Standardized Uptake Value Research Articles

Correlation between 18 F-FDG PET/CT metabolic parameters and microvascular invasion before liver transplantation in patients with hepatocellular carcinoma.

Microvascular infiltration (MVI) before liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) is associated with postoperative tumor recurrence and survival. MVI is mainly assessed by pathological analysis of tissue samples, which is invasive and heterogeneous. PET/computed tomography (PET/CT) with 18 F-labeled fluorodeoxyglucose ( 18 F-FDG) as a tracer has been widely used in the examination of malignant tumors. This study investigated the association between 18 F-FDG PET/CT metabolic parameters and MVI before LT in HCC patients. About 124 HCC patients who had 18 F-FDG PET/CT examination before LT were included. The patients' clinicopathological features and 18 F-FDG PET/CT metabolic parameters were recorded. Correlations between clinicopathological features, 18 F-FDG PET/CT metabolic parameters, and MVI were analyzed. ROC curve was used to determine the optimal diagnostic cutoff value, area under the curve (AUC), sensitivity, and specificity for predictors of MVI. In total 72 (58.06%) patients were detected with MVI among the 124 HCC patients. Univariate analysis showed that tumor size ( P = 0.001), T stage ( P < 0.001), maximum standardized uptake value (SUV max ) ( P < 0.001), minimum standardized uptake value (SUV min ) ( P = 0.031), mean standardized uptake value (SUV mean ) ( P = 0.001), peak standardized uptake value (SUV peak ) ( P = 0.001), tumor-to-liver ratio (SUV ratio ) ( P = 0.010), total lesion glycolysis (TLG) ( P = 0.006), metabolic tumor volume (MTV) ( P = 0.011) and MVI were significantly different. Multivariate logistic regression showed that tumor size ( P = 0.018), T stage ( P = 0.017), TLG ( P = 0.023), and MTV ( P = 0.015) were independent predictors of MVI. In the receiver operating characteristic curve, TLG predicted MVI with an AUC value of 0.645. MTV predicted MVI with an AUC value of 0.635. Patients with tumor size ≥5 cm, T3-4, TLG > 400.67, and MTV > 80.58 had a higher incidence of MVI. 18 F-FDG PET/CT metabolic parameters correlate with MVI and may be used as a noninvasive technique to predict MVI before LT in HCC patients.

Comparison of 68Ga-FAPI-04 and 18F-FDG PET/CT in diagnosing ovarian cancer.

This study assesses the diagnostic performance of 68Ga-FAPI-04 PET/CT compared to 18F-FDG PET/CT in primary, recurrent, and metastatic ovarian cancer. Seventy-nine ovarian cancer patients who performed 68Ga-FAPI-04 and 18F-FDG PET/CT were recruited. The target-to-background ratio (TBR), maximum standardized uptake value (SUVmax), the number of positive lesions, visual assessment, the peritoneal cancer index (PCI) score, staging/restaging, and treatment strategies were compared from the corresponding PET/CT. Additionally, we analyzed and contrasted the diagnostic efficacy in both scans. Among all patients, 6 were assessed for initial assessment and 73 for recurrence and metastasis detection. For all lesions, 68Ga-FAPI-04 PET/CT demonstrated greater TBR than 18F-FDG PET/CT. 68Ga-FAPI-04 PET/CT demonstrated higher sensitivity for peritoneal metastases including patient-based and lesion-based analysis (95.00% vs. 83.33%, P = 0.065; 90.16% vs. 60.66%, P < 0.001) and a higher PCI score [median PCI: 6 (4, 12) vs. 4 (2, 8), P < 0.001]. According to the visual assessment, 68Ga-FAPI-04 PET revealed larger extent metastases in 55.93% (33/59) of the patients with peritoneal metastases. 68Ga-FAPI-04 was upstaged in 7 patients (8.86%, 7/79) and discrepancies in both scans caused treatment strategies to change in 11 patients (13.92%, 11/79). 68Ga-FAPI-04 PET/CT outperforms 18F-FDG PET/CT in identifying metastases and can be a potential supplement for managing ovarian cancer patients.

