Nuclear Medicine Specialists Research Articles

Granulocyte Colony-Stimulating Factor-Associated Aortitis Unveiled by 18F-FDG PET/CT.

In oncology, G-CSF (granulocyte colony-stimulating factor) is often administered to counteract chemotherapy-induced neutropenia. Recent studies have highlighted a significant side effect, G-CSF-associated aortitis, with an incidence of ~0.4%. Identification of this condition's imaging characteristics is crucial for nuclear medicine specialists, given its substantial impact on clinical decision-making. It is notably prevalent in the follow-up of gynecologic malignancies and lymphoma. We detail a case of G-CSF-related aortitis in a metastatic ovarian cancer patient, diagnosed by increased 18F-FDG uptake in the aortic arch on PET/CT, confirmed by contrast-enhanced CT and biopsy, which regressed spontaneously in under 5 weeks without corticosteroid treatment.

Phase II study of uPAR-PET/CT for staging of primary breast cancer in comparison with ultrasound and fine needle biopsies

Accurate initial staging of patients with breast cancer is essential for planning optimal treatment strategies. However, currently, no imaging modality is able to detect lymph node metastases preoperatively with sufficient reliability; therefore, the N status depends on the sentinel node procedure for ~ 70% of patients. In a prospective clinical trial of breast cancer patients, we compared head-to-head uPAR-PET/CT with current standard-of-care, ultrasound (US) and fine needle biopsy (FNB) as staging methods. Forty-nine patients (48 women and 1 man) with biopsy-proven early breast cancer underwent uPAR-PET/CT prior to surgery. All image data were analyzed by two separate teams, each consisting of a highly experienced certified specialist in nuclear medicine and a highly experienced certified specialist in radiology for visualization of primary tumor lesions and detection of lymph node and distant metastases. Histopathological assessment and verification of malignancy in the excised tissues (primary tumors and lymph nodes) were considered standard-of-truth. On a per patient basis, uPAR PET/CT demonstrated a sensitivity of 94% [CI: 83–99%] for detecting the primary tumor (both teams). For the detection of axillary lymph nodes the pooled sensitivity of uPAR PET/CT was 33.3% [CI: 16.5–54.0%], specificity 87.0% [CI: 66.4–97.2%] and accuracy 58.0% [CI: 43.2–71.8%]. In comparison, the standard-of-care preoperative clinical staging algorithm with US and FNB had a sensitivity of 41% [CI: 22–61%] and specificity of 100% [CI: 85–100%] for axillary lymph node metastases. We conclude that the results do not support the use of uPAR PET/CT for staging in breast cancer patients. However, the finding that 94% of primary tumors were uPAR-PET positive may be encouraging for pursuing uPAR theranostics in localized disease. Additionally, other potential applications, such as using uPAR-PET as a prognostic imaging biomarker of tumor aggressiveness, remain to be investigated.

Head-to-head comparison of GA-68 PSMA PET/CT and multiparametric MRI findings with postoperative results in preoperative locoregional staging and localization of prostate cancer.

Accurate staging of prostate cancer (PCa) is essential for determining the appropriate treatment and predicting outcomes. This study is comparing the effectiveness of Gallium-68 Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography (Ga-68 PSMA PET/CT) and multiparametric MRI (mpMRI) in preoperative locoregional staging and localizing PCa. A retrospective analysis was conducted on 78 patients who underwent both mpMRI and Ga-68 PSMA PET/CT scans before surgery. The imaging was reviewed by radiologists and nuclear medicine specialists and compared with the final histopathology, which was reviewed by an experienced uropathologist. mpMRI demonstrated higher sensitivity in detecting extraprostatic extension (EPE) and bladder neck invasion (BNI) compared to Ga-68 PSMA PET/CT (83% vs. 44% and 29% vs. 17%, respectively). Conversely, Ga-68 PSMA PET/CT showed higher sensitivity in detecting seminal vesicle invasion (SVI) and lymph node metastasis (LNM) (75% vs. 55% and 50% vs. 30%, respectively). When both methods were combined, sensitivity increased in detecting both EPE and SVI. The index tumor localization in mpMRI and Ga-68 PSMA PET/CT was found to be in complete agreement with histopathological findings at 36.4% and 41.8%, respectively. When both imaging methods were combined, the agreement with histopathology in predicting index tumor localization reached 72.1%. Both mpMRI and Ga-68 PSMA PET/CT provide valuable and complementary information for tumor localization and locoregional staging. While mpMRI showed higher sensitivity in detecting EPE, Ga-68 PSMA PET/CT demonstrated superior performance in detecting LNM and SVI. The combined use of these imaging modalities enhance accuracy of index tumor localizations.

