Standardized Uptake Value Max Research Articles

18F-FDG PET imaging for treatment response assessment and management guidance in patients with skull base osteomyelitis.

The objective of this study is to evaluate the role of hybrid 18F-FDG PET for treatment response assessment and management guidance in patients with skull base osteomyelitis. Retrospectively, 33 patients, with at least a baseline and follow-up PET (computed tomography/MRI) scan, were included. Parameters like standardized uptake value (SUV) max, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) (initial, follow-up, percentage change) were analysed and outcomes based on 18F-FDG PET reports were classified into resolution (a), partial response (b), progression (c) and stable disease (d). The clinical course and response on anatomical imaging were also compared with 18F-FDG PET. There was mild correlation between initial SUV with ESR (0.338) and CRP (0.384). Moderate correlation was seen between follow-up SUV and CRP (0.619), percentage change in SUV max (PC SUV) with percentage change in ESR (0.456) and CRP (0.668). Mean PC SUV was 70% (a), 35% (b), -40% (c) and -18% (d), respectively. 48% (16/33) (resolution, progression, stable disease) patients had clear management change with 18F-FDG PET with either escalation or stopping of antibiotics/antifungals. Management decision in partial response group (52%, 17/33) was taken clinically. On retrospective PC SUV analysis, treatment continuation group (8 patients) showed 20% decrease, whereas the group that was only monitored further (9 patients) had 48% reduction in SUV. 18F-FDG PET showed a moderate association with clinical markers used in follow-up of patients with skull base osteomyelitis and is a reliable investigation for assessment of disease status. This can be used as a guide along with clinical evaluation for de-escalation of treatment.

Amelanotic melanoma detected by 18F-FDG PET-CT

BackgroundAmelanotic/hypomelanotic melanoma is an extremely rare cancer and accounts for less than 1/10,000 in the population. For losing and hypomelanotic pigment, amelanotic melanoma can lead to misdiagnosis with benign skin lesions. Therefore, early recognition and diagnosis is important to avoid a delay in treatment.Case presentationA 73-year-old man presented for a gradually enlarged nodule on the surface skin of the left crus, with no color change, ulceration, or bleeding. Malignant lesion was suspected based on computed tomography (CT) and magnetic resonance imaging (MRI), and biopsy was scheduled. Immunohistochemical (IHC) revealed amelanotic melanoma followed by biopsy.18Florine-fluoro-2-deoxy-2-d-glucose (18F-FDG) positron emission tomography-computed tomography (PET-CT) was employed to explore whether there are metastases or not. 18F-FDG PET-CT showed increased FDG accumulation with standardized uptake value max (SUVmax) of 5.6 of the lesion, and no other lesions were detected. The patient refused to be hospitalized and died 12 months later.ConclusionThis case highlights the need of considering melanoma even if there is no color change. Increased FDG uptake from PET-CT is prone to be consistent with malignant disease as well as whole body scan is crucial in determining the accurate TNM stage. Moreover, prompt treatment according to guidelines is necessary even if the disease is at its early stage.

68Ga]Ga-FAP-2286, a novel promising theragnostic approach for PET/CT imaging in patients with various type of metastatic cancers.

Fibroblast activation protein (FAP) has emerged as a promising target for diagnosis and therapeutic intervention due to high expression and accumulation in the stromal compartments of a variety of malignant tumors. FAP-2286 utilizes cyclic peptides with FAP-binding characteristics to enhance the retention of the imaging agent within tumors, in contrast to the small-molecule FAP inhibitors (FAPI) like FAPI-04/46. The aim of this study was to quantify the tumor uptake of [68Ga] Gallium-FAP-2286 within primary solid tumors, adjacent excised tissues, and metastatic lesions. In this prospective study, 21 patients (average age 51.9) with various diagnoses of remaining and metastatic cancers participated. Among them, six had metastatic sarcoma, and 14 had adenocarcinoma, including eight breast, two rectum, two lung, two pancreas, and one thyroid cases. The patients underwent a [68Ga]Ga-FAP-2286 PET/CT scan. An hour post-administration of [68Ga]Ga-FAP-2286, a visual assessment of whole body scans and semi-quantification of the PET/CT results were carried out. The standardized uptake values (SUV)max of [68Ga]Ga-FAP-2286 in tumor lesions and the tumor-to-background ratio (TBR) were then calculated. The vital signs of the patients, such as heart rate, blood pressure, and temperature, were observed before, during, and after the diagnostic procedure during the 4-h follow-up. All individuals underwent the [68Ga]Ga-FAP-2286 PET/CT scans without any signs of drug-associated pharmacological effects. The PET/CT scans displayed substantial absorption of [68Ga]Ga-FAP-2286 in tumor lesions in all patients (100% (21/21)). Irrespective of the tumors' origins (epithelial or mesothelium) and whether they exhibited local recurrence, distant recurrence, or metastatic lesions, the PET/CT scans revealed the uptake of [68Ga]Ga-FAP-2286 in these lesions. Overall, these data suggest that [68Ga]Ga-FAP-2286 is a promising FAP derivative for efficient metastatic cancer diagnosis and being considered as a potential compound for therapeutic application in patients with advanced metastatic cancers.