18F‐Florzolotau PET Imaging Unveils Tau Pathology in Dementia with Lewy Bodies

AbstractBackgroundDementia with Lewy bodies (DLB) commonly exhibits a complex neuropathology, sharing characteristics with Alzheimer's disease (AD), including tau aggregates. However, studies using the 18F‐AV‐1451 tau tracer have shown inconsistent findings regarding both the extent and topographical distribution of tau pathology in DLB.ObjectivesOur aim was to elucidate the topographical patterns of tau deposition in DLB and to investigate the in vivo pathological distinction between DLB and AD in virtue of the 18F‐Florzolotau positron emission tomography (PET) imaging.MethodsThis cross‐sectional study enrolled patients with DLB (n = 24), AD (n = 43), and cognitively healthy controls (n = 18). Clinical assessments and 18F‐Florzolotau PET imaging were performed. 18F‐Florzolotau binding was quantitatively assessed on PET images using standardized uptake value ratios and voxel‐wise analysis.Results18F‐Florzolotau PET imaging revealed widespread tau deposition across various cortical regions in DLB, uncovering heterogeneous topographical patterns. Among patients, 54.17% showed patterns similar to AD, whereas 16.67% exhibited distinct patterns. Compared to AD, DLB exhibited a unique in vivo neuropathological profile, characterized by a lower tau protein burden, heterogeneous topographical distributions, and a specific role of the medial temporal lobe in tau pathology.Conclusions18F‐Florzolotau PET imaging elucidated tau pathology patterns in DLB, providing valuable insights for future in vivo pathological differentiation and potential disease‐modifying therapies. © 2024 International Parkinson and Movement Disorder Society.

Correlation between glucose metabolism and body mass index in tumor lesions of patients with lung cancer.

Lung cancer, along with various other cancers, is characterized by increased glucose metabolism. The maximum standardized uptake value (SUVmax), derived from positron emission tomography-computed tomography (PET-CT), serves as an indicator of glucose metabolic activity in tumor lesions. This study aimed to evaluate the correlation between body mass index (BMI) and SUVmax in individuals with lung cancer. This study included 41 patients with lung cancer, who were divided into two groups: Group 1 (n = 21), with a BMI greater than 22.4, and Group 2 (n = 20), with a BMI less than 22.4. All participants underwent 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) imaging. The SUVmax was calculated by manually delineating the regions of interest. A t-test was performed to assess whether the differences in SUVmax between the two groups were statistically significant. The mean SUVmax for Group 1 was 11.20 ± 5.45, while for Group 2 it was 10.65 ± 5.96. Although the mean SUVmax was higher in Group 1 compared to Group 2, the difference between the groups was not statistically significant (P = 0.757). The findings indicate a non-significant difference in glucose metabolism in lung cancer lesions between patients with different BMI levels. These results offer valuable insights into the metabolic characteristics of lung cancer and contribute to a deeper understanding of its pathophysiology.

Primary mesenchymal tumors of the prostate:18F FDG PET/CT findings.

Primary mesenchymal tumors of the prostate are very rare, and there is no systematic report on fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT). The aim of this research was to characterize mesenchymal tumors of the prostate on 18F-FDG PET/CT. We included 13 patients with pathologically confirmed mesenchymal neoplasms of the prostate. The location, size, maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total glycolysis of the lesion (TLG), pathologic findings, and available imaging study of the tumors were reviewed. Of the 13 patients (median age, 38 years; ranged from 13 to 74 years), the mean size of the tumors was 8.8cm in diameter ranged from 5 to 16.1cm. SUVmax ranged from 3.1 to 17.6 (mean 9.5), MTV ranged from 4.9 to 398 cm3 (mean 109 cm3) and TLG ranged from 21.3 to 1216g (mean 96g). The seminal vesicles, rectum, and bladder are the most commonly affected sites of invasion, while metastasis typically occurs in the bones, lungs, and lymph nodes. Mesenchymal tumors of the prostate revealed large sizes and high SUVmax, MTV and TLG levels on 18F-FDG PET/CT. 18F-FDG PET/CT may be useful for accurate diagnosis, staging, and restaging, which plays an important role in the management of subsequent plans.

Combined [18F]-FDG PET-MR Imaging: A promising tool for diagnostics of small bowel Crohn's disease.

