SUVmax Of Lesions Research Articles

Increased 18F-FAPI uptake in bones and joints of lung cancer patients: characteristics and distributions.

This study investigated the distribution and characteristics of various bone and joint lesions on 18F-FAPI PET/CT in lung cancer patients. Seventy-four lung cancer patients who underwent 18F-FAPI PET/CT were reviewed. Bone and joint lesions with elevated 18F-FAPI uptake were recorded and analyzed. The distribution and maximum uptake value (SUVmax) of different benign lesions or bone metastases were presented. In addition, the SUVmax of bone metastases on 18F-FDG and 18F-FAPI-04 PET/CT were also compared. In 53 patients, a total of 262 lesions presented 18F-FAPI accumulation. Bone metastases were mainly in vertebrae, pelvis, and ribs, while benign lesions were in vertebral margins, alveolar bone, and shoulder joints. The SUVmax of bone metastases was significantly higher than that of benign lesions ([Formula: see text] vs. [Formula: see text], [Formula: see text]), with NSCLC cases having higher SUVmax values than SCLC cases ([Formula: see text] vs. [Formula: see text], [Formula: see text]). Among benign lesions, arthritis and periodontitis demonstrated higher SUVmax than degenerative lesions (arthritis: [Formula: see text]; periodontitis: [Formula: see text]; degenerative diseases: [Formula: see text]; [Formula: see text] and [Formula: see text], respectively). The SUVmax of bone metastases was comparable between 18F-FDG and 18F-FAPI PET/CT. However, 18F-FAPI PET/CT was found to be superior in identifying cranial metastases compared to 18F-FDG PET/CT (TBRmet/brain: [Formula: see text] vs. [Formula: see text], [Formula: see text]). This study demonstrated that 18F-FAPI PET/CT is a valuable imaging modality for detecting bone and joint lesions in lung cancer patients. The SUVmax of malignant lesions was higher than that of benign lesions, but cannot accurately distinguish benign and malignant lesions. The uptake of FAPI differs among lesions with different pathological types.

Correlation between metabolic uptake of F-18-FDG-PET/computed tomography and thyroglobulin level in differentiated thyroid cancer patients with suspected recurrence.

Our objective is to determine if there is correlation between serum thyroglobulin and SUVmax of the main lesion detected in F18-FDG-PET/CT scan, in differentiated thyroid cancer (DTC) patients with suspected recurrence. All DTC patients enrolled in this prospective study, received at least one dose of radioactive iodine. During follow-up, they are suspected to have a recurrence due to elevated tumor markers although negative iodine whole-body scans. For all patients, F18-FDG-PET/CT scanning was performed. A 3D volume of interest was generated over the liver and main lesion to obtain maximum standardized uptake value (SUVmax). We calculated the lesion/liver ratio. Follow-up and/or histopathological examination were the gold standard. Pearson's correlation coefficient was calculated between thyroglobulin and SUVmax of the main lesion. Sixty-eight patients were recruited in this study. F18-FDG-PET/CT identified suspicious malignant lesions in 42 patients, equivocal in 18 patients, while 8 patients showed no abnormal findings. Fifty-two, 6, 8, and 2 patients were true positive, true negative, false positive, and false negative respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 72%, 57% 87%, 35%, and 69% respectively. The median SUVmax and lesion/liver ratio were significantly higher in the malignant lesions than that of benign lesions (3.9 vs. 1.3 and 1.45 vs. 0.54 respectively). We found that the main lesion SUVmax and lesion/liver ratio have a positive moderate correlation with thyroglobulin (0.338 and 0.325 respectively). In DTC patients with suspected recurrence, SUVmax of F18-FDG-PET/CT lesion showed a moderate positive correlation with serum thyroglobulin.

Increased tryptophan, but not increased glucose metabolism, predict resistance of pembrolizumab in stage III/IV melanoma

ABSTRACT Clinical trials of combined IDO/PD1 blockade in metastatic melanoma (MM) failed to show additional clinical benefit compared to PD1-alone inhibition. We reasoned that a tryptophan-metabolizing pathway other than the kynurenine one is essential. We immunohistochemically stained tissues along the nevus-to-MM progression pathway for tryptophan-metabolizing enzymes (TMEs; TPH1, TPH2, TDO2, IDO1) and the tryptophan transporter, LAT1. We assessed tryptophan and glucose metabolism by performing baseline C11-labeled α-methyl tryptophan (C11-AMT) and fluorodeoxyglucose (FDG) PET imaging of tumor lesions in a prospective clinical trial of pembrolizumab in MM (clinicaltrials.gov, NCT03089606). We found higher protein expression of all TMEs and LAT1 in melanoma cells than tumor-infiltrating lymphocytes (TILs) within MM tumors (n = 68). Melanoma cell-specific TPH1 and LAT1 expressions were significantly anti-correlated with TIL presence in MM. High melanoma cell-specific LAT1 and low IDO1 expression were associated with worse overall survival (OS) in MM. Exploratory optimal cutpoint survival analysis of pretreatment ‘high’ vs. ‘low’ C11-AMT SUVmax of the hottest tumor lesion per patient revealed that the ‘low’ C11-AMT SUVmax was associated with longer progression-free survival in our clinical trial (n = 26). We saw no such trends with pretreatment FDG PET SUVmax. Treatment of melanoma cell lines with telotristat, a TPH1 inhibitor, increased IDO expression and kynurenine production in addition to suppression of serotonin production. High melanoma tryptophan metabolism is a poor predictor of pembrolizumab response and an adverse prognostic factor. Serotoninergic but not kynurenine pathway activation may be significant. Melanoma cells outcompete adjacent TILs, eventually depriving the latter of an essential amino acid.

