Hellenic journal of nuclear medicine最新文献

Objective: To explore the potential of intratumoral metabolism and its heterogeneous parameters, as measured by preoperative fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) imaging, to predict mediastinal occult lymph node metastasis in cN0 lung invasive adenocarcinoma.

Subjects and methods: Seventy five patients were consecutively enrolled from January 2018 to December 2022. All patients underwent ¹⁸F-FDG PET/CT scans within two weeks before surgery, and had mediastinal lymph node metastasis confirmed by pathologic diagnosis after surgery. Metabolic parameters including the maximum standardized uptake value (SUVmax), mean SUV (SUVmean), maximum average SUV (SUVpeak), tumor metabolic volume (MTV), and metabolic heterogeneity (HF) were measured. The relationship between primary focal metabolism, its heterogeneity parameters, and occult mediastinal lymph node metastasis was analyzed using an independent-sample t-test, analysis of covariance, and Mann-Whitney U test. A multivariate logistic regression model was used to analyze independent risk factors for mediastinal lymph node metastasis, while the receiver operating characteristic (ROC) curve assessed the predictive value of metabolic heterogeneity parameters for mediastinal occult lymph node metastasis.

Results: A total of 20 out of 75 patients (26.7%) were pathologically confirmed to have mediastinal lymph node metastasis. Analysis of covariance showed that the SUVmax, SUVmean, SUVpeak and MTV were significantly higher in patients with metastasis than in those without (all P<0.05). The metabolic heterogeneity parameters HF2 and HF3 were significantly higher in patients with mediastinal lymph node metastasis than in those without (P=0.013, 0.001), but not HF1. Multivariate Logistic regression analysis identified that tumor size, SUVmax, SUVpeak, lymph node SUVmax, and HF2 of the primary tumor as independent risk factors for mediastinal lymph node metastasis. Metabolic heterogeneity 3 demonstrated high predictive value for mediastinal occult lymph node metastasis (AUC=0.720, P=0.004).

Conclusion: Metabolism and heterogeneity, as measured by preoperative ¹⁸F-FDG PET/CT in lung invasive adenocarcinoma, potentially have clinical value for predicting mediastinal occult lymph node metastasis.

Objective: Numerous studies have shown that gallium-68-labeled fibroblast activation protein inhibitor (⁶⁸Ga-FAPI) positron emission tomography/computed tomography (PET/CT) scans would yield high intra-tumoral tracer uptake and low uptake in normal tissues as background, thus allowing for excellent visualization of lesions in the cancer microenvironment. This study set out to compare the suitability of novel ⁶⁸Ga-FAPI-46 PET versus routine fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET and other few cases of ⁶⁸Ga-DOTATATE/⁶⁸Ga-Pentixafor PET/CT for the assessment of different types of cancer.

Subjects and methods: A retrospective analysis of 11 patients (6 males, 5 females; average age: 53 years, range: 10-58 years) with histopathologically confirmed, well-differentiated adenocarcinoma, medullar thyroid cancer (MTC), papillary thyroid carcinoma (PTC), cervical, gastric, glioblastoma multiform (GBM), colon, Ewing's sarcoma, and breast cancer was performed. These patients underwent PET/CT scans using four different radiotracers (9 ¹⁸F-FDG, 11 ⁶⁸Ga- FAPI, 3 ⁶⁸Ga-DOTATATE, and 1 ⁶⁸Ga-Pentixafor). The patients' PET/CT images were visually evaluated for cancer detection, and analyzed semi-quantitatively through image- derived metrics, such as target-to-background ratio (TBR) and maximum standardized uptake value (SUVmax), for recurrence and metastasis.

Results: The study of 11 patients revealed that ⁶⁸Ga-FAPI-46 was more effective than other tracers for detecting metastases, with 55 vs. 49 metastases in the lymph nodes, 4 vs. 3 in the liver, and 4 vs. 3 in the bones detected in comparison to ¹⁸F-FDG. No significant differences were observed in ⁶⁸Ga-DOTATATE and ⁶⁸Ga-Pentixafor PET images. In addition, in five patients, the SUVmax and TBR values in ⁶⁸Ga-FAPI-46 PET images were significantly higher than those in ¹⁸F-FDG PET images for lymph nodes and bone metastases. Although the SUVmax in ⁶⁸Ga-FAPI-46 and ¹⁸F-FDG PET images for liver metastases was comparable, ⁶⁸Ga-FAPI- 46 had a significantly higher TBR than ¹⁸F-FDG.