Introduction Diagnostics of small bowel Crohn's disease (CD) can be difficult. Combined positron emission tomography-magnetic resonance enterography (PET-MRE) can be used to evaluate intestinal metabolism, but clinical use has been limited due to accessibility, costs, absence of standardized methods and diagnostic thresholds. Our aim was to show that combined PET-MRE can be used to diagnose active small bowel CD. Methods We performed a fusion PET-MRE-scan with [18F]-FDG-tracer to 30 patients with suspected small bowel CD in colonoscopy. Standardized uptake values (SUV) were measured from small bowel. The diagnosis was confirmed with small bowel capsule endoscopy. Clinicians chose appropriate medication to each patient blinded from SUV-results. Endoscopic, laboratory and MRE-findings were investigated in relation to SUV. Results Fusion PET-MRE outperformed MRE in diagnostic accuracy. Patients diagnosed with CD (N=24) had higher SUV than patients not diagnosed with CD (N=6) (3.34 vs. 1.84, p=0.022). A diagnostic cut-off at SUV at 2.5. could be used (AUROC=0.81). A higher SUV predicts need for immunosuppressive medication (p=0.0026) and biologics (p=0.0005). SUV correlates positively with SES-CD-score (Simple Endoscopic Score for Crohn's Disease), fecal calprotectin and CRP and negatively with Hb and serum albumin. Conclusion In future, [18F]-FDG PET-MRE can be used in diagnostics of small bowel CD as a safe alternative for capsule endoscopy. High SUV can predict a more progressive disease course and need for more advanced therapies.

Predictive value of 68[Ga]Ga-DOTA-TATE PET/CT volumetric parameters in assessing treatment response to long-acting somatostatin analogues in patients with well-differentiated neuroendocrine tumours.

Over the past decade, numerous treatment options have emerged for patients with locally advanced and metastatic neuroendocrine tumours (NETs). Nevertheless, the optimal timing of treatment interventions remains uncertain, given the highly variable disease course observed in these patients, even when patients have the same tumour stage and grade. The aim of the study was to evaluate the predictive role of standardized uptake values (SUVs) and volumetric parameters obtained from pretreatment [68Ga]Ga-DOTA-TATE for response to SSA therapy in patients with NET. In this retrospective study, we included 42 patients (21 women, 21 men; age range: 46-84years) with histologically confirmed, metastatic, NET (G1 13, G2 28 cases); median Ki-67 index 5%, range 1-16) who received long acting SSA as a first line treatment and underwent [68Ga]Ga-DOTA-TATE PET/CT before SSA treatment. For all [68Ga]Ga-DOTA-TATE avid lesion SUVmax, SUVmean, somatostatin receptor expression tumour volume (STV), total lesion somatostatin receptor expression (TLD, STV multiplied by SUV mean) and Tmean/Smean (SUVmean of tumours/metastases divided by SUVmean of normal spleen) were measured. Finally, the sum of STV (total STV, TSTV) and TLD (total TLD, TTLD) was calculated for each patient and used in the analysis. During the study period, 14 patients had stable disease (33.3%) and 28 patients experienced progression (66.7%), among whom 12 patients died. The median progression-free survival (PFS) and overall survival (OS) were 26.5 and 46.5months, respectively. In the univariate and multivariate analysis, in the whole population study, Tmean/Smean ratio (HR 1.88, 95% CI 1.06-3.35, p = 0.03), Ki-67 index (HR 1.14, CI 1.03-1.26, p = 0.01) and pre-treatment chromogranin A serum concentration (HR 1.01, CI 1.0-1.03, p = 0.01) were significantly associated with PFS. Among patients with small intestinal NETs, TSTV (< 125.85 cm3 vs. ≥ 125.85 cm3, p = 0.023) and TTLD (< 4168.95 vs. ≥ 4168.95, p = 0.026) were significantly associated with PFS in the univariate analyses. No significant correlation was found between measured volumetric parameters and OS. Volumetric parameters of pretreatment 68[Ga]Ga-DOTA-TATE PET/CT may be useful in prediction of the response to SSA (used in monotherapy as a first-line therapy) in patients with NET.

Does High Standard Uptake Value on Positron Emission Tomography Preclude Sublobar Resection in Stage IA Non-Small Cell Lung Cancer ≤2cm?

Recent randomized trials have shown equivalent survival after sublobar resection (SLR) versus lobectomy in patients with clinical stage IA non-small cell lung cancer (NSCLC)≤2cm. High SUVmax is a known risk factor in NSCLC, yet limited data exists on whether a high SUV should preclude a SLR. This study aims to determine if there is an association between SUVmax and survival based on the extent of parenchymal resection. A retrospective review of a prospectively maintained institutional database was conducted to identify patients with clinical stage IA NSCLC≤2cm (2011-2020) treated with SLR or lobectomy. The primary outcome was cancer-specific survival (CSS). Secondary outcomes were overall survival (OS) and disease-free survival (DFS). 543 patients were identified; 36.8% had SLR and 63.2% had lobectomy. Baseline characteristics were similar. Patients who had SLR had significantly worse ECOG performance status and higher rates of comorbidities. 5-year CSS, OS, and DFS for the whole cohort were similar between SLR and lobectomy. A receiver operating characteristic curve estimated the SUVmax cutoff point to be 4.15. For the whole cohort, patients with SUVmax>4.15 had worse CSS compared to SUVmax≤4.15. However, there was no significant difference in 5-year CSS after SLR versus lobectomy in patients with SUVmax≤4.15 (98% in both groups; P=0.77) or patients with SUVmax>4.15 (90% versus 94% respectively; P=0.12). SUVmax may not be a useful clinical determinant of the extent of parenchymal resection in patients with cT1N0 NSCLC≤2cm. Patients treated by SLR had comparable survival to lobectomy, irrespective of PET avidity.