First-in-human CLDN18.2 functional diagnostic pet imaging of digestive system neoplasms enables whole-body target mapping and lesion detection.

Claudin 18.2 (CLDN18.2) is a reliable target for lesion detection and could have clinical implications for epithelial tumors, especially digestive system neoplasms. However, there is no predictive technology for accurate whole-body mapping of CLDN18.2 expression in patients. This study assessed the safety of the 124I-18B10(10L) tracer and the feasibility of mapping whole-body CLDN18.2 expression using PET functional imaging. The 124I-18B10(10L) probe was synthesized manually, and preclinical experiments including binding affinity and specific targeting ability were conducted after testing in vitro model cells. Patients with pathologically confirmed digestive system neoplasms were enrolled in an ongoing, open-label, single-arm, first-in-human (FiH) phase 0 trial (NCT04883970). 124I-18B10(10L) PET/CT or PET/MR and 18F-FDG PET were performed within one week. 124I-18B10(10L) was successfully constructed with an over 95% radiochemical yield. The results of preclinical experiments showed that it had high stability in saline and high affinity in CLDN18.2 overexpressing cells (Kd = 4.11nM). Seventeen patients, including 12 with gastric cancers, 4 with pancreatic cancers, and 1 with cholangiocarcinoma were enrolled. 124I-18B10(10L) displayed high uptake in the spleen and liver, and slight uptake in the bone marrow, lung, stomach and pancreas. The tracer uptake SUVmax in tumor lesions ranged from 0.4 to 19.5. Compared with that in lesions that had been treated with CLDN18.2-targeted therapy, 124I-18B10(10L) uptake was significantly higher in lesions that had not. Regional 124I-18B10(10L) PET/MR in two patients showed high tracer uptake in metastatic lymph nodes. 124I-18B10(10L) was successfully prepared and exhibited a high binding affinity and CLDN18.2 specificity in preclinical studies. As an FiH CLDN18.2 PET tracer, 124I-18B10(10L) was shown to be safe with acceptable dosimetry and to clearly reveal most lesions overexpressing CLDN18.2. NCT04883970; URL: https://register. gov/ . Registered 07 May 2021.

Quantitative application of dual-phase 99mTc-sestamibi SPECT/CT imaging of parathyroid lesions: identification of optimal timing in secondary hyperparathyroidism

PurposeIn this retrospective study, we compared the maximum standardized uptake values (SUVmax) of parathyroid lesions and the target-to-background ratio (TBR) of parathyroid lesions to thyroid tissue in early-phase single-photon emission computed tomography/computed tomography (SPECT/CT) versus delayed-phase SPECT/CT in patients with secondary hyperparathyroidism (SHPT) in order to determine the optimal timing of 99mTc- methoxyisobutylisonitrile (99mTc-MIBI) SPECT/CT imaging.MethodsSeventeen patients with a history of chronic kidney failure stage 5 on hemodialysis, underwent pre-operative parathyroid scintigraphy for detection and localization of parathyroid lesions. Retrospective analysis was conducted for lesions with focal accumulation of 99mTc-MIBI. All patients underwent dual-phase 99mTc-MIBI parathyroid scintigraphy and dual-phase SPECT/CT. SUVmax of parathyroid lesions and thyroid tissues was measured.ResultsMean SUVmax of parathyroid lesions was 4.86 on early-phase and 2.58 on delayed-phase SPECT/CT, respectively. Mean TBR was 1.14 on early phase and 1.48 on delayed-phase SPECT/CT, respectively. Statistically significant differences in SUVmax and TBR between dual-phase SPECT/CT were observed (P < 0.001).ConclusionsDelayed-phase SPECT/CT in SHPT is required because of the better image contrast.

Towards a fast PET/MRI protocol for breast cancer imaging: maintaining diagnostic confidence while reducing PET and MRI acquisition times

ObjectivesTo investigate the diagnostic feasibility of a shortened breast PET/MRI protocol in breast cancer patients.MethodsAltogether 90 women with newly diagnosed T1tumor-staged (T1ts) and T2tumor-staged (T2ts) breast cancer were included in this retrospective study. All underwent a dedicated comprehensive breast [18F]FDG-PET/MRI. List-mode PET data were retrospectively reconstructed with 20, 15, 10, and 5 min for each patient to simulate the effect of reduced PET acquisition times. The SUVmax/mean of all malign breast lesions was measured. Furthermore, breast PET data reconstructions were analyzed regarding image quality, lesion detectability, signal-to-noise ratio (SNR), and image noise (IN). The simultaneously acquired comprehensive MRI protocol was then shortened by retrospectively removing sequences from the protocol. Differences in malignant breast lesion detectability between the original and the fast breast MRI protocol were evaluated lesion-based. The 20-min PET reconstructions and the original MRI protocol served as reference.ResultsIn all PET reconstructions, 127 congruent breast lesions could be detected. Group comparison and T1ts vs. T2ts subgroup comparison revealed no significant difference of subjective image quality between 20, 15, 10, and 5 min acquisition times. SNR of qualitative image evaluation revealed no significant difference between different PET acquisition times. A slight but significant increase of IN with decreasing PET acquisition times could be detected. Lesion SUVmax group comparison between all PET acquisition times revealed no significant differences. Lesion-based evaluation revealed no significant difference in breast lesion detectability between original and fast breast MRI protocols.ConclusionsBreast [18F]FDG-PET/MRI protocols can be shortened from 20 to below 10 min without losing essential diagnostic information.Key Points• A highly accurate breast cancer evaluation is possible by the shortened breast [18F]FDG-PET/MRI examination protocol.• Significant time saving at breast [18F]FDG-PET/MRI protocol could increase patient satisfaction and patient throughput for breast cancer patients at PET/MRI.

