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Although the novel coronavirus disease 2019 (COVID-19) can present as non-specific clinical forms, subclinical cases represent an important route of transmission and a significant source of mortality, mainly in high-risk subpopulations such as cancer patients. A deeper knowledge about the shift in cellular metabolism of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected cells could provide new insights about its pathogenic and host response and help to diagnose pulmonary involvement. We explored the association between metabolic and structural changes of lung parenchyma in asymptomatic cancer patients with suspected COVID-19 pneumonia, as a potential added diagnostic value of fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET/CT) scans in this subpopulation. Methods: Within the period of February 19 and May 29, 2020 18F-FDG PET/CT studies were reviewed to identify those cancer patients with suggestive incidental findings of COVID-19 pneumonia. PET studies were interpreted through qualitative (visual) and semiquantitative analysis (measurement of maximum standardized uptake value, SUVmax) evaluating lung findings. Several characteristic signs of COVID-19 pneumonia on computed tomography (CT) were described as COVID-19 Reporting and Data System (CO-RADS) categories (1-6). After comparing SUVmax values of pulmonary infiltrates among different CO-RADS categories, we explored the best potential cut-off values of pulmonary SUVmax against CO-RADS categories as "gold standard" result to discard the diagnosis of COVID-19 pneumonia. Results: CT signs classified as CO-RADS category 5 or 6 were found in 16/41 (39%) oncological patients derived to multimodal PET/CT imaging. SUVmax was higher in patients with CO-RADS 5 and 6 vs. 4 (6.17±0.82 vs. 3.78±0.50, P = 0.04) and vs. 2 and 3 categories (3.59±0.41, P = 0.01). A specificity of 93.8% (IC 95%: 71.7-99.7%) and an accuracy of 92.9% were obtained when combining a CO-RADS score 5-6 with a SUVmax of 2.45 in pulmonary infiltrates. Conclusion: In asymptomatic cancer patients, the metabolic activity in lung infiltrates is closely associated with several combined tomographic changes characteristic of COVID-19 pneumonia. Multimodal 18F-FDG PET/CT imaging could provide additional information during early diagnosis in selected predisposed patients during pandemic. The prognostic implications of simultaneous radiological and molecular findings in cancer and other high-risk subpopulations for COVID-19 pneumonia deserve further evaluation in prospective researches.

Aim We aimed to determine the frequency and clinical significance of breast incidental uptake (BIU) detected through fluorine-18 fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) in a single, high-load center. Patients and methods In this retrospective study, we analyzed a total of 13 763 PET/CT studies performed from January 2017 to January 2020. After excluding 3148 scans, the maximum standardized uptake value (SUVmax) and maximum diameter (cm) of each BIU were measured. Clinical management, ultrasound/mammography and pathology reports were analyzed. Results We found BIU in 27 scans of 26 patients (0.3% of the studies). Mean age was 62.2 years and 88.5% were women; 84.6% underwent PET/CT for oncological indications. Ultrasound/mammography was consequently performed in 23 patients (88.5%), and histological correlations were available for Breast Imaging Reporting and Data System categories 4 and 5. Finally, lesions were benign in 14 patients (60.9%; two of them with low/intermediate risk of malignancy) and malignant in nine patients (39.1%). The remaining three patients had no ultrasound/mammography reports. Mean SUVmax of benign and malignant lesions were 2.6 ± 1.4 and 5.8 ± 3.5, respectively (P = 0.002). Considering a SUVmax cut-off value of 4.0, the sensitivity and specificity for differentiating benign vs. malignant lesions were 67 and 93%, respectively. Benign lesions were smaller than malignant in CT (maximum diameter:1.3 ± 0.5 cm vs. 2.0 ± 1.0 cm, P = 0.02). Conclusion Although BIU detected by 18F-FDG PET/CT is infrequently found, the risk of malignancy remains very high (39.1%). Both SUVmax and maximum diameter were greater in malignant than in benign lesions. An exhaustive study with ultrasound/mammography and selective histopathological correlation is mandatory after BIU findings, even in small lesions.