MRI-free processing of tau PET images for early detection

Abstract Tau positron emission tomography (PET) imaging in Alzheimer’s Disease (AD) is becoming increasingly common to assess in vivo tau burden. MR images are often acquired to assist with processing of PET data, including for region-of-interest definitions in native space and for normalization to template space. However, in the real-world setting, corresponding MRIs may not be available and PET processing may require MRI-free pipelines. This is particularly important and challenging as the field moves towards early detection among clinically unimpaired (CU) individuals where changes in tau PET signal are expected to be subtle. We used two independent [18F]Flortaucipir tau PET datasets to evaluate whether MRI-free PET processing can detect subtle tau PET uptake differences in Amyloid+ (A+) CU individuals (preclinical AD) versus A-. Standardized Uptake Value Ratios (SUVRs) from MRI-free compared to MRI-based methods were evaluated using linear regression and linear mixed-effects regression models. Effect size differences between A+/- CU groups in MRI-free processed cross-sectional and longitudinal tau PET SUVRs were compared to differences quantified through MRI-based processing. Regional MRI-free SUVRs were highly correlated with MRI-based SUVRs within CU individuals (average ICC = 0.90 for ADNI CU and 0.81 for A4 CU). MRI-free and MRI-based pipelines resulted in similar estimates of cross-sectional and longitudinal differences between A- and A+ CU, even in early focal regions within the medial temporal lobe.

Extracerebral Normalization of 18F-FDG PET Imaging Combined with Behavioral CRS-R Scores Predict Recovery from Disorders of Consciousness.

Identifying patients likely to regain consciousness early on is a challenge. The assessment of consciousness levels and the prediction of wakefulness probabilities are facilitated by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET). This study aimed to develop a prognostic model for predicting 1-year postinjury outcomes in prolonged disorders of consciousness (DoC) using 18F-FDG PET alongside clinical behavioral scores. Eighty-seven patients with prolonged DoC newly diagnosed with behavioral Coma Recovery Scale-Revised (CRS-R) scores and 18F-FDG PET/computed tomography (18F-FDG PET/CT) scans were included. PET images were normalized by the cerebellum and extracerebral tissue, respectively. Images were divided into training and independent test sets at a ratio of 5:1. Image-based classification was conducted using the DenseNet121 network, whereas tabular-based deep learning was employed to train depth features extracted from imaging models and behavioral CRS-R scores. The performance of the models was assessed and compared using the McNemar test. Among the 87 patients with DoC who received routine treatments, 52 patients showed recovery of consciousness, whereas 35 did not. The classification of the standardized uptake value ratio by extracerebral tissue model demonstrated a higher specificity and lower sensitivity in predicting consciousness recovery than the classification of the standardized uptake value ratio by cerebellum model. With area under the curve values of 0.751 ± 0.093 and 0.412 ± 0.104 on the test sets, respectively, the difference is not statistically significant (P = 0.73). The combination of standardized uptake value ratio by extracerebral tissue and computed tomography depth features with behavioral CRS-R scores yielded the highest classification accuracy, with area under the curve values of 0.950 ± 0.027 and 0.933 ± 0.015 on the training and test sets, respectively, outperforming any individual mode. In this preliminary study, a multimodal prognostic model based on 18F-FDG PET extracerebral normalization and behavioral CRS-R scores facilitated the prediction of recovery in DoC.

