MR fingerprinting. Surgical sampling served as a gold standard for histopathological reference and assessment of mutational status. The 5-fold cross-validated area under the curve in predicting the ATRX mutation was 85.1%, MGMT mutation was 75.7%, IDH1 was 88.7%, and 1p19q was 97.8%. The area under the curve of differentiating low-grade glioma vs. high-grade glioma was 85.2%. 18F-FET PET-MRI and MR fingerprinting enable high-quality imaging-based tumor decoding and phenotyping for differentiation of low-grade vs. high-grade gliomas and for prediction of the mutational status of ATRX, IDH1, and 1p19q. These initial results underline the potential of 18F-FET PET-MRI to serve as an alternative to invasive tissue characterization.

Good clinical practice recommendations for the use of PET/CT in oncology.

Abstract: Positron emission tomography/computed tomography (PET/CT) is a nuclear medicine functional imaging technique with proven clinical value in oncology. PET/CT indications are continually evolving with fresh advances made through research. French practice on the use of PET in oncology was framed in recommendations based on Standards-Options-Recommendations methodology and coordinated by the French federation of Comprehensive Cancer Centres (FNLCC). The recommendations were originally issued in 2002 followed by an update in 2003, but since then, a huge number of scientific papers have been published and new tracers have been licenced for market release. The aim of this work is to bring the 2003 version recommendations up to date. For this purpose, a focus group was set up in collaboration with the French Society for Nuclear Medicine (SFMN) to work on developing good clinical practice recommendations. These good clinical practice recommendations have been awarded joint French National Heath Authority (HAS) and French Cancer Institute (INCa) label status-the stamp of methodological approval. The present document is the outcome of comprehensive literature review and rigorous appraisal by a panel of experts, organ specialists, clinical oncologists, surgeons and imaging specialists. These data were also used for the EANM referral guidelines.

Impact of liver tumour burden, alkaline phosphatase elevation, and target lesion size on treatment outcomes with 177Lu-Dotatate: an analysis of the NETTER-1 study.

Abstract: To assess the impact of baseline liver tumour burden, alkaline phosphatase (ALP) elevation, and target lesion size on treatment outcomes with 177Lu-Dotatate. In the phase 3 NETTER-1 trial, patients with advanced, progressive midgut neuroendocrine tumours (NET) were randomised to 177Lu-Dotatate (every 8 weeks, four cycles) plus octreotide long-acting release (LAR) or to octreotide LAR 60 mg. Primary endpoint was progression-free survival (PFS). Analyses of PFS by baseline factors, including liver tumour burden, ALP elevation, and target lesion size, were performed using Kaplan-Meier estimates; hazard ratios (HRs) with corresponding 95% CIs were estimated using Cox regression. Significantly prolonged median PFS occurred with 177Lu-Dotatate versus octreotide LAR 60 mg in patients with low ( 50%) liver tumour burden (HR 0.187, 0.216, 0.145), and normal or elevated ALP (HR 0.153, 0.177), and in the presence or absence of a large target lesion (diameter > 30 mm; HR, 0.213, 0.063). Within the 177Lu-Dotatate arm, no significant difference in PFS was observed amongst patients with low/moderate/high liver tumour burden (P = 0.7225) or with normal/elevated baseline ALP (P = 0.3532), but absence of a large target lesion was associated with improved PFS (P = 0.0222). Grade 3 and 4 liver function abnormalities were rare and did not appear to be associated with high baseline liver tumour burden. 177Lu-Dotatate demonstrated significant prolongation in PFS versus high-dose octreotide LAR in patients with advanced, progressive midgut NET, regardless of baseline liver tumour burden, elevated ALP, or the presence of a large target lesion. Clinicaltrials.gov : NCT01578239, EudraCT: 2011-005049-11

18 FDG PET/CT in the early assessment of non-small cell lung cancer response to immunotherapy: frequency and clinical significance of atypical evolutive patterns

