Mild 18F-FDG Research Articles

Multiple Bone Involvement in Low-grade Myofibroblastic Sarcoma Demonstrated on 18F-FDG PET/CT.

A 68-year-old woman with low back pain for 2 months was admitted. T2-weighted fat-saturated imaging revealed hyperintense lesions in multiple lumbar regions, suggesting the possibility of bone metastases. Multiple osteolytic and mixed osteolytic-osteoblastic lesions with significant 18F-fluorodeoxyglucose (18F-FDG) uptake, as well as multiple osteoblastic lesions with mild 18F-FDG uptake, were observed on subsequent 18F-FDG positron emission tomography/computed tomography without an identifiable primary lesion. This patient was pathologically diagnosed with low-grade myofibroblastic sarcoma (LGMS) after biopsy and surgery. Although multiple bone involvement in LGMS is extremely rare, this case suggests that it should be considered in the differential diagnosis of multiple bone metastases.

Comparison of 18F-FDG and 68Ga-FAPI PET/CT in a Patient With Hepatic Perivascular Epithelioid Cell Neoplasm.

The prevalence of hepatic perivascular epithelioid cell neoplasm (PEComa) is extremely low, and imaging diagnosis is very difficult. We presented 18F-FDG and 68Ga-FAPI PET/CT findings in a 58-year-old woman with pathologically confirmed hepatic PEComa. The tumor showed intense 68Ga-FAPI uptake but only mild 18F-FDG activity on PET/CT studies. This case suggested that 68Ga-FAPI PET/CT might be a useful tool for evaluation of hepatic PEComa with remarkable tumor-to-liver ratios.

18F-FDG PET/CT Findings in Monkeypox Infection in an HIV Patient.

A 29-year-old man diagnosed with monkeypox infection underwent an 18F-FDG PET/CT for the study of organic involvement in the context of a nonsatisfactory clinical evolution. He had a history of HIV (with undetectable viral load). FDG PET/CT showed multiple hypermetabolic lymphadenopathies and bilateral pulmonary nodules with mild 18F-FDG uptake.

Multimodality Imaging of Cardiac Angiolipoma

HomeRadiologyVol. 307, No. 5 PreviousNext Reviews and CommentaryFree AccessImages in RadiologyMultimodality Imaging of Cardiac AngiolipomaSimin Lin, Haojun Chen Simin Lin, Haojun Chen Author AffiliationsFrom the Department of Radiology, Xiamen Cardiovascular Hospital of Xiamen University, School of Medicine, Xiamen University, No. 2999 Jinshan Rd, Xiamen 361006, China (S.L.); and Department of Nuclear Medicine & Minnan PET Center, First Affiliated Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China (H.C.).Address correspondence to H.C. (email: [email protected]).Simin LinHaojun Chen Published Online:Jun 13 2023https://doi.org/10.1148/radiol.230116MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In A 39-year-old man presented with a history of abdominal pain for 2 months. A routine chest radiograph showed an increased cardiothoracic ratio, and US was subsequently performed. At transthoracic echocardiography, an isoechoic cardiac mass was incidentally found in the anterior wall of the right atrium. The patient had no symptoms of chest tightness, chest pain, or dyspnea. His tumor markers showed a mild elevation of cancer antigen 125 (36.50 U/mL) and cancer antigen 724 (14.98 U/mL). The patient was scheduled for cardiac MRI to further characterize the lesion. A static four-chamber view obtained with a steady-state free precession sequence showed a 7.3 × 4.0-cm mass with heterogeneous signal intensity in the right atrium and atrioventricular groove (Figure, A). First-pass perfusion imaging indicated no apparent perfusion in the mass, which encased the right coronary artery (Figure, B). Inhomogeneous enhancement was detected with late gadolinium enhancement sequences (Figure, C), raising suspicion for malignancy. Hence, correlative fluorine 18 (18F) fluorodeoxyglucose (FDG) PET/CT was performed for tumor staging. Axial PET/CT images (Figure, D) revealed areas of fat attenuation and low 18F-FDG uptake, yielding a tumor-to-background ratio of 1:1. No abnormal radioactivity was observed in the extracardiac areas. The patient subsequently underwent radical tumor resection and surgical reconstruction of the right atrium. Histopathologic workup showed adipose tissue and interspersed proliferating blood vessels, consistent with the diagnosis of cardiac angiolipoma.(A) Cardiac MRI scan obtained with steady-state free precession (SSFP) shows a soft-tissue mass with heterogeneous signal intensity in the right atrium and atrioventricular groove (arrow). (B) First-pass perfusion MRI scan shows the mass encasing the right coronary artery (coronary vessel floating sign) without evident perfusion (arrowheads). (C) Short-axial late gadolinium enhancement (LGE) MRI scan shows inhomogeneous enhancement of the mass (arrow). (D) Axial fluorine 18 (18F) fluorodeoxyglucose (FDG) PET/CT image reveals areas of fat attenuation and mild 18F-FDG uptake (arrow) within the lesion (maximum standardized uptake value, 2.9), with a tumor-to-background ratio of 1:1.Download as PowerPointOpen in Image Viewer Disclosures of conflicts of interest: S.L. No relevant relationships. H.C. No relevant relationships.Article HistoryReceived: Jan 17 2023Revision requested: Feb 15 2023Revision received: Feb 17 2023Accepted: Mar 10 2023Published online: June 13 2023 FiguresReferencesRelatedDetailsRecommended Articles Dissection of a Giant Coronary AneurysmRadiology: Cardiothoracic Imaging2023Volume: 5Issue: 1Multimodality Imaging of Transposition of the Great ArteriesRadioGraphics2021Volume: 41Issue: 2pp. 338-360Fibrous Skeleton of the Heart: Anatomic Overview and Evaluation of Pathologic Conditions with CT and MR ImagingRadioGraphics2017Volume: 37Issue: 5pp. 1330-1351Cinematic Rendering of Complex Coronary Artery Left Atrial FistulaRadiology2022Volume: 307Issue: 1Active Cardiac Sarcoidosis Imitating Cardiac MetastasesRadiology: Cardiothoracic Imaging2020Volume: 2Issue: 6See More RSNA Education Exhibits Pearls and Pitfalls in Cardiac ImagingDigital Posters2022Multimodal Imaging Characterization of Cardiac Tumors Emphasizing PET with Pathology Correlation Using the New 2021 WHO ClassificationDigital Posters2022Mulmodality Imaging of Atrioventricular Groove Masses - Diagnostic ApproachDigital Posters2022 RSNA Case Collection Cardiac metastasis from melanomaRSNA Case Collection2022Cardiac myxomaRSNA Case Collection2020Primary Cardiac ParagangliomaRSNA Case Collection2022 Vol. 307, No. 5 Metrics Altmetric Score PDF download

