Revista espanola de medicina nuclear e imagen molecular最新文献

Objective: To assess the diagnostic impact of using automatic segmentation and quantitative analysis of lung perfusion SPECT/CT in the evaluation of pulmonary reperfusion in patients undergoing follow-up for pulmonary thromboembolism (PTE).

Materials and methods: A prospective study was conducted from October 2021 to October 2024. We included 132 patients with PTE diagnosed by lung perfusion scintigraphy with SPECT/CT, who underwent a follow-up scan at 6 months. Reperfusion was assessed visually and quantitatively. Three grades were visually established: no reperfusion, partial reperfusion, and complete reperfusion. For quantitative analysis, automatic segmentation was performed, obtaining volumes and total counts in the baseline and follow-up SPECT/CT scans. Two parameters were established for comparison: the relative decrease in defect volume (RDV) and the relative increase in total perfused volume counts (RIC). Reperfusion was classified as: no reperfusion, partial reperfusion (minor and major), and complete reperfusion. The scintigraphic results were correlated with demographic variables, extension and size of the PTE and other complementary diagnostic tools (pulmonary function tests and echocardiogram).

Results: 82 patients were women (mean age 70 ± 16 years) and 50 were men (64 ± 15 years). Comparing the agreement between visual and quantitative analysis (weighted Cohen's Kappa index), a slight, but non-statistically significant, agreement was demonstrated between evaluators (κ = 0.04; p = 0.464). Pearson's assessment revealed a very high and positive assessment between RDV and RIC (r = 0.77; p < 0.001). Patients with abnormal complementary diagnostics tools at follow-up were not more likely to have residual thrombosis (p > 0.05 in the visual and quantitative analyses). The remaining variables also did not show statistical significance in the persistence of PTE.

Conclusions: In the assessment of post-PTE pulmonary reperfusion, quantitative analysis of lung perfusion SPECT/CT is superior to visual analysis. Furthermore, it suggests that it is a particularly useful tool in patients in whom visual analysis does not show improvement, as it could prevent unnecessary and prolonged treatment if reperfusion is observed through quantification.

Objective: The three treatment modalities for patients with hyperthyroidism are antithyroid drugs (ATDs), surgery, and radioactive iodine (RAI) therapy. The study aims to determine the predictors of a response to RAI in patients with hyperthyroidism.

Materials and methods: We retrospectively assessed 914 patients who received RAI for the treatment of hyperthyroidism between January 2000 and December 2023, with a follow-up of at least 6 months after the first dose.

Results: Hypothyroidism was ultimately achieved in 62.9% of the patients. Multiple variables are possible predictors in univariable logistic regression analysis. However, only shorter duration of ATD therapy (odds ratio 0.996; 95% confidence interval [CI], 0.093-0.999; P=.003, multivariable logistic regression analysis) and a diagnosis of Graves' disease (GD) (odds ratio 1.803; 95% confidence interval [CI], 1.042-3.141; P=.035, multivariable logistic regression analysis) are the independent predictors of post-treatment hypothyroidism, with decreasing age also being a late-response independent predictor of hypothyroidism 24 months after the treatment (odds ratio 0.983; 95% confidence interval [CI], 0.968-0.998; P=.028, multivariable logistic regression analysis). The median time to hypothyroidism was 10.0±0.7 months (Kaplan-Meier method), with a statistically significant difference in hypothyroidism-free survival (HFS) between patients with GD on one side and solitary toxic adenoma (STA) and toxic multinodular goiter (TMG) on the other (P<.001, log-rank test).

Conclusions: GD and a shorter duration of previous ATD therapy are independent predictors of post-therapeutic hypothyroidism in patients treated for hyperthyroidism with RAI, with younger age also being an independent predictor of a late response.

Objective: To assess whether parameters derived from ¹⁸F-FDG PET/CT imaging could be used for prognostic evaluation in pediatric patients with bone and soft tissue sarcomas.

Material and methods: This retrospective study included pediatric patients diagnosed with sarcoma who underwent ¹⁸F-FDG PET/CT between February 2013 and January 2021. A total of 63 patients were evaluated. Anatomical tumor volume, standardized uptake values (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured. Progression-free survival (PFS) and overall survival (OS) were calculated. Cox regression analysis was performed to identify independent predictors.