Comparison of [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/MRI in the Preoperative Diagnosis of Gastric Cancer.

Our objective was to compare the value of positron emission tomography/magnetic resonance imaging (PET/MRI) with the new imaging agent [68Ga]Ga-DOTA-FAPI-04 and the traditional imaging agent [18F]FDG for the preoperative diagnosis of gastric cancer. Forty patients with gastric cancer diagnosed by gastroscopy in gastrointestinal surgery at our hospital from June 2020 to January 2021 were analyzed. All patients underwent simultaneous [68Ga]Ga-DOTA-FAPI-04 and [18F]FDG PET/MRI. The standard uptake value (SUV), fat removal standard uptake value (SUL), and diagnostic sensitivity, specificity, and accuracy for primary and metastatic lesions were compared, and their diagnostic value for different lymph node dissection stages was analyzed. The median age of the patients in this cohort was 68 years. Twenty-nine patients underwent surgery, and 11 patients underwent gastroscopic biopsy. The SUVmax of primary lesions in the FDG group and the FAPI group was 5.74 ± 5.09 and 8.06 ± 4.88, respectively (P < 0.01); SULmax values were 3.52 ± 2.80 and 5.64 ± 3.25, respectively (P < 0.01). The SUVmax of metastases in the two groups was 3.81 ± 3.08 and 5.17 ± 2.80, respectively (P < 0.05). The diagnostic sensitivities for primary lesions in the FDG group and the FAPI group were 0.72 and 0.94, respectively (P < 0.05). Combined with postoperative pathological staging, there was no difference in diagnostic sensitivity and specificity of lymph node staging between the FDG and FAPI groups (P > 0.05). Compared with the traditional imaging agent, [68Ga]Ga-DOTA-FAPI-04 has better diagnostic efficiency but no substantial advantage for preoperative lymph node staging.

PD10-04 SUVMAX OF THE PRIMARY PROSTATE LESION ON THE PSMA PET CT: AN INDICATOR OF AGGRESSIVE PATHOLOGY

You have accessJournal of UrologyCME1 Apr 2023PD10-04 SUVMAX OF THE PRIMARY PROSTATE LESION ON THE PSMA PET CT: AN INDICATOR OF AGGRESSIVE PATHOLOGY Amandeep Arora, Archi Agarwal, Mahendra Pal, Ganesh Bakshi, Venkatesh Rangarajan, Gujela Ajit, Santosh Menon, and Gagan Prakash Amandeep AroraAmandeep Arora More articles by this author , Archi AgarwalArchi Agarwal More articles by this author , Mahendra PalMahendra Pal More articles by this author , Ganesh BakshiGanesh Bakshi More articles by this author , Venkatesh RangarajanVenkatesh Rangarajan More articles by this author , Gujela AjitGujela Ajit More articles by this author , Santosh MenonSantosh Menon More articles by this author , and Gagan PrakashGagan Prakash More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003250.04AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: PSMA PET CT scans are being increasingly utilized in the staging evaluation of prostate cancer. However, there is limited data regarding the utility of the standardized uptake value (SUVmax) of the primary prostate lesion in the PSMA PET scan. Here, we evaluated whether the SUVmax of the primary prostate lesion can indicate aggressive pathological features in patients undergoing radical prostatectomy (RP) with an extended pelvic nodal dissection (PLND). METHODS: We retrospectively reviewed a prospectively maintained institutional database for prostate cancer patients from 2015-2022 who had a PSMA PET scan for their staging evaluation followed by a RP with PLND. Data was collected for clinico-pathological variables. The SUVmax of the primary lesion in the prostate was noted & compared across the pathological Gleason grade groups (GGG). We also checked whether the SUVmax had an association with Gleason upgrading & pathological nodal status. RESULTS: A total of 205 patients were included & were stratified into the following clinical risk groups based on MRI & PSMA-PET scans: 6 (2.9%) low-risk, 49 (23.9%) intermediate-risk, 46 (22.4%) high-risk localized, 89 (43.4%) locally-advanced node-negative & 15 (7.3%) node-positive patients. The median SUVmax of the primary prostate lesion for pathological GGG 1, 2, 3, 4 & 5 were 6.45, 11.3, 18.11, 25.51 & 24.37 respectively (p<0.001). For the 153 patients with a Gleason score 6-7 on transrectal biopsy, 19 patients had an upgrading of their score to >8 on the final pathology. The median SUV max of the prostate lesion in these 19 patients was significantly higher [median 22.37 (IQR 15.5–33.1)] than that in the remaining 134 patients with biopsy Gleason score 6-7 who did not have an upgrading to >8 on the final pathology [median 11.3 (IQR 7.4–17.5)]; p<0.001 (Figure 1). Also, the median SUVmax of the primary prostate lesion in patients who were true negatives for nodes, as per the PSMA-PET scan & final pathology, was significantly lower (12.8 vs 26.4, p<0.001) than that in patients who were false negative (cN0 on PSMA but pN+ in final pathology). CONCLUSIONS: Higher SUVmax of the primary prostate lesion is an indicator of aggressive pathological behaviour in the form of Gleason upgrading positive pelvic nodal status. Source of Funding: No © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e327 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Amandeep Arora More articles by this author Archi Agarwal More articles by this author Mahendra Pal More articles by this author Ganesh Bakshi More articles by this author Venkatesh Rangarajan More articles by this author Gujela Ajit More articles by this author Santosh Menon More articles by this author Gagan Prakash More articles by this author Expand All Advertisement PDF downloadLoading ...

