Background: Gadolinium-1,4,7,10-Tetraazacyclodecane-1,4,7,10-tetraacetic acid (Gd DOTA) and similar magnetic resonance imaging (MRI) contrast agents are suggested as markers for myocardial blood flow (MBF). Contrary to MRI, the positron emission tomography (PET) signal is directly proportional to radioactivity concentration, and hence a PET-analog of Gd-DOTA could be used to assess the kinetics of DOTA-based agents without the challenges of measuring Gd concentrations with MRI. The aim of the present work was to assess the suitability of Gd-DOTA as a marker of MBF by comparing 68Ga-DOTA as a PET analog of Gd-DOTA to the gold standard for noninvasive measurement of MBF, 15 O-water PET. Methods: A total of 24 patients underwent dynamic 15 O-water-PET during rest and pharmacological stress, followed by 68Ga-DOTA-PET and Gd-DOTA dynamic contrast-enhanced MRI on an integrated PET/MR scanner. 68Ga-DOTA-PET was analyzed using single-tissue and two-tissue irreversible compartment models. The dynamic contrast-enhanced MRI perfusion data were analyzed using a single-tissue reversible compartment model. K 1 of 68Ga-DOTA was compared with 15 O-water. Permeability-surface area product for 68Ga-DOTA was estimated using the Renkin-Crone equation. Results: Kinetics of 68Ga-DOTA were well-described by a single-tissue compartment model. The permeability-surface area product of 68Ga-DOTA was 0.70 + 0.15 & times; MBF (mL/ cm3 /min), corresponding to an extraction of around 30% at typical hyperemic MBF values. Average whole-myocardium 68Ga-DOTA K 1 values ranged between 0.35 and 1.36 mL/cm3 /min compared to 0.68 and 4.55 mL/cm3 /min for 15 O-water. 68Ga-DOTA and Gd-DOTA K 1 values showed no significant differences. The correlation between 68Ga-DOTA MBF and 15 O-water MBF was moderate (r 2 = 0.66). Conclusions: Extraction of DOTA is low and depends on flow, resulting in a high variability and uncertainty of hyperemic MBF values.

Cardiac transthyretin amyloidosis (ATTR-CM) is a progressive myocardial disease ultimately leading to heart failure. Standard diagnostic workup includes 99mTc-DPD scintigraphy performed after 2.5–3 h. The purpose of this study is to compare early (1 h after injection) to late imaging of 99mTc-DPD scintigraphy and SPECT for the detection of ATTR-CM. Early imaging could improve patient comfort and examination efficiency. 50 patients undergoing 99mTc-DPD scintigraphy and SPECT for suspected ATTR-CM were included. Imaging was performed at both 1 h and 2.5–3 h post-injection. Tracer uptake was assessed visually (Perugini score), semi-quantitatively (e.g., heart-to-mediastinum ratio, HMR), and quantitatively (e.g., maximum standardized uptake value, SUVmax). ATTR-CM was diagnosed in 28

Ziel/Aim: Gastroenteropancreatic neuroendocrine tumors (GEP-NET) are a rare disease [1] [2]. Current guidelines recommend treatment with somatostatin receptor (SSTR) targeting radioligand therapy (RLT) [1] [3]. SSTR-RLT is available as 177Lu-radiolabeled somatostatin analogues locally compounded by hospitals (non-licensed product) and as EMA approved product with standardized formulation and application. Limited real-world data exist on the German care situation with SSTR-RLT.

This paper presents the results of the 10th survey of myocardial perfusion SPECT (MPS) from the year 2024. A total of 198 questionnaires were evaluated, comprising 115 practices (PR), 57 hospitals (HO) and 26 university hospitals (UH). The results of the previous survey 2021 are shown in squared brackets. MPS data from 128.707 [133.057] patients (–3.3%) with 125.175 [131.868] stress and 102.903 [106.546] rest MPS were analysed. A comparison with official data revealed that 53% of all MPS were recorded. From 2018 to 2024, official data showed an increase in MPS every year. In 2024, on average, 650 [610] MPS patients (+7%) were examined in each department. Of the participating departments, 69% [74%] reported an increase or no changes in their patient numbers. As always ambulatory care cardiologists represented the major referral group (68% [69%]). Pharmacological stress was performed more frequently than ergometry (43% [42%]). Regadenoson was mostly used. The use of the different protocols remained almost unchanged. Two-day protocols were predominantly applied (49% [49%]). Multi-head cameras were used in (56% [58%] of the departments and SPECT-CT systems in (31% [28%]). Attenuation correction was performed in 35% [33%] of all MPS. 95% [89%] of all stress, 93% [88%] of all rest and 92% [87%] of all stress and rest scan were acquired as gated SPECT. 84% [72%] of the departments performed scoring by default. The proportion of departments not scoring decreased to 4% [13%]. The MPS 2024 survey indicates that the long-term positive development of MPS imaging is continuing. The procedural and technical details of MPS imaging demonstrate a high level of conformity with guidelines, with a slight improvement observed from 2021 to 2024.