NIMG-80. IMPACT OF KETOGENIC DIET ON MOLECULAR METABOLIC IMAGING WITH [18F]FDG AND [18F]DASA-23 POSITRON EMISSION TOMOGRAPHY IN A PATIENT WITH GLIOBLASTOMA

Abstract The standard-of-care for neuroimaging in patients with glioblastoma is contrast-enhanced MRI, which does not provide tumor metabolism information. Although [18F]FDG PET is used to image tumor metabolism in many solid organ cancers, it has limited benefit in atients with brain tumors due to the high level of glucose uptake in normal brain cells. [18F]DASA-23 is a novel PET radiotracer that assesses the levels of pyruvate kinase M2 (PKM2), a protein highly expressed in cancer cells, which undergo aberrant glycolysis. Despite [18F]DASA-23 having a higher tumor-to-background ratio (TBR) of standardized uptake values (SUVs) in the brain compared to [18F]FDG, both may be susceptible to altered carbohydrate metabolism in the setting of a ketogenic diet (KD). We report the case of a patient with glioblastoma on a KD, whose [18F]FDG and [18F]DASA-23 PET brain scans were limited in identifying disease progression (PD). Background was defined as the white matter contralateral to the tumor, at the level of the centrum semiovale, for TBR of SUVmax. A 39-year-old man was diagnosed with right temporal glioblastoma after previous diagnoses of grade 2 gliofibrillary oligodendroglioma (age 20) and grade 3 anaplastic oligodendroglioma (age 22). He began a KD after the glioblastoma diagnosis. 21 months later, TBR on [18F]DASA-23 PET was 1.38. One month later, surveillance brain MRI showed PD. Ten days later, TBR on [18F]FDG PET was 1.03. The patient died 15 months later. Despite MRI-based PD, the TBR of each radiotracer was not markedly elevated, although the [18F]DASA-23 TBR 1-month pre-PD was 34% greater than the [18F]FDG PET TBR 10-days post-PD. This may suggest a limitation of metabolic imaging by PET in the setting of a KD, and provide an opportunity to develop novel PET radiotracers that are not susceptible to the patient’s diet.

NIMG-78. THE ROLE OF FDG PET/CT IN MANAGING DIFFUSE MIDLINE GLIOMA WITH H3K27M MUTATION: A CASE STUDY AND PATHOLOGICAL CORRELATION

Abstract The clinical utility of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in the management of high grade gliomas has been a topic of ongoing debate, with limited cases reported that correlated FDG PET/CT findings with pathology, particularly in diffuse midline glioma with HdK27M mutation cases. We present the case of a 24-year-old male patient with diffuse midline glioma with H3K27M mutation centered in the left thalamus. Head FDG PET/CT was used for clinical management decisions with pathological correlation. Patient had stable follow up brain magnetic resonance images(MRIs) after initial Stupp protocol treatment comprised 6-week radiation therapy with concurrent temozolomide, followed by 12 cycles of adjuvant temozolomide. Despite stable MRI scans, subsequent evaluation using FDG PET/CT demonstrated a high standardized uptake value (SUV) of 13.8 that prompted craniotomy and partial resection of the lesion to confirm tissue diagnosis. Pathological findings confirmed the persistence of densely cellular malignant glioma, but with Ki-67 proliferation index of 4-5%. Following the surgery, the patient was closely monitored with surveillance MRIs for approximately four months post-surgery and follow up MRI’s showed slow growth of the tumor prompting additional therapeutic interventions. This case is an example of FDG PET/CT and pathological correlation and highlights the potential role of FDG PET/CT as an adjunctive imaging tool in the management of high grade gliomas.

A Rare Case of Osteoblastoma of the Sacrum

Osteoblastoma (OB) is a rare bone tumor. It is classified as benign and represents about 1% of all bone neoplasms. While it typically occurs in the axial skeleton, sacral involvement is extremely rare. Despite its non-malignant nature, OB can be locally aggressive and may lead to considerable morbidity if not addressed in a timely manner. This report discusses a unique case of sacral, focusing on the clinical, radiological, and surgical features.A 14-year-old male patient reported experiencing increasing pain in his left lower limb and lumbosacral region for two years. A magnetic resonance imaging (MRI) of the lumbosacral area identified a mass measuring 50x43 mm on the left side of the sacrum in T2-weighted images. Further evaluation with a positron emission tomography/computerized tomography (PET/CT) scan indicated a destructive bone lesion in the left sacrum, measuring 43x40 mm, with a soft tissue component and increased fluorodeoxyglucose (FDG) uptake (standardized uptake value maximum: 11). The patient underwent surgical excision by a neurosurgery team, and histopathological analysis confirmed the diagnosis of OB.Although OB is a benign tumor, its location can cause significant symptoms, particularly in rare areas like the sacrum. Diagnostic imaging modalities such as MRI and PET/CT are crucial for identifying the tumor and planning surgical intervention. The elevated FDG uptake observed on PET/CT indicated a metabolically active lesion, reinforcing the need for surgical treatment.Sacral OB is an exceptionally rare entity. This case underscores the need to include OB in the differential diagnosis of sacral lesions and illustrates the value of imaging in facilitating accurate diagnosis and management. Surgical resection remains the cornerstone of treatment, offering good clinical outcomes.

