SUVmax Cutoff Research Articles

The prognostic value of baseline EARL standardized FDG PET indices in pediatric and adolescent high-grade osteosarcoma.

To investigate the prognostic value of baseline European Association of Nuclear Medicine Research Ltd. (EARL) standardized [18F]fluorodeoxyglucose positron emission tomography-computed tomography ([18F]FDG PET-CT) quantitative values for survival and to evaluate cutoff values identified in other studies. Pediatric and adolescent patients with high-grade osteosarcoma were included. Baseline [18F]FDG PET-CT, with EARL-accredited reconstructions, was the standard diagnostic staging procedure. Cox proportional hazard analysis for event-free survival (EFS) and overall survival (OS) was performed with clinical prognostic factors. Kaplan-Meier analysis and log-rank tests were applied to investigate the prognostic performance of the [18F]FDG PET indices. In total, 66 patients were included in this study. In the univariable Cox regression analysis, peak lean-body mass corrected SUV (SULpeak) (hazard ratio (HR): 1.04), total lesion glycolysis (TLG) (HR: 1.0), and metabolic tumor volume (MTV) (HR: 1.0) were not associated with EFS or OS. Log-rank analysis showed a significant difference in EFS for all SULmax and SULpeak cutoffs. For MTVtotal the maximum Youden, and for TLGtotal, the maximum Youden and maximally selected rank cutoff resulted in a significant EFS difference. No cutoff for any measure showed a significant difference in OS between the groups. ROC curves for event status had an AUC of 0.67, 0.66, 0.64, and 0.64 for SULmax, SULpeak, MTVtotal, and TLGtotal, respectively. In this study, the baseline EARL-standardized [18F]FDG PET indices of children and adolescents with osteosarcoma were not prognostic of EFS or OS. The proposed prognostic cutoffs from earlier studies suffer from important technical and statistical issues. Question Prognostic value of baseline [18F]FDG PET-CT imaging markers have been reported for histologic response and survival in high-grade osteosarcoma but have not been validated for clinical practice. Findings Baseline SUVpeak, TLGtotal, and MTVtotal measured on EARL-accredited reconstructions were not prognostic factors for survival in pediatric and adolescent patients with high-grade osteosarcoma. Clinical relevance A wide range of values for SUVpeak and SUVmax cutoffs with similar prognostic value were identified, questioning the value of a single proposed cutoff. Lack of validation, with important technical and statistical issues of proposed prognostic cutoffs, limits clinical implementation.

The Role of [18F]F-FDG PET/CT for Predicting Histology and Prognosis in Patients with Thymic Lesions.

To investigate whether 18F-fluorodeoxyglucose positron emission tomography-computed tomography ([18F]F-FDG PET/CT) metabolic parameters were associated with histology and to assess their prognostic role in patients with thymic lesions. In total, 116 patients (49/67 M/F; mean age 59.5 years) who underwent preoperative [18F]F-FDG PET/CT and thymectomy from 2012 to 2022 were retrospectively analyzed. Associations between histology and metabolic parameters (maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), peak standardized uptake value (SUVpeak), total lesion glycolysis (TLG), metabolic tumor volume (MTV), ratio between target lesion and liver SUVmax (rPET), quotient of SUVpeak in the tumor residual and SUVmean in a 20-cm3 volume of interest (qPET), and tumor-to-mediastinum (T/M) were analyzed. Freedom from recurrence (FFR) was determined and compared using the Kaplan-Meier and the log-rank test. The median follow-up was 38 months (range 14-72 months). In total, 27 thymic hyperplasia, 41 low-risk thymomas (LRT) (types A, AB, and B1), and 48 high-risk thymomas (HRT) (B2, B3 thymoma, and carcinoma) were included. SUVmax, SUVmean, SUVpeak, rPET, qPET, and T/M were significantly higher in HRT than LRT and hyperplasia (p < 0.001). TLG and MTV were significantly higher in patients with LRT (p < 0.001). Only rPET, qPET, and T/M remained significantly higher in HRT than in LRT subgroups (p = 0.042, p = 0.049, and p = 0.028, respectively). SUVmax, SUVmean, and SUVpeak cutoffs of < 4.3, < 2.87, and 4.03, respectively, significantly distinguished patients with longer FFR (p = 0.009, p = 0.05, and p = 0.05). Positron emission tomography (PET) metabolic parameters could help to differentiate thymic histotypes. Standardized uptake value (SUV)-based parameters appear promising to predict recurrent disease.

HER2-Targeted Affibody Molecule 99mTc-ABH2 for Imaging HER2 Expression in Breast Cancer.