An evaluation of the physiological uptake range of 18F-fluoro-2-deoxy-D-glucose in normal ovaries of seven dogs using positron emission tomography/computed tomography.

This study evaluated the physiological uptake range of 18F-fluoro-2-deoxy-D-glucose (18F-FDG) in the normal ovaries of seven dogs using positron emission tomography/computed tomography (PET/CT). The dogs were subjected to general anesthesia and were positioned in ventral recumbency for PET/CT scans. The dosage of 18F-FDG ranged from 0.14 to 0.17 mCi/kg and was administered intravenously followed by 0.9% NaCl flushing; PET/CT images of each dog were obtained precisely 60 min after the injection of 18F-FDG. The regions of interest were drawn manually, and standardized uptake values (SUV) were calculated to evaluate the 18F-FDG uptake in each ovary. The maximum and mean SUVs (SUV max and SUV mean) for all the ovaries of the dogs were then computed. The range of SUV max and SUV mean of the normal ovaries of the dogs were 1.28-1.62 and 1.07-1.31 (mean ± standard deviation), respectively. This is the first study to investigate the normal 18F-FDG uptake baseline data of normal canine ovaries using PET/CT scans. These data will help clinicians in identifying malignant tumors before anatomical changes in the ovary through PET/CT scans.

Reduction of Metabolic Active Tumor Volume Prior to CAR T-Cell Therapy Improves Survival Outcomes in Patients with Large B-Cell Lymphoma

Introduction CD19-targeted chimeric antigen receptor (CAR) T-cell therapy has become the standard 2 nd or 3 rd line therapy for patients with relapsed or refractory Large B-cell lymphoma (r/r LBCL). As part of this treatment bridging therapy is frequently used between T-cell apheresis and CAR T-cell infusion in order to limit disease progression, diminish lymphoma-related symptoms and/or reduce tumor volume. Bridging therapy has shown to be feasible, safe and effective in patients prior to infusion. In addition, a lower tumor volume is associated with better treatment outcomes and less toxicity. However, the exact reduction and dynamics in metabolic active tumor volume (MATV) are unknown. Here we investigated the relation of changes in pre-apheresis (baseline) MATV, based on 18F-FDG PET scans, and pre-lymphodepleting chemotherapy (pre-LD) MATV with CAR T-cell outcomes and toxicities in patients with r/r LBCL. Methods Baseline and pre-LD MATVs and PET characteristics were calculated semi-automatically of patients who were treated with CAR T-cell therapy. A Standardized Uptake Value (SUV) threshold of 2.5 was used to maintain robustness and avoid MATV underestimation. Bridging strategies consisted of radiotherapy, chemotherapy, or a combination of both. Primary endpoints were duration of response (DOR) and overall survival (OS). Secondary endpoints included cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). The Youden index was used to identify the optimal cut-off for dividing patients into low- and high-MATV groups to predict DOR at 2 years. Two-year DOR and OS rates were estimated using Kaplan-Meier curves and the log-rank test was utilized to compare the differences among low- and high-MATV patient groups. Univariable analysis was performed with Cox regression for DOR and OS, and with logistic regression for CRS and ICANS. Results Seventy-four patients with LBCL and treated with CAR T-cell therapy were included in the study. For all patients baseline 18F-FDG PET scans were available, whereof in 68 patients the pre-LD scans. The median baseline MATV was 180 cc (IQR 64 - 426) with a median SUV max of 18.8 (IQR 11.9 - 28.1) and increased to 241 cc (IQR 75 - 525) at pre-LD, with a median SUV max of 21.0 (IQR 12.8 - 31.3). The optimal cut-offs for low- and high-MATV patient groups at baseline and pre-LD were 190 cc and 480 cc, respectively. Patients with a low MATV baseline had a better DOR (Figure 1A) and OS compared to high MATV baseline patients (both p < 0.001). Patients with a high MATV baseline that was reduced to a low MATV pre-LD showed a significant improvement in DOR (Figure 1B) and OS, compared to patients with a high MATV pre-LD ( p = 0.036 for DOR; p = 0.015 for OS). Univariable analysis showed that a high baseline MATV was associated with a worse DOR (HR 6.43 CI [2.15 - 19.20]; p < 0.001) and OS (HR 6.97 CI [2.33 - 20.80]; p < 0.001). A high pre-LD MATV was also associated with a worse DOR (HR 4.86 CI [1.98 - 12.00]; p < 0.001) and OS (HR 5.87 [2.41 - 14.30]; p < 0.001). Other significant associations with DOR and OS were observed for pre-LD lactate dehydrogenase (LDH), the IPI score for DOR exclusively, and gender and bridging therapy for OS exclusively. Conclusions We showed that patients with a low MATV compared to a high MATV at baseline have better survival outcomes and less toxicity. Additionally, reducing tumor volume by applying bridging therapy in patients with a high baseline MATV, results in a significant better DOR and OS. Reducing the MATV before CAR T-cell infusion is therefore essential in CAR T-cell therapy patient care and provides a rationale for the use of more intensive bridging therapies.