Deep learning-based binary classification of beta-amyloid plaques using 18 F florapronol PET.

This study aimed to investigate a deep learning model to classify amyloid plaque deposition in the brain PET images of patients suspected of Alzheimer's disease. A retrospective study was conducted on patients who were suspected of having a mild cognitive impairment or dementia, and brain amyloid 18 F florapronol PET/computed tomography images were obtained from 2019 to 2022. Brain PET images were visually assessed by two nuclear medicine specialists, who classified them as either positive or negative. Image rotation was applied for data augmentation. The dataset was split into training and testing sets at a ratio of 8 : 2. For the convolutional neural network (CNN) analysis, stratified k-fold ( k = 5) cross-validation was applied using training set. Trained model was evaluated using testing set. A total of 175 patients were included in this study. The average age at the time of PET imaging was 70.4 ± 9.3 years and included 77 men and 98 women (44.0% and 56.0%, respectively). The visual assessment revealed positivity in 62 patients (35.4%) and negativity in 113 patients (64.6%). After stratified k-fold cross-validation, the CNN model showed an average accuracy of 0.917 ± 0.027. The model exhibited an accuracy of 0.914 and an area under the curve of 0.958 in the testing set. These findings affirm the model's high reliability in distinguishing between positive and negative cases. The study verifies the potential of the CNN model to classify amyloid positive and negative cases using brain PET images. This model may serve as a supplementary tool to enhance the accuracy of clinical diagnoses.

Optimization of Image Quality in Pelvis Lymphoscintigraphy SPECT/CT Using Discovery NM/CT 670

Abstract Aim A lymphoscintigraphy is a crucial diagnostic tool for visualizing lymph nodes. This scan plays a significant role in determining the treatment and recovery plan for the patients. Due to the small lymph node size, obtaining high-quality images is important to prevent inaccurate results. We aimed to identify the most effective method for enhancing image quality through postprocessing techniques and altering the image reconstruction process. Methods Two data sets were utilized in this study. First, National Electrical Manufacturers Association body phantom was filled with [99mTc]Tc-pertechnetate and prepared with and without any activity in the background of the body. Second, the images of 50 patients who underwent single-photon emission computed tomography/computed tomography imaging received [99mTc]Tc-phytate were collected. Discovery 670 GE gamma camera was used for imaging. Preprocessing of all images was performed by Xeleris and 3DSlicer 5.2.2 software was used for quantification. The effect of image reconstruction parameters such as resolution recovery (RR) algorithm, iteration, subsets, cutoff, and power in Butterworth filter, and full width at half maximum (FWHM) of Gaussian filter was assessed. The image quality index was determined based on contrast-to-noise ratio (CNR), contrast, and coefficient of variation. Results The utilization of the RR algorithm showed notable improvements equal to 74, 35, and 38% of CNR, contrast, and noise reduction, respectively. Significant differences were observed in subiteration of 40 to 112 (p-value < 0.05). The alteration of effective parameters in both smoothing filters yielded statistically significant results, leading to enhanced detectability, reduced noise, and improved contrast simultaneously. Optimum results in terms of noise reduction and CNR were achieved with subiteration (i × s) 4 × 12 using a Gaussian filter with FWHM of 4 or Butterworth filter with power of 10 and cutoff of 1. The highest contrast was observed at subiteration 40 using the Butterworth filter with cutoff of 0.5 and power of 5 or Gaussian filter with 2 mm FWHM. Qualitative analysis by two nuclear medicine specialists validated the quantified image quality. Conclusion The reconstruction setting involving subiteration 48 with the Butterworth filter using cutoff of 1 and power of 10 or 4 mm FWHM of Gaussian filter produced the highest quality images.

18F]FDG PET/CT Integration in Evaluating Immunotherapy for Lung Cancer: A Clinician's Practical Approach.