Accuracy in in vivo assessment of human epidermal growth factor receptor type 2 (HER2) status is crucial for predicting the response to HER2-targeted therapies in breast cancer. This study assessed the safety, feasibility, and diagnostic accuracy of 99mTc-ABH2, a reengineered affibody molecule with radionuclide labeling, for HER2 expression in breast cancer using SPECT/CT imaging, compared with 18F-FDG PET/CT. Thirty-six patients suspected of primary breast cancer were enrolled in this prospective, single-center study from March to July in 2023. Each participant underwent SPECT/CT imaging with 99mTc-ABH2 SPECT/CT and 18F-FDG PET/CT. The imaging results were validated against immunohistochemistry and fluorescence in situ hybridization, employing visual scores and quantitative values for analysis. Optimal imaging contrast was observed around 2 hours postinjection of 99mTc-ABH2. Among the evaluated 27 patients with immunohistochemistry and fluorescence in situ hybridization findings, the 99mTc-ABH2 SPECT/CT visual evaluation displayed a sensitivity of 71.4%, specificity of 72.2%, and accuracy of 71.9%. Using an SUVmax cutoff of 2.32, the sensitivity, specificity, and accuracy for detecting HER2 status were 92.86%, 72.22%, and 81.25%, respectively. Notably, 99mTc-ABH2 precisely identified all immunohistochemistry (3+) tumors and showed increased uptake in bone and lymph node metastases. Meanwhile, 18F-FDG PET/CT showed no significant difference in uptake between HER2 (2+/3+) and HER2 (0/1+) tumors (P = 0.81). This study validated 99mTc-ABH2 SPECT/CT as a promising diagnostic tool for precise HER2 assessment. The robust sensitivity for immunohistochemistry (3+) tumors and the visualization of metastases highlight its diagnostic significance, potentially impacting patient outcomes positively.

68Ga-PSMA PET CT/MRI in the initial diagnosis and staging of prostate cancer: A review

Prostate-specific membrane antigen-positron emission tomography (PSMA-PET) imaging has demonstrated potential in addressing prostate cancer (PCa) diagnostic difficulties. According to current guidelines, gallium-68 (68Ga)-PSMA-PET is used as an adjunct to traditional imaging modalities in patients with primary PCa. The purpose of this review, conducted using Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, is to give an overview of studies that have examined the role of 68Ga-PSMA in the initial diagnosis of PCa, its performance in TNM staging, its correlation with prostate-specific antigen (PSA) levels, targeted biopsies, and the International Society of Urological Pathology (ISUP) scores using computed tomography (CT) or magnetic resonance imaging (MRI). The findings demonstrate that, in addition to MRI alone, combining 68Ga-PSMA-PET with MRI-targeted biopsy improves the initial identification of clinically significant prostate cancer (csPCa), particularly for ambiguous prostate imaging-reporting and data system (PI-RADS) three lesions. 68Ga-PSMA-PET/CT is useful when MRI results for csPCa are uncertain, but consistent techniques are required. Regarding risk assessment and therapy planning, 68Ga-PSMA-PET has a strong correlation with both PSA levels and ISUP scores. It accurately detects primary PCa lesions, making it suitable for high-risk patients. In 68Ga-PSMA-PET, higher maximum standardized uptake value (SUVmax) readings are linked to more aggressive illness. For N and M staging, 68Ga-PSMA-PET/CT is more sensitive and specific than conventional imaging; however, for T-staging, multiparametric MRI (mpMRI) provides better accuracy. 68Ga-PSMA-PET/MRI shows improved accuracy for primary PCa detection compared to mpMRI alone. Challenges include the lack of standardized SUVmax cutoff values. 68Ga-PSMA-PET is useful for the initial diagnosis and staging of PCa, complementing MRI, although further research is needed to standardize imaging techniques and interpretations.

Evaluation of fibroinflammatory activity in thyroid eye disease using [18F]AlF-NOTA-FAPI-04 PET/CT: A prospective study.

This study evaluates the value of [18F]AlF-NOTA-FAPI-04PET/CT in assessing the disease activity of thyroid eye disease (TED). Twenty-three TED patients and ten healthy controls were prospectively recruited and underwent [18F]AlF-NOTA-FAPI-04 PET/CT scans. TED eyes were classified by Clinical Activity Score (CAS) as active (CAS +) or inactive (CAS-). PET analysis included qualitative and quantitative evaluations. Qualitative analysis categorized TED eyes as positive (FAPI +) or negative (FAPI-), while quantitative analysis including SUVmax and target-to-backgroud ratio (TBR) of each extraocular muscle (EOM). Pathological assessment of 16 EOM samples from 15 TED eyes was used as a gold standard to evaluate the diagnostic accuracy of CAS-driven and FAPI-driven assessments. Eye-based analysis included 42 TED eyes and 20 control eyes. SUVmax did not differ significantly between CAS-/FAPI + (n = 8) and CAS + /FAPI + (n = 17) eyes; though both groups had significantly higher SUVmax than CAS-/FAPI- (n = 16), CAS + /FAPI- (n = 1), and control eyes (n = 20) (all P < .05). Diffuse high FAPI uptake with excellent TBR was observed in pathologically active EOMs and had higher SUVmax and TBR than inactive EOMs (SUVmax: 9.57 ± 2.79 vs. 4.04 ± 1.02, TBR: 2.99 ± 1.00 vs. 1.00 ± 0.35, both P < .001). An SUVmax cutoff value of 5.95 yielded an area under the receiver operating characteristic curve of 0.98 for predicting active disease. Sensitivity and specificity of CAS-driven and FAPI-driven assessments for TED activity were 72.7% and 100%, 100% and 100%, respectively. SUVmax positively correlated with pathological fibroinflammatory score (r = 0.68, P = .004). The diffuse high FAPI uptake with excellent TBR in the EOMs could illustrate the activity of TED, positively correlated with pathological fibroinflammatory scores. These findings suggest that [18F]AlF-NOTA-FAPI-04 PET/CT may serve as a promising reliable non-invasive approach for assessing disease activity in TED, potentially superior to the CAS.