Abstract: This prospective study aimed (1) to assess the non-small cell lung cancer (NSCLC) evolutive patterns to immunotherapy using FDG-PET and (2) to describe their association with clinical outcome. Fifty patients with metastatic NSCLC were included before pembrolizumab or nivolumab initiation. FDG-PET scan was performed at baseline and after 7 weeks of treatment (PETinterim1) and different criteria/parameters of tumor response were assessed, including PET response criteria in solid tumors (PERCIST). If a first PERCIST progressive disease (PD) without clinical worsening was observed, treatment was continued and a subsequent FDG-PET (PETinterim2) was performed at 3 months of treatment. Pseudo-progression (PsPD) was defined as a PERCIST response/stability on PETinterim2 after an initial PD. If a second PERCIST PD was assessed on PETinterim2, a homogeneous progression of lesions (termed immune homogeneous progressive-disease: iPDhomogeneous) was distinguished from a heterogeneous evolution (termed immune dissociated-response: iDR). A durable clinical benefit (DCB) of immunotherapy was defined as treatment continuation over a 6-month period. The association between PET evolutive profiles and DCB was assessed. Using PERCIST on PETinterim1, 42% (21/50) of patients showed a response or stable disease, most of them (18/21) reached a DCB. In contrast, 58% (29/50) showed a PD, but more than one-third (11/29) were misclassified as they finally reached a DCB. No standard PETinterim1 criteria could accurately distinguished responding from non-responding patients. Treatment was continued in 19/29 of patients with a first PERCIST PD; the subsequent PETinterim2 demonstrated iPDhomogeneous, iDR and PsPD in 42% (8/19), 26% (5/19), and 32% (6/19), respectively. Whereas no patients with iPDhomogeneous experienced a DCB, all patients with iDR and PsPD reached a clinical benefit to immunotherapy. In patients with a first PD on PERCIST and treatment continuation, a subsequent PET identifies more than half of them with iDR and PsPD, both patterns being strongly associated with a clinical benefit of immunotherapy.

End-to-end automatic differentiation of the coronavirus disease 2019 (COVID-19) from viral pneumonia based on chest CT.

Abstract: In the absence of a virus nucleic acid real-time reverse transcriptase-polymerase chain reaction (RT-PCR) test and experienced radiologists, clinical diagnosis is challenging for viral pneumonia with clinical symptoms and CT signs similar to that of coronavirus disease 2019 (COVID-19) We developed an end-to-end automatic differentiation method based on CT images to identify COVID-19 pneumonia patients in real time From January 18 to February 23, 2020, we conducted a retrospective study and enrolled 201 patients from two hospitals in China who underwent chest CT and RT-PCR tests, of which 98 patients tested positive for COVID-19 (118 males and 83 females, with an average age of 42 years) Patient CT images from one hospital were divided among training, validation and test datasets with an 80%:10%:10% ratio An end-to-end representation learning method using a large-scale bi-directional generative adversarial network (BigBiGAN) architecture was designed to extract semantic features from the CT images The semantic feature matrix was input for linear classifier construction Patients from the other hospital were used for external validation Differentiation accuracy was evaluated using a receiver operating characteristic curve Based on the 120-dimensional semantic features extracted by BigBiGAN from each image, the linear classifier results indicated that the area under the curve (AUC) in the training, validation and test datasets were 0979, 0968 and 0972, respectively, with an average sensitivity of 92% and specificity of 91% The AUC for external validation was 0850, with a sensitivity of 80% and specificity of 75% Publicly available architecture and computing resources were used throughout the study to ensure reproducibility This study provides an efficient recognition method for coronavirus disease 2019 pneumonia, using an end-to-end design to implement targeted and effective isolation for the containment of this communicable disease

EANM practice guideline for PET/CT imaging in medullary thyroid carcinoma.

