UNASSIGNED: Primary liver tumors constitute one of the most common tumors. These are aggressive tumors with poor survival. Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), most commonly used functional imaging, shows limited tracer retention and poor tumor to background ratios (TBR). Novel 68Ga-fibroblast-activation-protein inhibitor (FAPI) PET/CT has shown better tracer uptake and detection efficacy in liver tumors. However, most of the available literature is limited to single center studies with limited number of patients. So, we tried to review and analyze the head-to-head comparison of 18F-FDG PET/CT and 68Ga-FAPI PET/CT in evaluation of liver tumors.
UNASSIGNED: Literature available on head to head comparison of diagnostic accuracy of 18F-FDG PET/CT and 68Ga-FAPI PET/CT was searched in databases like PubMed, SCOPUS, EMBASE and Google Scholar for published original studies till April 2023. The relevant studies were selected and assessed using the Revised Tool for the Quality Assessment of Diagnostic Accuracy Studies-2 checklist. A random-effect model was used for calculating pooled sensitivity and specificity. They were represented with 95% confidence intervals (95% CI) and demonstrated in Forest plots. I-square statistic was used to assess heterogeneity in the studies.
UNASSIGNED: Pooled sensitivity and specificity of FAPI PET/CT and 18F-FDG PET/CT for detection of primary liver tumors was 94.3% (95% CI: 90.6-96.8%); 89.3% (95% CI: 71.8-97.7%) and 56.1% (95% CI: 49.7-62.5%); 96.4% (95% CI: 81.7-99.9%) respectively. Pooled sensitivity for detection of extrahepatic metastatic disease was 92.2% (range: 88.1-100%; 95% CI: 87.8-95.4%) and 72.4% (range: 69.8-76.5; 95% CI: 65.9-78.2%) respectively. Also, the maximum standardized uptake value (SUVmax) and TBR were higher for FAPI PET/CT than 18F-FDG PET/CT in the included studies.
UNASSIGNED: Overall, FAPI PET/CT showed higher sensitivity for detection of liver tumors with better SUVmax and TBR than 18F-FDG PET/CT.
UNASSIGNED: Primer karaciğer tümörleri en sık görülen tümörlerdendir. Bunlar hayatta kalma oranı düşük olan agresif tümörlerdir. En sık kullanılan fonksiyonel görüntüleme olan florodeoksiglukoz (FDG) pozitron emisyon tomografisi/bilgisayarlı tomografi (PET/BT), sınırlı radyofarmasötik tutulumu ve zayıf tümör/arka plan oranları (TBR) gösterir. Yeni 68Ga-fibroblast aktivasyon protein inhibitörü (FAPI) PET/BT, karaciğer tümörlerinde daha iyi radyofarmasötik tutulumu ve tespit etkinliği göstermiştir. Ancak mevcut literatürün çoğu, sınırlı hasta sayısıyla yapılan tek merkezli çalışmalarla sınırlıdır. Bu nedenle, karaciğer tümörlerinin değerlendirilmesinde 18F-FDG PET/BT ve 68Ga-FAPI PET/BT’nin birebir karşılaştırmasını gözden geçirip analiz etmeye çalıştık.
UNASSIGNED: 18F-FDG PET/BT ve 68Ga-FAPI PET/BT’nin tanısal doğruluğunun birebir karşılaştırılması konusunda mevcut literatür, Nisan 2023’e kadar yayınlanmış araştırma makaleleri için PubMed, SCOPUS, EMBASE ve Google Scholar gibi veritabanlarında tarandı. İlgili çalışmalar Tanısal Doğruluk Çalışmalarının Kalite Değerlendirmesi için Gözden Geçirilmiş Araç-2 kontrol listesi kullanılarak seçilmiş ve değerlendirilmiştir. Birleştirilmiş duyarlılığı ve özgüllüğü hesaplamak için rastgele etki modeli kullanıldı. Bunlar %95 güven aralıklarıyla (%95 GA) temsil edildi ve Orman grafiklerinde gösterildi. Çalışmalardaki heterojenliği değerlendirmek için I-kare istatistiği kullanıldı.
UNASSIGNED: Primer karaciğer tümörlerinin tespiti için FAPI PET/BT’nin havuzlanmış duyarlılığı ve özgüllüğü sırasıyla %94,3 (%95 GA: %90,6-96,8) ve %89,3 (%95 GA: %71,8-97,7); 18F-FDG PET/BT’nin havuzlanmış duyarlılığı ve özgüllüğü sırasıyla %56,1 (%95 GA: %49,7-62,5) ve %96,4 (%95 GA: %81,7-99,9) idi. Ekstrahepatik metastatik hastalığın saptanması için havuzlanmış duyarlılık FAPI PET/BT ve 18F-FDG PET/BT için sırasıyla %92,2 (aralık: %88,1-100; %95 GA: %87,8-95,4) ve %72,4 (aralık: 69,8-76,5; %95 GA: %65,9-78,2) idi. Ayrıca, dahil edilen çalışmalarda FAPI PET/BT için maksimum standardize tutulum değeri (SUVmaks) ve TBR, 18F-FDG PET/BT’den daha yüksekti.
UNASSIGNED: Genel olarak, FAPI PET/BT, karaciğer tümörlerinin tespitinde 18F-FDG PET/BT’ye göre daha iyi SUVmaks ve TBR ile daha yüksek duyarlılık gösterdi.