Comparative Study of [18F]AlF-LNC1007, [18F]FDG, and [18F]AlF-NOTA-FAPI-04 PET/CT in Breast Cancer Diagnosis: A Methodological Exploration and Analytical Insight.

Objective: To compare the diagnostic value of [18F]AlF-LNC1007, [18F]FDG, and [18F]AlF-NOTA-FAPI-04 PET/CT in breast cancer. Methods: 33 patients with highly suspected or already diagnosed but untreated breast cancer were enrolled in the study and underwent [18F]AlF-LNC1007 (30 patients), [18F]FDG (22 patients), and [18F]AlF-NOTA-FAPI-04 (8 patients) PET/CT. Quantitative measurements included the SUVmax and tumor-to-background ratio (TBR) for all lesions and background tissues. The Chi-square test was used for intergroup diagnostic efficacy, and the Wilcoxon test was used for intergroup SUVmax or TBR. Diagnostic efficacy for lymph node metastasis was evaluated using receiver operating characteristic (ROC) analysis. Results: Compared to [18F]FDG, [18F]AlF-LNC1007 had a higher positive predictive value (100% vs 91%, P = 0.0004) in lymph node metastases (42 vs 46) and higher sensitivity (100 vs 76%, P = 0.0003) in bone metastases (33 vs 25) but lower sensitivity (93 vs 100%, P = 0.001) in liver metastases. Apart from liver metastases, [18F]AlF-LNC1007 PET/CT had higher SUVmax in primary tumor and other metastases, with no statistical difference in TBR. Compared to [18F]AlF-NOTA-FAPI-04 PET/CT, [18F]AlF-LNC1007 had less false-positive and a higher positive predictive value in bone metastases (99 vs 95%, P = 0.0003) but had lower SUVmax(P < 0.01) in all primary and metastases lesions. The TBR difference between [18F]AlF-LNC1007 and [18F]AlF-NOTA-FAPI-04 was statistically significant only in bone metastases (5.97 vs 5.02, P = 0.001). The comparison of lymph node detection efficacy between [18F]AlF-LNC1007 and [18F]FDG PET/CT showed significant differences in SUVmax cutoff values for diagnosing lymph node metastases (2.62 vs 3.90), sensitivity (95.2% vs 66.67), and specificity (100% vs 85.00) (all P < 0.001). Conclusion: [18F]AlF-LNC1007 demonstrated superior efficacy compared to [18F]FDG and [18F]AlF-NOTA-FAPI-04 and higher uptake than [18F]FDG in primary tumor, lymph node and bone metastases, and higher TBR than [18F]AlF-NOTA-FAPI-04, especially in bone metastases. [18F]AlF-LNC1007 also showed high specificity in differentiating inflammatory and metastatic lymph nodes.

PRIMARY scoring in 68Ga-PSMA PET/CT: correlation with prostate cancer risk groups and its potential impact on active surveillance.

The PRIMARY scoring system is a scale designed to identify clinically significant intraprostatic malignancies on 68Ga-PSMA PET/CT images. Active surveillance is a management method for patients with low-risk prostate cancer. In this study, we aimed to assess the efficacy of PRIMARY scoring in identifying appropriate candidates for active surveillance based on the distribution within prostate cancer risk groups. The data of 134 patients diagnosed with PCa by biopsy who underwent 68Ga-PSMA PET/CT imaging for post-diagnostic staging purposes were retrospectively analyzed. Age, total PSA, ISUP grade, prostate lesion SUVmax values, PI-RADS scores, and PRIMARY scores were recorded. Patients were classified into low-risk and intermediate/high-risk groups. In the intermediate/high-risk group, the PRIMARY score was 1-2 in 17.6% and 3-5 in 82.4% of patients. In the low-risk group, the PRIMARY score was 1-2 in 34.7% and 3-5 in 65.3% of patients. None of the patients in the low-risk group had a PRIMARY score of 5. The most frequent PRIMARY score in both groups was 4, and there was a significant difference between the average SUVmax values of the intermediate/high and low-risk groups with a PRIMARY score of 4 (p = 0.018). The sensitivity of PRIMARY scoring in detecting patients in the intermediate/high-risk group was 82.3%, the specificity was 34.6%, and the positive predictive value (PPV) was 68.6%. When a cut-off SUVmax value 5.0 was used for the PRIMARY score of 4, the sensitivity was 67.0%, the specificity was 65.3% and the PPV was 77.0%. In the ROC analysis, the area under the curve was 0.727 for PRIMARY scoring, 0.662 for PI-RADS, and 0.744 for their combined mean. The PRIMARY scoring system can complement PI-RADS scoring in mpMRI for selecting patients suitable for active surveillance. Revising the PRIMARY score 4 with an SUVmax cut-off value may increase the specificity.

