Hellenic journal of nuclear medicine最新文献

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.

Objective: To investigate the automatic synthesis of β-amyloid (Aβ) positron emission tomography (PET) imaging agent (E) -4- (2- (6- (2- (2-¹⁸F fluoroethoxy) ethoxy) ethoxy) pyridine-3-yl) vinyl) - N-methylaniline (¹⁸F-AV-45) for the diagnosis of Alzheimer's disease (AD) and its clinical application in AD patients.

Materials and methods: Fluorine-18-AV-45 was synthesized with AV-105 as the precursor, and the factors affecting the synthesis efficiency, such as the amount of precursor, nucleophilic reaction temperature were studied. At the same time, ¹⁸F-AV-45 PET/computed tomography (CT) brain scanning was performed in 15 patients with dementia to determine whether AD was the cause of the dementia.

Results: After optimizing the parameters, it was discovered that the highest synthesis efficiency was achieved with a AV-105 dosage of 2mg, a reaction temperature of 130^oC, and 1mL of DMSO. The radiochemical yield (RCP) was greater than 98, and the uncorrected synthesis efficiency was about 31.0%±2.8%. Ten of the 15 patients with dementia showed positive Aβ protein deposition, and the main deposition site of the imaging agent was the gray matter area of the brain, which was consistent with AD diagnosis, while the other 5 patients showed negative Aβ protein deposition, suggesting non-AD dementia.

Conclusion: β-amyloid protein ¹⁸F-AV-45 imaging agent can be easily and quickly prepared by the All in One radiochemical synthesis module. Our preliminary results offer hope that it can effectively detect β-amyloid deposition in the brain of AD patients in order to determine the etiology of dementia.

Objective: The purpose of this study was to evaluate the contribution of single photon emission computed tomography/computed tomography (SPECT/CT) standardized uptake value (SUV) metrics in classifying patients with suspected transthyretin cardiac amyloidosis (ATTR-CA) among the different Perugini grades.

Subjects and methods: One hundred four patients suspected of ATTR-CA underwent planar scintigraphy with bone seeking tracer (^99mTc pyrophosphate-PYP). Patients were classified according to the Perugini scale, the H/CL, H/Bone and H/Bkg ratios. A subset of 48 patients received additional SPECT/CT. Single photon emission computed tomography/CT SUV quantitative parameters, of the heart, myocardium, lungs, liver, soft tissues, bone, and SUV ratios (SUV_maxmyo, SUV_maxlungs, SUV_maxliver, SUV_maxbone and SUV_maxsoft tissue ratios), were evaluated in order to investigate potential metrics that could more clearly differentiate Perugini grades.

Results: A total of 33.7% of patients were considered grade 0, 34.6% grade 1 and 31.7% grade 2/3. A combination of H/CL >1.33 and H/Bone >0.85 showed the highest sensitivity 100%. Standardized uptake value-based metrics clearly differentiated grade 0 or 1 vs grades 2 or 3, whereas no significant difference was found between grades 0 and 1, or between grades 1 and 2. The combined cut-off values H/CL 1.33 and SUV_maxmyo 2.88 yielded 100% sensitivity and 84.6% specificity in differentiating ATTR-CA positives vs negatives. The metric SUV_maxmyo/SUV_maxliver was the best metric to classify patients with grade 1 as negative (grade 0) or positive (grade 2 or 3).

Conclusion: Single photon emission computed tomography/CT SUV metrics could be complementary to planar scintigraphy in classifying patients among the different Perugini grades. The ratio SUV_maxmyo/SUV_maxliver was the only parameter with high affinity to differentiate patients with grade 1, as grade 0 or grade 2/3 for ATTR-CA.

Langerhans cell histiocytosis (LCH) is a haematological disorder, affecting single or multiple organs, characterized by abnormal proliferation of Langerhans cells in children. Accurate tumour delineation (number of lesions, organs involved) is crucial for staging/re-staging, and follow-up (response to therapy). Conventional imaging techniques (computed tomography (CT), magnetic resonance imaging (MRI)) have been employed for initial diagnosis, staging and assessment of response to therapy focusing on the healing effect therapeutic protocols have on the disease. In this case report, whole-body positron emission tomography/computed tomography (PET/CT) was shown either to provide information on the metabolic activity of histiocytes, or identify lesions otherwise asymptomatic. It is clear that PET/CT, combining anatomic and metabolic information, provides data for accurate staging, therapeutic protocol selection and assessment of response to therapy.

Pericardial inflammatory myofibroblastic tumor (IMT) is very rare. Herein, we report fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) findings of pericardial IMT in a 57-year-old woman. On conventional image, it presented as a pericardial mass with heterogeneous delay enhancement. On ¹⁸F-FDG PET/CT image, this lesion had mild ¹⁸F-FDG uptake with a maximum standardized uptake value (SUV_max) of 1.84. The postoperative pathology supported a diagnosis of IMT. Our case hints us that IMT should be regarded as a differential diagnosis when we meet a solitary pericardial mass with ¹⁸F-FDG uptake.