Background: The objective of this study is to evaluate the diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in detecting recurrence in patients with differentiated thyroid cancer (DTC) who have negative whole-body scans (WBSs) but elevated serum thyroglobulin (Tg) or thyroglobulin antibody (TgAb) levels. Methods: This systematic review/meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Diagnostic Test Accuracy criteria (International Prospective Register of Systematic Reviews registration number: CRD42022340924). A comprehensive search of the MEDLINE, EMBASE, and Cochrane databases identified articles reporting the diagnostic accuracy of FDG PET/CT for the detection of recurrence in patients with DTC with negative WBS and elevated serum Tg or TgAb levels published between January 2012 and June 2023. Meta-analyses were performed to determine the diagnostic accuracy of FDG PET/CT on the total target population as well as on subgroups stratified by serum Tg or TgAb, and thyrotropin (TSH) stimulation status at the time of FDG PET/CT. The Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework was applied to evaluate the quality of evidence and the strength of recommendations to facilitate translation of the meta-analysis results into practical recommendations for clinical guidelines. Results: A total of 24 studies involving 1988 patients were included for analysis. The overall pooled sensitivity and specificity values were 0.87 (95% confidence interval [CI] = 0.83-0.92; I2 = 75%) and 0.84 (CI = 0.80-0.89; I2 = 44%), respectively. Subgroup analyses revealed no significant differences in the diagnostic accuracy of FDG PET/CT in patients stratified by serum Tg or TgAb levels, and TSH stimulation status at the time of PET/CT. Treatment plans were changed following FDG PET/CT imaging in 40% (CI = 34-47%; I2 = 39%) of cases. The quality level of evidence for using FDG PET/CT was moderate in both sensitivity and specificity according to the GRADE system. Conclusion: There is moderate quality evidence demonstrating the high diagnostic accuracy of FDG PET/CT in detecting recurrence in patients with DTC with negative WBS and elevated serum Tg or TgAb levels. This evidence corroborates the current guidelines\' endorsement of FDG PET/CT as a diagnostic tool in such patients.

BACKGROUND: An ectopic meningioma, such as a primary pulmonary meningioma (PPM), is a rare type of tumor that primarily originates outside of the central nervous system. The most common presentation of PPM is isolated pulmonary nodules or masses, and most of them are benign. Only sporadic cases have been reported. This case reported a giant primary pulmonary meningioma and systematically reviewed previously reported cases in the literature.
METHODS: A 55-year-old female suffered from asthma after activity, chest tightness, and a persistent dry cough for 2 months. Chest computed tomography (CT) showed a huge mass with calcification in the left lower lobe. And positron emission tomography (PET)/CT revealed mild FDG accumulation of the mass. The mass was finally surgically removed and PPM was confirmed according to histopathologic examinations.
CONCLUSIONS: PPM is a rare disease with heterogeneity not only in CT features but also in glucose metabolism. FDG uptake levels do not identify benign from malignant, benign PPM may have high FDG uptake and malignant may have low.