The advent of immune checkpoint inhibitors (ICIs) has revolutionized the treatment paradigm of lung cancer, resulting in notable enhancements in patient survival. Nevertheless, evaluating treatment response in patients undergoing immunotherapy poses distinct challenges due to unconventional response patterns like pseudoprogressive disease (PPD), dissociated response (DR), and hyperprogressive disease (HPD). Conventional response criteria such as the RECIST 1.1 may not adequately address these complexities. To tackle this issue, novel response criteria such as the iRECIST and imRECIST have been proposed, enabling a more comprehensive assessment of treatment response by incorporating additional scans and considering the best overall response even after radiologic progressive disease evaluation. Additionally, [18F]FDG PET/CT imaging has emerged as a valuable modality for evaluating treatment response, with various metabolic response criteria such as the PERCIMT, imPERCIST, and iPERCIST developed to overcome the limitations of traditional criteria, particularly in detecting pseudoprogression. A multidisciplinary approach involving oncologists, radiologists, and nuclear medicine specialists is crucial for effectively navigating these complexities and enhancing patient outcomes in the era of immunotherapy for lung cancer. In this review, we delineate the key components of these guidelines, summarizing essential aspects for radiologists and nuclear medicine physicians. Furthermore, we provide insights into how imaging can guide the management of individual lung cancer patients in real-world multidisciplinary settings.

Visual assessments of 11 C-Pittsburgh compound-B PET vs. 18 F-flutemetamol PET across the age spectrum.

Visual assessments of amyloid-β PET, used for Alzheimer's disease (AD) diagnosis and treatment evaluation, require a careful approach when different PET ligands are utilized. Because the gray matter (GM) and white matter (WM) ligand bindings vary with age, the objective was to investigate the agreement between visual reads of 11 C- and 18 F-PET scans. Cognitively unimpaired (CU) younger adults ( N = 30; 39.5 ± 6.0 years), CU older adults ( N = 30; 68.6 ± 5.9 years), and adults with AD ( N = 22; 67.0 ± 8.5 years) underwent brain MRI, 11 C-Pittsburgh compound-B (PiB)-PET, and 18 F-flutemetamol-PET. Amyloid-β deposition was assessed visually by two nuclear medicine specialists on 11 C-PiB-PET and 18 F-flutemetamol-PET, and quantitatively by PET centiloids. Seventy-two 11 C-PiB-PET and 18 F-flutemetamol-PET visual reads were concordant. However, 1 18 F-flutemetamol-PET and 9 11 C-PiB-PET were discordant with quantitative values. In four additional cases, while 11 C-PiB-PET and 18 F-flutemetamol-PET visual reads were concordant, they were discordant with quantitative values. Disagreements in CU younger adults were only with 11 C-PiB-PET visual reads. The remaining disagreements were with CU older adults. Age, GM/WM binding, amyloid-β load, and disease severity may affect visual assessments of PET ligands. Increase in WM binding with age causes a loss of contrast between GM and WM on 11 C-PiB-PET, particularly in CU younger adults, leading to false positivity. In CU older adults, increased WM signal may bleed more into cortical regions, hiding subtle cortical uptake, especially with 18 F-flutemetamol, whereas 11 C-PiB can detect true regional positivity. Understanding these differences will improve patient care and treatment evaluation in clinic and clinical trials.

Pharmacopeial parametric release strategy in microbiological quality control of radiopharmaceuticals

Nuclear medicine is used to assess body functionality at various levels of biological organization and is increasingly employed for both diagnostic and therapeutic purposes. Nearly 5% of radiopharmaceuticals are used therapeutically, whereas approximately 95% are used for diagnosis. Diagnostic radiopharmaceuticals are generally considered safe because they are administered in subpharmacological doses, and the radiotracer components are employed in minimal doses. Consequently, the radiation exposure to the body during nuclear medicine investigations is typically low. However, when radiopharmaceuticals are used for therapeutic applications such as tumor ablation and bone pain palliation, the emitted radiation is highly localized and potent. Radiotracers and radiation doses are more carefully selected for young patients, as the radiation-induced risk of adverse health effects is greater in children than in adults. Radiopharmaceutical preparations should adhere to the established standards of pharmacopoeia worldwide to ensure safety and efficacy. Adherence to current good manufacturing practices, sterility, and good radiation practices are prerequisites for ensuring effective quality assurance and quality control systems during radiopharmaceutical preparation. The quality control test parameter for radiopharmaceuticals primarily involves physicochemical and biological tests. However, significant concerns exist regarding the biological testing of radiopharmaceuticals, necessitating their parametric release. The time-intensive traditional sterility test, bacterial endotoxin test, and rabbit pyrogen tests have been critical quality control issues due to the short half-lives of most radiopharmaceuticals, as they should be dispensed at the earliest to ensure optimal diagnostic/therapeutic benefit. Therefore, manufacturers of radiopharmaceuticals, dispensers, and nuclear medicine specialists should be cognizant of the issues posed by biological quality control as a primary obstacle to ensuring consistent quality through parametric release from a compendial test method standpoint.

