Nuclear Medicine Communications最新文献

Objectives: The present study investigated various image reconstruction protocols for amyloid PET using phantom test criteria published by the Japanese Society of Nuclear Medicine (JSNM) and compared them with the composite standardized uptake value ratio (cSUVR) in clinical imaging.

Methods: Hoffman 3D phantoms and cylindrical phantoms were collected for 30 min according to the JSNM guidelines. Images were created under various reconstruction protocols by three physical evaluation items in the guidelines and were assessed: gray matter/white matter contrast (%contrast), uniformity (SDuROImean), and image noise [coefficient of variation (CV)]. We compared the cSUVR of images reconstructed under 15 protocols using 18F-flutemetamol and 18F-florbetapir in 15 cases each and the guidelines for physical evaluation of reconstruction parameters.

Results: No significant differences were observed in cSUVR between reconstruction protocols that satisfied the guidelines' criteria for %contrast and CV and those that did not; however, the visual impression of images differed. SDuROImean, which evaluated uniformity, met the criteria in all data.

Conclusion: Reconstruction protocols should be selected appropriately using guidelines and other information, as cSUVR remains largely the same even if the visual impression of the images differs between different reconstruction protocols. When the relationship between %contrast and CV is expressed in terms of several reconstruction protocols, the graph shows a curved shape, and the optimal protocols for both %contrast and CV are near its center. Since cSUVR is similar to optimal parameters, even under parameters outside this range, multiple parameters need to be considered when selecting image reconstruction protocols for amyloid PET.

Objective: 18 F-fluorocholine PET/CT is considered the imaging gold standard for detection of hyperfunctioning parathyroid glands . However, increased uptake might also occur in the thyroid gland. The aim of our study was to assess the incidence and significance of 18 F-fluorocholine uptake in the thyroid gland in patients with hyperparathyroidism.

Materials and methods: This retrospective study includes 195 consecutive patients with hyperparathyroidism, who underwent 18 F-fluorocholine PET/CT, for detection of hyperfunctioning parathyroid glands. PET/CT images were reviewed by two nuclear medicine physicians for the presence of focal or diffuse thyroid uptake. PET/CT results were compared with laboratory parameters, ultrasonography, EU-TIRADS classification in the presence of thyroid nodules, cytology, and final histology.

Results: 25 patients (13%) showed 18 F-fluorocholine uptake in the thyroid gland: focal thyroid uptake (FTU) in 7 patients (4%), diffuse thyroid uptake (DTU) in 8 patients (4%), and combined uptake (FTU + DTU) in 10 patients (5%), with a total of 20 active thyroid nodules. There was no correlation between EU-TIRADS classification and PET parameters. One highly 18 F-fluorocholine active thyroid nodule and one isoactive thyroid nodule turned out to be papillary thyroid cancers in the final histology; 50% of the patients with DTU had Hashimoto's thyroiditis.

Conclusion: Incidental 18 F-fluorocholine uptake in the thyroid gland was observed in 13% of patients. As reported for 18 F-FDG, focal 18 F-fluorocholine uptake might represent thyroid cancer and should be evaluated with ultrasound and, if indicated, with fine-needle aspiration cytology. Diffuse 18 F-fluorocholine uptake most likely represents multinodular goiter or Hashimoto's thyroiditis.

Purpose: This study demonstrates the feasibility and benefits of using a deep learning-based approach for attenuation correction in [ 68 Ga]Ga-PSMA PET scans.

Methods: A dataset of 700 prostate cancer patients (mean age: 67.6 ± 5.9 years, range: 45-85 years) who underwent [ 68 Ga]Ga-PSMA PET/computed tomography was collected. A deep learning model was trained to perform attenuation correction on these images. Quantitative accuracy was assessed using clinical data from 92 patients, comparing the deep learning-based attenuation correction (DLAC) to computed tomography-based PET attenuation correction (PET-CTAC) using mean error, mean absolute error, and root mean square error based on standard uptake value. Clinical evaluation was conducted by three specialists who performed a blinded assessment of lesion detectability and overall image quality in a subset of 50 subjects, comparing DLAC and PET-CTAC images.

Results: The DLAC model yielded mean error, mean absolute error, and root mean square error values of -0.007 ± 0.032, 0.08 ± 0.033, and 0.252 ± 125 standard uptake value, respectively. Regarding lesion detection and image quality, DLAC showed superior performance in 16 of the 50 cases, while in 56% of the cases, the images generated by DLAC and PET-CTAC were found to have closely comparable quality and lesion detectability.

Conclusion: This study highlights significant improvements in image quality and lesion detection capabilities through the integration of DLAC in [ 68 Ga]Ga-PSMA PET imaging. This innovative approach not only addresses challenges such as bladder radioactivity but also represents a promising method to minimize patient radiation exposure by integrating low-dose computed tomography and DLAC, ultimately improving diagnostic accuracy and patient outcomes.