PSMA-PET is a reference standard examination for patients with prostate cancer, but even using recently introduced digital PET detectors image acquisition with standard field-of-view scanners is still in the range of 20 min. This may cause limited access to examination slots because of the growing demand for PSMA-PET. Ultra-fast PSMA-PET may enhance throughput but comes at the cost of poor image quality. The aim of this manuscript is to evaluate the accuracy of AI-enhanced ultra-fast PSMA-PET for staging of patients with prostate cancer. A total number of 357 whole-body [68Ga]Ga-PSMA-11 PET datasets were included. Patients underwent two digital PET scans, one at standard and one at ultra-fast speed (table speed: 0.6–1.2 mm/s vs. 50 mm/s). A modified pix2pixHD generative adversarial network to enhance the ultra-fast images was trained with 286 datasets and evaluated with the remaining 71 datasets. The staging accuracy of ultra-fast PSMA-PET and AI-enhanced ultra-fast PET was compared with the reference standard PET separately for miTNM regions proposed by PROMISE V2.0. The AI-network significantly improved the visual image quality and detection rate in most miTNM regions compared with the non-enhanced image data (T: 69.6

Purpose : Although ventilation/perfusion (V/Q) scintigraphy is a widely used imaging test, different options are possible for the acquisition and interpretation of the scan. The aim of this study was to assess current practices regarding the use and interpretation of lung scintigraphy in various clinical indications. Patients and Methods : An online survey comprising 25 questions was sent to nuclear medicine departments in Australia, Canada, France, Germany, and United States between 2022 and 2023. A single response per department was consolidated. Results : Four hundred nineteen responses were collected (Australia: 32, Canada: 58, France: 149, Germany: 92, and United States: 88). For acute pulmonary embolism (PE) diagnosis, 82.8% of centers reported using SPECT acquisitions (Australia: 93.3%, Canada: 91.8%, France: 99.2%, Germany: 96.2%, and United States: 32.1%). Among them, SPECT images were combined with a CT scan in 70.5% of centers. A total of 10.6% of centers reported not using ventilation for acute PE diagnosis. SPECT acquisition was used in 97.8% of centers using Tc-99m carbon particles, 97.1% Kr-81m gas, 58.7% Tc-99m-DTPA, and 19.4% Xe-133 gas, respectively. For V/Q SPECT interpretation, the EANM criteria were used in 65.0% of departments. A very wide variety of practices were observed in pregnant women and in COVID-19 patients. SPECT acquisition was widely used in the follow-up of PE and for the screening of chronic thromboembolic pulmonary hypertension (>90% of centers), with inconsistency regarding the interpretation of matched perfusion defects in this setting. Conclusions : This survey shows the strong adoption of SPECT in the various clinical indications of lung scintigraphy, except in the United States, where planar imaging is still mostly used. The survey also shows variability in interpretation criteria both for PE diagnosis and screening for chronic thromboembolic pulmonary hypertension, highlighting the need for further standardizations of practices.