The effect of hepatic steatosis on 18F-FDG uptake in PET-CT examinations of cancer Egyptian patients

BackgroundHepatic steatosis is the most common chronic hepatic disease. Imaging diagnosis of hepatic steatosis has been evaluated as an alternative to invasive histological diagnosis.Study aimsThe study aimed to assess the effect of hepatic steatosis on Flourine-18 fluorodeoxyglucose (18F-FDG) uptakes in cancer patients.Patients and MethodsBlood samples were collected from 50 cancer patients and analyzed to calculate fatty liver index and Hepatic steatosis index (HIS). Hepatic steatosis examined using high-resolution ultrasound and positron emission tomography—computed tomography (PET-CT). Linear attenuation coefficient, standardized-uptake value (SUV) mean (SUV mean), and SUV maximum (SUVmax) were measured. Accordingly, patients were divided equally into non-fatty liver, and fatty liver groups.ResultsA significant increase in SUVmax and SUV mean was observed in the fatty liver group more than in the non-fatty liver group. HSI significantly increased in the fatty liver group compared to the non-fatty liver group. Liver tissue uptake FDG was significantly correlated with HSI values. SUV max significantly correlated with body mass index (BMI) in the non-fatty group only.ConclusionHepatic changes in cancer patients affect the liver metabolic activity and thus the 18 F-FDG uptake. Therefore, further corrections should be considered when the liver is used as a comparator for PET-CT scans of cancer patients.

Variaciones en los parámetros cuantitativos y en la puntuación de la escala de Deauville aplicando diferentes algoritmos de reconstrucción en las imágenes PET/TC con [18F]FDG de pacientes con linfoma

Introduction and Objectives18F-FDG PET with the Deauville score (DS) is a unique semiquantitative method for lymphoma. However, type of standard uptake values (max, mean, and peak) reconstruction algorithms could affect DS. We compared the Bayesian Penalized Likelihood reconstruction algorithm (BPL) with Ordered Subsets Expectation Maximization (OSEM) on quantitative parameters and DS in lymphoma. We investigated the effect of the size of the lymph node on quantitative variation. Patients and MethodsRaw PET data of 255 lymphoma patients were reconstructed separately with Q.Clear (GE Healthcare), a BPL, and SharpIR (GE Healthcare), an OSEM algorithm. In both images, each patient's liver, mediastinal blood pool, and SUVs (SUVmax, SUVmean, and SUVpeak) of a total of 487 lesions selected from the patients were performed. DSmax, DSmean, and DSpeak were compared. ResultsIn our study, DS increased significantly with BPL (p<0.001), and the DS increased to 4-5 in 30 patients evaluated as 1-2-3 with OSEM. It was found that the quantitative values of the lymph nodes increased statistically with BPL (p<0.001), and the liver from the reference regions were significantly decreased (p<0.001). In addition, difference in lymph node was independently associated with size of lesion and was significantly more pronounced in small lesions (p<0.001). The effects of BPL algorithm were more pronounced in SUVmax than in SUVmean and SUVpeak. DS-mean and DS-peak scores were less changed by BPL than DS-max. ConclusionDifferent reconstruction algorithms in FDG PET/CT affect the quantitative evaluation. That variation may affect the change in DS in lymphoma patients, thus affecting patient management.

Quantitative uptake in 99m Tc-EDDA/HYNIC-TOC somatostatin receptor imaging - the effect of long-acting release somatostatin analogue therapy.