Background: It remains unclear whether the time interval between total thyroidectomy and radioactive iodine (RAI) therapy influences clinical outcomes in papillary thyroid carcinoma (PTC). This study aims to evaluate the impact of the timing to initiate RAI therapy on the response in PTC patients.

Methods: We retrospectively included 405 patients who underwent total thyroidectomy and subsequent RAI therapy at two tertiary hospitals in southwest China. Patients were categorized into two groups based on the interval between thyroidectomy and initial RAI therapy, that is, an early group (interval ≤90 days, n  = 317) and a delayed group (interval >90 days, n  = 88). Responses to RAI therapy were classified as excellent, indeterminate, biochemical incomplete, or structural incomplete. Univariate and multivariate analyses were conducted to identify factors associated with a nonexcellent response.

Results: Excellent responses were observed in 77.3% of the early group and 83.0% of the delayed group ( P  = 0.252). No significant impact of RAI therapy timing was also observed across all American Thyroid Association risk classification categories. These findings persisted when patients were analyzed separately according to RAI dose (intermediate-dose group: 3.7 GBq [ n  = 332]; high-activity group: ≥5.5 GBq [ n  = 73]), further subdivided by the timing of RAI therapy. Multivariate analysis identified lymph node dissection, RAI dose, and stimulated thyroglobulin as independent risk factors for excellent response ( P  < 0.05).

Conclusion: The timing of initial RAI therapy following surgery did not significantly affect outcomes in patients with PTC.

Methods: This prospective study included 92 patients who underwent BLVR with quantitative SPECT/CT study pre- and post-procedure between November 2018 and June 2023. The mean age was 70 years (range 56-85). with 51 males and 41 females. SPECT/CT quantified perfusion for each lobe, and the lowest counts/volume ratio determined the procedural target. Postprocedure SPECT/CT assessed total atelectasis and perfusion shifts. The 6-minute walk test and pulmonary function tests were compared pre- and post-BLVR.

Results: SPECT/CT-guided BLVR showed clinical benefits (decreased oxygen requirements) and physiological improvements in total lung capacity, forced expiratory volume, and forced vital capacity ( P < 0.05). Significant perfusion shifts were observed away from the target lobe, with unique patterns noted for ipsilateral and contralateral nontarget lobes ( P < 0.05).

Conclusion: Quantitative lobar SPECT/CT in preprocedural guidance for BLVR proved useful in identifying suitable targets in multi-lobe homogeneous emphysema, resulting in physiological and clinical improvements for this patient group. The perfusion shift information provided by SPECT/CT offers valuable insights for pulmonologists.

The aim of this study was to quantify the diagnostic value of dual-tracer PET/computed tomography (CT) with 11 C-acetate and fluorodeoxyglucose (FDG) in per-lesion and per-patient and its effect on clinical decision-making for choosing the most appropriate management. The study protocol is registered a priori at https://osf.io/rvm75/ . PubMed, Web of Science, Embase , and Cochrane Library were searched for relevant studies until 1 June 2023. Studies regarding the review question were included. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used to assess bias risk. Per-lesion and per-patient diagnostic performance were calculated for: (1) 11 C-acetate alone; (2) FDG alone; and (3) dual tracer of 11 C-acetate and FDG. A direct comparison of these three combinations was made. The possible sources of statistical heterogeneity were also examined. We also calculated the percentage change in clinical decision-making when dual-tracer PET/CT was added to conventional imaging routinely used for metastatic evaluation (CT/MRI). Grading of Recommendations, Assessment, Development, and Evaluations tool was used to evaluate the certainty of evidence. Eight studies including 521 patients and 672 metastatic lesions were included. Dual-tracer PET/CT had a per-lesion sensitivity of 96.3% [95% confidence interval (CI), 91.8-98.4%] and per-patient sensitivity of 95.5% (95% CI, 89.1-98.2%) which were highly superior to either of tracers alone. Per-patient specificity was 98.5% (84.1-99.9%) which was similar to either of tracers alone. Overall, 9.3% (95% CI, 4.7-13.9%) of the patients had their management beneficially altered by adding dual-tracer PET/CT to their conventional CT/MRI results. Dual-tracer PET/CT substantially outperforms single-tracer methods in detecting extrahepatic hepatocellular carcinoma metastases, evidencing its reliability and significant role in refining clinical management strategies based on robust diagnostic performance.

Objectives: Fatty atrophy and fatty infiltration have been considered as limiting factors for rotator cuff repair. The metabolic activity of the muscle can be measured noninvasively by PET. In our study, we aim to compare the metabolic activity between the shoulders with rotator cuff tears and normal shoulders.

Methods: All the patients with unilateral full-thickness rotator cuff tears were included. The patients were divided into two groups based on fatty atrophy and the metabolic activities of the rotator cuff muscles, trapezius, and deltoid were calculated using an 18 F-2-deoxy- d -glucose PET-computed tomography scan for comparison.