131I]6ß-Iodomethyl-19-norcholesterol SPECT/CT for the Lateralization of Mineralocorticoid Overproduction in Primary Aldosteronism.

In 42 consecutive patients with confirmed primary aldosteronism, molecular imaging has been performed. After dexamethasone suppression of the non-affected adrenal tissue, 37 MBq [131I]6ß-iodomethyl-19-norcholesterol was injected i.v., and SPECT/CT images were taken 7 days later. Based on the visual evaluation of the images by two nuclear medicine specialists, patients with one-sided tracer accumulation underwent adrenalectomy. To identify a SPECT/CT parameter that best characterizes the side difference, the maximum counts and the mean counts of spherical VOIs were analyzed. Of the 42 patients, 24 had one-sided aldosterone overproduction by SPECT/CT. After surgical removal of the involved adrenal, all 24 patients with SPECT/CT-identified unilateral aldosteronism achieved biochemical cure, defined as a normalized potassium level combined with an aldosterone-to-renin ratio ≤ 30. To identify the best measurable parameter of SPECT/CT side difference, the mean counts and maximum counts of a series of spherical VOIs of different diameters were analyzed. The ratio of the mean counts of 3 cm spherical VOIs of the right and left adrenal regions (lateralization index) was the best discriminator; a ratio of ≥1.29 was characteristic of one-sided disease, without overlap between the one-sided and two-sided patient groups. [131I]6ß-iodomethyl-19-norcholesterol SPECT/CT with a count-based image interpretation and side-ratio calculation may be an equipollent non-invasive substitute for adrenal venous sampling in the lateralization of mineralocorticoid overproduction. It reliably identifies unilateral disease and facilitates patients' selection for surgical intervention. If confirmed by others, this functional imaging may replace AVS when lateralization is required for management decisions in primary aldosteronism.

Prognostic Significance of Baseline Clinical and [68Ga]Ga-PSMA PET Derived Parameters on Biochemical Response, Overall Survival, and PSA Progression-Free Survival in Metastatic Castration-Resistant Prostate Cancer (mCRPC) Patients Undergoing [177Lu]Lu-PSMA Therapy.

In this study, we sought to identify the clinical baseline characteristics and pre-therapy 68Ga-PSMA PET derived parameters that can have impact on PSA (biochemical) response, OS and PSA PFS in patients with metastatic castration-resistant prostate cancer (mCRPC) who undergo RLT with [177Lu]Lu-PSMA-617. Various pre-treatment clinical and PSMA PET derived parameters were gathered and computed. We used PSA response as the criteria for more than a 50% decrease in PSA level, and OS and PSA PFS as endpoints. We assessed the collected parameters in relation to PSA response. Additionally, we employed univariable Cox regression and Kaplan-Meier analysis with log rank to evaluate the influence of the parameters on OS and PFS. A total of 125 mCRPC patients were included in this study. The median age was 68 years (range: 49-89). Among the cases, 77 patients (62%) showed PSARS, while 48 patients (38%) did not show PSA response. The median OS was 14 months (range: 1-60), and the median PSA-PFS was 10 months (range: 1-56). Age, prior history of chemotherapy, and SUVmax had a significant impact on PSA response (p<0.05). PSA response, RBC count, hemoglobin, hematocrit, neutrophil to lymphocyte ratio (NLR), alkaline phosphatase (ALP), number of metastases, wbPSMA-TV, and wbTL-PSMA significantly affected OS. GS, platelet count, NLR, and number of metastases were found to have a significant impact on PSA PFS. We have identified several baseline clinical and PSMA PET derived parameters that can serve as prognostic factors for predicting PSA response, OS, and PSA PFS after RLT. Based on the findings, we believe that these clinical baseline characteristics can assist nuclear medicine specialists in identifying RLT responders who have long-term survival and PFS.

