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INTRODUCTION: Cerebral small vessel disease (SVD) and amyloid beta (Aß) pathology frequently co-exist. The impact of concurrent pathology on the pattern of hippocampal atrophy, a key substrate of memory impacted early and extensively in dementia, remains poorly understood. METHODS: In a unique cohort of mixed Alzheimer's disease and moderate-severe SVD, we examined whether total and regional neuroimaging measures of SVD, white matter hyperintensities (WMH), and Aß, as assessed by 18F-AV45 positron emission tomography, exert additive or synergistic effects on hippocampal volume and shape. RESULTS: Frontal WMH, occipital WMH, and Aß were independently associated with smaller hippocampal volume. Frontal WMH had a spatially distinct impact on hippocampal shape relative to Aß. In contrast, hippocampal shape alterations associated with occipital WMH spatially overlapped with Aß-vulnerable subregions. DISCUSSION: Hippocampal degeneration is differentially sensitive to SVD and Aß pathology. The pattern of hippocampal atrophy could serve as a disease-specific biomarker, and thus guide clinical diagnosis and individualized treatment strategies for mixed dementia.
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Doença de Alzheimer , Peptídeos beta-Amiloides , Doenças de Pequenos Vasos Cerebrais , Hipocampo , Tomografia por Emissão de Pósitrons , Humanos , Hipocampo/patologia , Hipocampo/diagnóstico por imagem , Doenças de Pequenos Vasos Cerebrais/patologia , Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , Masculino , Idoso , Feminino , Doença de Alzheimer/patologia , Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides/metabolismo , Substância Branca/patologia , Substância Branca/diagnóstico por imagem , Atrofia/patologia , Imageamento por Ressonância Magnética , Idoso de 80 Anos ou mais , Neuroimagem , Estudos de CoortesRESUMO
Prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) is rapidly becoming widely accepted as the standard-of-care for imaging of men with prostate cancer. Labeled indications for regulatoryapproved agents include primary staging and recurrent disease in men at risk of metastases. The first commercial PSMA PET agent to become available was 18F-DCFPyL (piflufolastat F 18), a radiofluorinated small molecule with high-affinity for PSMA. The regulatory approval of 18F-DCFPyL hinged upon two key, multi-center, registration trials, OSPREY (patient population: highrisk primary staging) and CONDOR (patient population: biochemical recurrence). In this manuscript, we will (1) review key findings from the OSPREY and CONDOR trials, (2) discuss the clinical acquisition protocol we use for 18F-DCFPyL PET scanning, (3) present information on important pearls and pitfalls, (4) provide an overview of the PSMA reporting and data system (PSMA-RADS) interpretive framework, and (5) posit important future directions for research in PSMA PET. Our overall goal is to provide a brief introduction for practices and academic groups that are adopting 18F-DCFPyL PET scans for use in their patients with prostate cancer.
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Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata , Masculino , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Tomografia por Emissão de Pósitrons , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , LisinaRESUMO
It remains unclear to what extent cerebrovascular burden relates to amyloid beta (Aß) deposition, neurodegeneration, and cognitive dysfunction in mixed disease populations with small vessel disease and Alzheimer's disease (AD) pathology. In 120 subjects, we investigated the association of vascular burden (white matter hyperintensity [WMH] volumes) with cognition. Using mediation analyses, we tested the indirect effects of WMH on cognition via Aß deposition (18 F-AV45 positron emission tomography [PET]) and neurodegeneration (cortical thickness or 18 F fluorodeoxyglucose PET) in AD signature regions. We observed that increased total WMH volume was associated with poorer performance in all tested cognitive domains, with the strongest effects observed for semantic fluency. These relationships were mediated mainly via cortical thinning, particularly of the temporal lobe, and to a lesser extent serially mediated via Aß and cortical thinning of AD signature regions. WMH volumes differentially impacted cognition depending on lobar location and Aß status. In summary, our study suggests mainly an amyloid-independent pathway in which vascular burden affects cognitive function via localized neurodegeneration. HIGHLIGHTS: Alzheimer's disease often co-exists with vascular pathology. We studied a unique cohort enriched for high white matter hyperintensities (WMH). High WMH related to cognitive impairment of semantic fluency and executive function. This relationship was mediated via temporo-parietal atrophy rather than metabolism. This relationship was, to lesser extent, serially mediated via amyloid beta and atrophy.