Conclusion: Our findings suggest that FAPI PET/CT is not suitable for evaluating GBM and Ewing sarcoma but generally outperforms ¹⁸F-FDG PET/CT in various types of breast cancer, gastrointestinal, gynecological, PTC and MTC. However, larger trials are needed to validate these preliminary findings.

Tuberculosis continues to be a significant global health concern, impacting various parts of the body aside from the lungs. Muscular tuberculosis (MT), while rare, poses diagnostic hurdles due to its nonspecific imaging features. Presenting a case of a 66-year-old man with multiple MT lesions, we underscore the vital contribution of positron emission tomography/computed tomography (PET/CT) in both diagnosis and treatment assessment. Fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET/CT imaging revealed hypermetabolism in bilateral chest and back muscles, facilitating accurate diagnosis and monitoring treatment response. This highlights the pivotal role of ¹⁸F-FDG PET/CT in managing MT, especially in cases with multiple lesions.

Objective: This study was carried out to understand whether Q.Clear and ordered subset expectation maximization (OSEM), reconstruction algorithms used in fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) applications, and parameters such as time of flight (TOF) and point spread function (PSF) cause different results in semi-quantitative measurements.

Subjects and methods: Raw PET data of 264 patients who were referred to ¹⁸F-FDG PET/CT imaging with the purpose of evaluation of known or suspicious malignant disease were reconstructed separately with Q.Clear (GE Healthcare), a BPL, an OSEM algorithm, PSF (SharpIR®) and TOF (VUE Point FX®) methods. Each patient's liver, mediastinal blood pool, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and standardized uptake values (SUV) (SUVmax, SUVmean, and SUVpeak) of a total of 264 lesions selected from the patients were performed.

Results: β350+ToF yielded higher measurement results than all other variables for all of the lesion SUVmax, lesion SUVmean, L/AP SUVmax, and L/AP SUVmean parameters. OSEM+ToF and OSEM+TOF+PSF algorithms yielded higher mean and median SUVmax values for the reference structures (liver and mediastinum) and for lesions SUVmax and SUVmean values were statistically significantly lower than the β350+ToF method. The method with the lowest mean value for the L/Liver SUVmax variable was OSEM+ToF 4iter16ss (mean=1.76), while the method with the highest mean value was β350+ToF (mean=2.26). β350+ToF was the reconstruction method with the highest ratios for L/AP SUVmax and SUVmean for both lesions below and above 1 cm. β350+ToF algorithm had also statistically significantly higher results for these variables compared to all other parameters in malignant lesions.

Conclusion: When comparing ¹⁸F-FDG PET/CT images, the use of different reconstruction algorithms may lead to misleading results, especially in the evaluation of response to treatment of malignancies.

Objective: To analyze the diagnostic value of computed tomography (CT) radiomics models in differentiating gastrointestinal stromal tumors (GIST) and other mesenchymal tumors.

Material and methods: A retrospective analysis of clinical data from 153 patients with pathologically confirmed gastrointestinal mesenchymal tumors treated in our hospital from July 2019 to March 2024 was conducted, including 107 cases of GIST, 18 cases of leiomyoma, and 28 cases of schwannoma. LASSO regression was used for feature selection. Logistic regression and Random Forest (RF) models were established based on selected features using machine learning algorithms, with the dataset divided into training (107 cases) and validation sets (46 cases) at a 7:3 ratio. The diagnostic performance of the models was evaluated using receiver operating characteristic (ROC) curves.

Results: In the training set, there were significant differences between GIST and non-GIST in terms of enhancement degree, age, maximum diameter, and tumor location distribution (P<0.05). A total of 180 radiomics features were extracted using A.K software. LASSO regression reduced the high-dimensional data to 13 radiomics features. Logistic regression and RF models were established based on these 13 features. The AUC for the Logistic regression model was 0.753 in the training set and 0.582 in the validation set, while the AUC for the RF model was 0.941 in the training set and 0.746 in the validation set. The RF model showed higher diagnostic performance than the Logistic regression model (P<0.05). Decision curve analysis showed that the net benefit of the RF model in differentiating GIST was superior to classifying all patients as either GIST or non-GIST and also superior to the Logistic regression model within a probability threshold range of 20%-90%.