PD10-02 USING THE NEGATIVE PREDICTIVE VALUE AND SUVMAX OF PSMA PET/CT FOR AVOIDING PELVIC LYMPH NODE DISSECTION WITH RADICAL PROSTATECTOMY

You have accessJournal of UrologyCME1 Apr 2023PD10-02 USING THE NEGATIVE PREDICTIVE VALUE AND SUVMAX OF PSMA PET/CT FOR AVOIDING PELVIC LYMPH NODE DISSECTION WITH RADICAL PROSTATECTOMY Amandeep Arora, Archi Agarwal, Mahendra Pal, Ganesh Bakshi, Santosh Menon, Gujela Ajit, and Gagan Prakash Amandeep AroraAmandeep Arora More articles by this author , Archi AgarwalArchi Agarwal More articles by this author , Mahendra PalMahendra Pal More articles by this author , Ganesh BakshiGanesh Bakshi More articles by this author , Santosh MenonSantosh Menon More articles by this author , Gujela AjitGujela Ajit More articles by this author , and Gagan PrakashGagan Prakash More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003250.02AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The prostate-specific membrane antigen positron-emission-tomography (PSMA-PET) scan is increasingly being utilized for staging prostate cancer (PCa). Here, we sought to evaluate the accuracy of the PSMA-PET scan with the aim of identifying patients who could be spared a pelvic lymph node dissection (PLND) at the time of radical prostatectomy (RP) based on the results of the PSMA-PET scan. METHODS: We retrospectively reviewed records of patients who underwent a PSMA-PET scan followed by an RP with extended PLND (external iliac, obturator and common iliac nodes) at our tertiary cancer care centre from Aug 2015 - September 2022. Patients were classified as clinically node negative or positive (cN0 or cN+) based on the PSMA PET scan. The nodal status in the PSMA-PET scan was compared with the final histopathology of the PLND (pN0 or pN+). RESULTS: A total of 205 patients were included and were stratified as follows based on MRI and PSMA-PET scans: 6 (2.9%) low-risk, 49 (23.9%) intermediate-risk, 46 (22.4%) high-risk localized, 89 (43.4%) locally-advanced node-negative and 15 (7.3%) node-positive patients. The sensitivity, specificity, positive predictive value, and negative predictive value of the PSMA PET scan for nodal status were 37.5%, 98.2%, 80% and 89.4% respectively. The NPV was 89.4%, 93.8%, 87% and 86.6% for overall, intermediate-risk, high-risk localized and locally-advanced node-negative patients respectively. The median SUVmax of the primary prostate lesion in patients who were true negatives for nodes, as identified by the PSMA-PET scan, was significantly lower (12.8 vs 26.4, p<0.001) than that in patients who were false negative (cN0 on PSMA but pN+ in final pathology). Of the 190 cN0 patients, 20 had a false negative PSMA PET scan. Three of the 49 intermediate-risk patients had a false negative PSMA PET scan for nodes; the SUVmax scores of their prostate lesions were 26.59, 40.06 and 54.55 which were much higher than the median SUVmax score (12.8) in patients with a true negative scan. For the 135 high-risk cN0 patients, the 17 false negative patients had a median SUVmax of 24.37 compared to those with a true negative scan (13.57), p<0.001. CONCLUSIONS: The high NPV of PSMA-PET scan coupled with the SUVmax of the primary prostatic lesion can help avoid a PLND in intermediate and high-risk patients with a ‘negative’ PSMA-PET scan. The results can be considered as hypothesis generating and indicate the use of PSMA as a biomarker for predicting nodal disease. Further larger studies can help determine the ideal cut-off values for the SUVmax of the primary lesion. Source of Funding: No © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e326 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Amandeep Arora More articles by this author Archi Agarwal More articles by this author Mahendra Pal More articles by this author Ganesh Bakshi More articles by this author Santosh Menon More articles by this author Gujela Ajit More articles by this author Gagan Prakash More articles by this author Expand All Advertisement PDF downloadLoading ...

Characterizing Rosai-Dorfman disease with [18F]FDG PET/CT: a retrospective analysis of a single-center study.

Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytic proliferative disorder. We performed a retrospective study to characterize the clinical and [18F]FDG PET/CT features of RDD. We retrospectively recruited 38 RDD patients with [18F]FDG PET/CT scan in our center. [18F]FDG PET/CT features were assessed, and clinical and follow-up data were recorded. In the recruited patients, 20/38 (52.6%) patients had single-system disease, while others (18/38, 47.4%) had disease affecting multiple system. RDD most commonly involved the upper respiratory tract (47.4%), followed by cutaneous/subcutaneous lesion (39.5%), lymph node (36.8%), bone (31.6%), central nervous system (28.9%), and cardiovascular system (13.2%) in the recruited patients. In PET/CT, the RDD lesions were FDG-avid, and the SUVmax of the hottest lesion in an individual patient was positively correlated with C-reactive protein levels (r = 0.418, p = 0.014), and negatively correlated with hemoglobin levels (r = -0.359, p = 0.036). The overall response rate of the first-line treatment was 80.8% in newly diagnosed RDD patients, and for patients with relapsed/progressive RDD, the overall response rate was 72.7%. [18F]FDG PET/CT could be a useful tool for evaluating RDD. • About half of the patients with Rosai-Dorfman disease had single-system disease, while others had disease affecting multiple system. Rosai-Dorfman disease most commonly involved the upper respiratory tract, followed by cutaneous/subcutaneous lesion, lymph node, bone, central nervous system, and cardiovascular system. • In [18F]FDG PET/CT, Rosai-Dorfman disease was usually hypermetabolic, and the SUVmax of the hottest lesion in an individual patient was positively correlated with C-reactive protein levels. • Rosai-Dorfman disease usually has a high overall response rate after treatment.

Multiple primary malignant tumours of lung and colorectal adenocarcinoma: A case report

Multiple primary malignant tumors of lung and colorectal incidence were extremely rare and in most cases, diagnosed incidentally. Due to its rarity, most physicians consider pulmonary lesions found in patients with a history of colorectal cancer as lung metastasis. To avoid misdiagnosis and treatment delays, it is critical to properly screen and explore for possible metastasis or the occurrence of a second primary tumor after a primary cancer has been diagnosed. We describe a 72-year-old woman who presented with rectal bleeding associated with altered bowel movement. Rectal biopsy revealed colon adenocarcinoma and subsequent CT scan showed sigmoid colon mass and right lower lobe lung mass with multiple mediastinal lymphadenopathies. Biopsies of the mediastinal lymph nodes also showed adenocarcinoma. PET/CT scans showed different SUVmax of lesions in the sigmoid colon and right lower lobe, which raised the possibility of separate colonic and lung primary tumors as opposed to colonic primary with lung metastasis. Further immunohistology studies confirmed separate primary lung tumor. These diagnoses facilitate the clinical approach and define treatment options for the patient.

Retrospective Analysis of the Predictive Value of 18F-FDG PET/CT Metabolic Parameters for PD-L1 Expression in Cervical Cancer

Immunotherapy targeting PD-1/PD-L1 has been proven to be effective for cervical cancer treatment. To explore non-invasive examinations for assessing the PD-L1 status in cervical cancer, we performed a retrospective study to investigate the predictive value of 18F-FDG PET/CT. The correlations between PD-L1 expression, clinicopathological characteristics and 18F-FDG PET/CT metabolic parameters were evaluated in 74 cervical cancer patients. The clinicopathological characteristics included age, histologic type, tumor differentiation, FIGO stage and tumor size. The metabolic parameters included maximum standard uptake (SUVmax), mean standard uptake (SUVmean), total lesion glycolysis (TLG) and tumor metabolic volume (MTV). In univariate analysis, SUVmax, SUVmean, TLG, tumor size and tumor differentiation were obviously associated with PD-L1 status. SUVmax (rs = 0.42) and SUVmean (rs = 0.40) were moderately positively correlated with the combined positive score (CPS) for PD-L1 in Spearman correlation analysis. The results of multivariable analysis showed that the higher SUVmax (odds ratio = 2.849) and the lower degree of differentiation (Odds Ratio = 0.168), the greater probability of being PD-L1 positive. The ROC curve analysis demonstrated that when the cut-off values of SUVmax, SUVmean and TLG were 10.45, 6.75 and 143.4, respectively, the highest accuracy for predicting PD-L1 expression was 77.0%, 71.6% and 62.2%, respectively. The comprehensive predictive ability of PD-L1 expression, assessed by combining SUVmax with tumor differentiation, showed that the PD-L1-negative rate was 100% in the low probability group, whereas the PD-L1-positive rate was 84.6% in the high probability group. In addition, we also found that the H-score of HIF-1α was moderately positively correlated with PD-L1 CPS (rs = 0.51). The SUVmax and differentiation of the primary lesion were the optimum predictors for PD-L1 expression in cervical cancer. There was a great potential for 18F-FDG PET/CT in predicting PD-L1 status and selecting cervical cancer candidates for PD1/PD-L1 immune checkpoint therapy.

An exploration of the feasibility and clinical value of half-dose 5-h total-body 18F-FDG PET/CT scan in patients with Takayasu arteritis.

To explore the feasibility and clinical value of 5-h delayed 18F-fluorodeoxyglucose (18F-FDG) total-body (TB) positron emission tomography/computed tomography (PET/CT) in patients with Takayasu arteritis (TA). This study included nine healthy volunteers who underwent 1-, 2.5-, and 5-h triple-time TB PET/CT scans and 55 patients with TA who underwent 2- and 5-h dual-time TB PET/CT scans with 1.85MBq/kg 18F-FDG. The liver, blood pool, and gluteus maximus muscle signal-to-noise ratios (SNRs) were calculated by dividing the SUVmean by its standard deviation to evaluate imaging quality. TA lesions' 18F-FDG uptake was graded on a three-point scale (I, II, III), with grades II and III considered positive lesions. Lesion-to-blood maximum standardised uptake value (SUVmax) ratio (LBR) was calculated by dividing the lesion SUVmax by the blood pool SUVmax. The liver, blood pool, and muscle SNR of the healthy volunteers at 2.5- and 5-h were similar (0.117 and 0.115, respectively, p=0.095). We detected 415 TA lesions in 39 patients with active TA. The average 2- and 5-h scan LBRs were 3.67 and 7.59, respectively (p<0.001). Similar TA lesion detection rates were noted in the 2-h (92.0%; 382/415) and 5-h (94.2%; 391/415) scans (p=0.140). We detected 143 TA lesions in 19 patients with inactive TA. The 2- and 5-h scan LBRs were 2.99 and 5.71, respectively (p<0.001). Similar positive detection rates in inactive TA were noted in the 2-h (97.9%; 140/143) and 5-h (98.6%; 141/143) scans (p=0.500). The 2- and 5-h 18F-FDG TB PET/CT scans had similar positive detection rates, but both combined could better detect inflammatory lesions in patients with TA.