Withdrawal of long-acting release somatostatin analogue (LAR-SSA) treatment before somatostatin receptor imaging is based on empirical reasoning that it may block uptake at receptor sites. This study aims to quantify differences in uptake of 99m Tc-EDDA/HYNIC-TOC between patients receiving LAR-SSA and those who were not. Quantification of 177 patients (55 on LAR-SSA) imaged with 99m Tc-EDDA/HYNIC-TOC was performed, with analysis of pathological tissue and organs with physiological uptake using thresholded volumes of interest. Standardised uptake values (SUVs) and tumour/background (T/B) ratios were calculated and compared between the two patient groups. SUVs were significantly lower for physiological organ uptake for patients on LAR-SSA (e.g. spleen: SUV max 13.3 ± 5.9 versus 33.9 ± 9.0, P < 0.001); there was no significant difference for sites of pathological uptake (e.g. nodal metastases: SUV max 19.2 ± 13.0 versus 17.4 ± 11.5, P = 0.552) apart from bone metastases (SUV max 14.1 ± 13.5 versus 7.7 ± 8.0, P = 0.017) where it was significantly higher. LAR-SSA has an effect only on physiological organ uptake of 99m Tc-EDDA/HYNIC-TOC, reducing uptake. It has no significant effect on pathological uptake for most sites of primary and metastatic disease. This should be taken into account if making quantitative measurements, calculating T/B ratios or assigning Krenning Scores. There is the potential for improved dosimetric results in Peptide Receptor Radionuclide Therapy by maintaining patients on LAR-SSA.

Utility of Targeted Positron Emission Tomography Imaging to Predict Schwannoma Growth in a Murine Tumor Model.

To identify if targeted positron emission tomography (PET) imaging with radiolabeled antibodies can predict tumor growth rate and ultimate tumor size in a murine flank schwannoma model. Animal research study. Rat schwannoma cells were cultured and implanted into 40 athymic nude mice. Once tumors reached 5 mm in diameter, 30 mice were injected with zirconium-89 labeled antibodies (HER2/Neu, vascular endothelial growth factor receptor 2 (VEGFR2), or IgG isotype). PET/CT was performed, and standardized uptake values (SUV) were recorded. Tumors were serially measured until mice were sacrificed per IACUC protocol. Statistical analysis was performed to measure correlations between SUV values, tumor size, and growth. Mean tumor sizes in mm3 on Day 0 were 144 ± 162 for anti-HER2/Neu, 212 ± 247 for anti-VEGFR2, and 172 ± 204 for IgG isotype groups respectively. Mean growth rates in mm3 /day were 531 ± 250 for HER2, 584 ± 188 for VEGFR2, and 416 ± 163 for the IgG isotype group. For both initial tumor size and growth rates, there was no significant difference between groups. There were significant correlations between maximum tumor volume and both the SUV max in the HER2 group (p = 0.0218, R2 = 0.5020), and we observed significant correlations between growth rate, and SUV values (p = 0.0156, R2 = 0.5394). Respectively, in the anti-VEGFR2 group, there were no significant correlations. In a murine schwannoma model, immunotargeted PET imaging with anti-HER2/Neu antibodies predicted tumor growth rate and final tumor size. Laryngoscope, 134:1372-1380, 2024.

Pre- and post-treatment FDG PET-CT as a predictor of patient outcomes in anal squamous cell carcinoma: A systematic review and meta-analysis.

Anal squamous cell carcinoma (ASCC) has a generally acceptable outlook in terms of survival. 18-fluorodeoxyglucose-positron emission tomography/computer tomography (FDG PET-CT) is not recommended for routine monitoring post-ASCC treatment. We examine herein if FDG PET-CT has a use in the prognostic evaluation of patients with ASCC, what FDG PET-CT metrics are of value and if a pre- or post-chemo/radiotherapy scan is more prognostic of outcomes. PubMed, EMBASE and Cochrane Central Registry of Controlled Trials were comprehensively searched until 3 May, 2023. A modified Newcastle Ottawa scale was used to assess for study bias. We present our systematic review alongside pooled hazard ratios (HR) for maximum standardised uptake values (SUV) as a predictor of overall survival (OS) and progression-free survival (PFS). Seven studies including 523 patients were included in our systematic review. Current evidence suggests that SUV maximum and median, metabolic tumour volume, total lesion glycolysis and complete and partial metabolic response may be prognostic when considering overall or progression-free survival (OS)/(PFS) along with local recurrence (LR). Pooled HR from two included studies indicate SUV max is prognostic of OS, HR 1.179, CI (1.039-1.338), P = 0.011 and PFS 1.176, CI (1.076-1.285), P < 0.01. FDG PET-CT may have a role to play in the prognostic evaluation of ASCC patients. Current evidence suggests post-treatment scanning may hold superior prognostic value at this time.