Abstract: Medullary thyroid carcinoma (MTC) is a malignant tumour derived from the para-follicular thyroid C cells. It may occur in sporadic or hereditary forms and surgery represent the primary cure. Ultrasound examination and, in selected cases, cross-sectional anatomic imaging procedures, are adopted to stage the disease before primary surgery while different anatomic/morphologic and functional/molecular imaging procedures can be adopted in detecting persistent/recurrent disease. Positron emitting radiopharmaceuticals including fluorine-18 fluorodeoxyglucose (18F-FDG), fluorine-18 dihydroxyphenylalanine (18F-FDOPA) and somatostatin analogues labelled with gallium-68 (68Ga-SSA) tracks different metabolic pathways or receptor expression/functioning, and proved to be useful in detecting MTC recurrences/metastasis. This practice guideline from the Thyroid Committee of the European Association of Nuclear Medicine (EANM), with involvement of external experts, provides recommendations based on updated literature’s evidences. The purpose of this practice guideline is to assist imaging specialists and clinicians in recommending, performing and interpreting the results of PET/CT with various radiopharmaceuticals in patients with MTC.

PRRT neuroendocrine tumor response monitored using circulating transcript analysis: the NETest.

Abstract: Peptide receptor radionuclide therapy (PRRT) is effective for metastatic/inoperable neuroendocrine tumors (NETs). Imaging response assessment is usually efficient subsequent to treatment completion. Blood biomarkers such as PRRT Predictive Quotient (PPQ) and NETest are effective in real-time. PPQ predicts PRRT efficacy; NETest monitors disease. We prospectively evaluated: (1) NETest as a surrogate biomarker for RECIST; (2) the correlation of NETest levels with PPQ prediction. Three independent 177Lu-PRRT-treated GEP-NET and lung cohorts (Meldola, Italy: n = 72; Bad-Berka, Germany: n = 44; Rotterdam, Netherlands: n = 41). Treatment response: RECIST1.1 (responder (stable, partial, and complete response) vs non-responder). Blood sampling: pre-PRRT, before each cycle and follow-up (2–12 months). PPQ (positive/negative) and NETest (0–100 score) by PCR. Stable 40). CgA (ELISA) as comparator. Samples de-identified, measurement and analyses blinded. Kaplan–Meier survival and standard statistics. One hundred twenty-two of the 157 were evaluable. RECIST stabilization or response in 67%; 33% progressed. NETest significantly (p 40 (progressive) vs stable ( 97%) with the pretreatment PPQ response predictor. CgA was non-informative.

Deep learning-based attenuation map generation for myocardial perfusion SPECT.

Abstract: Attenuation correction using CT transmission scanning increases the accuracy of single-photon emission computed tomography (SPECT) and enables quantitative analysis. Current existing SPECT-only systems normally do not support transmission scanning and therefore scans on these systems are susceptible to attenuation artifacts. Moreover, the use of CT scans also increases radiation dose to patients and significant artifacts can occur due to the misregistration between the SPECT and CT scans as a result of patient motion. The purpose of this study is to develop an approach to estimate attenuation maps directly from SPECT emission data using deep learning methods. Both photopeak window and scatter window SPECT images were used as inputs to better utilize the underlying attenuation information embedded in the emission data. The CT-based attenuation maps were used as labels with which cardiac SPECT/CT images of 65 patients were included for training and testing. We implemented and evaluated deep fully convolutional neural networks using both standard training and training using an adversarial strategy. The synthetic attenuation maps were qualitatively and quantitatively consistent with the CT-based attenuation map. The globally normalized mean absolute error (NMAE) between the synthetic and CT-based attenuation maps were 3.60% ± 0.85% among the 25 testing subjects. The SPECT reconstructed images corrected using the CT-based attenuation map and synthetic attenuation map are highly consistent. The NMAE between the reconstructed SPECT images that were corrected using the synthetic and CT-based attenuation maps was 0.26% ± 0.15%, whereas the localized absolute percentage error was 1.33% ± 3.80% in the left ventricle (LV) myocardium and 1.07% ± 2.58% in the LV blood pool. We developed a deep convolutional neural network to estimate attenuation maps for SPECT directly from the emission data. The proposed method is capable of generating highly reliable attenuation maps to facilitate attenuation correction for SPECT-only scanners for myocardial perfusion imaging.