Abstract P2-03-25: Pilot study to evaluate circulating tumor DNA (ctDNA) to PET/CT imaging using 18F-Fluorodeoxyglucose (FDG) and 18F-Fluoroestradiol (FES) PET/CT imaging as biomarkers in patients with metastatic breast cancer

Abstract Background: 18F-FES is an FDA-approved estrogen analogue PET imaging tracer (Cerianna) which measures tumor estrogen receptor (ER) expression at multiple tumor sites simultaneously and predicts response to endocrine therapy. 18F-FDG is a commonly used glucose PET imaging tracer which measures glycolytic metabolic activity in tumors. Elevated plasma ctDNA has been associated with an increased risk of relapse and can identify actionable genomic alterations. This pilot research study explored the relationship between somatic copy-number variants (CNVs) and cell-free DNA mass using low-pass-whole-genome (LPWG) ctDNA in the blood to FES and FDG PET/CT findings with both qualitative and quantitative image analysis in metastatic breast cancer patients. Methods: Two(2) 10ml Streck tubes were collected from 20 patients with metastatic ER+ breast cancer +/-30 days of their FDG-PET/CT scan (n=19) or their FES-PET/CT scan (n=9). 8 patients had both scans. Somatic mutations were assessed using comprehensive genomic profiling of tissue samples from 19 patients using the clinically validated UW-Oncoplex assay. Qualitative analysis included detection of LPWG ctDNA, presence of PIK3A mutations in tissue, and intensity of uptake in PET/CT imaging. LPWG ctDNA of blood samples evaluated ctDNA mass and CNVs that comprised at least 8% of total ctDNA. Total lesion glycolysis (TLG) in FDG scans and total lesion estrogen receptors (TLER) in FES scans were calculated using a dedicated workflow in MiM software (MiM Software Inc. Cleveland OH). Quantitative analysis included the circulating fraction (ctDNA), PET/CT SUVmax of the index lesion, number of lesions, TLG and TLER. For TLG, the threshold for determining measurable lesions was calculated using liver SULmean + 1.5*SD. The threshold for TLER was calculated using SUVmean of the mediastinal blood pool. The ctDNA fraction and the number of lesions for both FDG and FES were each ranked into 3 categories. FDG and FES data (SUVmax of index lesion, # of lesions, and TLG or TLER) were correlated to the calculated ctDNA fraction values. TLG and TLER were also correlated to each other. Results: ctDNA was classified as no ctDNA present (n=9), ctDNA present (n=8) and indeterminate (n=3). Average neoplastic ctDNA fraction was 0.114 (range 0.03-0.423). PIKC3A mutations were: 10 absent and 9 present. Ranked categories for ctDNA fraction, FDG TLG and FES TLER are shown in Table 1. Table 2 shows results of FDG and FES analysis and correlation with ctDNA. Ranked ctDNA findings correlated with both the FDG number of lesions (R2=0.69) and TLG (R2=0.83), but not the SUVmax of the index lesion (R2=0.29). Correlation decreased for ctDNA versus FES number of lesions (R2=0.51), TLER (R2=0.61), and SUVmax of index lesion (R2=0.16). TLG and TLER significantly correlated with the 8 patients that had both an FDG and FES PET/CT scan (R2=0.77). Conclusions: In this pilot study, FDG TLG showed a significant correlation with ctDNA. There is an encouraging association with ctDNA fraction and number of FDG lesions and with ctDNA fraction and extent of FES avid disease (TLER) in the 9 patients that had FES. Research Support: RG1005258 Table 1. Categorical rankings for qualitative analysis of ctDNA, TLG and TLER Table 2. FDG and FES imaging results and correlation with ctDNA Citation Format: Natasha Hunter, Lanell M. Peterson, Mark Muzi, Eric Q. Konnick, Jonathan Reichel, Paul Kinahan, Jennifer M. Specht, Rachel Yung, William R. Gwin, Hannah Linden, Christina Tran. Pilot study to evaluate circulating tumor DNA (ctDNA) to PET/CT imaging using 18F-Fluorodeoxyglucose (FDG) and 18F-Fluoroestradiol (FES) PET/CT imaging as biomarkers in patients with metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-03-25.