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 vs lobectomy in patients with clinical stage IA non-small cell lung cancer (NSCLC) ≤2 cm. High maximum standard uptake value (SUVmax) is a known risk factor in NSCLC, yet limited data exist on whether a high SUV should preclude a sublobar resection. This study aimed to determine whether 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 ≤2 cm (2011-2020) treated with sublobar resection or lobectomy. The primary outcome was cancer-specific survival (CSS). Secondary outcomes were overall survival and disease-free survival. There were 543 patients identified; 36.8% had sublobar resection and 63.2% had lobectomy. Baseline characteristics were similar. Patients who had sublobar resection hadsignificantly worse Eastern Cooperative Oncology Group performance status and higher rates of comorbidities. The 5-year CSS, overall survival, and disease-free survival for the wholecohort were similar between sublobar resection 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 with SUVmax ≤4.15. However, there was no significant difference in 5-year CSS after sublobar resection vs lobectomy in patients with SUVmax ≤4.15 (98% in both groups; P= .77) or patients with SUVmax >4.15 (90% vs 94%, respectively; P= .12). SUVmax may not be a useful clinical determinant of the extent of parenchymal resection in patients with cT1 N0 NSCLC ≤2 cm. Patients treated by sublobar resection had comparable survival to lobectomy, irrespective of positron emission tomography avidity.

Head-to-Head Comparison of [68Ga]Ga-NOTA-RM26 and [18F]FDG PET/CT in Patients with Gastrointestinal Stromal Tumors: A Prospective Study.

Gastrointestinal stromal tumors (GISTs) are the most common stromal tumors in the gastrointestinal tract. This study was designed to evaluate a gastrin-releasing peptide receptor antagonist PET tracer, [68Ga]Ga-NOTA-RM26, and compare it with [18F]FDG PET/CT in the assessment of patients with GISTs. Methods: With institutional review board approval and informed consent, 30 patients with suspected or proven GISTs based on abdominal CT or gastroscopy were recruited. All patients underwent [68Ga]Ga-NOTA-RM26 and [18F]FDG PET/CT scans. Pathology and other patient information were collected. Results: No radiopharmaceutical-related adverse events were observed in the patients. In total, 18 lesions in 16 patients were diagnosed as GIST, 3 patients were diagnosed with schwannoma, and 4 patients were diagnosed with leiomyoma. In 18 GISTs, the mean SUVmax of [68Ga]Ga-NOTA-RM26 PET was significantly higher than that of [18F]FDG PET (17.07 ± 19.57 vs. 2.28 ± 1.65; P < 0.01), and [68Ga]Ga-NOTA-RM26 PET/CT had a higher tumor detection rate than did [18F]FDG PET/CT (88.9% vs. 50%; P < 0.01). The uptake of [68Ga]Ga-NOTA-RM26 in GISTs was significantly higher than that in 2 other benign tumors (leiomyoma or schwannoma) (17.07 ± 19.57 vs. 4.23 ± 1.77; P = 0.014). With the SUVmax cutoff value of 6.0, the sensitivity of 68Ga-NOTA-RM26 PET/CT in diagnosing GISTs is 72% and the specificity is 85.7%. Conclusion: Compared with [18F]FDG PET/CT, [68Ga]Ga-NOTA-RM26 PET/CT is a promising and effective imaging modality for the detection of GISTs.

Enhancing Prostate Cancer Staging: Association of 68Ga-PSMA PET/CT Imaging with Histopathological Grading in Treatment-Naive Patients.

This study aimed to evaluate the correlation between 68Ga-PSMA uptake in PSMA PET/CT in primary prostate cancer (PC) and its histopathological grading (Gleason score and ISUP grade). Additionally, we compared preoperative biopsy histopathological findings with definitive pathology results in radical prostatectomy (RP) specimens. We retrospectively analyzed 86 patients who underwent 68Ga-PSMA PET/CT for primary PC staging, of which 40 patients later underwent radical prostatectomy. PET/CT results, including SUVmax values, were correlated with GS and PSA concentrations. Histopathology reports were analyzed and compared between biopsy and final pathology results following RP. A significant positive correlation was observed between SUVmax and ISUP grades (Pearson's ρ = 0.34, p < 0.001), with higher SUVmax values associated with more advanced grades. A cut-off SUVmax value of 5.64 was determined to predict upstaging in patients, yielding a sensitivity of 76% and a specificity of 60% (AUC = 0.82, 95% CI: 0.70-0.94). Additionally, 57.5% of patients experienced a grade shift following RP, with a 35% upgrade and 22.5% downgrade in ISUP grades. 68Ga-PSMA PET/CT demonstrated high sensitivity in detecting high-risk prostate cancer, particularly in patients with GS > 7 or PSA levels ≥ 10 ng/mL. The findings suggest that this imaging modality may be less effective for the staging of patients with lower GS or PSA values, that is, low-risk PCa. Further prospective studies are necessary to validate these results.