NIMG-34. CXCR4-TARGETED PET IMAGING OF CENTRAL NERVOUS SYSTEM LYMPHOMA AND GLIOMA USING [68GA]GA-PENTIXAFOR

Abstract BACKGROUND Initial results suggest that PET imaging of the chemokine receptor CXCR4 is of considerable interest for differential diagnosis and theranostic approaches. Here, we summarized findings of CXCR4 PET imaging in an institutional series of lymphoma of the central nervous system (CNSL) and glioma. METHODS Twenty-three patients with CNSL and 16 patients with glioma (IDH-wildtype, n=9) underwent PET imaging using the CXCR4-directed tracer [68Ga]Ga-Pentixafor. In 18 patients, serial PET imaging was performed (range, 2-14 scans), resulting in a total of 104 PET scans. For evaluation, PET scans were classified as [68Ga]Ga-Pentixafor-positive and -negative visually, and the maximum standardized uptake value (SUVmax) was obtained from [68Ga]Ga-Pentixafor-PET. RESULTS Twenty-four of all 39 patients (62%) had at least one [68Ga]Ga-Pentixafor-positive PET (CNSL, 57%; glioma, 69%). [68Ga]Ga-Pentixafor-positive PET scans were more common in patients with IDH-wildtype gliomas (89%) than in IDH-mutant gliomas (43%). In patients with [68Ga]Ga-Pentixafor-positive PET, the average SUVmax was 6.4±4.0 in CNSL, and 3.4±1.0 in gliomas (P=0.155). Besides visualization of tumors, [68Ga]Ga-Pentixafor uptake was observed in two patients with radionecrosis. In four CNSL patients who had undergone methotrexate/cytarabine-based first-line therapy, serial PET revealed a significant reduction of SUVmax after chemotherapy completion (average decrease of SUVmax from 4.5±3.8 to 0.6±0.7; P=0.044). In three of those four patients, tumor progression has not been reached (range of time after the follow-up PET, 4-55 months); one patient deceased 44 months after the follow-up PET. In contrast, another patient with an increase in SUVmax from 6.9 to 11.0 after first-line treatment died one month after the follow-up PET. DISCUSSION [68Ga]Ga-Pentixafor PET seems to be of value for non-invasively visualizing and quantifying CXCR4 receptor binding. In CNSL, changes in [68Ga]Ga-Pentixafor uptake following therapy may indicate potential for response assessment. CXCR4-targeting radioligand therapies might be more promising in CNSL than in glioma.

Case report: a rare clinical presentation of a difficult diagnosis of dedifferentiated liposarcoma showing leiomyosarcoma phenotype in the ileocecal region

Dedifferentiated liposarcoma is a malignant lipomatous tumor that rarely occurs in the gastrointestinal tract, including the ileocecal region. In this case, computed tomography and magnetic resonance imaging showed no fatty mass located in the mesenteric or submucosal lesion, and positron emission tomography–computed tomography showed a high maximum standardized uptake value, collectively indicating the gastrointestinal stroma tumor and lymphoma. The pathological findings resemble leiomyosarcoma; the immunohistochemistry findings including mouse double minute 2 homolog and cyclin D-dependent kinase-4 and amplification of mouse double minute 2 homolog in fluorescence in situ hybridization just favored the diagnosis of dedifferentiated liposarcoma with leiomyosarcoma phenotype and not leiomyosarcoma. Recently, a new inhibitor for mouse double minute 2 homolog and cyclin D-dependent kinase-4 has been developed, and clinical trials for dedifferentiated liposarcoma are currently ongoing. This could change the treatment strategy drastically compared with other soft tissue sarcomas. Hence, a correct diagnosis of dedifferentiated liposarcoma is required.

Optimisation of Animal Handing and Timing of 2-deoxy-2-[18F]fluoro-D-glucose PET Tumour Imaging in Mice.