Prognostic value of pre-treatment FDG PET/CT SUVmax for metastatic lesions in de novo metastatic nasopharyngeal carcinoma following chemotherapy and locoregional radiotherapy

BackgroundTo explore the prognostic role of FDG PET/CT maximal standard uptake values of metastatic lesions (SUVmax-M) in patients with de novo metastatic nasopharyngeal carcinoma (mNPC) following palliative chemotherapy and locoregional radiotherapy (LRRT).MethodsWe retrospectively collected the information of 86 eligible patients between Jan 2012 and Oct 2020. All the parameters involving SUVmax and serum lactate dehydrogenase (LDH) at diagnosis were evaluated and cutoff values were determined by the maximum log-rank statistic method. The multivariate analysis was performed using Cox proportional hazards regression to identify the independent prognostic factors associated with overall survival (OS). All estimated survival rates were conducted with Kaplan–Meier method.ResultsMedian survival and progression time in the cohort were 38.2 and 13.9 months, respectively. The univariable analysis showed that male, number of metastatic sites ≥ 4, presence of liver, serum LDH ≥ 229, SUVmax-M ≥ 10, SUVmax-M-sum ≥ 10, and SUVmax-M-mean ≥ 8.8 were significant prognostic factors. Five variables were identified after LASSO regression and entered into the multivariate analysis. Furthermore, liver involvement (P = 0.039), elevated LDH (≥ 229) (P = 0.05) and higher SUVmax-M (≥ 10) (P = 0.004) were significantly associated with worse OS.ConclusionThe high SUVmax of metastatic lesions (≥ 10), liver involvement, and elevated serum LDH (≥ 229) at diagnosis could independently predict poor survival for de novo mNPC patients treated with palliative chemotherapy following LRRT.

Deep Learning-Based Image Quality Improvement in Digital Positron Emission Tomography for Breast Cancer

We investigated whether 18F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography images restored via deep learning (DL) improved image quality and affected axillary lymph node (ALN) metastasis diagnosis in patients with breast cancer. Using a five-point scale, two readers compared the image quality of DL-PET and conventional PET (cPET) in 53 consecutive patients from September 2020 to October 2021. Visually analyzed ipsilateral ALNs were rated on a three-point scale. The standard uptake values SUVmax and SUVpeak were calculated for breast cancer regions of interest. For "depiction of primary lesion", reader 2 scored DL-PET significantly higher than cPET. For "noise", "clarity of mammary gland", and "overall image quality", both readers scored DL-PET significantly higher than cPET. The SUVmax and SUVpeak for primary lesions and normal breasts were significantly higher in DL-PET than in cPET (p < 0.001). Considering the ALN metastasis scores 1 and 2 as negative and 3 as positive, the McNemar test revealed no significant difference between cPET and DL-PET scores for either reader (p = 0.250, 0.625). DL-PET improved visual image quality for breast cancer compared with cPET. SUVmax and SUVpeak were significantly higher in DL-PET than in cPET. DL-PET and cPET exhibited comparable diagnostic abilities for ALN metastasis.

Positron emission tomography of patients with confirmed prostate cancer using 64Cu-SAR-bisPSMA.

318 Background: Prostate cancer (PC) is the second most frequent malignancy in men worldwide. 68Ga-PSMA-11 is one of the most widely used radiotracers for positron emission tomography (PET) of prostate-specific membrane antigen (PSMA) positive lesions in men with PC and is part of standard clinical practice at many centres. Due to the longer half-life and shorter positron range of copper-64 (t1/2=12.7 hours; mean positron range=0.56 mm), a novel PSMA-targeting radiotracer labelled with this radionuclide, 64Cu-SAR-bisPSMA, has the potential to provide advantages over 68Ga-PSMA-11 (t1/2=68 minutes; mean positron range=3.5 mm). The 12.7 hour half-life of Cu-64 allows the central manufacturing of 64Cu-SAR-bisPSMA with a product shelf-life of up to 2 days. The longer half-life enables PET imaging from 1 to 72 hours after administration which offers greater flexibility in terms of scheduling of patients and may translate into detection of additional lesions due to increased Standardized Uptake Values (SUV) in the lesions relative to background following biological clearance of the tracer from organs over time. The shorter positron range may lead to improved resolution on the scan and thus, better detection of small lesions, including those that are in close proximity to each other, or to organs involved in clearance of the product such as the bladder and kidneys. In addition to the potential imaging and supply benefits of Cu-64, current generation PSMA targeting agents such as 68Ga-PSMA-11 have only a single targeting functional group. 64Cu-SAR-bisPSMA has two PSMA-targeting functional groups, which can lead to improved tumor uptake and retention. This was shown in a preclinical study, where 64Cu-SAR-bisPSMA outperformed the monomeric 64Cu-SAR-PSMA with respect to both tumor uptake and retention (Zia et al, 2019). Methods: Patients with untreated, histopathology-proven, intermediate- to high-risk PC, planned for radical prostatectomy underwent 68Ga-PSMA-11 PET/CT per institutional practice and were subsequently allocated to 1 out of 3 dose cohorts (1:1:3) to receive either 100 MBq, 150 MBq or 200 MBq of 64Cu-SAR-bisPSMA, respectively. A PET/CT was acquired at 3-hours (±1 hour) post-injection of 64Cu-SAR-bisPSMA. Two independent, blinded, central readers assessed the detection of primary PC on the 200 MBq 64Cu-SAR-bisPSMA PET/CTs as the primary endpoint. To compare the intensity of lesions on 68Ga-PSMA-11 and 64Cu-SAR-bisPSMA PET, both readers determined the SUVs (SUVmax, SUVmean) and tumour-to-background ratio (ratio of lesion SUVmax and background SUVmean) in up to 5 concordant lesions between 68Ga-PSMA-11 and 64Cu-SAR-bisPSMA PET/CT as an exploratory endpoint. Clinical trial information: NCT04839367 .

Benign lesions with 68Ga-FAPI uptake: a retrospective study.