The variation of quantitative parameters and Deauville scores with different reconstruction algorithms in FDG PET/CT imaging of lymphoma patients

Introduction and objectives18F-FDG PET with the Deauville score (DS) is a unique semiquantitative method for lymphoma. However, type of standard uptake values (max, mean, and peak) reconstruction algorithms could affect DS. We compared the Bayesian Penalized Likelihood reconstruction algorithm (BPL) with Ordered Subsets Expectation Maximization (OSEM) on quantitative parameters and DS in lymphoma. We investigated the effect of the size of the lymph node on quantitative variation. Patients and methodsRaw PET data of 255 lymphoma patients were reconstructed separately with Q.Clear (GE Healthcare), a BPL, and SharpIR (GE Healthcare), an OSEM algorithm. In both images, each patient's liver, mediastinal blood pool, and SUVs (SUVmax, SUVmean, and SUVpeak) of a total of 487 lesions selected from the patients were performed. DSmax, DSmean, and DSpeak were compared. ResultsIn our study, DS increased significantly with BPL (p < 0.001), and the DS increased to 4–5 in thirty patients evaluated as 1−2–3 with OSEM. It was found that the quantitative values of the lymph nodes increased statistically with BPL (p < 0.001), and the liver from the reference regions were significantly decreased (p < 0.001). In addition, difference in lymph node was independently associated with size of lesion and was significantly more pronounced in small lesions (p < 0.001). The effects of BPL algorithm were more pronounced in SUVmax than in SUVmean and SUVpeak. DS-mean and DS-peak scores were less changed by BPL than DS-max. ConclusionDifferent reconstruction algorithms in FDG PET/CT affect the quantitative evaluation. That variation may affect the change in DS in lymphoma patients, thus affecting patient management.

A case of bronchiolar adenoma/ciliated muconodular papillary tumor in the pulmonary center with high FDG accumulation on PET

BackgroundBronchiolar adenoma/ciliated muconodular papillary tumor (BA/CMPT) is listed in the World Health Organization (WHO) Classification 5th edition as a rare benign tumor with papillary growth of ciliary, goblet, and basal cells.Case presentationThe patient was a 67-year-old female in whom a nodular shadow of 20 mm in diameter in the right lower lobe S10 center was found in chest computed tomography (CT) for examination of dorsal pain. Positron emission tomography/computed tomography (PET-CT) showed the accumulation of 18F-fluorodeoxyglucose (FDG) with a standardized uptake value (SUV)max of 13.0. Primary lung cancer was suspected, and surgery was scheduled as a therapeutic strategy. Thoracoscopic resection of the right lower lobe was performed, and possible BA/CMPT or adenocarcinoma was suggested in the differential diagnosis by the intra-perioperative rapid pathologic diagnosis. The final diagnosis was BA/CMPT. Histological findings indicated that the cause of the high FDG-PET scan might be due to many inflammatory cell infiltration in the tumor.ConclusionsWe report a resected case of BA/CMPT with exceptionally high FDG accumulation in PET.

Prognostic Value of 18F-Fluorodeoxyglucose Uptake of Bone Marrow on PET/CT in Patients with Limited Disease Small Cell Lung Cancer

