Hellenic journal of nuclear medicine最新文献

Objective: To analyze the application value of standardized uptake value (SUV) in quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) based on the maximum expectation reconstruction algorithm for diagnosing benign and malignant bone lesions.

Subjects and methods: A retrospective analysis was conducted on the clinical data of 83 patients suspected of bone metastasis who underwent quantitative SPECT/CT bone scans in our hospital from September 2023 to July 2024. A total of 91 high-metabolic bone lesions were outlined for SUV measurement, while the spinal SUV of patients with normal bone metabolism were outlined as the control group (46 vertebral bodies). The maximum SUV (SUVmax), mean SUV (SUVmean), and minimum SUV (SUVmin) of benign lesions (benign group), malignant lesions (malignant group), and the control group were measured and compared. Receiver operating characteristic (ROC) curves were plotted to analyze the diagnostic value of SUV in differentiating benign and malignant bone lesions using quantitative SPECT/CT.

Results: Based on the final diagnosis determined by pathology and/or imaging follow-up for 6-12 months or more, 50 malignant bone lesions and 41 benign bone lesions were identified. The levels of SUVmax, SUVmean, and SUVmin in the malignant and benign groups were higher than those in the control group, with the malignant group showing higher levels than the benign group (P<0.05). Receiver operating characteristic curve analysis showed that the areas under the curves for SUVmax, SUVmean, and SUVmin were 0.867, 0.909, and 0.896, respectively. The optimal cut-off value for SUVmax was 26.58g/mL, with a specificity of 100% and a sensitivity of 65.27%; for SUVmean, the optimal cutoff value was 12.75g/mL, with a sensitivity of 78.36% and a specificity of 93.54%; for SUVmin, the optimal cut-off value was 9.13g/mL, with a sensitivity and specificity of 81.42% and 89.87%, respectively. The diagnostic detection rate of quantitative SPECT/CT fusion imaging combined with SUVmean analysis (91.21%) was higher than that of conventional SPECT/CT fusion imaging qualitative analysis (74.73%) (P<0.05).

Conclusion: Standardized uptake value in quantitative SPECT/CT to some extent supplements the qualitative analysis of tumor bone metastasis and benign bone lesions, offering a higher accuracy in diagnosing tumor bone metastasis and differentiating between benign and malignant lesions compared to conventional SPECT/CT bone fusion imaging.

Objective: This study compares volume-based metabolic parameters in early-stage invasive ductal breast cancer using different standardized uptake value (SUV) thresholds and examines their association with immunohistochemical factors.

Subjects and methods: A retrospective analysis included 135 patients with early-stage invasive ductal breast cancer who underwent preoperative fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) scans. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were derived using absolute SUV threshold methods and fixed % maximum tumor SUV threshold methods. Associations with immunohistochemical factors were explored, and receiver operating characteristic curves were generated.

Results: Metabolic tumor volume 2.5 and TLG 2.5 showed stronger correlations with maximum tumor SUV values. Metabolic tumor volume 2.0 and TLG 2.0 had superior area under the curve (AUC) values in predicting estrogen and progesterone receptor negativity. Metabolic tumor volume 2.0 and TLG 2.0 were superior in distinguishing low and high-grade tumors.

Conclusion: Absolute SUV threshold methods with a threshold of 2.0 are recommended for calculating volume-based metabolic parameters due to their strong correlation with immunohistochemical factors in invasive ductal breast cancer.

Fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) is a multimodal imaging technique that combines PET and CT, utilizing FAP inhibitors as radiotracers. Fibroblast activation protein, a serine protease highly expressed in many epithelial tumor-associated fibroblasts, plays a crucial role in tumor stroma formation and remodeling. Through the detection of FAP expression, FAPI PET/CT facilitates the diagnosis and staging of both benign and malignant pulmonary tumors. In contrast to traditional fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET/CT focusing on glucose metabolism, FAPI PET/CT offers benefits such as enhanced specificity, reduced background noise, accelerated imaging speed, and decreased radiation exposure. This review provides an overview of the progress in applying FAPI PET/CT and ¹⁸F-FDG PET/CT in pulmonary malignancies and discusses current challenges and future prospects.

Objective: Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) are complementary in staging of nasopharyngeal carcinoma (NPC). The combination of MRI and functional imaging from PET in PET/MR is promising in NPC management. Diagnostic performance of PET/CT and PET/MR was compared in 46 patients with histologically confirmed NPC under different disease scenarios, including primary non-metastatic cases, primary metastatic cases, recurrence and/or metastasis after treatment, and post-treatment follow-up cases.

Subjects and methods: Forty-six patients underwent both PET/CT and PET/MR in the same day. Primary tumor extension into risk-stratified anatomic structures, retropharyngeal and cervical lymph node metastasis, distant metastasis and post-treatment follow-up results, were compared.

Results: For high-risk structures, PET/MR detected two more sides of tensor/levator veli palatine muscle involvement, one more case of clivus involvement, and ruled out 12 false-positive sides of prevertebral muscle involvement by PET/CT. For medium-risk structures, PET/MR detected four more sides of medial pterygoid muscle involvement. For low-risk structures, abnormal signal on massa lateralis atlantis was detected by PET/MR. PET/MR detected 14 more positive retropharyngeal lymph nodes and more liver micrometastases than PET/CT. Overall, PET/MR changed two patients' T staging.

Conclusion: Positron emission tomography/MR outperforms PET/CT in delineating muscle, skull-base bone, and nodal involvement, and identifying liver micrometastases, may serve as a single-step staging modality for NPC.

Objective: Cryptococcus, a genus of fungi, primarily includes Cryptococcus neoformans and Cryptococcus gattii, both known to cause human infections. Skeletal infections are rare, and there have been no reported cases of bone cryptococcal infection in conjunction with differentiated thyroid carcinoma.

Subject and methods: A 56-year-old female presented with a one-month history of "cough and throat irritation." Chest CT revealed scattered small nodules in both lungs,suggestive of metastasis.There was minimal inflammation in both lungs, and scattered lymph nodes were observed in the mediastinum and upper pulmonary hilum.

Results: The patient was diagnosed with differentiated thyroid carcinoma complicated by cryptococcal infection. Antifungal treatment with itraconazole 200mg/day was initiated, and after 3 months, clinical symptoms disappeared, with a reduction in lung nodules observed in follow-up chest CT.

Conclusion: When diagnosing distant metastasis in differentiated thyroid carcinoma, a comprehensive analysis combining imaging studies and serum thyroid globulin plays a complementary role, as illustrated in this case of differentiated thyroid carcinoma concurrent with cryptococcal infection.

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: This paper reviews the current status and future development of positron emission tomography/magnetic resonance (PET/MR) co-imaging technology in the field of cardiovascular diseases.

Material and methods: By combining PET and MRI, PET/MR co-imaging provides comprehensive assessment advantages by simultaneously offering functional and anatomical information.

Results: Firstly, the basic principles of PET/MR are introduced, and the current state is discussed. Subsequently, a detailed discussion on the application of PET/MR in the diagnosis of cardiovascular diseases, including early detection and comprehensive assessment of conditions like coronary artery disease and myocarditis, is presented. Finally, the challenges and future prospects in PET/MR applications are outlined.

Conclusion: Despite facing several technical challenges, PET/MR co-imaging technology is expected to play a crucial role in the early diagnosis, treatment, and research of cardiovascular diseases, paving the way for new directions and possibilities in future medical imaging research.

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.