Incidental Uptake in Gastrointestinal Tract on 18F-FDG-PET/CT: Is It Worth to Investigate? A Study with 371 Patients

Background and Study Aims: Positron emission tomography/computed tomography (PET/CT) with 2-[18F]FDG (FDG) has been increasingly used to detect or monitor neoplasms. Gastrointestinal tract (GIT) is one of the most common sites of FDG uptake, leading to increasing requests for endoscopic examinations. We aimed to evaluate the nature and significance of unexpected PET/CT-FDG findings in the GIT. Patients and Methods: We retrospectively analyzed 371 consecutive patients with incidental GIT findings on PET/CT-FDG between June 2016 and October 2021 who were subsequently referred to endoscopic examinations. Demographic data, PET/CT-FDG results, endoscopic findings, and histological analysis were analyzed. Results: Of 194 colonic incidental uptakes, 102 (52.6%) corresponded to at least premalignant lesions, being 57 (29.4%) advanced adenomas and 23 (11.9%) adenocarcinomas. Of 193 upper GIT incidental uptakes, there were 11 (13.8%) esophageal and 14 (14.4%) gastric malignant/premalignant lesions. The maximum standardized uptake value (SUVmax) significantly varied according to the nature of the lesion, being higher in malignant lesions (in the esophagus, stomach, and colon). However, an optimal SUVmax cutoff was only found for stomach (SUVmax 8.2; sensitivity of 79% and specificity of 76%). There was a significant association between the site of uptake and the nature of the lesion – left colon and gastric body uptake were associated with neoplastic origin whereas rectum and lower esophagus were associated with inflammatory or no endoscopic changes. Conclusions: Any incidental uptake in the lower GIT should be investigated provided that patients are suitable for further treatment. However, in the upper GIT the characteristics of uptake on 18F‐FDG‐PET/CT may allow to select those who need endoscopic examination.

Physiological biodistribution on Ga68-PSMA PET/CT and the factors effecting biodistribution

AimThe study aims to determine the physiological and pathophysiological distribution of the radiopharmaceutical (Ga68-PSMA-617) and investigate whether there are differences in distribution according to the laboratory, histopathological and clinical findings that can affect image evaluation. Also, we aimed to determine cut-off values to distinguish physiological and pathological uptake in prostate, bone, and lymph nodes.Materials and Methods229 prostate cancer patients who underwent Ga68-PSMA PET/CT at our department were retrospectively analyzed. The patients were grouped according to PET/CT results, Gleason scores, PSA values, received treatments, metastatic status and other laboratory values. The SUV values of the organs, tissues, and pathological lesions of the patients in these subgroups were compared among themselves.ResultsNo significant difference was detected in the physiological uptake of lymph nodes and bone between the groups. In the group with patients that received androgen deprivation therapy (ADT), the bone metastasis SUV values were found to be higher and the SUV values of the submandibular gland and renal cortex were found to be lower (Mann–Whitney U, p = 0.043; 0.004; 0.01, respectively). In the group with patients who received radiotherapy, the normal prostate tissue SUV values were determined to be higher (Mann–Whitney U, p = 0.009). The SUV values of the submandibular gland, muscle, liver, and blood pool were found to be lower in the group of patients with high serum LDH values. The cut-off SUVmax value was determined to be 6.945 (sensitivity 89.6%, specificity 98.1%) for primary prostate lesion; 4.72 for lymph node metastasis; 4.25 for bone metastasis. The serum PSA cut-off value to distinguish the negative/positive groups was found to be 1,505 (sensitivity 79.7%, specificity 77.3%).ConclusionIn conclusion, PSMA-617 demonstrates a similar biodistribution with other PSMA ligands. The physiological uptake of lymph nodes and bone which are mostly metastasized in prostate cancer, are not affected by the factors we examined. It should be kept in mind that the normal prostate tissue uptake may increase in patients receiving radiotherapy, and the physiological/pathological uptake of the organs may differ due to the changes in PSMA expression in patients receiving ADT, tumor burden, and kidney function may affect the biodistribution.

Retrospective analysis of thyroid incidentalomas detected by [68Ga]Ga-PSMA-11 PET/CT.