Merve AYIK TURK1, Berna KOMURCUOGLU2, Ahmet YANARTAS3, Ozgur BATUM2, Yunus TURK4, Mehmet Ufuk YILMAZ5 1Izmir Bozyaka Training and Research Hospital, Department of Pulmonology, İzmir 2Dr. Suat Seren Chest Diseases and Surgery Training and Research Hospital, Department of Pulmonology, İzmir 3Dr. Suat Seren Chest Diseases and Surgery Training and Research Hospital, Department of Nuclear Medicine, İzmir 4Dr. Suat Seren Chest Diseases and Surgery Training and Research Hospital, Department of Thoracic Surgery, İzmir 5Medicana Health Groups, Department of Pulmonology, İzmir Keywords: Small cell lung cancer, Prognostic factors, Limited stage, Bone marrow FDG uptake Small cell lung cancer (SCLC) is a malignancy from the neuroendocrine tumor family, which has a poor prognosis and presents with metastases at the time of the diagnosis. The present study investigated the relationship between bone marrow fluorodeoxy-D-glucose (FDG) uptake and survival to evaluate prognosis in limited-stage SCLC. This single-center retrospective study examined a total of 220 patients diagnosed with limited-stage SCLC between January 2010 and June 2019. Bone marrow FDG uptake, serum inflammatory markers, and other factors used to determine the prognosis, as well as overall survival (OS) and progression-free survival (PFS), were recorded and retrospectively analyzed. Within physiological limits, bone marrow standardized uptake value (SUV) mean of &gt; 1.95 was identified as a good prognostic factor for PFS (p= 0.03). The multivariate analysis of OS and PFS revealed that the Eastern Cooperative Oncology Group (ECOG) performance scale (p= 0.001) was a common independent prognostic factor. Stages of the disease, albumin levels and bone marrow-to-liver ratio (BLR) [one of the positron emission tomography/computed tomography (PET/CT) parameters] of &lt; 0.8 were prognostic factors for OS. The bone marrow SUV mean was positively correlated with the primary tumor SUV max and SUV mean. The bone marrow SUV mean is a parameter that can be used to predict PFS in limited-stage SCLC. For OS, in turn, the BLR was identified as an independent factor.

Incidental findings at FDG PET/CT in carriers of cardiovascular implantable electronic devices

Abstract Funding Acknowledgements Type of funding sources: None. Background FDG-PET/CT clinical use for cardiovascular implantable electronic device (CIED) infection is of relevant importance, since it provides information about presence and extension of the infection. However, asymptomatic patients with incidental FDG uptake on CIED are challenging. Purpose The primary objective of this observational study was to assess the diagnostic role of FDG PET/CT in patients without a suspicious of CIED infection. The secondary objective was to identify qualitative and semiquantitative predictors of CIED infection. Methods From 2017 to 2019 all FDG-PET/CT scans of CIED patients were analysed, the indications were a suspicious of CIED or non-cardiovascular infection, or oncological follow up. Four expert nuclear medicine physicians blindly reviewed all scans, focusing on FDG uptake in pocket and/or in extracardiac lead parts. They reported standardized uptake values (SUV), liver and blood pool target-to-background ratios, metabolic tumour volume (MTV). 6 months follow up after PET/CT scan was performed for eventual CIED extraction because of infection. Results 320 FDG-PET/CT scans were considered. Median age was 74 [33-94] years, 219/320 (68%) males. 122/320 (38%) scans presented FDG uptake around pocket and/or extracardiac lead parts; and 65/320 (20%) scans reported suspicious uptake. We identified these cut-off criteria as predictors of CIED extraction: TARGET SUV max &amp;gt;2.6 (sensitivity 71%, specificity 89%), LIVER-TARGET SUV max &amp;gt;1.3 (sensitivity 68%, specificity 89%). Both these values also demonstrated to be good predictors of CIED infection after 6 months follow up (p&amp;lt;0,001). Conclusion FDG-PET/CT uptake in asymptomatic CIED patients is underestimated and may be related to subtle CIED infection. By introducing high-specific SUV cut-off values, a considerable impact on patient management is expected.

Multicenter quantitative 18F-fluorodeoxyglucose positron emission tomography performance harmonization: use of hottest voxels towards more robust quantification.

Harmonization methods reduce variability between different make and models of positron emission tomography (PET) scanners. The study aims to explore harmonization strategies that lead to comparable and robust quantitative metrics in a multicenter setting. NEMA IEC Phantom data acquisition was performed for low and high spheres-to-background ratios (SBR4:1 and 10:1) on six PET/CT (computed tomography) scanners. Different reconstruction sets, including the number of sub-iterations, number of subsets, and full width at half maximum (FWHM) for each scanner, were evaluated towards optimized and harmonized reconstruction settings. Recovery coefficients (RCs) of four quantitative metrics, including standardized uptake value (SUV)max, SUVISO-50 (SUVmean in 50% isocontour), SUVpeak, and mean uptake of 10 highest concentration voxels were evaluated as RCmax, RCISO-50, RCpeak, and RC10V, representing percent difference relative to the static ground truth case as functions of sphere sizes. A set of image reconstruction parameters was proposed for harmonized reconstruction to minimize variability between scanners. The root mean square error (RMSE), curvature, and reproducibility were examined. The proposed reconstruction protocols for harmonization and standard clinical reconstruction settings were compared to each other across all scanners. A significant difference (P value <0.0001) was observed in the aforementioned quantitative metrics between SBR10 and SBR4. Reconstruction parameter sets with the smallest RMSE and RC values within 10% bias were identified as the best candidate for harmonization. The coefficient of variation of the mean value of RCs (CVMRC) shows a remarkable reduction of about 28%, 26%, 32%, and 19% in harmonized reconstruction settings for MRCmax, MRCISO-50, MRCpeak, and MRC10V, respectively. CVMRC for MRC10V in the harmonized reconstruction setting was 5.9% in SBR4, while the smallest value in SBR10 belongs to MRCpeak, with a value of 5.8%. The reproducibility of RC is improved by deriving the value from ten hottest voxels and is equally reproducible with RCpeak. Compared to RCmax and RCISO-50, the variability is reduced by 18% and 22% if ten voxels are pooled. Harmonizing PET/CT systems with and without point spread function/time of flight (PSF/TOF) using various vendor-developed image reconstruction algorithms improves the quantification reproducibility. RC10V, likewise RCpeak, is superior to the rest of the quantitative indices in terms of accuracy and reproducibility and helpful in quantifying lesion volume below 1 mL.