In humans, 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) tumour-to-background contrast continues to increase long after a typical uptake period of 45 - 60min. Similar studies have not been performed in mice and the static imaging time point for most studies is arbitrarily set at 30 - 60min post-injection of [18F]FDG. Ideally, static PET imaging should be performed after the initial period of rapid uptake but this period has not been defined in mice, with previous dynamic studies in mice being limited to 60min. This study aimed to define the kinetics of [18F]FDG biodistribution over periods of 3 - 4h in different murine tumour models, both subcutaneous and autochthonous, and to further refine fasting and warming protocols used prior to imaging. Dynamic [18F]FDG PET-CT scans lasting 3 or 4h were performed with C57BL/6J and Balb/c nude mice bearing subcutaneous EL4 murine T-cell lymphoma and Colo205 human colorectal tumours, respectively, and with transgenic Eμ-Myc lymphoma mice. Prior to [18F]FDG injection, four combinations of different animal handling conditions were used: warming for 1h at 31°C; maintenance at room temperature (20 - 24°C), fasting for 6 - 10h and a fed state. Tumour mean standardised uptake value (SUVmean) peaked at 147 ± 48min post injection in subcutaneous tumours and 74 ± 31min in autochthonous Eμ-Myc lymphomas. The tumour-to-blood ratio (TBR) peaked at 171 ± 57 and 83 ± 33min in subcutaneous and autochthonous Eμ-Myc tumours, respectively. Fasting increased tumour [18F]FDG uptake and suppressed myocardial uptake in EL4 tumour-bearing mice. There was a good correlation between tumour SUVmean and Ki calculated using an input function (IDIF) derived from the inferior vena cava. Delayed static [18F]FDG-PET imaging (> 60min) in both autochthonous and subcutaneous tumours in improved tumour-to-background contrast and increased reproducibility.

Comparison Between Prone SPECT-Based Semi-Quantitative Parameters and MBI-Based Semi-Quantitative Parameters in Patients with Locally Advanced Breast Cancer.

This study evaluates the semi-quantitative single-photon emission computed tomography (SPECT) parameters of prone SPECT using [99mTc]Tc-sestamibi and compares them with Molecular Breast Imaging (MBI)-derived semi-quantitative parameters for the potential use of response prediction in women with locally advanced breast cancer (LABC). Patients with proven LABC with a tumor ≥ 2cm on mammography and an indication for MBI using [99mTc]Tc-sestamibi were prospectively enrolled. All patients underwent a prone SPECT/CT at 5min (early exam) and an additional scan at 90min (delayed exam) after injection of 600MBq [99mTc]Tc-sestamibi to compose wash-out rates (WOR). All patients underwent MBI after early SPECT/CT. Volumes of interest of the primary tumor were drawn semi-automatically on early and delayed SPECT images. Semi-quantitative analysis included maximum and mean standardized uptake values (SUVmax,SUVmean,), functional tumor volume (FTVSPECT), total lesion mitochondrial uptake (TLMU), tumor-to-background ratios (TBRmaxand TBRmean), WOR and coefficient of variation (COVSPECT). Subsequently, the FTVSPECT,TBRSPECTand COVSPECTwere compared to FTVMBI,TBRMBIand COVMBI. Eighteen patients were included. Early SUVmax, and TBRmax showed significantly higher interquartile range (IQR) compared to SUVmean and TBRmean, respectively 2.22 (2.33) g/mL, 6.86 (8.69), 1.29 (1.39) g/mL and 3.99 (5.07) (median (IQR), p < 0.05). WOR showed a large IQR (62.28), indicating that there is WOR variation among the LABC patients. FTV showed no difference between MBI and early SPECT semi-quantitative parameter (p = 0.46). In LABC patients it is feasible to obtain semi-quantitative parameters from prone SPECT/CT. The FTV derived from early prone SPECT/CT is comparable with MBI-based FTV. Studies with comprehensive clinical parameters are needed to establish the clinical relevance of these semi-quantitative parameters, including WOR, for response prediction before its use in clinical routine.

Assessing Changes in Vascular Inflammation and Urate Deposition in the Vasculature of Gout Patients After Administration of Pegloticase Using Positron Emission Tomography and Dual-Energy Computed Tomography—A Pilot Study