Semi-automatic detection and evaluation of metastases in lymph nodes in diagnostics of the prostate from PET-CT data

Abstract We present a novel tool designed for the semiautomatic detection and assessment of prostate cancer during recurrence diagnostics using PET-CT with prostate-specific membrane antigen (PSMA). The tool automatically generates a structured report, which is enhanced by 3D images and ensures the reproducibility of the findings. Moreover, the area of the findings is automatically determined and can be corrected manually. Image data from 50 patients following radical prostatectomy was used. Our approach and its user interface were qualitatively evaluated by a nuclear medicine specialist. The segmentation analysis revealed a requirement for further automation. The resulting report was deemed highly beneficial, particularly in terms of the resulting reproducibility and the presentation of 3D images depicting the findings. The presented tool has great potential for much-needed support in everyday clinical practice, as it facilitates the communication of the diagnostic results to colleagues and patients and thus prevents misunderstandings.

Measurement of Iodine (I-131) Contamination in Staff Working in Nuclear Medicine Facilities

The increasing use of the radiopharmaceutical Iodine-131 (I-131) in nuclear medicine services has implications for the potential for internal radiation received by workers. I-131 has high volatility so it has the potential to become an air contaminant and be inhaled by nuclear medicine staff as internal radiation exposure. This study aims to estimate I-131 contamination in staff at a nuclear medicine facility using a gamma spectrometer. Measurements of I-131 activity in the thyroid were carried out on 38 staff including medical physicists, nuclear medicine specialists, radiographers, radio-pharmacists, nurses, house attendants, and cleaners. The I-131 activity value measured in the staff's thyroid had an activity value range of 13.1 – 238.2 Bq in 13 nuclear medicine staff. Meanwhile, for 25 other medical staff, the I-131 activity values ??measured in the thyroid had activity values ??below the detection limit of the device (14.2 ± 4.3 Bq for men and 11.8 ± 3.5 Bq for women). The highest internal dose rate measured in the thyroid of Pramu Husada nuclear medicine staff and radiopharmaceuticals was 0.1-0.5 mSv/year. This value is still below the dose limit value for internal radiation.

Canadian Medical Imaging Inventory 2022–2023: The Medical Imaging Team

A workforce comprising medical radiation technologists (MRTs), radiologists, nuclear medicine specialists, medical imaging physicists, and other medical staff is essential for the delivery of medical imaging services. There is wide variation in the numbers of staff in each profession in Canada, ranging from 45 positions located in 6 provinces for medical imaging physicists to 25,000 positions located across all provinces and territories for MRTs. Data from 2022–2023 suggest that the number of full-time staff has not grown at the same pace as the volume of exams. Sufficient staffing is needed to ensure the sustainable operation and delivery of medical imaging services that is supported by investment in the workforce through equitable education and training opportunities. According to a Canadian Medical Imaging Inventory (CMII) report on wait time strategies, staffing shortages may extend wait times and may lead to disruptions in service delivery. Managing the growing demand for imaging services and clearing the backlog of exams deferred during the pandemic has exacerbated existing staffing shortages and contributed to increased workloads and decreased staff well-being. The adoption of supportive tools and technologies — such as clinical decision support tools, automated order entry, and AI-driven solutions — may assist the workforce by creating efficiencies, improving image quality, and increasing access to medical imaging.

Utility of 64Cu-Sarcophagine-Bombesin PET/CT in Men with Biochemically Recurrent Prostate Cancer and Negative or Equivocal Findings on 68Ga-PSMA-11 PET/CT.