Ultrasound-Guided Coarse Needle Biopsy Diagnosed Isolated Hepatic Malignant Melanoma with Undetermined Origin in TB Patient: A Case Report

Isolated hepatic malignant melanoma with undetermined origin is relatively rare and the imaging findings vary significantly in published studies. In this report, we described an elderly male patient with pulmonary tuberculosis who was diagnosed with isolated hepatic malignant melanoma with undetermined origin by ultrasound-guided percutaneous coarse needle biopsy (US-CNB). The hepatic melanoma was detected accidentally on chest CT. On contrast-enhanced ultrasound (CEUS), it presented an enhancement pattern of fast washin and slow washout. However, on magnetic resonance imaging (CEMRI), it showed non-rim hyperenhancement in the arterial phase but hypointensity in the late phase, mimicking hepatocellular carcinoma. With inconsistent results, the patient underwent fluorine-18-fluro-2-deoxy-D-glucose-positron emission tomography/computed tomography (18F-FDG-PET/CT). The mass showed mild 18F-FDG uptake with SUVmax of 4.7, and hypermetabolic nodules were observed in the lung, chest wall, thoracic vertebra, and pelvis. Due to the advanced stage of the tumor, US-CNB was performed to acquire a pathological diagnosis. The immunohistochemical staining suggested malignant melanoma. Of note, no primary tumor was revealed. Finally, the patient refused systemic therapy and died from tumor progression seven months later. Hence, CEUS and CEMRI is fundamental in the diagnosis of hepatic melanoma, and PET-CT is helpful in clinical staging. For controversial results, US-CNB is required to establish the pathological diagnosis.

Comparative Findings Between 68Ga-PSMA and 18F-FDG PET/CT for Hepatocellular Carcinoma

We have reported here the case of a 69-year-old man who presented with spinal cord compression due to bone metastases as the first manifestation of hepatocellular carcinoma (HCC). For the initial staging, the patient underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) imaging, which demonstrated mild 18F-FDG uptake in the multiple expansile osteolytic bone lesions, but no remarkable atypical 18F-FDG uptake in the liver lesion on low-doses CT. An additional PET/CT scan was performed to evaluate the prostate-specific membrane antigen (PSMA) expression, which has recently been reported to be a potential biological marker in a variety of tumors including HCC. High PSMA uptake was recorded in both the metastatic bone lesions and the primary liver lesion/tumor by the 68Ga-PSMA PET/CT.