Purpose of the Report:Combined cardiac 68Ga-Fibroblast-Activation Protein-alpha inhibitor (FAPI) positron-emission tomography (PET) and cardiac magnetic resonance imaging (MRI) constitute a novel diagnostic tool in patients for the assessment of myocardial damage after an acute myocardial infarction (AMI). Purpose of this pilot study was to evaluate simultaneous Ga-68-FAPI-46-PET/MR imaging in the delayed phase after AMI. Material and Methods:Eleven patients underwent hybrid 68Ga-FAPI-46 PET/MRI post AMI. Standardized uptake values and fibroblast activation volume (FAV) were calculated and correlated with serum biomarkers and MRI parameters. Results:Significant 68Ga-FAPI-46 uptake could be demonstrated in 11 (100 %) patients after a mean period of 30.9 ± 22.0 days. FAV significantly exceeded the infarction size in MRI and showed a good correlation to MRI parameters as well as to serum biomarkers of myocardial damage. Conclusions:68Ga-FAPI-46 PET/MRI offers molecular and morphological imaging of affected myocardium after AMI. This study demonstrates ongoing fibroblast activation in a delayed phase after AMI and generates hypotheses for future studies while aiming for a better understanding of myocardial remodeling following ischemic tissue damage.

Historically amyloidosis was regarded as an orphan disease and was often treated centralized in a few specialized centers. Resulting from advances in noninvasive cardiac diagnostics, increased disease awareness and first availability of causal treatment, amyloidosis was detected more frequently in recent years and the incidence of transthyretin cardiomyopathy increased. In the context of new, albeit cost-intensive drug treatment forms, the observed developments necessitate the expansion of amyloidosis care structures. In order to provide comprehensive care of amyloidosis patients with high quality and standardized procedures, both primary care and interdisciplinary centers need to be embraced in transsectoral networks. This consensus paper describes the requirements for the implementation of such network structures with the aim to provide high-quality and timely care of patients with amyloidosis.

Aims: The optimal strategy to identify transthyretin-type cardiac amyloidosis (ATTR-CA) in patients with aortic stenosis (AS) is still unclear. This study aimed to investigate if targeted screening for ATTR-CA in patients with severe AS and amyloid red flags is associated with higher detection rates. Methods: The study prospectively enrolled patients ≥65 years with severe AS. Patients who fulfilled ≥1 major (carpal tunnel syndrome (CTS), ruptured biceps tendon, spinal stenosis, N-terminal pro B-type natriuretic peptide ≥1000 pg/mL, cardiac troponin >99th percentile) or ≥2 minor criteria (diastolic dysfunction ≥2 grade/lateral e’ <10 cm/s, atrial fibrillation, atrioventricular conduction disease/pacemaker) received bone scintigraphy and biochemical analysis for light chain amyloidosis. Hypertensive patients (>140/90 mmHg) and those with interventricular septal thickness (IVSd) ≤13 mm were excluded. Results: Overall, 264 patients were screened, of whom 85 were included in the analysis. Tracer uptake Perugini grade ≥1 was detected in nine patients (11%). An endomyocardial biopsy was additionally performed in four of nine patients, yielding a prevalence of 7% (n = 6). All patients with dual AS-ATTR were male. Syncope was more commonly reported in AS-ATTR patients (50% vs. 6%, p = 0.010), who also tended to have more severe hypertrophy (IVSd of 18 vs. 16 mm, p = 0.075). Pericardial effusion and CTS were more common in patients with dual pathology (67% vs. 8%, p < 0.001, and 83% vs. 24%, p = 0.003, respectively). Conclusion: Targeted screening for ATTR-CA in patients with AS and amyloid red flags does not yield higher detection rates than those reported previously in all comers with AS.

Hybrid imaging consists of a combination of two or more imaging modalities, which equally contribute to image information. To date, hybrid cardiovascular imaging can be performed by either merging images acquired on different scanners, or with truly hybrid PET/CT and PET/MR scanners. The European Association of Nuclear Medicine (EANM), and the European Association of Cardiovascular Imaging (EACVI) of the European Society of Cardiology (ESC) aim to review clinical situations that may benefit from the use of hybrid cardiac imaging and provide advice on acquisition protocols providing the most relevant information to reach diagnosis in various clinical situations.