Prostate cancer patients, undergo imaging procedures, with [68Ga]Ga-PSMA-11 PET/CT (prostate-specific membrane antigen based positron emission tomography/computed tomography) utilized for primary and secondary staging. PSMA thyroid incidentalomas (PTI) are discovered in the thyroid gland while imaging prostate cancer patients with [68Ga]Ga-PSMA-11 PET/CT. The aim of the study was to determine the clinical significance of PTIs detected on [68Ga]Ga-PSMA-11 PET/CT. Another goal was to identify a possible threshold for the maximum standardized uptake value (SUVmax), above which a malignant growth could be suspected. A retrospective cross-sectional study. 769 patients with prostat cancer who underwent [68Ga]Ga-PSMA-11 PET/CT scans in the nuclear medicine department of a tertiary care hospital between January 2020 and December 2022 were retrospectively screened in this study. We analyzed 67 patients in whom PTI was detected. Patients who exceeded the inclusion criteria had their thyroid ultrasonography and ultrasonography -guided fine needle aspiration findings analyzed. PTI was discovered in 67 patients (8%). 42 patients who met the inclusion and exclusion criteria were included in the study. Of the 4 malignant patients (9.5%) in the study population, 2 were classified as TIRADS 3 and 2 were classified as TIRADS 4. The cut-off SUVmax value was found to be 5.6. With 100% sensitivity and 47.37% specificity, a cutoff SUVmax of 5.3 was determined through receiver-operator characteristic analysis in order to predict malignant cytology. PTI is a significant clinical finding; most of diffuse and focal uptakes are frequently related to benign diseases. Each center should establish its own a possible SUVmax cut-off over which a malignant lesion should be suspected.

The Role of 68 Ga PSMA Imaging in Evaluating Adrenal Lesions in Prostate Cancer Patients.

Objectives Gallium-68 prostate-specific membrane antigen ( 68 Ga-PSMA) imaging is valuable for staging because an accurate diagnosis, metastatic or nonmetastatic for prostate cancer patients, is required for deciding to treatment approaches and prognostic assessment. The aim of this study was primarily to distinguish between benign and metastatic adrenal gland lesions detected during 68 Ga-PSMA positron emission tomography (PET)/CT imaging, to evaluate the presence of factors predicting its development, and then to determine the life expectancy of patients with metastatic adrenal lesions. Materials and Methods We performed a database search for PET/CT records generated from June 2016 to February 2021 for "adrenal gland" in report for patients who underwent 68 Ga-PSMA examination with prostate cancer patients. Results Twenty-three patients (10 benign and 13 metastatic) were included in this study. The total prostate-specific antigen, adrenal gland size, adrenal gland density, and maximum standardized uptake (SUVmax) values are significantly different between groups ( p < 0.05). On receiver operating characteristic curve analysis, the SUVmax cutoff value > 6.8 provided both sensitivity and specificity of 100%. However, with 29 mm as the adrenal gland size cutoff and 21.2 as Hounsfield unit, the sensitivity and specificity were 56.2 and 92.3%, and 93.8 and 92.3%, respectively. The survival of the benign and metastatic groups was compared and a statistically significant difference was found ( p = 0.006). The presence of pelvic lymph nodes was statistically negatively affected the surveillance between the groups. Conclusion The presence of atypical metastases such as adrenal gland is not insignificant in prostate cancer patients. Because of this degree of impact on patient management, accurate staging by imaging with 68 Ga-PSMA should be an integral part of prostate cancer management.

The Monocle Sign on 18 F-FDG PET Indicates Contralateral Peripheral Facial Nerve Palsy.

The aim of our study was to retrospectively analyze FDG PET/CT data in patients with facial nerve palsy (FNP) for the presence of the monocle sign. A total of 85 patients with unilateral FNP were included into our study, thereof 73 with peripheral FNP and 12 with central FNP. FDG uptake (SUV max , SUV mean , total lesion glycolysis) was measured in both orbicularis oculi muscles (OOMs). FDG uptake of paretic and nonparetic muscles was compared in patients with FNP (Wilcoxon test and Mann-Whitney U test) and was also compared with FDG uptake in 33 patients without FNP (Mann-Whitney U test). SUV max ratios of OOM were compared. A receiver operating characteristic curve and Youden Index were used to determine the optimal cutoff SUV max ratio for the prevalence of contralateral peripheral FNP. The SUV max ratio of OOM was significantly higher in patients with peripheral FNP compared with patients with central FNP and those without FNP (1.70 ± 0.94 vs 1.16 ± 0.09 vs 1.18 ± 0.21, respectively; P < 0.001). The SUV max ratio of OOM yielded an area under the curve (AUC) of 0.719 (95% confidence interval, 0.630-0.809), with an optimal cutoff of 1.41, yielding a specificity of 94.4% and a sensitivity of 44.1% for identifying contralateral peripheral FNP. One hundred percent specificity is achieved using a cutoff of 1.91 (sensitivity, 29.4%). Asymmetrically increased FDG uptake of the OOM (the "monocle sign") indicates contralateral peripheral FNP. A nearly 2-fold higher SUV max represents a practically useful cutoff.

