Hellenic journal of nuclear medicine最新文献

Diffuse-type tenosynovial giant cell tumor (D-TSGCT) is a destructive benign tumor-like proliferative disease. Diffuse-type tenosynovial giant cell tumorrarely arises from the axial skeleton. We report a case of image findings of D-TSGCT in the thoracic vertebra. On fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) image, it presented a lytic bone destruction of 6^th thoracic vertebra, vertebral processes as well as adjacent sixth rib with intense ¹⁸F-FDG uptake. Our case hints another unusual D-TSGCT image characteristic, which should be considered as a differential diagnosis when we interpret similar sign on ¹⁸F-FDG PET/CT.

Objective: Patients with indeterminate thyroid cytology often have a diagnostic hemithyroidectomy. The role of molecular imaging, particularly fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET), is controversial, and demographic variations in tumor prevalence and histology influence test performance and clinical utility. We retrospectively assessed the prevalence of indeterminate thyroid cytology and the malignancy rate in patients from an iodine deficient area, and evaluated the diagnostic value of preoperative thyroid scintigraphy and ¹⁸F-FDG PET/CT among operated patients.

Subjects and methods: From 2006-2018, all patients with indeterminate thyroid cytology from the North Denmark region were included in the study (population 600,000).Clinical data, including operation rate, preoperative molecular imaging, and histopathological diagnosis, were retrieved. The results from preoperative thyroid scintigraphy and ¹⁸F-FDG PET/CT-scanning were compared to the final histopathological diagnosis.

Results: Four hundred and thirty-three patients were found with indeterminate thyroid cytology.The main registered reasons for conducting a fine needle aspiration biopsy (FNAB) were "cold nodule", goiter or a palpable nodule (n=312). In 40 patients (9%), FNAB was registered as conducted due to a PET incidentaloma. Four hundred and two patients (93%) underwent diagnostic lobectomy, and this population formed the study population for the following explorative study: One-hundred and two patients (25%) had a malignant diagnosis. In 226 (56%) and 51 (25%) patients, respectively, preoperative thyroid scintigraphy and ¹⁸F-FDG PET/computed tomography (CT) was performed. Among patients with a final malignant disease who had a thyroid scintigraphy (40 patients), a cold nodule was seen in 90% of cases; one (atypical) patient presented a warm nodule. Among patients with a final malignant disease 16 patients (16%) had a ¹⁸F-FDG PET (incl. 3 missing PET scans). Among the 51 patients with preoperative ¹⁸F-FDG PET/CT, no difference in the PET-derived parameters was found between benign (n=33) and malignant tumors (n=13).

Conclusion: The prevalence of malignancy (25%) was comparable with that in other studies. In patients with a preoperative thyroid scintigraphy, 90% of malignant cases had a cold nodule on scintigraphy. In patients with a preoperative PET/CT-scanning presenting focal ¹⁸F-FDG-uptake, PET-derived parameters had no diagnostic value. However, the diagnostic value of ¹⁸F-FDG-avidity vs. non-avidity needs to be addressed prospectively.

Objective: This study was conducted to compare the diagnostic accuracy of gallium-68-radiolabeled fibroblast activation protein inhibitor (⁶⁸Ga-FAPI-04), positron emission tomography/computed tomography (PET/CT), and fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET/CT based on the peritoneal carcinomatosis (PC) index for detecting peritoneal metastases of various cancer types, and to evaluate the potential benefits of FAPI PET/CT in patients with peritoneal metastases.

Subjects and methods: This retrospective study included 57 patients with peritoneal metastases between November 2020 and December 2021. All patients underwent ⁶⁸Ga-FAPI-04 PET/CT and ¹⁸F-FDG PET/CT scans within 7 days.

Results: Among the 57 patients included, 32 (56.1%) were male and the median age was 54 years (22-86 years). In the visual evaluation made from a total of 13 quadrants on the abdominopelvic peritoneal surfaces, positive findings were observed in 111 quadrants in 39 patients by ¹⁸F-FDG PET/CT and in 280 quadrants in 57 patients by ⁶⁸Ga-FAPI-04 PET/CT (P<0.001). The maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) values of ⁶⁸Ga-FAPI-04 PET/CT for the PC lesions were significantly higher than the SUVmax and TBR values of ¹⁸F-FDG PET/CT in all patients and in all quadrants (SUVmax 6.45 vs 4.1; P<0.001; TBR 14.9 vs 6.8; P<0.001).

Conclusion: Gallium-68-FAPI-04 PET/CT showed superior sensitivity compared to ¹⁸F-FDG PET/CT in both quantitative and visual evaluations of PC. Considering the low background activity and higher specific activity uptake values, ⁶⁸Ga-FAPI-04 PET/CT helped improve diagnostic accuracy.