Despite a high detection rate of 68Ga-prostate-specific membrane antigen (PSMA) PET/CT in biochemical recurrence (BCR) of prostate cancer, a significant proportion of men have negative 68Ga-PSMA-11 PET/CT results. Gastrin-releasing peptide receptor, targeted by the copper-chelated bombesin analog 64Cu-sarcophagine-bombesin (SAR-BBN) PET/CT, is also overexpressed in prostate cancer. In this prospective imaging study, we investigate the detection rate of 64Cu-SAR-BBN PET/CT in patients with BCR and negative or equivocal 68Ga-PSMA-11 PET/CT results. Methods: Men with confirmed adenocarcinoma of the prostate, prior definitive therapy, and BCR (defined as a prostate-specific antigen [PSA] level > 0.2 ng/mL) with negative or equivocal 68Ga-PSMA-11 PET/CT results within 3 mo were eligible for enrollment. 64Cu-SAR-BBN PET/CT scans were acquired at 1 and 3 h after administration of 200 MBq of 64Cu-SAR-BBN, with further delayed imaging undertaken optionally at 24 h. PSA (ng/mL) was determined at baseline. All PET (PSMA and bombesin) scans were assessed visually. Images were read with masking of the clinical results by 2 experienced nuclear medicine specialists, with a third reader in cases of discordance. Accuracy was defined using a standard of truth that included biopsy confirmation, confirmatory imaging, or response to targeted treatment. Results: Twenty-five patients were enrolled. Prior definitive therapy was radical prostatectomy (n = 24, 96%) or radiotherapy (n = 1, 4%). The median time since definitive therapy was 7 y (interquartile range [IQR], 4-11 y), and the Gleason score was 7 or less (n = 15, 60%), 8 (n = 3, 12%), or 9 (n = 7, 28%). The median PSA was 0.69 ng/mL (IQR, 0.28-2.45 ng/mL). Baseline PSMA PET scans were negative in 19 patients (76%) and equivocal in 6 (24%). 64Cu-SAR-BBN PET-avid disease was identified in 44% (11/25): 12% (3/25) with local recurrence, 20% (5/25) with pelvic node metastases, and 12% (3/25) with distant metastases. The κ-score between readers was 0.49 (95% CI, 0.16-0.82). Patients were followed up for a median of 10 mo (IQR, 9-12 mo). Bombesin PET/CT results were true-positive in 5 of 25 patients (20%), false-positive in 2 of 25 (8%), false-negative in 7 of 25 (28%), and unverified in 11 of 25 (44%). Conclusion: 64Cu-SAR-BBN PET/CT demonstrated sites of disease recurrence in 44% of BCR cases with negative or equivocal 68Ga-PSMA-11 PET/CT results. Further evaluation to confirm diagnostic benefit is warranted.

Neuropathologic Validation and Diagnostic Accuracy of Presynaptic Dopaminergic Imaging in the Diagnosis of Parkinsonism.

Degeneration of the presynaptic nigrostriatal dopaminergic system is one of the main biological features of Parkinson disease (PD), multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD), which can be measured using single-photon emission CT imaging for diagnostic purposes. Despite its widespread use in clinical practice and research, the diagnostic properties of presynaptic nigrostriatal dopaminergic (DAT) imaging in parkinsonism have never been evaluated against the diagnostic gold standard of neuropathology. The aim of this study was to evaluate the diagnostic parameters of DAT imaging compared with pathologic diagnosis in patients with parkinsonism. Retrospective cohort study of patients with DAT imaging for the investigation of a clinically uncertain parkinsonism with brain donation between 2010 and 2021 to the Queen Square Brain Bank (London). Patients with DAT imaging for investigation of pure ataxia or dementia syndromes without parkinsonism were excluded. Those with a pathologic diagnosis of PD, MSA, PSP, or CBD were considered presynaptic dopaminergic parkinsonism, and other pathologies were considered postsynaptic for the analysis. DAT imaging was performed in routine clinical practice and visually classified by hospital nuclear medicine specialists as normal or abnormal. The results were correlated with neuropathologic diagnosis to calculate diagnostic accuracy parameters for the diagnosis of presynaptic dopaminergic parkinsonism. All of 47 patients with PD, 41 of 42 with MSA, 68 of 73 with PSP, and 6 of 10 with CBD (sensitivity 100%, 97.6%, 93.2%, and 60%, respectively) had abnormal presynaptic dopaminergic imaging. Eight of 17 patients with presumed postsynaptic parkinsonism had abnormal scans (specificity 52.9%). DAT imaging has very high sensitivity and negative predictive value for the diagnosis of presynaptic dopaminergic parkinsonism, particularly for PD. However, patients with CBD, and to a lesser extent PSP (of various phenotypes) and MSA (with predominant ataxia), can show normal DAT imaging. A range of other neurodegenerative disorders may have abnormal DAT scans with low specificity in the differential diagnosis of parkinsonism. DAT imaging is a useful diagnostic tool in the differential diagnosis of parkinsonism, although clinicians should be aware of its diagnostic properties and limitations. This study provides Class II evidence that DAT imaging does not accurately distinguish between presynaptic dopaminergic parkinsonism and non-presynaptic dopaminergic parkinsonism.