Objective: to assess the capacity of the PET/CT to predict pulmonary function deterioration and increased mortality risk in patients with idiopathic interstitial pneumonia (IIP) and to establish a possible SUVmax cutoff which identifies these patients. Material and methods: retrospective study between January 2007-December 2020. Inclusion criteria: patients > 18 years of age, diagnosed with IIP by PET/CT and pulmonary function test, with less than 6 months’ difference between the two tests. A study was made of the outcome variables associated with the PET/CT, the pulmonary function test measured at 2 stages (initially at the time of the PET/CT and at the end of follow-up), the mortality risk (using the GAP index) and the relationship between them all. Other variables of interest observed were age, sex, department requesting the PET/CT, indication, and the presence of lung cancer (LC). The statistical analysis was performed using the SPSS program. Results: 39 patients were analysed: 34 males (87%), with an age of 75 ± 8 years (mean ± DS). The mean ± SD of the SUVmax was 2.57 ± 1.17, with a statistically insignificant difference (p = 0.670) between patients with and without lung cancer. LC was confirmed in 21 cases (54%). There is a small inverse correlation between the SUVmax and the initial and final predicted FVC% (r= -0.154, r= -0.252), together with a medium correlation for the initial and final predicted DLCO% (r= -0.523, r= -0.514). The mean ± SD of the GAP index was 3.77 ± 1.08. There is a medium correlation between the SUVmax and the mortality risk of stages I and II (r = 0.468). By means of ROC curve analysis, an SUVmax of 2.2 was established to predict the fall of the FVC below 80%, of 1.9 to predict the fall of the DLCO below 60%, and of 2.15 to predict the progression from GAP stage I to II in mortality risk. Conclusions: There is an inverse correlation between the SUVmax and the pulmonary function, together with a direct relationship between the SUVmax and the mortality risk.

Background Infective endocarditis (IE) in patients with a valve-tube ascending aortic graft (AAG) is a rare entity with a challenging diagnosis and treatment. This study describes the clinical features, diagnosis and outcome of these patients. Methods Between 1996 and 2019, 1654 episodes of IE were recruited in 3 centres, of which 37 patients (2.2%) had prosthetic aortic valve and AAG-IE (21 composite valve graft, 16 supracoronary graft) and conformed our study group. Results Patients with aortic grafts were predominantly male (91.9%) and the mean age was 67.7 years. Staphylococci were the most frequently isolated microorganisms (32%). Viridans group streptococci were only isolated in patients with composite valve graft. TEE was positive in 89.2%. PET/CT was positive in all 15 patients in whom it was performed. Surgical treatment was performed in 62.2% of patients. In-hospital mortality was 16.2%. Heart failure and the type of infected graft (supracoronary aortic graft) were associated with mortality. Mortality among operated patients was 21.7%. Interestingly, 14 patients received antibiotic therapy alone, and only one died. Mortality was lower among patients with a composite valve graft compared to those with a supracoronary graft (4.8% vs 31.3%; p = 0.03). Conclusions In patients with AAG and prosthetic aortic valve IE, mortality is not higher than in other patients with prosthetic IE. Multimodality imaging plays an important role in the diagnosis and management of these patients. Heart failure and the type of surgery were risk factors associated with in-hospital mortality. Although surgical treatment is usually recommended, a conservative management might be a valid alternative treatment in selected patients.

Background Lung involvement in patients with coronavirus disease 2019 (COVID-19) undergoing PET-CT has been previously reported. However, FDG uptake outside lung parenchyma was poorly characterized in detail. We evaluated the extra-parenchymal lung involvement in asymptomatic cancer patients with COVID-19 pneumonia through 18F-FDG PET-CT. Methods A total of 1079 oncologic 18F-FDG PET-CT were performed between February 2 and May 18, 2020. Confirmed COVID-19 pneumonia was defined as characteristic ground-glass bilateral CT infiltrates and positive genetic/serologic tests. Nonmetastatic extra-parenchymal lung PET-CT findings were evaluated through qualitative (visual), quantitative (measurements on CT), and semiquantitative (maximum standardized uptake value: SUVmax on PET) interpretation. Clinical data, blood tests, and PET-CT results were compared between patients with and without COVID-19 pneumonia. Results A total of 23 18F-FDG PET-CT scans with pulmonary infiltrates suggestive of COVID-19 and available laboratory data were included: 14 positive (cases) and 9 negative (controls) for COVID-19 infection, representing a low prevalence of COVID-19 pneumonia (1.3%). Serum lactate dehydrogenase and D-dimers tended to be increased in COVID-19 cases. Extra-parenchymal lung findings were found in 42.9% of patients with COVID-19, most frequently as mediastinal and hilar nodes with 18F-FDG uptake (35.7%), followed by incidental pulmonary embolism in two patients (14.3%). In the control group, extra-pulmonary findings were observed in a single patient (11.1%) with 18F-FDG uptake located to mediastinal, hilar, and cervical nodes. Nasopharyngeal and hepatic SUVmax were similar in both groups. Conclusion In cancer patients with asymptomatic COVID-19 pneumonia, 18F-FDG PET-CT findings are more frequently limited to thoracic structures, suggesting that an early and silent distant involvement is very rare. Pulmonary embolism is a frequent and potentially severe finding raising special concern. PET-CT can provide new pathogenic insights about this novel disease.