UNASSIGNED: Intravascular large B-cell lymphoma (IVLBCL) is a rare entity among large B-cell non-Hodgkin lymphomas and is often difficult to diagnose. We report the case of a patient with IVLBCL who presented with central nervous system (CNS) symptoms alone, in which positron emission tomography (PET) enabled a rapid and accurate diagnosis.
UNASSIGNED: An 81-year-old woman was admitted to our hospital with a 3-month history of gradually progressive dementia and declining spontaneity. Magnetic resonance imaging revealed multiple hyperintense lesions bilaterally on diffusion-weighted imaging without enhancement on gadolinium-enhanced T1-weighted imaging. Laboratory findings showed elevated serum lactate dehydrogenase (626 U/L) and soluble interleukin-2 receptor (sIL-2R) (4692 U/mL). Cerebrospinal fluid (CSF) analysis showed slightly elevated levels of protein (166 mg/dL) and lymphocytic cells (29/μL), and β2-microglobulin (β2-MG) (4.6 mg/L) was highly elevated. Whole-body computed tomography revealed faint ground-glass opacities in the upper and middle lung fields and diffuse enlargement of both kidneys without lymph node swelling. 18F-fluorodeoxyglucose (FDG)-PET showed diffuse and remarkably high FDG uptake in both upper lungs and kidneys without uptake by lymph nodes, suggesting a malignant hematological disease. IVLBCL was confirmed histologically by incisional random skin biopsy from the abdomen. Chemotherapy using R-CHOP regimen in combination with intrathecal methotrexate injection was started on day 5 after admission and follow-up neuroimaging showed no signs of recurrence.
UNASSIGNED: IVLBCL presenting with CNS symptoms alone is rare and often has a poor prognosis associated with delayed diagnosis, and various evaluations (including systemic analysis) are therefore necessary for early diagnosis. FDG-PET, in addition to identification of clinical symptoms and evaluation of serum sIL-2R and CSF β2-MG, enables rapid therapeutic intervention in IVLBCL presenting with CNS symptoms.

The role of 2-deoxy-2-[18F]fluoro-D-glucose Positron Emission Tomography/Computed Tomography (FDG PET/CT) in the management of prostate cancer (PCa) patients is increasingly recognised. However, its clinical role is still controversial. Many published studies showed that FDG PET/CT might have a prognostic value in the metastatic castration-resistant phase of the disease, but its role in other settings of PCa and, more importantly, its impact on final clinical management remains to be further investigated. We describe a series of six representative clinical cases of PCa in different clinical settings, but all characterised by a measurable clinical impact of FDG PET/CT on the patients\' management. Starting from their clinical history, we report a concise narrative literature review on the advantages and limitations of FDG PET/CT beyond its prognostic value in PCa. What emerges is that in selected cases, this imaging technique may represent a useful tool in managing PCa patients. However, in the absence of dedicated studies to define the optimal clinical setting of its application, no standard recommendations on its use in PCa patients can be made.

Prosthetic valve endocarditis (PVE) is a sinister complication, with high morbidity and mortality. Diagnosis is conventionally based on modified Duke Criteria. 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) has shown high accuracy in diagnosing PVE. Positive 18F-FDG uptake in prosthetic valves on PET-CT is now considered major criteria for diagnosis of PVE. We share our experience of 18F-FDG PET-CT imaging as a problem solving tool in a case of suspected PVE and review the relevant literature.

To conduct a systematic review of articles on PET imaging of carotid atherosclerosis with emphasis on clinical usefulness and comparison with other imaging modalities.
Research articles reporting carotid artery PET imaging with different radiotracers until 30 November 2018 were systematically searched for in Medline/PubMed, Scopus, Embase, Google Scholar, and Cochrane Library. Duplicates were removed, and editorials, case studies, and investigations on feasibility or reproducibility of PET imaging and of patients with end-stage diseases or immunosuppressive medications were omitted. After quality assessment of included articles using Joanna Briggs Institute checklists, all eligible articles were reviewed.
Of 1718 primary hits, 53 studies comprising 4472 patients, aged 47-91 years (78.8% males), were included and grouped under the following headlines: diagnostic performance, risk factors, laboratory findings, imaging modalities, and treatment. 18F-fluorodeoxyglucose (FDG) (49/53) and 18F-sodium fluoride (NaF) (5/53) were the most utilized tracers to visualize carotid wall inflammation and microcalcification, respectively. Higher carotid FDG uptake was demonstrated in patients with than without symptomatic carotid atherosclerosis. Normal carotid arteries presented with the lowest FDG uptake. In symptomatic atherosclerosis, carotid arteries ipsilateral to a cerebrovascular event had higher FDG uptake than the contralateral carotid artery. FDG uptake was significantly associated with age, male gender, and body mass index in healthy individuals, and in addition with arterial hypertension, hypercholesterolemia, and diabetes mellitus in patients. Histological assessment indicated a strong correlation between microcalcification and NaF uptake in symptomatic patients. Histological evidence of calcification correlated inversely with FDG uptake, which was associated with increased macrophage and CD68 count, both accounting for increased local inflammatory response.
FDG-PET visualizes the inflammatory part of carotid atherosclerosis enabling risk stratification to a certain degree, whereas NaF-PET seems to indicate long-term consequences of ongoing inflammation by demonstrating microcalcification allowing discrimination of atherosclerotic from normal arteries and suggesting clinically significant carotid atherosclerosis.