We assessed changes in vascular inflammation and monosodium urate (MSU)-coded deposits after administration of Pegloticase in the vasculature of tophaceous gout patients using 18F-fluorodeoxyglucose (18F-FDG) Positron emission tomography/computed tomography (PET/CT) and dual-energy CT (DECT). Ten patients with tophaceous gout, intolerant or refractory to urate-lowering therapy (ULT), were treated with Pegloticase every two weeks for six months. 18F-FDG PET/CT and DECT were performed at baseline and after Pegloticase therapy to detect vessel wall inflammation (Standard uptake value, SUVmean, and SUVmax) and vascular MSU-coded deposition (MSU volume). Data were summarized using means and standard deviations. Baseline and follow-up values were compared for each variable using mixed-effect models. Significant decreases in SUVmean (p = 0.0003) and SUVmax (p = 0.009) were found with a trend towards a decrease in vessel wall MSU volume after treatment. There was a significant decrease in serum urate, correlating with reduction in SUVmean (R2 = 0.65), with a trend towards a decrease in CRP and blood pressure in all patients. Despite the small sample size, we were able to demonstrate a decrease in vessel wall inflammation and a trend towards a decrease in MSU volume by intensively lowering serum urate. These findings suggest that MSU-coded deposits and hyperuricemia may play a role in vascular wall inflammation. It remains to be seen whether this correlates with a decrease in adverse cardiovascular outcomes.

PET/computed tomography radiomics combined with clinical features in predicting sarcopenia and prognosis of diffuse large B-cell lymphoma.

The study aimed to assess the role of 18F-fluorodeoxyglucose (FDG) PET/computed tomography (CT) radiomics combined with clinical features using machine learning (ML) in predicting sarcopenia and prognosis of patients with diffuse large B-cell lymphoma (DLBCL). A total of 178 DLBCL patients (118 and 60 applied for training and test sets, respectively) who underwent pretreatment 18F-FDG PET/CT were retrospectively enrolled. Clinical characteristics and PET/CT radiomics features were analyzed, and feature selection was performed using univariate logistic regression and correlation analysis. Sarcopenia prediction models were built by ML algorithms and evaluated. Besides, prognostic models were also developed, and their associations with progression-free survival (PFS) and overall survival (OS) were identified. Fourteen features were finally selected to build sarcopenia prediction and prognosis models, including two clinical (maximum standard uptake value of muscle and BMI), nine PET (seven gray-level and two first-order), and three CT (three gray-level) radiomics features. Among sarcopenia prediction models, combined clinical-PET/CT radiomics features models outperformed other models; especially the support vector machine algorithm achieved the highest area under curve of 0.862, with the sensitivity, specificity, and accuracy of 79.2, 83.3, and 78.3% in the test set. Furthermore, the consistency index based on the prognostic models was 0.753 and 0.807 for PFS and OS, respectively. The enrolled patients were subsequently divided into high-risk and low-risk groups with significant differences, regardless of PFS or OS (P < 0.05). ML models incorporating clinical and PET/CT radiomics features could effectively predict the presence of sarcopenia and assess the prognosis in patients with DLBCL.

Bone Mineral Density and First Line Imaging with [18F]fluorocholine PET/CT in Normocalcemic and Hypercalcemic Primary Hyperparathyroidism: Results from a Single Center

Objectives: Primary hyperparathyroidism (PHPT) is associated with normal or elevated calcium levels and affects bone mineral density. The proportion of cases predisposed to metabolic bone disease is unknown in patients with PHPT. The aim of this study was to assess bone mineral density and bone quality in patients with normo- or hypercalcemic primary hyperparathyroidism undergoing baseline parathyroid gland assessment with [18F]fluorocholine PET/CT imaging. Methods: A total of 140 consecutive patients were enrolled in this observational study. All patients with normo- or hypercalcemic primary hyperparathyroidism underwent dual-energy X-ray absorptiometry (DXA) for assessment of bone mineral density (BMD) and trabecular bone score (TBS). [18F]fluorocholine PET/CT was performed in all patients for the detection and localization of parathyroid adenoma. Hyper- and normocalcemic patients were compared with regard to the proportion of osteoporosis and osteopenia, T-Score, TBS, serum calcium, phosphorus and parathyroid hormone levels, the maximum standardized uptake value (SUVmax) in PET/CT imaging, and laboratory results. Results: The majority of patients was female (88.57%) and had a pathologic bone mineral density (52.86%). Overall, 33 patients had osteoporosis and 41 osteopenia. The mean lumbar T-Score was −1.48 (SD 1.37) and the T-Score of the femoral neck was −1.21 (SD 0.92). Mean TBS was also decreased (−2.13). No difference was found between normo- or hypercalcemic patients regarding bone metabolism and imaging parameters. Conclusions: More than half of patients with normo- or hypercalcemic PHPT showed abnormal BMD. First-line [18F]fluorocholine PET/CT identified parathyroid adenoma in a high proportion of patients, even in patients with normocalcemic PHPT. The early evaluation of metabolic bone disease seems desirable in clinical management of females with PHPT.