Combined PET/CT with thoracic contrast-enhanced CT in assessment of primary cardiac tumors in adult patients

Background18F-FDG PET/CT is a key molecular imaging modality to noninvasively assess and differentiate benign and malignant cardiac tumors. However, few benign cardiac tumors can be characterized by increased 18F-FDG uptake, which makes differential diagnosis difficult. This study sought to retrospectively evaluate whether combined 18F-FDG PET/CT with thoracic contrast-enhanced CT (CECT) helps in assessing primary cardiac tumors in adult patients, compared with CECT or PET/CT alone.MethodsForty-six consecutive patients who were diagnosed as primary cardiac tumors were enrolled. All patients underwent 18F-FDG PET/CT followed by thoracic CECT before biopsy or surgery. Visual qualitative interpretation and quantitative analysis were performed, and diagnostic performance was evaluated.ResultsMore than half (16/29) of benign tumors exhibited with mild 18F-FDG uptake. There were significant differences in 18F-FDG uptake and the degree of absolute enhancement between benign and malignant tumors (P < 0.001). The combination of two modalities improved the specificity from 79 to 93%, the positive predictive value from 73 to 89%, and the accuracy of diagnosis from 85 to 93%. There were significant differences between PET/CT alone or thoracic CECT alone and combined modalities (P = 0.034 and P = 0.026, respectively). The combination with the optimal SUVmax cutoff value generated 94% sensitivity, 100% specificity, 97% negative predictive values, 100% positive predictive values, and 98% accuracy rates.ConclusionsCombining 18F-FDG PET/C with thoracic CECT significantly improved specificity and accuracy compared to CECT or PET/CT alone in detecting tumors. This combination of diagnostic imaging is effective in differentiating malignant from benign masses.

The diagnostic ability of 18F-FDG PET/CT for mediastinal lymph node staging using 18F-FDG uptake and volumetric CT histogram analysis in non-small cell lung cancer.

To evaluate the clinical implications of lymph node (LN) density on 18F-FDG PET/CT for mediastinal LN characterization in non-small cell lung cancer (NSCLC). One hundred and fifty-two patients with 271 mediastinal LNs who underwent PET/CT and endobronchial ultrasound-guided transbronchial needle aspiration for staging were enrolled. Maximum standardized uptake value (SUVmax), short axis diameter, LN-to-primary cancer ratio of SUVmax, and median Hounsfield unit (HU) based on CT histogram were correlated to histopathology. Of 271 nodes, 162 (59.8%) were malignant. SUVmax, short axis diameter, and LPR of malignant LNs were higher than those of benign nodes. Among malignant LNs, 71.0% had median HU between 25 and 45, while 78.9% of benign LNs had values <25 HU or >45 HU. Using a cutoff value of 4.0, SUVmax showed the highest diagnostic ability for detecting malignant LNs with a specificity of 94.5%, but showing a sensitivity of 70.4%. Using additional density criteria (median HU 25-45) in LNs with 2.0< SUVmax ≤4.0, the sensitivity increased to 88.3% with the specificity of 82.6%. LN density is useful for the characterization of LNs with mild 18F-FDG uptake. The risk of mediastinal LN metastasis in NSCLC patients could be further stratified using both 18F-FDG uptake and LN density. • SUVmax showed the highest diagnostic ability for detecting malignant LNs. • LN density was useful in characterization of LNs with mild FDG uptake. • SUVmax and LN density together could stratify the risk of LN metastasis.

PET/CT Characterization of Fibroosseous Defects in Children:18F-FDG Uptake Can Mimic Metastatic Disease

The purpose of this study was to characterize the anatomic appearance and metabolic activity of nonossifying fibromas, fibrous cortical defects, and cortical desmoids on PET/CT images. Over a 14-month period, we identified eight nonossifying fibromas, four fibrous cortical defects, and two cortical desmoids in 330 children who underwent PET/CT for the evaluation of a known or suspected malignancy. CT, conventional radiography, MRI, or clinical follow-up was used to confirm the diagnoses of these fibroosseous lesions. Eleven of the 14 children underwent multiple PET/CT examinations; thus, 34 studies were included. The lesions showed variable metabolic activity as indicated by 18F-FDG uptake: 19 PET/CT examinations showed lesions with mild 18F-FDG uptake, eight showed moderate 18F-FDG uptake, and seven showed intense uptake. When PET reveals metabolically active osseous abnormalities in children who are at risk for bone metastases, benign fibroosseous lesions should be considered in the differential diagnosis before additional diagnostic procedures are undertaken. Benign fibroosseous lesions may be metabolically active and thus mimic metastatic osseous disease in children with underlying malignancies. Correlative CT or other anatomic imaging can confirm the benign nature of these lesions.