Objectives This study aimed to evaluate the level of evidence of expert recommendations and guidelines for clinical indications and procedurals in hybrid nuclear cardiovascular imaging. Methods From inception to August 2023, a PubMed literature analysis of the latest version of guidelines for clinical hybrid cardiovascular imaging techniques including SPECT(/CT), PET(/CT), and PET(/MRI) was performed in two categories: (1) for clinical indications for all-in primary diagnosis; subgroup in prognosis and therapy evaluation; and for (2) imaging procedurals. We surveyed to what degree these followed a standard methodology to collect the data and provide levels of evidence, and for which topic systematic review evidence was executed. Results A total of 76 guidelines, published between 2013 and 2023, were included. The evidence of guidelines was based on systematic reviews in 7.9% of cases, non-systematic reviews in 47.4% of cases, a mix of systematic and non-systematic reviews in 19.7%, and 25% of guidelines did not report any evidence. Search strategy was reported in 36.8% of cases. Strengths of recommendation were clearly reported in 25% of guidelines. The notion of external review was explicitly reported in 23.7% of cases. Finally, the support of a methodologist was reported in 11.8% of the included guidelines. Conclusion The use of evidence procedures for developing for evidence-based cardiovascular hybrid imaging recommendations and guidelines is currently suboptimal, highlighting the need for more standardized methodological procedures.

ZusammenfassungDie Qualitätssicherung in der Nuklearmedizin wird vor allem durch die ärztlichen Stellen sichergestellt. Daneben gibt es zahlreiche Zertifizierungen, die durch Auszeichnung von Zentren bzw. Experten die Qualität medizinischer Leistungen gewährleisten und verbessern sollen. Auf dem Gebiet der kardiovaskulären Bildgebung gibt es mittlerweile zahlreiche Zertifizierungen, wobei die meisten auf radiologische Bildgebungsverfahren wie kardiovaskuläre Computertomografie oder Magnetresonanztomografie abzielen. Für die nuklearkardiologische Bildgebung gab es bis vor Kurzem keine Zertifizierung in Deutschland. Dies hat sich seit Anfang des Jahres 2023 geändert, da seitdem die Deutsche Gesellschaft Nuklearmedizin (DGN) eine Zertifizierung zum nuklearkardiologischen Zentrum anbietet. In diesem Artikel wird das Ziel der Qualitätssicherung durch Zertifizierungen auf dem Gebiet der nuklearkardiologischen Diagnostik diskutiert.

Purpose Although ventilation/perfusion (V/Q) scintigraphy is a widely used imaging test, different options are possible for the acquisition and interpretation of the scan. The aim of this study was to assess current practices regarding the use and interpretation of lung scintigraphy in various clinical indications. Patients and Methods An online survey comprising 25 questions was sent to nuclear medicine departments in Australia, Canada, France, Germany, and United States between 2022 and 2023. A single response per department was consolidated. Results Four hundred nineteen responses were collected (Australia: 32, Canada: 58, France: 149, Germany: 92, and United States: 88). For acute pulmonary embolism (PE) diagnosis, 82.8% of centers reported using SPECT acquisitions (Australia: 93.3%, Canada: 91.8%, France: 99.2%, Germany: 96.2%, and United States: 32.1%). Among them, SPECT images were combined with a CT scan in 70.5% of centers. A total of 10.6% of centers reported not using ventilation for acute PE diagnosis. SPECT acquisition was used in 97.8% of centers using 99m Tc carbon particles, 97.1% 81m Kr gas, 58.7% 99m Tc-DTPA, and 19.4% 133 Xe gas, respectively. For V/Q SPECT interpretation, the EANM criteria were used in 65.0% of departments. A very wide variety of practices were observed in pregnant women and in COVID-19 patients. SPECT acquisition was widely used in the follow-up of PE and for the screening of chronic thromboembolic pulmonary hypertension (>90% of centers), with inconsistency regarding the interpretation of matched perfusion defects in this setting. Conclusions This survey shows the strong adoption of SPECT in the various clinical indications of lung scintigraphy, except in the United States, where planar imaging is still mostly used. The survey also shows variability in interpretation criteria both for PE diagnosis and screening for chronic thromboembolic pulmonary hypertension, highlighting the need for further standardizations of practices.