Objective: The aim of this study is to compare the results of three gauge (G) needles (22G, 23G and 25G) in terms of cell amount in thyroid fine needle aspiration (FNA).

Subjects and methods: In the retrospective study, a total of 443 patients undergoing FNA for the first time between 2017 and 2018 were included in the study, and assigned to 3 groups with 22-gauge, 23-gauge and 25-gauge needles, respectively.

Results: The cell amount of a suspicion for the four diagnosis groups, including malignancy and malignant, benign nodules, follicular of undetermined significance (FLUS), and follicular neoplasia was mainly in the range of 0-10000, 0-300, 0-150, and 500-2500, respectively. The cut-off values of 22G needle 20000, 300, 1000, and 2500, while the cut-off values of 23G and 25G were 10000, 400, 1000, and 2500; 5000, 400, 1500, and 2000, respectively for the four diagnosis groups.

Conclusion: Large-gauge needles resulted in more cellular specimens than small-gauge needles only in the cases of malignant tumors. Small-gauge needles resulted in a higher comfort level of the patients, and had no difference in cell number in nodules with abundant blood supply, compared with large-gauge needles.

Objective: This study aimed to explore the availability of striatal dopamine transporter (DAT) after deep brain stimulation (DBS) by single photon emission computed tomography (SPECT) using technetium-99m-labeled tropane derivative (^99mTc-Trodat-1).

Subjects and methods: In this cohort, 28 patients with PD were enrolled (including 18 males and 10 females). Among these patients, the age range was 55-75 years. All patients referred for optimized DBS programming were recruited for ^99mTc-Trodat-1 imaging and symptom assessment. Dopamine transporter SPECT was performed under medication-off state before DBS and at the 6^th month after DBS, respectively. The clinical scales including Unified Parkinson Disease Rating Scale (UPDRS), Modified Hoehn & Yahr Scale (MHYS) and Ability of Daily Life Scale (ADLS) were carried out before DBS and at 6 months after DBS under medication-on and medication-off, respectively. Dopamine transporter availability was assessed based on DAT SPECT. In addition, the correlation between DAT availability and clinical scales was investigated. The data were analyzed using SPSS 23.0.

Results: The mean UPDRS total, MHYS and ADLS scores were 62.36, 2.23 and 42.07 under medication-on, respectively. The medication improvement rate of UPDRS total, MHYS and ADLS scores were 27.55%, 21.88% and 54.19%, respectively. Interestingly, we found PD patients with MHYS grade I usually presented unilateral symptoms, but DAT imaging showed that DAT uptake of the bilateral striatum was lower than that of the normal and the S-value of the contralateral side was significantly lower than that of the ipsilateral side. Furthermore, we found that DBS can improve the laterality of symptoms. The DBS improvement rate of UPDRS total scores, ADLS scores and DAT S-value were 37.65%, 72.51% and 18.21%, respectively. The symptom laterality was significantly correlated with the DAT S-value at baseline and at 6 months after DBS (r=0.63, 0.69 and 0.66, 0.75). The dosage of levodopa was 696.43±146.52 and was 455.36±107.44 before DBS surgery and at DBS-on, respectively.

Conclusion: Deep brain stimulation can significantly improve the symptom of PD. Dopamine transporter S-value was well correlated with the change of symptoms laterality. Therefore, DAT imaging can be used to diagnose PD in the early stage and to evaluate the curative effect of DBS. However, the validation of this result requires further study.

Objective: To assess the intra- and inter-observer repeatability of popular software packages for the quantitative determination of abnormality size in stress myocardial perfusion scintigraphy.

Subjects and methods: A total of 182 tomographic stress myocardial perfusion scans were processed in duplicate by an experienced and trainee observer to assess SSSext (summed stress score multiplied by 100/68) and total defect extent (TDE), as % of the left ventricle, with 4 dimension-myocardial (4DM), emory cardiac toolbox (ECTb) and quantitative perfusion SPECT (QPS) packages. The Bland-Altman (B-A) analysis and Lin's concordance correlation coefficient (CCC) were used to assess agreement.

Results: In SSSext's intra-observer repeatability, CCC showed substantial agreement for 4DM and QPS, and moderate agreement for ECTb for both observers. In inter-observer repeatability, CCC revealed substantial agreement for 4DM and QPS, and poor agreement for ECTb. Regarding TDE, CCC showed substantial intra-observer repeatability for both operators using all packages, while the inter-observer repeatability was substantial for 4DM and QPS, and moderate for ECTb.In SSSext's intra-observer repeatability for 4DM, ECTb and QPS, the B-A analysis provided (mean±1.96SD of paired measurements) 0.0±4.3, 0.2±7.8, -0.6±7.6 for the experienced physician and 0.2±5.9, 0.0±7.5, -0.5±5.4 for the trainee, respectively; in inter-observer repeatability it provided 0.2±5.4, 0.1±9.6, 0.2±8.1, respectively. Regarding TDE, the B-A values for intra-observer repeatability were 0.1±5.2, 0.1±7.9, 0.1±2.8 for the experienced reader and 0.3±6.6, -0.1±6.4, -0.1±2.4 for the trainee, respectively; in inter-observer agreement the B-A provided 0.6±6.4, -0.2±10.3, -0.1±4.3, respectively.