Utility ofFrom 2013 to 2018, all patients (n = 63) admitted to a hospital with suspected CIED infection were prospectively recruited, undergoing a diagnostic work-up including a PET/CT. Explanted devices and material from the pocket were cultured. 14 cases corresponded to isolated PI and 13 were categorized as CIED-IE. Considering radionuclide uptake in the intracardiac portion of the lead, sensitivity and specificity of PET/CT for CIED-IE were 38.5% and 98.0%, respectively. Positive (19.2) and negative (0.6) likelihood ratio values, suggest that a positive PET/CT is much more probable to correspond to a patient with CIED-IE, whereas it is not possible to exclude this diagnosis when negative. For PI, sensitivity and specificity were 72.2% and 95.6%, respectively.The yield of

Positron emission tomography/computed tomography (PET/CT) is helpful in prosthetic valve (PV) infective endocarditis (IE), but its usefulness in other settings is less established [(1)][1]. We aim to evaluate the yield of PET/CT in patients with suspicion of IE in 3 scenarios: PV, native valves (NV

ObjectiveThe incidence of aortitis in patients with thoracic aortic diseases is not well established. The aim of this study was to analyse the frequency and clinical course of patients with aortitis in a surgical series.Methods320 consecutive patients with ascending aorta/aortic arch aneurysm or acute aortic syndrome who underwent surgery from 2012 to 2017 in a single tertiary referral hospital were retrospectively reviewed. Epidemiological data, clinical course and variables related to diagnosis, treatment and follow-up were collected from patients with histologically proven aortitis.ResultsFrom 320 examined aortic samples, 279 (87.2%) thoracic aneurysms and 41 acute aortic syndromes (12.8%), 9 (2.8%) were aortitis: 3 cases of Takayasu’s arteritis, 3 of IgG4-related aortitis, 2 of giant cell, and 1 classified as idiopathic. Median age at surgery was 53.4 (51–69.2) years and six cases were female. Seven patients presented with non-specific symptoms and the diagnosis was made at pathology. Surgery was elective in eight patients and emergent in one case of IgG4-related aortitis. 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) was performed for disease extension study and as a monitoring technique during the follow-up of five patients, with just one case performed presurgically. All the patients with IgG4-related disease showed extrathoracic aortic involvement. There were no deaths, neither in-hospital nor during the 1.7 years of median follow-up.ConclusionsIn surgically treated thoracic aorta pathology, the frequency of aortitis is low; IgG4-related disease is among the most common aetiologies with a frequency similar to other types of aortitis, such as Takayasu’s and giant cell arteritis, and clinical manifestations are non-specific making presurgical diagnosis difficult. 18F-FDG PET/CT allows a better assessment of disease extension and therapeutic response. Surgery can be successfully performed and corticosteroid therapy ensures a good mid-term follow-up.