Advances in nuclear cardiology molecular imaging improve decision making in clinical cardiology. Fibroblast activation protein alpha (FAP) is a homodimeric membrane-bound serine protease with intracellular and extracellular soluble forms. Positron emission tomography (PET) imaging using radiolabeled fibroblast activation protein alpha inhibitors (FAPIs) has emerged as a promising molecular imaging tool for oncology but also cardiology, possibly providing new insights into the pathophysiology of diseases. FAP is specifically expressed by early-stage activated fibroblasts during wound healing and cardiac remodeling. Therefore, FAPI PET provides a unique opportunity to visualize and quantify cardiac fibrosis, a key pathophysiological process involved in several cardiovascular diseases. Hence, this imaging modality is a powerful tool that can aid in clinical decision making. The complete potential of FAPI PET in nuclear cardiology has not been recognized fully to date. The purpose of this pictorial imaging vignette is to demonstrate potential applications of this modality in understanding the pathophysiologic aspects of common and rare myocardial diseases.

Cardiac transthyretin amyloidosis is an infiltrative cardiomyopathy with high mortality. To date, there are no specific biomarkers to directly assess disease activity and response to specific treatments. Our aim was to evaluate scintigraphic changes after treatment with the transthyretin stabilizer tafamidis. Methods: We included patients who had undergone 99mTc-3,3-diphosphono-1,2-propanodi-carboxylic acid (99mTc-DPD) scintigraphy before tafamidis initiation and after at least 9 mo. Tracer activity was assessed visually and quantitatively as SUVmax. Results: The study included 14 patients who were on tafamidis for 44 6 14 mo. We observed regression of Perugini grade in 5 patients, unchanged grade in 9 patients, and regression of mean heart-to-contralateral-lung ratio (P = 0.015) and SUVmax (P = 0.005). There were no changes in N-terminal pro-B-type natriuretic peptide or echocardiographic measures. Conclusion: Treatment with tafamidis results in regression of myocardial 99mTc-DPD uptake. 99mTc-DPD scintigraphy may provide useful imaging biomarkers to assess response to treatment.

68Ga-fibroblast activation protein inhibitors (FAPIs) are promising radio-tracers for cancer imaging, with emerging data in the recent years. Nonetheless, the interobserver agreement on 68Ga-FAPI PET/CT study interpretations in cancer patients remains poorly understood. Methods: 68Ga-FAPI PET/CT was performed on 50 patients with various tumor entities (sarcoma [n = 10], colorectal cancer [n = 10], pancreatic adeno-carcinoma [n = 10], genitourinary cancer [n = 10], and other types of cancer [n = 10]). Fifteen masked observers reviewed and interpreted the images using a standardized approach for local, local nodal, and metastatic involvement. Observers were grouped by experience as having a low (<30 prior 68Ga-FAPI PET/CT studies; n = 5), intermediate (30-300 studies; n = 5), or high level of experience (>300 studies; n = 5). Two independent readers with a high level of experience and unmasked to clinical information, histopathology, tumor markers, and follow-up imaging (CT/MRI or PET/CT) served as the standard of refer-ence (SOR). Observer groups were compared by overall agreement (percentage of patients matching SOR) and Fleiss K with mean and cor-responding 95% CI. We defined acceptable agreement as a K value of at least 0.6 (substantial or higher) and acceptable accuracy as at least 80%. Results: Highly experienced observers agreed substantially on all categories (primary tumor: K = 0.71; 95% CI, 0.71-0.71; local nodal involvement: K = 0.62; 95% CI, 0.61-0.62; distant metastasis: K = 0.75; 95% CI, 0.75-0.75), whereas observers with intermediate experience showed substantial agreement on primary tumor (K = 0.73; 95% CI, 0.73-0.73) and distant metastasis (K = 0.65; 95% CI, 0.65-0.65) but moderate agreement on local nodal stages (K = 0.55; 95% CI, 0.55- 0.55). Observers with low experience had moderate agreement on all categories (primary tumor: K = 0.57; 95% CI, 0.57-0.58; local nodal involvement: K = 0.51; 95% CI, 0.51-0.52; distant metastasis: K = 0.54; 95% CI, 0.53-0.54). Compared with SOR, the accuracy for readers with high, intermediate, and low experience was 85%, 83%, and 78%, respectively. In summary, only highly experienced readers showed sub-stantial agreement anda diagnostic accuracy of at least 80% in all cate-gories. Conclusion: The interpretation of 68Ga-FAPI PET/CT for cancer imaging had substantial reproducibility and accuracy among highly experienced observers only, especially for local nodal and metastatic assessments. Therefore, for accurate interpretation of different tumor entities and pitfalls, we recommend training or experience with at least 300 representative scans for future clinical readers.