Results: A total of 17 patients were included. The standardized uptake values were compared between the affected shoulder and the normal shoulders. There was a significant increase in uptake in the insertion sites and musculotendinous junctions in the rotator cuff torn group. The standardized uptake values showed no significant difference between the low-grade and high-grade groups.

Conclusion: Our first hypothesis was also proven wrong; when we found that there was no statistically significant difference in the metabolic activity in muscle bellies of normal shoulders and those with rotator cuff tears. Our second hypothesis was proven wrong when found that there was no statistically significant difference in the metabolic activities of rotator cuff muscles between high-grade and low-grade fatty atrophy groups. The metabolic activities of the middle deltoid and trapezius are inversely related. Based on the findings of our study, fatty atrophy or fatty infiltration alone cannot be considered a limiting factor for rotator cuff repair.

Objective: The objective of this retrospective study was to identify the uptake patterns and suggest a quantitative method to detect hyperostosis frontalis interna (HFI) on fluorine-18 sodium fluoride ([ 18 F]NaF) PET/computed tomography (CT).

Methods: Between January 2019 and December 2021, patients who underwent [ 18 F]NaF PET/CT with a BMI of 30 and above, were included. Three nuclear medicine consultants reviewed the studies to determine the presence and identify the uptake patterns of HFI. Quantitative evaluation was performed on PET images using the total number of counts over the frontal bone and the ratio of counts between the frontal bone and iliac crest.

Results: A total of 105 out of 249 cases were included in this study. Among these scans, there were 67 positive HFI in [ 18 F]NaF PET scans representing 64% of the studied population. As for the [ 18 F]NaF PET uptake pattern, there were 53 with uniformly diffused and 14 with heterogeneous uptake pattern. There were 17 out of 67 with positive HFI in [ 18 F]NaF PET scans but negative CT scans.

Conclusion: HFI is a common finding on [ 18 F]NaF PET in obese patients and is probably underdiagnosed. HFI may present with a heterogeneous and diffuse pattern of uptake on [ 18 F]NaF PET. The proposed quantitative analysis using the count ratios is in agreement with the visual evaluation of [ 18 F]NaF PET images regardless of the CT findings. Awareness of this condition and its scintigraphic patterns is warranted since it can have clinical significance and may mimic other pathologies including metastasis in cancer patients.

Objective: This study compared the radiomic features and quantitative biomarkers of 18 F-PSMA-1007 [prostate-specific membrane antigen (PSMA)] and 18 F-fluorocholine (FCH) PET/computed tomography (CT) in prostate cancer patients with biochemical recurrence (BCR) enrolled in the phase 3, prospective, multicenter BIO-CT-001 trial.

Methods: A total of 106 patients with BCR, who had undergone primary definitive treatment for prostate cancer, were recruited to this prospective study. All patients underwent one PSMA and one FCH PET/CT examination in randomized order within 10 days. They were followed up for a minimum of 6 months. Pathology, prostate-specific antigen (PSA), PSA doubling time, PSA velocity, and previous or ongoing treatment were analyzed. Using LifeX software, standardized uptake value (SUV) maximum, SUV mean , PSMA and choline total volume (PSMA-TV/FCH-TV), and total lesion PSMA and choline (TL-PSMA/TL-FCH) of all identified metastatic lesions in both tracers were calculated.

Results: Of the 286 lesions identified, the majority 140 (49%) were lymph node metastases, 118 (41.2%) were bone metastases and 28 lesions (9.8%) were locoregional recurrences of prostate cancer. The median SUV max value was significantly higher for 18 F-PSMA compared with FCH for all 286 lesions (8.26 vs. 4.99, respectively, P  < 0.001). There were statistically significant differences in median SUV mean , TL-PSMA/FCH, and PSMA/FCH-TV between the two radiotracers (4.29 vs. 2.92, 1.97 vs. 1.53, and 7.31 vs. 4.37, respectively, P  < 0.001). The correlation between SUV mean /SUV max and PSA level was moderate, both for 18 F-PSMA ( r  = 0.44, P  < 0.001; r  = 0.44, P  < 0.001) and FCH ( r  = 0.35, P  < 0.001; r  = 0.41, P  < 0.001). TL-PSMA/FCH demonstrated statistically significant positive correlations with both PSA level and PSA velocity for both 18 F-PSMA ( r  = 0.56, P  < 0.001; r  = 0.57, P  < 0.001) and FCH ( r  = 0.49, P  < 0.001; r  = 0.51, P  < 0.001). While patients who received hormone therapy showed higher median SUV max values for both radiotracers compared with those who did not, the difference was statistically significant only for 18 F-PSMA ( P  < 0.05).

Conclusion: Our analysis using both radiomic features and quantitative biomarkers demonstrated the improved performance of 18 F-PSMA-1007 compared with FCH in identifying metastatic lesions in prostate cancer patients with BCR.