Diagnosing progressive primary aphasia (PPA) and its variants is of great clinical importance, and fluorodeoxyglucose (FDG) positron emission tomography (PET) may be a useful diagnostic technique. The purpose of this study was to evaluate interobserver variability in the interpretation of FDG PET images in PPA as well as the diagnostic sensitivity and specificity of the technique. We also aimed to compare visual and statistical analyses of these images. There were 10 raters who analysed 44 FDG PET scans from 33 PPA patients and 11 controls. Five raters analysed the images visually, while the other five used maps created using Statistical Parametric Mapping software. Two spatial normalization procedures were performed: global mean normalization and cerebellar normalization. Clinical diagnosis was considered the gold standard. Inter-rater concordance was moderate for visual analysis (Fleiss’ kappa 0.568) and substantial for statistical analysis (kappa 0.756–0.881). Agreement was good for all three variants of PPA except for the nonfluent/agrammatic variant studied with visual analysis. The sensitivity and specificity of each rater’s diagnosis of PPA was high, averaging 87.8 and 89.9 % for visual analysis and 96.9 and 90.9 % for statistical analysis using global mean normalization, respectively. In cerebellar normalization, sensitivity was 88.9 % and specificity 100 %. FDG PET demonstrated high diagnostic accuracy for the diagnosis of PPA and its variants. Inter-rater concordance was higher for statistical analysis, especially for the nonfluent/agrammatic variant. These data support the use of FDG PET to evaluate patients with PPA and show that statistical analysis methods are particularly useful for identifying the nonfluent/agrammatic variant of PPA.

ObjectiveInfection of valved aortic grafts is a rare entity whose diagnosis remains challenging. Positron emission tomography (PET)/CT has become a criterion for the diagnosis of infective endocarditis (IE) in prosthetic valves, but its role on ascending aortic graft infections remains unclear. This study aims to assess the diagnostic value of PET/CT in patients with valved aortic graft infection.Methods12 episodes with a valved aortic graft who had undergone a PET/CT due to suspicion of IE were prospectively included (group I) and compared with five controls free of infection who underwent PET/CT for other reasons (group II). Pathological uptake of 18F-fluorodeoxyglucose (FDG) and its pattern at the prosthetic valve and aortic graft were studied.ResultsDiagnosis of IE was confirmed in 9 out of 12 episodes of group I. 18F-FDG uptake was detectable in eight out of nine cases with a final diagnosis of IE. The most repeated pattern of uptake was homogeneous around the valve and heterogeneous around the tube. There was one false-negative study. Of the three patients in which IE was ruled out, there were two false positives and one true negative. In group II, there were three patients with a positive PET/CT study, two of them had active aortitis and the third was considered false positive.Conclusions18F-FDG PET/CT shows high sensitivity in the detection of infected aortic grafts. Thus, this technique should be considered in the diagnostic work-up of patients with suspicion of aortic graft infection. However, further validation of this approach is needed.

A 55-year-old man with a personal history of left pheochromocytoma 2 years previously presented with an abdominal mass. Tumor relapse was suspected.Abdominal ultrasound showed a large left upper quadrant solid mass (calipers), with heterogeneous echogenicity and central cystic degeneration areas or necrosis (Fig. 1a). A computed tomography (CT) scan showed surgical clips of left adrenalectomy and multiple confluent left upper quadrant masses with a maximal diameter of 19 cm and heterogeneous enhancement (Fig. 1b). Both CT scan and ultrasound images were suspicious of adrenocortical carcinoma (ACC): size, heterogeneity and diaphragm invasion among other radiological features. Clinically, the mass grew in a few months and there were no paroxysmal hypertension episodes, nor elevation of catecholamines (cathecholamine urine test: 37.2 μg/g creatinine, normal range 0.1-260). F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT was performed as ACC was suspected (2). ACC is an uncommon malignant neoplasm of unknown cause; however, smoking and oral contraceptives may be risk factors [1, 2]. Patients usually present with advanced-stage disease and have poor prognosis [3], with a 2-year recurrence rate that ranges from 73 to 86 % [4]. CT or magnetic resonance (MR) is most often used for initial staging of ACC and usually shows heterogeneous adrenal mass with variable enhancement of solid components [4]. F-18 FDG PET has been used successfully for detection of adrenal metastases and for staging ACC [5]. Most ACCs accumulate and retain FDG [2, 6]. However, FDG PET cannot differentiate among malignant lesions (metastases, ACC, malignant pheochromocytoma, and lymphoma). Also, most pheochromocytomas (benign or malignant) are metabolically active and might accumulate FDG [7, 8]. A whole-body FDG PET scan (coronal and axial view) shows increased irregular FDG uptake in the abdominal masses (Fig. 2). An I-123 metaiodobenzylguanedine (MIBG) scan was requested to rule out pheochromocytoma because, although conventional image methods (ultrasound and CT) and also PET/CT scan were suspicious of ACC, the primary histology of the tumor was consistent with pheochromocytoma. An MIBG scan was performed after injection of 185 MBq of I123 MIBG intravenously. Single photon emission tomography (SPECT)/CT scan showed abnormal isotope accumulation in the tumor region. The patient underwent total resection of the tumor. The histology was of ACC, with areas of necrosis and cystic areas, so the result of the MIBG scan was a false positive. No positive chromaffin staining or chromogranin ISSN (print) 1869-3474 ISSN (online) 1869-3482