Results: The mortality rate was 31.7%, and the median OS was 54.9 months. Lung (p<0.001) and lymph node metastases (p=0.049) were associated with shorter OS. Younger age at diagnosis (p=0.014), higher anatomical tumor volume (p=0.002), and lung metastasis (p=0.004) were independently associated with increased mortality risk. High MTV was independently associated with higher progression risk (p<0.001).

Conclusion: Anatomical tumor volume and lung metastasis predict mortality, while MTV predicts progression in pediatric sarcoma. Further prospective studies are needed to validate these findings.

Objectives: Programmed death-ligand 1 (PD-L1) expression serves as a critical biomarker for selecting patients eligible for treatment with immune checkpoint inhibitors. Herein, we investigated the association between PD-L1 expression and various FDG PET/CT-derived metabolic parameters in patients with non-small cell lung cancer (NSCLC).

Materials and methods: This retrospective study included 81 NSCLC patients who underwent pre-treatment F-18 FDG PET/CT imaging and histopathological evaluation of PD-L1 expression. PD-L1 tumour proportion score (TPS) was determined using the SP263 immunohistochemical assay. PD-L1 positivity was defined as TPS ≥ 1%. Quantitative PET/CT parameters-SUVmax, SUVmean, SULpeak, SULmax, metabolic tumor volume (MTV), total lesion glycolysis (TLG), and heterogeneity indices (coefficient of variation [COV] and SUV-based heterogeneity index [HI])-were analyzed in relation to PD-L1 TPS.

Results: PD-L1 positivity was identified in 30 patients (37%). Although SUVmax, SUVmean, SULpeak, and SULmax values tended to be higher in PD-L1-positive patients, these differences were not statistically significant. Conversely, MTV and TLG were higher in the PD-L1-negative group. Among all parameters, HI was significantly elevated in the PD-L1-positive group (P = .031), and remained significant across PD-L1 expression strata (P = .037). In metastatic patients, HI and COV showed significant positive correlation with PD-L1 expression (r = 0.34 and 0.33, respectively). ROC analysis identified a HI cut-off of 1.59 to predict PD-L1 positivity with 90% sensitivity and 50% specificity (AUC = 0.674).

Conclusions: Tumor heterogeneity indices, particularly HI and COV derived from FDG PET/CT, demonstrated stronger predictive value for PD-L1 expression than conventional metabolic parameters. These findings suggest that metabolic heterogeneity may serve as a useful noninvasive imaging biomarker for guiding immunotherapy in NSCLC.

Objective: This study aimed to determine the functional expression of somatostatin receptors in patients with primary brain tumors including meningiomas and gliomas using ^99mTc-HYNIC-octreotide SPECT/CT imaging.

Method: This cross-sectional study was conducted at Ghaem Hospital, Mashhad, in 2023. Patients with histopathologically confirmed primary brain tumors (gliomas and meningiomas) who had previously received treatment and presented with suspected tumor recurrence based on imaging findings were included. After injection of ^99mTc-HYNIC-Octreotide, whole-body SPECT/CT imaging of the head and other suspicious areas was performed. Two nuclear medicine specialists independently reviewed scans. Radiopharmaceutical uptake was assessed qualitatively by comparing absorption in lesions to liver and splenic uptake, with scoring based on the Krenning score. The uptake in lesions (target) and their corresponding mirrored normal brain regions (non-target) was calculated using ROI measurements.

Results: Out of 24 patients, scans from 18 (mean age: 51.39±12.25 years; range: 35-74) were analyzed due to technical issues and missing images. Of these, 10 (55.6%) were women. Somatostatin receptor expression was observed in all lesions. Meningioma had significantly higher receptor expression compared to gliomas (P=.003). Maximum and target-to-non-target uptake differences were significantly greater in meningioma than in astrocytoma (P=.047, P=.044) and glioblastomas (P=.025, P=.026). Gliomas, including astrocytoma and glioblastomas, consistently showed low receptor expression, and no significant differences in receptor expression were observed between astrocytoma and glioblastomas.

Conclusion: This study demonstrates that ^99mTc-HYNIC-octreotide SPECT/CT imaging is an effective method for detecting somatostatin receptor expression in brain tumors, offering a low-cost and accessible alternative to more enhanced imaging techniques, both meningioma and glial tumors express somatostatin receptors, but receptor expression is significantly higher in meningioma.