Conclusion: The machine learning models based on radiomics features have good diagnostic value in predicting the pathological classification of GIST and other mesenchymal tumors, with the RF model showing superior diagnostic value compared to the Logistic regression model.

Objective: Thyroid cancer (TC) is the most common endocrine malignancy with constantly growing incidence. Radioiodine ablation is a safe and effective method for managing TC. Recently various Guidelines (GL) have been published on whom should be ablated, when and under which circumstances. Our study compares 6 GL with a given patient cohort. Additionally, we evaluated each GL's quality via an independent tool.

Material and methods: We compared six Guidelines (GL) for TC ablation on a cohort of 336 patients, implementing GL retrospectively: 2009 and 2016 American Thyroid Association (ATA), European Thyroid Association's (ETA) Consensus Statement, UK's National Institute for Health and Care Excellence (NICE), German position paper from Surgery and Nuclear Medicine (German) and European Association of Nuclear Medicine and Society of Nuclear Medicine and Molecular Image (EANM/SNMMI). Quality assessment was conducted using the Appraisal of Guidelines, Research and Evaluation instrument II (AGREE II).

Results: Results showed significant variability among GL. American Thyroid Association 2016, a clear improvement of the ATA 2009, presents a large grey area of "probable ablation candidates". European Thyroid Association and NICE agree that only a small portion of our ablated patients would benefit from it and the AGREE II tool shows a lack of applicability, but very good scores elsewhere. German and EANM/SNMMI GL agree that most of our clinical decisions to ablate were correct and their AGREE II scores are the highest in all six domains.

Conclusion: Considering that dynamic risk classification plays a major role in determining the most appropriate treatment, it appears that the guidelines should be updated in order to support individualized patient management. However, it is the experience of the individual physician that will determine the final decision.

NK/T cell lymphoma in the sacroiliac joint is very rare. We reportfluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) findings of NK/T cell lymphoma in the sacroiliac joint in a 48-year-old man. On ¹⁸F-FDG PET/CT image, it manifested a soft tissue mass with adjacent bone destruction in the sacroiliac joint, which had intense ¹⁸F-FDG uptake. The final pathology supported a diagnosis of NK/T cell lymphoma. Our case added the knowledge of another rare site of NK/T cell lymphoma, which should be regarded as a differential diagnosis for sacroiliac joint mass with intense ¹⁸F-FDG uptake.

Objective: Recent studies have utilized fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) specifically to diagnose cases of idiopathic inflammatory myopathies (IIM), excluding inclusion body myositis (IBM). Conversely, carbon-11 (¹¹C) labeled Pittsburgh compound B (PIB)-PET imaging is exclusively used for the detection of IBM. This research is designed to evaluate the diagnostic accuracy of PET/CT in identifying IIM by employing rigorous diagnostic accuracy testing methodologies.

Materials and methods: A systematic review and meta-analysis were conducted across multiple databases including PubMed, and Embase. We focused on the diagnostic utility of PET/CT in IIM, assessing sensitivities, specificities, and deriving likelihood ratios (LR+ and LR-). The study was registered with PROSPERO (CRD42022343222).

Results: This systematic review identified 635 citations, of which 10 eligible trials were included, with a total of 419 participants. The results indicated a sensitivity of 0.86 (0.81-0.90), and a specificity of 0.93 (0.88-0.96). The synthesis of LR revealed the LR+ of 10.35 (6.31-16.98), and LR-of 0.15 (0.07-0.32). The summary receiver operating characteristic curve (SROC) showed an area under the curve (AUC) of 0.9658. Regarding IBM, the sensitivity was 0.84 (0.60-0.97), and the specificity was 1 (0.69-1). The synthesis of LR showed the LR+ of 9.61 (1.46-63.15) and an LR- of 0.21 (0.09-0.51). For disease activity, the sensitivity was 0.96 (0.92-0.99), and the specificity was 0.91 (0.084-0.96). The synthesis of LR showed an LR+ of 9.43 (5.39-16.51) and an LR- of 0.05 (0.02-0.11).

Conclusion: Positron emission tomography/CT has great potential for accurately diagnosing and monitoring patients with IIM, and may have implications for their clinical management.