First-in-human dosimetry of gastrin-releasing peptide receptor antagonist [ 177 Lu]Lu-RM2: a radiopharmaceutical for the treatment of metastatic castration-resistant prostate cancer

Abstract: Besides PSMA, prostate cancer cells also express gastrin-releasing peptide receptor (GRPr) which is therefore a promising target for theranostic approaches. The high affinity GRPr antagonist RM2 can be labeled with beta-emitting radiometals for therapeutic purposes. The aim of this study was to calculate absorbed doses for critical organs and tumor lesions for [177Lu]Lu-RM2 therapy administered in a group of metastatic castration-resistant prostate cancer (mCRPC) patients who had insufficient PSMA expression or showed lower PSMA accumulation after previous cycles of [177Lu]Lu-PSMA-617 therapy. Thirty-five patients suffering from mCRPC without further treatment options for approved therapies were examined with [68Ga]Ga-RM2-PET/CT. Out of these, 4 patients (mean age 68 years) were treated with [177Lu]Lu-RM2; two of these also received a 2nd therapy cycle. Mean activity was 4.5 ± 0.9 GBq. For dosimetry, patients underwent planar WB-scintigraphy and SPECT/CT imaging of the upper and lower abdomen at approximately 1, 24, 48, and 72 h p.i. along with blood sampling. Absorbed doses for kidneys, pancreas, liver, spleen, gallbladder wall, and tumor lesions were derived based on quantitative SPECT/CT according to RADAR dosimetry scheme; individual organ masses were extracted from CT. Absorbed dose to bone marrow was calculated based on serial whole-body images and blood sampling according to the EANM guideline. Therapy was well tolerated by all patients and no side effects were observed. An increased uptake in tumor lesions and the pancreas was seen within the first 1 h. Mean absorbed organ doses were 1.08 ± 0.44 Gy/GBq in the pancreas, 0.35 ± 0.14 Gy/GBq in the kidneys, 0.05 ± 0.02 Gy/GBq in the liver, 0.07 ± 0.02 Gy/GBq in the gallbladder wall, 0.10 ± 0.06 Gy/GBq in the spleen, and 0.02 ± 0.01 Gy/GBq for the red bone marrow. The mean dose for tumor lesions was 6.20 ± 3.00 Gy/GBq. Application of GRPr antagonist [177Lu]Lu-RM2 is suitable for targeted radiotherapy of mCRPC as it shows high tumor uptake and rapid clearance from normal organs. Absorbed doses in tumor lesions are therapeutically relevant. The critical organ receiving the highest absorbed dose was the pancreas. Results suggest that the activity administered for each cycle could be increased to maximize the absorbed dose of tumors and metastases.

The indispensable role of chest CT in the detection of coronavirus disease 2019 (COVID-19).