Although FAPI, as a pan-tumor tracer, shows high expression in the malignancy imaging, FAPI uptake is also seen in some benign lesions. The purpose of this study was to retrospectively analyze the characteristics of benign lesions with FAPI uptake on 68Ga-FAPI PET/CT imaging. The electronic medical and imaging records of patients undergoing 68Ga-FAPI PET/CT imaging in the Department of Nuclear Medicine of our hospital from March 2020 to March 2022 were retrospectively analyzed. Patients with benign lesions confirmed by histopathological analysis or long-term follow-up of FAPI-positive lesions were included in the study. A total of 44 patients (i.e., 44 benign lesions) were included in this study, including 14 women and 30 men, ranging in age from 19 to 74 years. Benign lesions involved eight systems, including liver (n = 3), tail of pancreas (n = 3), stomach (n = 3), esophagus (n = 1), lung (n = 14), and mediastinum (n = 2), sinuses (n = 1), brain (n = 2), lymph nodes (n = 5), kidneys (n = 4), bones (n = 2), muscles (n = 1), thyroid (n = 1), parathyroid gland (n = 1), and breast (n = 1). The mean SUVmax (p = 0.471) and mean TBR (p = 0.830) of benign lesions in the eight systems were not significantly different. Our studies have shown that in addition to malignant tumors, certain benign lesions also show uptake of FAPI, and it is necessary for doctors to distinguish these benign lesions from true malignant tumors. Benign lesions may also show FAPI expression, which may make the differential diagnosis of benign and malignant lesions difficult and should be alerted by physicians.

Bayesian penalized likelihood PET reconstruction impact on quantitative metrics in diffuse large B-cell lymphoma.

Evaluate the quantitative, subjective (Deauville score [DS]) and reader agreement differences between standard ordered subset expectation maximization (OSEM) and Bayesian penalized likelihood (BPL) positron emission tomography (PET) reconstruction methods. A retrospective review of 104 F-18 fluorodeoxyglucose PET/computed tomography (CT) exams among 52 patients with diffuse large B-cell lymphoma. An unblinded radiologist moderator reviewed both BPL and OSEM PET/CT exams. Four blinded radiologists then reviewed the annotated cases to provide a visual DS for each annotated lesion. Significant (P < .001) differences in BPL and OSEM PET methods were identified with greater standard uptake value (SUV) maximum and SUV mean for BPL. The DS was altered in 25% of cases when BPL and OSEM were reviewed by the same radiologist. Interobserver DS agreement was higher for OSEM (>1 cm lesion = 0.89 and ≤1 cm lesion = 0.84) compared to BPL (>1 cm lesion = 0.85 and ≤1 cm lesion = 0.81). Among the 4 readers, average intraobserver visual DS agreement between OSEM and BPL was 0.67 for lesions >1cm and 0.4 for lesions ≤1 cm. F-18 Fluorodeoxyglucose PET/CT of diffuse large B-cell lymphoma reconstructed with BPL has higher SUV values, altered DSs and reader agreement when compared to OSEM. This report finds volumetric PET measurements such as metabolic tumor volume to be similar between BPL and OSEM PET reconstructions. Efforts such as adoption of European Association Research Ltd accreditation should be made to harmonize PET data with an aim at balancing the need for harmonization and sensitivity for lesion detection.

The value of preoperative positron emission tomography/computed tomography in differentiating the invasive degree of hypometabolic lung adenocarcinoma

ObjectivesTo investigate the value of preoperative positron emission tomography/computed tomography (PET/CT) in differentiating the invasive degree of hypometabolic lung adenocarcinoma.MethodsWe retrospectively analyzed the data of patients who underwent PET/CT examination, high-resolution computed tomography, and surgical resection for low-metabolism lung adenocarcinoma in our hospital between June 2016 and December 2021. We also investigated the relationship between the preoperative PET/CT findings and the pathological subtype of hypometabolic lung adenocarcinoma.ResultsA total of 128 lesions were found in 113 patients who underwent resection for lung adenocarcinoma, including 20 minimally invasive adenocarcinomas (MIA) and 108 invasive adenocarcinomas (IAC), whose preoperative PET/CT showed low metabolism. There were significant differences in the largest diameter (Dmax), lesion type, maximum standard uptake value (SUVmax), SUVindex (the ratio of SUVmax of lesion to SUVmax of contralateral normal lung paranchyma), fasting blood glucose, lobulation, spiculation, and pleura indentation between the MIA and IAC groups (p < 0.05). Multivariate logistic regression analysis showed that the Dmax (odds ratio (OR) = 1.413, 95% confidence interval (CI: 1.155–1.729, p = 0.001)) and SUVmax (OR = 12.137, 95% CI: 1.068–137.900, p = 0.044) were independent risk factors for predicting the hypometabolic IAC (p < 0.05). Receiver operating characteristic (ROC) curve analysis showed that the Dmax ≥ 10.5 mm and SUVmax ≥ 0.85 were the cut-off values for differentiating MIA from IAC, with high sensitivity (84.3% and 75.9%, respectively) and specificity (84.5% and 85.0%, respectively), the Combined Diagnosis showed higher sensitivity (91.7%) and specificity (85.0%).ConclusionsThe PET/CT findings correlated with the subtype of hypometabolic lung adenocarcinoma. The parameters Dmax and SUVmax were independent risk factors for predicting IAC, and the sensitivity of Combined Diagnosis prediction is better.