Quality metrics analysis in patients who received Lutetium-177 PSMA-617 (177Lu–PSMA) therapy in a real-world practice setting.

e17049 Background: 177Lu–PSMA is a radiolabeled small molecule that delivers β radiation to cells expressing prostate-specific membrane antigen (PSMA). It has been approved for use in metastatic castration-resistant prostate cancer (mCPRC) in 3/2022, based on VISION study. The Food and Drug Administration (FDA) label for 177Lu–PSMA requires prior therapy with an androgen receptor pathway inhibitor (ARPI) and taxane-based chemotherapy as well as presence of at least one PSMA-positive tumor with uptake greater than normal liver and no PSMA-negative lesions on a PSMA positron emission tomography (PET) scan. In the VISION study, PSMA PET was performed within 4 weeks of therapy start. Further, patient received either 177Lu–PSMA plus protocol permitted standard of care (SOC), including ARPI, or SOC alone. Given the relatively recent approval of this therapy, real-world familiarity with administration of this agent may not be optimal. Methods: A retrospective analysis of 25 patients with mCRPC who received 177Lu–PSMA therapy since 3/2022 at the University of California Irvine (24/25) and Hoag Hospital (1/25) was performed. Multiple variables were analyzed and compared to the FDA label for this agent as well as design of the VISION study. Results: All patients in this study had received an ARPI and at least one taxane chemotherapy prior to 177Lu–PSMA. A PSMA-PET scan was obtained prior to 177Lu–PSMA therapy in all patients. The timing of the scan was within 4 weeks of starting 177Lu–PSMA therapy in only 5/25 (20.0%) patients. The average time from PSMA PET scan to 177Lu–PSMA therapy start was 66 days [range: 18 - 326 days]. None of the PSMA PET scan reports included a baseline liver standardized uptake value (SUV) or mentioned whether any lesions were non PSMA-avid. All reports provided SUV values for some, but not all, PSMA-avid lesions. The average maximum SUV of the most PSMA-avid lesion noted on the reports was 34.7. All PSMA PET scans were retrospectively reviewed by a nuclear medicine specialist and the average maximum SUV of the most PSMA-avid lesion on re-review was 42.0 (p &lt;0.05). During 177Lu–PSMA therapy, co-administration of ARPI occurred in 10/24 (23.8%) of patients. Conclusions: This study highlights the differences in quality metrics between patients who received 177Lu–PSMA therapy in a real-world practice setting compared to the FDA label for this agent and VISION study design. Differences included lack of uniform PSMA PET scan reporting, timing of obtaining pre-treatment PSMA PET imaging, and co-administration of ARPI. Development of institutional algorithms around administration of 177Lu–PSMA therapy may be needed.

Infective Native Aortic Aneurysm: a Delphi Consensus Document on Treatment, Follow Up, and Definition of Cure

Abstract Background Evidence is lacking to guide the management of infective native aortic aneurysm (INAA). Aims The aim of this study was to establish expert consensus on surgical and antimicrobial treatment and follow up, and to define when an INAA is considered cured. Methods Delphi methodology was used. The principal investigators invited 47 international experts (specialists in infectious diseases, radiology, nuclear medicine, and vascular and cardiothoracic surgery) via email. Four Delphi rounds were performed, 3 weeks each, using an online questionnaire with initially 28 statements. The panelists rated the statements on a 5-point Likert scale. Comments on statements were analysed, statements were revised and added or deleted, and the results were presented in the iterative rounds. Consensus was defined as ≥ 75% of the panel rating a statement as strongly agree or agree on the Likert scale, and consensus on the final assessment was defined as Cronbach’s α &amp;gt; 0.80. Results All 49 panelists fulfilled all four rounds, resulting in 100% participation. One statement was added based on the results and comments of the panel, resulting in 29 final statements: n = 3 on need for consensus, n = 20 on treatment, n = 5 on follow up, and n = 1 on definition of cure. All 29 statements reached agreement of ≥ 86%. Cronbach’s α increased for each consecutive round; round 1, 0.85; round 2, 0.90; round 3, 0.91; and round 4, 0.94. Thus, consensus was reached for all statements. Conclusion INAA is rare, and high-level evidence is lacking to guide optimal management. This consensus document was established with the aim of helping clinicians manage these challenging patients, as a supplement to current guidelines. The presented consensus will need future amendments in accordance with newly acquired knowledge.