Conclusion: Considerable differences in intra- and inter- observer agreement were noted for the quantitative determination of defect size using widely employed software packages, suggesting limitations in the clinical use of these measurements. Quantitative perfusion SPECT appears preferable, but with no significant advantage over 4DM. There were no significant differences between the observers.

Objective: Myocardial perfusion imaging (MPI) can be challenging in some cases of multi vessel involvement. Our aim was to examine specific group of patients with diabetes mellitus (DM), who did not have significant reversible ischaemia diagnosed on perfusion study itself, and asses additional value of functional parameters obtained from gated acquisition and added information from coronary artery calcium score (CACS).

Subjects and methods: One hundred and seventy eight patients with a history of DM, with summed difference score (SDS)≤1, were included in the study. All patients underwent gated acquisition with recording of functional parameters and CACS evaluation. During the follow-up, cardiac events (CE) were recorded.

Results: During the median follow-up of 20.3 months there were 23 CE encountered. Optimal cut-off value for CACS to predict CE was found at 1427, higher values were significantly related to CE (P<0.001). Low stress left ventricular ejection fraction (LVEF) <45% and induced stress LVEF drop for 5% were also more frequent in CE group (P=0.001, P=0.008). Multivariable Cox analysis revealed low stress LVEF (P=0.001, HR=4.48, 95%CI 1.79-11.22), stress induced LVEF drop (P=0.017, HR 3.13, 95%CI 1.22-8.01) and high CACS (P<0.001, HR 10.52, 95%CI 4.32-25.63) as significant predictors of CE.

Conclusion: Low stress LVEF under 45%, post-stress LVEF drop for more than 5% and CACS more than or equal to 1427 are significant predictors of CE in patients with DM, who did not have reversible ischemia detected on MPI single photon emission computed tomography (SPECT).

Extensive tumor thrombus and simultaneous pulmonary metastasis in glioma patient is rare. Herein, we reported a 45-year-old woman with extensive tumor thrombus in sagittal sinus and sigmoid sinus with obvious enhancement on magnetic resonance imaging (MRI). Fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) showed extensive tumor thrombus in sagittal sinus, sigmoid sinus andinternal jugular vein, and simultaneous left hilar lymph node andpulmonary metastasis. Our case demonstrated the value of ¹⁸F-FDG PET/CT for correctly identifying tumor thrombus,detecting extent of tumor thrombus and distant metastasis in high grade glioma patients.

A 45-year-old man had right chest and back pain for 15+ days without any cause, each lasting 3-10 minutes, and sometimes it could radiate to the right shoulder. Chest computed tomography (CT) scan showed bony destruction in the dorsal segment of the 4^th rib on the right. Metastatic disease was suspected and for this reason, fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT was performed. The images demonstrated increased ¹⁸F-FDG activity in the dorsal segment of the 4^th rib on the right with osteolytic bony destruction. Postsurgical pathological examination showed aneosinophilic abscess (EA).

Objective: The aim of this study is to compare the activity amounts used in the standard activity approach with the activity amounts calculated with the dosimetric method for the ablation of post-operative differentiated thyroid cancer residual tissue.

Subjects and methods: Seventeen patients (mean age=47.5±8.4 years) were included in the study. Time-activity curves were created by measuring iodine-131 (¹³¹I) uptake values of residual tissue at 4^th, 24^th, 48^th and 96^th hours following oral administration of ¹³¹I. In a dosimetric approach, activity amounts exposing 300Gy to residual tissue were calculated using medicalinternal radiation dose (MIRD) formulation.

Results: Dosimetric calculation could not be made in 3 patients because there was not enough radioactive iodine uptake (RAIU) at the neck to calculate the radioactive iodine treatment (RAIT) dose. The lowest and highest activity amounts determined by dosimetric calculations were 259MBq and 10860MBq, respectively. Dose amounts for the proposed treatment were decreased in 8 and increased in 6 patients compared to the standard activity approach. Cumulative activity (CA) and total cumulative activity (TCA) levels were found to be high in 1 patient who could not achieve adequate ablation.

Conclusion: We recommend the dosimetric approach for ablation of residual postoperative thyroid tissue to find patients with high levels of CA and TCA levels to consider higher activity doses compared to risk stratification assessment.