Objective: To investigate the positron emission tomography/computed tomography (PET/CT) findings of T1/T2N0M0 glottic cancer (hereafter referred to as T1/T2) and dose distribution in radiotherapy.

Subjects and methods: We retrospectively collected data from patients diagnosed with T1/T2N0M0 glottic cancer who received radiotherapy. The extent of fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) accumulation in primary tumors, maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), tumor volume of primary tumors on PET/CT were compared. Furthermore, the tumor identified on PET/CT was incorporated into the radiotherapy plans. A dummy plan (radiation field 6x6cm, prescription point facing the vertebral body, maximum dose ≤107%, T1/T2 66Gy/33 fractions) was developed for three-dimensional conformal radiotherapy, and the dose distribution of primary tumors was calculated.

Results: Twenty-nine patients (27 men and two women) were included; their mean age was 67.2±15.0 years. Increased ¹⁸F-FDG accumulation in primary tumors was observed on PET/CT in 22/29 (78.5%; T1: 14/21 [67%], T2: 8/8 [100%]) patients. The median SUVmax, TLG, and primary tumor volume were significantly different between T1 and T2 (SUVmax, T1: 4.56 vs. T2: 8.43, P=0.035; TLG, T1: 1.01 vs. T2: 3.71 SUVxmL, P<0.01; primary tumor volume, T1: 0.38mL vs. T2: 0.80mL, P=0.01). At a TLG cut-off value of 3.470, the area under the curve was 0.875, sensitivity was 0.875, and specificity was 0.929 for T1-T2 differentiation. In 20 patients with ¹⁸F-FDG accumulation, the minimum radiation dose was significantly different between T1 and T2 (66Gy vs. 64Gy, P<0.01) at the same 66Gy prescription. The minimum radiation dose and primary tumor volume show the correlation value (r=-0.516, P=0.02).

Conclusion: In glottic cancer, T1 and T2 can be differentiated by the extent of ¹⁸F-FDG accumulation in primary tumors on PET/CT. The minimum radiation dose rate decreases as volume increases.

Objective: We aimed to evaluate the efficacy oflutetium-177-prostate-specific membrane antigen-617 (¹⁷⁷Lu-PSMA-617) with the luteinizing hormone releasing hormone (LHRH) analogues in the first or in the second-line setting formetastatic castration sensitive patients and metastatic castration resistance after progression with LHRH analogues.

Subjects and methods: Sixteen consecutive patients with high volume metastatic prostate cancer undergone ¹⁷⁷Lu-PSMA-617 therapy who were refused chemotherapy and were unable to use new generation anti-androgen drugs because of unavailibility of reimbursement, were included in this retrospective study. Prostate specific antigen (PSA) response (>50% decrease), disease control rate (DCR: complete or partial response), progression-free survival (PFS) and overall survival (OS) were calculated to evaluate according to the clinicopathological features of the patients. Treatment response evaluated by ⁶⁸Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT).

Results: Mean age was 74,6 (SD±8,36). Among them, 7 (43,8%) patients has castration resistant disease, while the remaining has castration sensitive disease. Lutetium-177-PSMA-617 was administered to 10 (62,5%) patients as one of the first-line treatment and 6 patients received the treatment after progression on LHRH as a second-line treatment. Considering all patients, PSA response rate and DCR were 50% and 62% respectively. The median PFS and OS (with 95% CI) were 11,2 months (11-15) and 29 months (25,6-32,4), respectively in patients treated with ¹⁷⁷Lu-PSMA-617 and LHRH analogues. Clinicopathological features and basal PSA level did not have effect on PSA response rates, DCR, OS and PFS. On the other hand, increment in PFS and OS (with 95% CI) was observed in castration resistant disease and in the second-line therapy; for castration resistant disease 16,5 months (12.3-19.7); 30 months (25.3-32.7), for the second-line therapy 14.5 months (12-20.5); 29 months (NR), respectively but statistically not significant. Serious toxicity was observed in a limited number of patients (18,7%), treatment-related death was not observed.

Conclusion: Favorable results can be achived with second-line ¹⁷⁷Lu-PSMA-617 treatment in terms of OS and PFS, especially in castration-resistant disease, when chemotherapy and new generation ADT's cannot be used.