EANM consensus document on the use of [18F]FDG PET/CT in fever and inflammation of unknown origin

PurposePatients with fever and inflammation of unknown origin (FUO/IUO) are clinically challenging due to variable clinical presentations with nonspecific symptoms and many differential diagnoses. Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is increasingly used in FUO and IUO, but the optimal diagnostic strategy remains controversial. This consensus document aims to assist clinicians and nuclear medicine specialists in the appropriate use of [18F]FDG-PET/CT in FUO and IUO based on current evidence.MethodsA working group created by the EANM infection and inflammation committee performed a systematic literature search based on PICOs with “patients with FUO/IUO” as population, “[18F]FDG-PET/CT” as intervention, and several outcomes including pre-scan characteristics, scan protocol, diagnostic yield, impact on management, prognosis, and cost-effectiveness.ResultsWe included 68 articles published from 2001 to 2023: 9 systematic reviews, 49 original papers on general adult populations, and 10 original papers on specific populations. All papers were analysed and included in the evidence-based recommendations.ConclusionFUO and IUO remains a clinical challenge and [18F]FDG PET/CT has a definite role in the diagnostic pathway with an overall diagnostic yield or helpfulness in 50–60% of patients. A positive scan is often contributory by directly guiding treatment or subsequent diagnostic procedure. However, a negative scan may be equally important by excluding focal disease and predicting a favorable prognosis. Similar results are obtained in specific populations such as ICU-patients, children and HIV-patients.

Development and implementation of a treatment pathway to reduce coronary angiograms - lessons from a failure

BackgroundThe rates of coronary angiograms (CA) and related procedures (percutaneous intervention [PCI]) are significantly higher in Germany than in other Organisation for Economic Co-ordination and Development (OECD) countries. The current guidelines recommend non-invasive diagnosis of coronary heart disease (CHD); CA should only have a limited role in choosing the appropriate revascularisation procedure. The aim of the present study was to explore whether improvements in guideline adherence can be achieved through the implementation of regional treatment pathways. We chose four regions of Germany with high utilisation of CAs for the study. Here we report the results of the concomitant qualitative study.MethodsGeneral practitioners and specialist physicians (cardiologists, hospital-based cardiologists, emergency physicians, radiologists and nuclear medicine specialists) caring for patients with suspected CHD were invited to develop regional treatment pathways. Four academic departments provided support for moderation, provision of materials, etc. The study team observed session discussions and took notes. After the development of the treatment pathways, 45 semi-structured interviews were conducted with the participating physicians. Interviews and field notes were transcribed verbatim and underwent qualitative content analysis.ResultsPathway development received little support among the participants. Although consensus documents were produced, the results were unlikely to improve practice. The participants expressed very little commitment to change. Although this attempt clearly failed in all study regions, our experience provides relevant insights into the process of evidence appraisal and implementation. A lack of organisational skills, ignorance of current evidence and guidelines, and a lack of feedback regarding one’s own clinical behaviour proved to be insurmountable. CA was still seen as the diagnostic gold standard by most interviewees.ConclusionsOversupply and overutilisation can be assumed to be present in study regions but are not immediately perceived by clinicians. The problem is unlikely to be solved by regional collaborative initiatives; optimised resource planning within the health care system combined with appropriate economic incentives might best address these issues.

Improvement of Basal Ganglia Detectability in Brain Single Photon Emission Computerized Tomography by Wavelet Transformation in Image Processing Domain: A XCAT Phantom Study

Purpose: Noise in brain Single Photon Emission Computed Tomography (SPECT) images limits an early diagnosis of Parkinson's Disease (PD). To overcome the limitation, as an image processing approach, wavelet transformation was used to denoising the images also with a segmentation method to differentiate the basal ganglia in brain SPECT.&#x0D; Materials and Methods: The brain scans of the human 4D Extended Cardiac Torso (XCAT) phantom through the Simulating Medical Imaging Nuclear Detectors (SIMIND) simulated SPECT system were imported to the MATLAB toolkit for image processing. The reconstructed brain images by iterative reconstruction were de-noised through 9 methods of wavelet transformation at different levels, and then six segmentation methods were applied to differentiate the caudate and putamen. The Dice coefficient, Specificity, and Sensitivity evaluation criteria were calculated based on the adaptive thresholding of the selected images from segmentation. A ground truth image was manually marked by a clinical nuclear medicine specialist.&#x0D; Results: The dice coefficient was obtained in a range from 0.3979 to 0.6299, as well as the specificity criterion from 0.7682 to 0.8168 and the sensitivity from 0.9049 to 0.9871.&#x0D; The results from adaptive threshold segmentation and the evaluation criteria showed that the best levels of the nucleuses detectability were provided by level 7 of Biorthogonal, levels 4 and 7 of Coiflet, level 6 of Daubechies, level 5 of Haar, level 6 of Morlet and level 6 of Symlet methods.&#x0D; Conclusion: Parkinson’s disease may be diagnosed in the early stage by an image processing approach to improve the quality of brain SPECT images.