MP55-03 CORRELATION BETWEEN PSMA PET/CT DATA AND PATHOLOGICAL TUMOUR STAGING AND GRADING OF PROSTATE CANCER

MP55-03 CORRELATION BETWEEN PSMA PET/CT DATA AND PATHOLOGICAL TUMOUR STAGING AND GRADING OF PROSTATE CANCER

The Chart Diagnostic System Improves the Diagnostic Accuracy of Cervical Lymph Node Metastasis in Oral Squamous Cell Carcinoma

Purpose: To establish a diagnosis method based on imaging findings and histopathological factors associated with cervical lymph node metastasis. Methods: A total of 1587 cervical lymph nodes that were detected using imaging tools in 73 OSCC patients who underwent surgical treatment were enrolled to evaluate the association between imaging findings (long diameter, short diameter, long–short ratio, US findings (hilum and internal echo), contrast effect with enhanced CT, standardized uptake value (SUV) max and SUV average with 18F FDG-Positron Emission Tomography (PET)) and metastatic cervical lymph nodes. In 57 OSCC patients, biopsy specimens were evaluated for histopathologic factors (budding score, lymphatic invasion, vascular invasion, nerve invasion, and YK classification) and the presence of cervical lymph node metastases. Cervical lymph node metastasis was determined based on histopathological examination of the lymph nodes of patients with no metastasis observed 3 years after primary surgery. Results: In total, 22 of the 73 patients had cervical lymph node metastasis pathologically. In the comparison of the presence of metastatic lymph nodes, univariate analysis showed significant differences in cervical lymph node long and short diameter, long/short ratio, internal echo, rim enhancement, SUV max, SUV average, budding score, and vascular invasion. Multivariable analysis showed significant differences in internal echo, rim enhancement, SUV max, and budding score. Conclusions: We propose a chart diagnostic system that combines imaging and histopathological findings to improve the diagnosis of cervical lymph node metastasis.

Clinical Analysis of Pulmonary Lymphoma

To study the clinical, imaging, and pathological features of pulmonary lymphoma. Patients with pulmonary lymphoma diagnosed by lung biopsy in Zhongda Hospital Affiliated to Southeast University from November 2013 to December 2020 were collected and divided into secondary pulmonary lymphoma (SPL) group and primary pulmonary lymphoma (PPL) group according to the primary site of lymphoma. The clinical characteristics, stages, imaging features, diagnostic methods and pathological types of the two groups were analyzed. A total of 22 patients were included, 10 cases were PPL and 12 cases were SPL. The main symptoms of the two groups were cough, dyspnea and chest pain. The proportion of stage III/IV patients and international prognostic index (IPI) in SPL group were significantly higher than those in PPL group (P<0.05). Chest high-resolution computed tomography (HRCT) mainly showed masses, nodules and consolidation in both groups. The proportions of single mass and air bronchial sign in PPL group were significantly higher than those in SPL group, while the proportions of multiple nodules, mediastinal/hilar lymphadenopathy and pleural effusion were significantly lower (P<0.05). The max standardized uptake value (SUVmax), peak standardized uptake value (SUVpeak), total lesion glycolysis (TLG) and metabolic tumor volume (MTV) of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in PPL group were lower than those in SPL group, but the differences were not statistically significant (P>0.05). In PPL group, 8 cases were diagnosed by transbronchial lung biopsy (TBLB) and 2 cases by percutaneous lung puncture. In SPL group, 4 cases were diagnosed by TBLB, 7 cases by percutaneous lung puncture, and 1 case by surgery. 95.5% patients were diagnosed by non-surgical methods. The main pathological type of PPL was mucosa-associated lymphoid tissue (MALT) lymphoma, while that of SPL was diffuse large B-cell lymphoma (P<0.05). The clinical symptoms of pulmonary lymphoma are nonspecific, but the chest HRCT has characteristic manifestations, which can also help to distinguish between SPL and PPL. 18F-FDG PET/CT is also a potential method to distinguish between SPL and PPL. TBLB and percutaneous lung puncture biopsy are reliable methods for the diagnosis of lung lymphoma. The main pathological type of PPL is MALT lymphoma, while that of SPL is diffuse large B-cell lymphoma.