Optimal [18F]FDG PET/CT Cutoff for Pathologic Complete Response in HER2-Positive Early Breast Cancer Patients Treated with Neoadjuvant Trastuzumab and Pertuzumab in the PHERGain Trial.

The PHERGain trial investigated the potential of metabolic imaging to identify candidates for chemotherapy deescalation in human epidermal growth factor receptor 2 (HER2)-positive, invasive, operable breast cancer with at least 1 breast lesion evaluable by [18F]FDG PET/CT. [18F]FDG PET/CT responders were defined as patients with an SUVmax reduction (ΔSUVmax) of at least 40% in all of their target lesions after 2 cycles of trastuzumab and pertuzumab (HP) (with or without endocrine therapy). In total, 227 of 285 patients (80%) included in the HP arm showed a predefined metabolic response and received a total of 8 cycles of HP (with or without endocrine therapy). Pathologic complete response (pCR), defined as ypT0/isN0, was achieved in 37.9% of the patients. Here, we describe the secondary preplanned analysis of the best cutoff of ΔSUVmax for pCR prediction. Methods: Receiver-operating-characteristic analysis was applied to look for the most appropriate ΔSUVmax cutoff in HER2-positive early breast cancer patients treated exclusively with neoadjuvant HP (with or without endocrine therapy). Results: The ΔSUVmax capability of predicting pCR in terms of the area under the receiver-operating-characteristic curve was 72.1% (95% CI, 65.1-79.2%). The optimal ΔSUVmax cutoff was found to be 77.0%, with a 51.2% sensitivity and a 78.7% specificity. With this cutoff, 74 of 285 patients (26%) would be classified as metabolic responders, increasing the pCR rate from 37.9% (cutoff ≥ 40%) to 59.5% (44/74 patients) (P < 0.01). With this optimized cutoff, 44 of 285 patients (15.4%) would avoid chemotherapy in either the neoadjuvant or the adjuvant setting compared with 86 of 285 patients (30.2%) using the original cutoff (P < 0.001). Conclusion: In the PHERGain trial, an increased SUVmax cutoff (≥77%) after 2 cycles of exclusive HP (with or without endocrine therapy) achieves a pCR in the range of the control arm with chemotherapy plus HP (59.5% vs. 57.7%, respectively), further identifying a subgroup of patients with HER2-addicted tumors. However, the original cutoff (≥40%) maximizes the number of patients who could avoid chemotherapy.

Molecular insights and the role of 18F-FDG-PET/CT in the diagnosis of spinal gliomas.

In recent years, molecular findings on spinal gliomas have become increasingly important. This study aimed to investigate the role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in the diagnosis of spinal glioma. This study included patients diagnosed with spinal cord glioma who underwent 18F-FDG-PET examination at the Department of Neurosurgery, Nagoya University Hospital between January 2016 and November 2023. The gliomas were divided into two groups, high-grade and low-grade, based on pathological and molecular studies. The maximum standardized uptake values (SUVmax) of the tumors were quantified and subsequently represented using receiver operating characteristic (ROC) curves. Eighteen participants were included in this study. Of the participants, seven had high-grade glioma with an SUVmax of 6.76 ± 0.72, and eleven had low-grade glioma with an SUVmax of 4.02 ± 1.78, and a statistically significant difference between the two groups. The ROC curve delineated an SUVmax cutoff value of 5.650, with an area under the curve (AUC) of approximately 0.909. Based on the cutoff value, the results of the diagnostic performance rendered a sensitivity and negative predictive value of 1.0, whereas the specificity and positive predictive value were 0.909 and 0.875, respectively. The present study shows that 18F-FDG-PET exhibits a markedly sensitive and negative predictive value in the assessment of spinal gliomas. Additionally, these findings have potential implications for the qualitative assessment of spinal gliomas using 18F-FDG-PET/CT. This imaging modality may be useful for making timely treatment decisions in situations where a detailed diagnosis by molecular analysis is not possible.

Radiologic Parameters Predicting the Histologic Invasiveness of Pure Ground-Glass Nodules