Abstract: Dear Sir, We have read with interest the original article published online of the EJNMMI [1]. The authors introduced the imaging and clinical characteristics of SARS-CoV-2 infected patients in Guangzhou, China. Notably, they reported the fact that a few patients who initially had negative nucleic acid test results presented characteristic pneumonia features on CT. In contrast, another small proportion of confirmed cases had a negative baseline CT scan. With a speedily spread of the SARS-CoV-2 infection (COVID-19) worldwide, we need a more rounded view on the role of chest CT in the detection of COVID-19, which is still in controversy. Currently, RT-PCR-based viral nucleic acid assay is used as the reference standard method to confirm COVID-19 infection [2]. However, such a laboratory test is time-consuming, and the supply of test kits may be the bottle-neck for a rapidly growing suspicious population even for many developed countries such as the United States. More importantly, initial false-negative or weakly positive RT-PCR test results were found in some later-confirmed cases, whereas highly suspicious CT imaging features were present [1, 3].While the exact reason is still under investigation, it may be caused by insufficient quantities of viral microbes extracted for testing or incorrect extraction methods were used. Considering the exponentially increasing number of COVID-19-infected patients worldwide, these patients with initial false-negative RT-PCR test results are not trivial and could lead to occult transmission in key infection areas. Chest CT is an indispensable tool for early screening and diagnosing suspected COVID-19 patients. Previous studies confirmed that the majority of patients infected with COVID-19 exhibited common chest CT characteristics, including ground-glass opacities and consolidation, which reflect lesions affecting multi-lobes or infections in bilateral lung parenchyma [1, 3]. Increasing evidence suggested that these chest CT characteristics can not only be used to screen suspected patients but also serve a diagnostic tool for COVID19-caused acute respiratory diseases (ARDS) [3]. These findings have led to the modification of the diagnosis and treatment protocols of SARS-CoV-2-caused pneumonia to include patients with characteristic pneumonia features on chest CT but negative RT-PCR results in severe epidemic areas such as Wuhan city and Hubei province [4]. Meanwhile, patients with negative RT-PCR but positive CT findings should be isolated or quarantined to prevent clustered or wide-spread infections. The critical role of CT in early detection and diagnosis of COVID-19 becomes more and more publicly acceptable. However, several studies also reported that a proportion of RT-PCR positive patients, including some severe cases, had initially normal chest X-ray or CT findings [1, 5, 6]. According to the diagnostic criteria of COVID-19, patients might have no or atypical radiological manifestations even at the mild or moderate stages. This can be attributed to the fact that some lesions are easily missed in the low-density resolution of chest X-ray, suggestive of chest CT may be a better modality with a lower false-negative rate. Another possible explanation is that, in some patients, the targeted organ of COVID-19 may not be the lung. Multiple organ dysfunctions, including ARDS, acute cardiac injury, hepatic injury, and kidney injury, have been reported during COVID-19 infection [7]. For those patients with severe clinical symptom but ‘normal’ chest imaging findings, comprehensive exams should be performed to prevent multiple organ impairment. Regardless of the reasons, the absence of characteristic chest CT features in some COVID-19 patients remains a hurdle for accurately early screening and detection. This article is part of the Topical Collection on Letter to the Editor.

Biodistribution and first clinical results of 18F-SiFAlin-TATE PET: a novel 18F-labeled somatostatin analog for imaging of neuroendocrine tumors

Abstract: PET/CT using 68Ga-labeled somatostatin analogs (SSA) targeting somatostatin receptors (SSR) on the cell surface of well-differentiated neuroendocrine tumors (NET) represents the clinical reference standard for imaging. However, economic and logistic challenges of the 68Ge/68Ga generator-based approach have disadvantages over 18F-labeled compounds. Here, we present the first in-human data of 18F-SiFAlin-TATE, a novel 18F-labeled, SSR-targeting peptide. The aim was to compare the intra-individual biodistribution, tumor uptake, and image quality of 18F-SiFAlin-TATE to the clinical reference standard 68Ga-DOTA-TOC. Thirteen patients with NET staged with both 68Ga-DOTA-TOC and 18F-SiFAlin-TATE PET/CT have been included in this retrospective analysis. We compared the biodistribution in normal organs and tumor uptake of NET lesions by SUVmean and SUVmax measurement for tracers. Additionally mean and max tumor-to-liver (TLR) and tumor-to-spleen ratios (TSR) have been calculated by division of SUVmean and SUVmax of tumor lesions by the SUVmean of the liver and spleen, respectively. Additionally, image quality was visually rated by 5 blinded readers and an intra-class correlation (ICC) analysis on inter-observer agreement has been performed. Compared with 68Ga-DOTA-TOC, the biodistribution of 18F-SiFAlin-TATE showed somewhat higher, however, statistically not significant higher uptake in the liver, spleen, and adrenal glands. Significantly higher uptake was observed in the kidneys. Tumor uptake was higher in most tumor lesions with significantly higher uptake in common metastatic sites of NET including the liver (SUVmax 18.8 ± 8.4 vs. 12.8 ± 5.6; p < 0.001), lymph nodes (SUVmax 23.8 ± 20.7 vs. 17.4 ± 16.1; p < 0.001) and bone (SUVmax 16.0 ± 10.1 vs. 10.3 ± 5.7; p < 0.01) for 18F-SiFAlin-TATE. The high tumor uptake resulted in favorable TLR and TSR, comparable with that of 68Ga-DOTA-TOC. The ICC analysis on the inter-observer agreement on image quality was substantial and almost perfect. Image quality was rated as excellent in most cases in both 68Ga-DOTA-TOC and 18F-SiFAlin-TATE PET. The favorable characteristics of 18F-SiFAlin-TATE with a high image quality, the kit-like labeling procedure, and the promising clinical performance enable improved logistics and diagnostic possibilities for PET imaging of NET. Our first clinical results warrant further systematic studies investigating the clinical use of 18F-SiFAlin-TATE in NET patients.