Malignant lymphoma commonly occurs in adults, with a peak incidence between the seventh and ninth decades of life. Although malignant lymphoma usually occurs in the lymph nodes, it rarely occurs primarily in the bone. We herein describe an extremely rare case of primary malignant lymphoma of the talus in a 74-year-old man. Although plain radiographs showed no abnormality, gadolinium-enhanced magnetic resonance imaging (MRI) revealed a well-circumscribed intra- and extraosseous tumor of the talus. 18F-fluorodeoxyglucose (FDG) positron emission tomography/MRI revealed a marked increase of FDG uptake in the right ankle and the right inguinal lymph nodes. As the tumor was diagnosed as diffuse large B-cell lymphoma by core needle biopsy, combination therapy with chemo- and radiotherapy was initiated. The patient achieved complete remission, with no sign of recurrence at 8 months after initial chemoradiotherapy. Since primary malignant lymphoma of the bone is chemo- and radiosensitive and has a good prognosis, accurate staging by radiological investigation as well as correct pathological diagnosis by biopsy are required for optimal treatment.

BACKGROUND: 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and PET/CT have become two of the most powerful tools for malignant lymphoma exploration, but their diagnostic role in primary central nervous system lymphoma (PCNSL) is still disputed. The purpose of our study is to identify the usefulness of 18F-FDG PET and PET/CT for detecting PCNSL.
RESULTS: A total of 129 patients, obtained from eight eligible studies, were included for this systematic review and meta-analysis. The performance of 18F-FDG PET and PET/CT for diagnosing PCNSL were as follows: the pooled sensitivity was 0.88 (95% CI: 0.80-0.94), specificity was 0.86 (95% CI: 0.73-0.94), positive likelihood ratio (PLR) was 3.99 (95% CI: 2.31-6.90), negative likelihood ratio (NLR) was 0.11 (95% CI: 0.04-0.32), and diagnostic odds ratio (DOR) was 33.40 (95% CI: 10.40-107.3). In addition, the area under the curve (AUC) and Q index were 0.9192 and 0.8525, respectively.
METHODS: PubMed/MEDLINE, Embase and Cochrane Library were systematically searched for potential publications (last updated on July 16th, 2016). Reference lists of included articles were also checked. Original articles that reported data on patients who were suspected of having PCNSL were considered suitable for inclusion. The sensitivities and specificities of 18F-FDG PET and PET/CT in each study were evaluated. The Stata software and Meta-Disc software were employed in the process of data analysis.
CONCLUSIONS: 18F-FDG PET and PET/CT showed considerable accuracy in identifying PCNSL in immunocompetent patients and could be a valuable radiological diagnostic tool for PCNSL.

Langerhans cell histiocytosis (LCH) is a rare clonal proliferative disease, with an incidence rate of 4.0-5.4/1 million individuals. LCH encompasses a spectrum of disorders with diverse clinical presentations ranging from a single organ to multiple organ involvement. LCH rarely involves the thyroid gland. We presented a case with LCH of thyroid gland. The patient had painless progressive neck enlargement and then diabetes insipidus. Ultrasonic scan and magnetic resonance imaging scan revealed nodular goiter and pituitary stalk enlargement, respectively. Histopathological analysis revealed features of histiocytoid cells. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) was performed in order to rule out the presence of whole body infiltration. 18F-FDG PET/CT also demonstrated increased uptake in the thickening pituitary stalk and maxillofacial skin lesion, in addition to the bilateral thyroid nodules, CT showed the left lung nodule and the skull destruction without 18F-FDG uptake. This report emphasizes the role of 18F-FDG PET/CT in multiple organs involvement of patients with LCH.