Prognostic factors of toxicity of immune checkpoint inhibitors in nonsmall cell lung cancer and small cell lung cancer patients: The ToxImmune study.

Immunotherapy alone or in combination has clearly improved the survival of patients with lung cancer. However, it may also be responsible for adverse events impacting these patients' quality of life. The ToxImmune study aims to identify prognostic factors that can help to predict immune-related adverse events. We included all patients aged 18 years and older who had received at least one dose of immune checkpoint inhibitors, with or without other therapy, between June 2015 and December 2020 and were diagnosed with nonsmall cell lung cancer or small-cell lung cancer. Patients' baseline demographic characteristics, biological blood markers, and imaging by PET-scanner were collected from electronic medical records. All adverse events (AEs) and immune-related AEs (irAEs) were recorded (Common Terminology Criteria For Adverse Events V.5.0). Sixty-four patients were included, of whom 60 (94%) presented at least one irAE. The incidence of Common Terminology Criteria for Adverse Events (CTCAE) grade 2 and grade 3-4 was 34% and 8% respectively. Female sex, Primitive Tumor Standardized Uptake Value Max (SUVmax) <5, number of metastases ≥3 and immunotherapy received after the first line were found to be significant risk factors for immune-related adverse events. Based on the number of risk factors, the ToxImmune score predicts the risk of having a grade ≥2 adverse event (primitive tumor SUV ≥ 5=0 vs. primitive tumor SUV <5=1, number of metastases <3=0 vs. number of metastases ≥3=1 and L1=0 vs. L1 ≥ 1). The incidence of grade ≥2 adverse events was 20%, 55% and 90% with ToxImmune scores 0, 1 and=2 respectively (p=.003). Median progression-free survival (PFS) times were 19.2months, 6.64 months and 2.63 months for ToxImmune scores 0, 1 and=2 respectively, p=.13. Median overall survival times were 22.6months, 16.4months and 9.8months for ToxImmune scores 0, 1 and ≥2 respectively, p=.24. The disease control rate (DRR) was 78% in ToxIummune score 0 group, and 50% in ToxImmune score 1 and ≥2 groups (p=.363). The ToxImmune score, which is grounded on objective clinical parameters, indicates that cases with a high score had an advanced threat of severe adverse events. The ToxImmune score could therefore be used in clinical practice to identify patients treated for lung cancer with immunotherapy and at risk of severe AE.

18 F-FDG PET/CT parameters for prediction of response to neoadjuvant therapy and prognosis in rectal cancer.

This study aims to investigate the role of F-18 fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) parameters in the prediction of treatment response and the prognosis in locally advanced rectal cancer. We investigated the relationship of 18F-FDG PET/CT parameters [rectal metabolic tumor volume (MTV), rectal total lesion glycolysis (TLG), rectal standard uptake value (SUV) max, rectal highest peak SUV, lymph node MTV, lymph node TLG, lymph node highest peak SUV] with the pathological response and disease-free survival (DFS) in 60 patients who received neoadjuvant therapy for a diagnosis of locally advanced rectal cancer. Patients with a total score of 0 were assigned to the low-risk group, patients with a score of 1 were assigned to the intermediate-risk group and patients with a score of 2 were assigned to the high-risk group. The multivariate analysis revealed that, from baseline PET CT parameters, lymph node highest peak SUV strongly predicted the pathological response at a cutoff value of 2.23. DFS was predicted by the lymph node highest peak SUV at a cutoff value of 3.13 and by the MTV value at a cutoff value of 27 cm 3 . The risk scoring performed with regard to rectal MTV and lymph node highest peak SUV values determined a median DFS of 19 months in patients with a risk score of 2, whereas the median DFS was not reached in patients with risk scores of 0 and 1 (P < 0.001). This study determined that rectal MTV and lymph node highest peak SUV predicted the response to neoadjuvant therapy and DFS.