Influence of androgen deprivation therapy on PSMA expression and PSMA-ligand PET imaging of prostate cancer patients.

Abstract: Prostate cancer (PCa) is the second most common solid tumour in men with more than 1.3 million cases diagnosed and more than 350,000 deaths estimated to have occurred in 2018 [1]. ADT is an integral part of treatment for high-risk, recurrent or metastatic prostate cancer. Therefore, imaging of patients prior to, during or after ADT is common. It is known that results from molecular imaging can be influenced by various treatments (e.g. chemotherapy in FDG PET, somatostatin-analogues in DOTA-peptide PET). This editorial aims to outline the current knowledge of interaction between PSMA-ligand uptake in PET and ADT. ADT acts by reducing the synthesis of androgens, which activate the androgen receptor, the primary regulator of growth and survival of prostate cancer cells. The following ADT options are commonly used: orchiectomy; luteinizing hormone-releasing hormone (LHRH) agonists (i.e. leuprolide, goserelin, triptorelin and histrelin); LHRH antagonists (i.e. degarelix). Other mechanisms to interfere with the androgen receptor (AR) pathway are as follows: AR inhibitors (i.e. bicalutamide, flutamide, nilutamide), the more recent AR inhibitors (i.e. enzalutamide, apalutamide and darolutamide) and androgen synthesis inhibitors (i.e. abiraterone). In current clinical routine, up to one-third of the patients referred for PSMA-ligand PET are on some form of ADT, which highlights that the effects of ADTon PSMA expression and subsequently imaging results need careful consideration. Nuclear medicine physicians have to consider possible ADT interferences when reporting PSMA-ligand PET scans. Its relevance lies both in important implications for PSMA-ligand PET interpretation and for defining the best timing and sequencing of PSMA-ligand scans.

FDG-PET/CT findings highly suspicious for COVID-19 in an Italian case series of asymptomatic patients.

Abstract: To illustrate the [18F]FDG-PET/CT findings in patients affected by cancer with clinical diagnosis of Covid-19 We retrospectively reviewed the cases of patients who showed pulmonary involvement unrelated to cancer metastases on March 13 and 16 2020. We reviewed the scans, collected medical history, and exposure information. Among the 13 scans, we identified 5 cases with imaging findings suspicious for viral infection. Peripheral lung consolidations and/or ground-glass opacities in two or more lobes were found. Lung abnormalities displayed increased [18F]FDG uptake (SUVmax 4.3–11.3). All the patients on the day of PET/CT acquisition were asymptomatic, and they did not have fever or cough. In view of the PET/CT findings, home isolation, symptom surveillance, and treatment (in 3/5 patients) were indicated. At 1-week follow-up, 2/5 patients experienced the onset of mild respiratory symptoms. The [18F]FDG-PET/CT can identify probable Covid-19 disease in the absence or before symptoms onset and can guide patient management. Nuclear medicine staff needs to be aware of the possibility of contact with patients affected by the SARS-CoV-2 infection even if they do not present any symptom. Therefore, safety measures need to be adopted for other patients and hospital staff in order to block the spread of infection.