Diagnosing progressive primary aphasia (PPA) and its variants is of great clinical importance, and fluorodeoxyglucose (FDG) positron emission tomography (PET) may be a useful diagnostic technique. The purpose of this study was to evaluate interobserver variability in the interpretation of FDG PET images in PPA as well as the diagnostic sensitivity and specificity of the technique. We also aimed to compare visual and statistical analyses of these images.There were 10 raters who analysed 44 FDG PET scans from 33 PPA patients and 11 controls. Five raters analysed the images visually, while the other five used maps created using Statistical Parametric Mapping software. Two spatial normalization procedures were performed: global mean normalization and cerebellar normalization. Clinical diagnosis was considered the gold standard.Inter-rater concordance was moderate for visual analysis (Fleiss' kappa 0.568) and substantial for statistical analysis (kappa 0.756-0.881). Agreement was good for all three variants of PPA except for the nonfluent/agrammatic variant studied with visual analysis. The sensitivity and specificity of each rater's diagnosis of PPA was high, averaging 87.8 and 89.9% for visual analysis and 96.9 and 90.9% for statistical analysis using global mean normalization, respectively. In cerebellar normalization, sensitivity was 88.9% and specificity 100%.FDG PET demonstrated high diagnostic accuracy for the diagnosis of PPA and its variants. Inter-rater concordance was higher for statistical analysis, especially for the nonfluent/agrammatic variant. These data support the use of FDG PET to evaluate patients with PPA and show that statistical analysis methods are particularly useful for identifying the nonfluent/agrammatic variant of PPA.

In this chapter we try to synthesize the emerging role of functional imaging techniques in esophagic and gastric tumors as well as in small bowel malignancies. In relation to small bowel malignancies, we focused on gastrointestinal stromal tumors (GIST) and carcinoid tumors. Positron emission tomography/computed tomography (PET/CT) represents an essential nuclear medicine technique showing superiority against conventional diagnostic imaging methods in the detection of lymphatic and distant metastases, detection of recurrences, and evaluation of tumor response to different treatments in these tumors. We mainly give attention to the most common PET radiotracer (18F-FDG), but other new PET radiotracers are also mentioned such as 68Ga-labeled somatostatin analogs (DOTA-TOC, DOTA-TATE, and DOTA-NOC) that are basically used in the evaluation of carcinoid tumors.

a b s t r a c t Purpose: To prospectively study the value of PET-CT with fluorine-18 fluorodeoxyglucose (FDG) to pre- dict neoadjuvant chemotherapy (NAC) response of locoregional disease of stages II and III breast cancer patients. Material and methods: A written informed consent and approval were obtained from the Ethics Commit- tee. PET-CT accuracy in the prediction of pathologic complete response (pCR) after NAC was studied in primary tumors and lymph node metastasis in 43 women (mean age: 50 years: range: 27-71 years) with histologically proven breast cancer between December 2009 and January 2011. PET-CT was performed at baseline and after NAC. SUVmax percentage changes (� SUVmax) were compared with pathology findings at surgery. Receiver-operator characteristic (ROC) analysis was used to discriminate between locoregional pCR and non-pCR. In patients not achieving pCR, it was investigated ifSUVmax could accu- rately identify the residual cancer burden (RCB) classes: RCB-I (minimal residual disease (MRD)), RCB-II (moderate RD), and RCB-III (extensive RD). Results: pCR was obtained in 11 patients (25.6%). Residual disease was found in 32 patients (74.4%): 16 (37.2%) RCB-I, 15 (35.6%) RCB-II and 2 (4.7%) RCB-III. Sensitivity, specificity, and accuracy to predict pCR were 90.9%, 90.6%, and 90.7%, respectively. Specificity was 94.1% in the identification of a subset of patients who had either pCR or MRD. Conclusion: Accuracy ofSUVmax in the locoregional disease of stages II and III breast cancer patients after NAC is high for the identification of pCR cases. Its specificity is potentially sufficient to identify a subgroup of patients who could be managed with conservative surgery.