BackgroundThis study aimed to investigate the diagnostic performance of combined computed tomography (CT) and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for predicting histologic invasiveness of pure ground-glass nodules (pGGNs). MethodsThe study analyzed 91 patients who underwent resection of pGGNs and examined the correlation of pathologic invasiveness with preoperative CT and FDG PET findings. ResultsOverall, 24, 36, and 31 patients had adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAD), respectively. Compared with AIS and MIA, IAD was significantly correlated with larger CT size (P = .001), maximum CT value (P = .026), and high maximum standardized uptake value (SUVmax; P < .001). Multivariable logistic analyses revealed that CT size (odds ratio [OR], 3.848; P = .019) and SUVmax (OR, 4.968; P = .009) were independent predictors of histologic invasiveness. Receiver operating characteristic curve analysis revealed that a cutoff CT size value of 18 mm predicted histologic invasiveness with a sensitivity and specificity of 65% and 80%, respectively; similarly, a cutoff SUVmax value of 1.5 predicted histologic invasiveness with a sensitivity and specificity of 61% and 90%, respectively. Of 20 lesions with CT size ≥18 mm and SUVmax ≥1.5, 16 (80%) were IAD. Of 54 lesions with CT size <18 mm and SUVmax <1.5, 46 (85%) were non-IAD lesions. Furthermore, all pGGNs with SUVmax ≥2.5 were IAD. ConclusionsCT size and SUVmax were significantly correlated with the histologic invasiveness of pGGNs. These factors may aid in determining optimal surgical procedures.

18F-FAPI PET/CT performs better in evaluating mediastinal and hilar lymph nodes in patients with lung cancer: comparison with 18F-FDG PET/CT

BackgroundThe aim of this study was to evaluate the efficacy of fluorine 18 (18F) labeled fibroblast activation protein inhibitor (FAPI) in identifying mediastinal and hilar lymph node metastases and to develop a model to quantitatively and repeatedly identify lymph node status.MethodsTwenty-seven patients with 137 lymph nodes were identified by two PET/CT images. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of lymph node status were analyzed, and the optimal cut-off value was identified by ROC analysis.ResultsThe SUVmax of metastatic lymph nodes on 18F-FAPI was higher than that on 18F-FDG PET/CT (10.87 ± 7.29 vs 6.08 ± 5.37, p < 0.001). 18F-FAPI presented much greater lymph node detection sensitivity, specificity, accuracy, PPV and NPV than 18F-FDG PET/CT (84% vs. 71%; 92% vs. 67%; 90% vs. 69%, 84% vs. 52%, and 92% vs. 83%, respectively). Additionally, the diagnostic effectiveness of 18F-FAPI in small lymph nodes was greater than that of 18F-FDG PET/CT (specificity: 96% vs. 72%; accuracy: 93% vs. 73%; PPV: 77% vs. 33%, respectively). Notably, the optimal cut-off value for specificity and PPV of 18F-FAPI SUVmax was 5.3; the optimal cut-off value for sensitivity and NPV was 2.5.Conclusion18F-FAPI showed promising diagnostic efficacy in metastatic mediastinal and hilar lymph nodes from lung cancer patients, with a higher SUVmax, especially in small metastatic nodes, compared with 18F-FDG. In addition, this exploratory work recommended optimal SUVmax cutoff values to distinguish between nonmetastatic and metastatic lymph nodes, thereby advancing the development of image-guided radiation.Trial registration ClinicalTrials.gov identifier: ChiCTR2000036091.

The diagnostic value of quantitative bone SPECT/CT in solitary undetermined bone lesions.

To investigate the diagnostic value of the maximum standard uptake value (SUVmax) of quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) in solitary undetermined bone lesions. In Part I, retrospective study, 167 untreated patients with extra-skeletal malignant tumors by pathology were consecutively enrolled for staging with Tc-99m methyl-diphosphonate (99mTc-MDP) whole-body bone scan (WBS) and quantitative SPECT/CT, and a total of 396 bone lesions with abnormal radioactivity concentration in 167 patients were included from April 2019 to September 2020. The differences in SUVmax among the benign bone lesions, malignant bone lesions, and normal vertebrae were analyzed. The receiver operating characteristic (ROC) curve and cutoff value of SUVmax were obtained. Part II, prospective study, 49 solitary undetermined bone lesions in SPECT/CT in 49 untreated patients with extra-skeletal malignant tumors were enrolled from October 2020 to August 2022. The diagnostic efficacy of SUVmax in solitary undetermined bone lesions was assessed. The final diagnosis was based on follow-up imaging (CT, MRI, or 2-deoxy-2-[18F]fluoro-D-glucose-positron emission tomography/computed tomography) for at least 12 months. In Part I, a total of 156 malignant and 240 benign bone lesions was determined; the SUVmax of malignant lesions (26.49 ± 12.63) was significantly higher than those of benign lesions (13.92 ± 7.16) and normal vertebrae (6.97 ± 1.52) (P = 0.00). The diagnostic efficiency of the SUVmax of quantitative SPECT/CT revealed a sensitivity of 75.00% and a specificity of 81.70% at a cutoff value of 18.07. In Part II, 17 malignant and 32 benign lesions were determined. Using SUVmax ≥18.07 as a diagnostic criterion of malignancy, it has a sensitivity of 82.35%, a specificity of 93.75%, and an accuracy of 89.80%. The SUVmax of quantitative SPECT/CT is valuable in evaluating solitary undetermined bone lesions. Using a cutoff SUVmax value of 18.07, quantitative SPECT/CT demonstrated high sensitivity, specificity, and accuracy in differentiating malignant from benign bone lesions.