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Doença de Alzheimer , Disfunção Cognitiva , Substância Branca , Humanos , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Afinamento Cortical Cerebral/patologia , Imageamento por Ressonância Magnética , Cognição , Disfunção Cognitiva/metabolismo , Tomografia por Emissão de Pósitrons , Amiloide/metabolismo , Atrofia/patologia , Substância Branca/patologiaRESUMO
BACKGROUND: Detection of skeletal metastases in patients with prostate cancer or breast cancer remains a major clinical challenge. We aimed to compare the diagnostic performance of 99mTc-methylene diphosphonate (99mTc-MDP) single-photon emission CT (SPECT) and 18F-sodium fluoride (18F-NaF) PET-CT for the detection of osseous metastases in patients with high-risk prostate or breast cancer. METHODS: MITNEC-A1 was a prospective, multicentre, single-cohort, phase 3 trial conducted in ten hospitals across Canada. Patients aged 18 years or older with breast or prostate cancer with a WHO performance status of 0-2 and with high risk or clinical suspicion for bone metastasis, but without previously documented bone involvement, were eligible. 18F-NaF PET-CT and 99mTc-MDP SPECT were done within 14 days of each other for each participant. Two independent reviewers interpreted each modality without knowledge of other imaging findings. The primary endpoint was the overall accuracy of 99mTc-MDP SPECT and 18F-NaF PET-CT scans for the detection of bone metastases in the per-protocol population. A combination of histopathological, clinical, and imaging follow-up for up to 24 months was used as the reference standard to assess the imaging results. Safety was assessed in all enrolled participants. This study is registered with ClinicalTrials.gov, NCT01930812, and is complete. FINDINGS: Between July 11, 2014, and March 3, 2017, 290 patients were screened, 288 of whom were enrolled (64 participants with breast cancer and 224 with prostate cancer). 261 participants underwent both 18F-NaF PET-CT and 99mTc-MDP SPECT and completed the required follow-up for statistical analysis. Median follow-up was 735 days (IQR 727-750). Based on the reference methods used, 109 (42%) of 261 patients had bone metastases. In the patient-based analysis, 18F-NaF PET-CT was more accurate than 99mTc-MDP SPECT (84·3% [95% CI 79·9-88·7] vs 77·4% [72·3-82·5], difference 6·9% [95% CI 1·3-12·5]; p=0·016). No adverse events were reported for the 288 patients recruited. INTERPRETATION: 18F-NaF has the potential to displace 99mTc-MDP as the bone imaging radiopharmaceutical of choice in patients with high-risk prostate or breast cancer. FUNDING: Canadian Institutes of Health Research.
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Neoplasias Ósseas , Neoplasias da Mama , Neoplasias da Próstata , Masculino , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Fluoreto de Sódio , Fluordesoxiglucose F18 , Imagem Multimodal/métodos , Tomografia por Emissão de Pósitrons/métodos , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Estudos Prospectivos , Canadá , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Neoplasias Ósseas/secundário , Cintilografia , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Background The high positivity rate of prostate-specific membrane antigen (PSMA) PET in the setting of biochemical failure (BCF), even when conventional imaging is negative, is promising. Purpose To assess the disease detection rate of PSMA-based PET/CT with fluorine 18-DCFPyL as a radiotracer and the PET-directed management change in men with suspected limited recurrent prostate cancer. Materials and Methods This prospective multicenter registry (Ontario PSMA-PET Registry for Recurrent Prostate Cancer, or PREP) enrolled men with BCF after primary therapy (radical prostatectomy plus or minus salvage radiation therapy or primary radiation therapy) and zero to four disease sites at conventional imaging (CT and bone scintigraphy). The positivity rate of PSMA PET according to serum prostate-specific antigen (PSA) level; frequency of local-egional, oligometastatic, and extensive metastatic recurrence; and rate of change in management after PET findings were recorded. The nonparametric Mood median test was used to assess the association between serum PSA level and change in management. Results A total of 1289 men (median age, 71 years [interquartile range, 65-75 years]) were evaluated. PSMA PET helped detect disease in 841 of 1289 men (65%) and in 615 of 999 men (62%) with negative conventional imaging. The recurrence detection rates according to serum PSA level at enrollment were 38% (160 of 424 men), 63% (107 of 171 men), and 83% (573 of 692 men) for PSA under 0.5 ng/mL, 0.5-1.0 ng/mL, and above 1.0 ng/mL, respectively. At PSMA PET, 399 of 1289 men (31%) had local-regional recurrence, 314 (24%) had oligometastatic disease, and 128 (10%) had extensive metastases. Following PET examination, a change in planned management was recorded in 748 of 1289 men (58%), and in 371 of 1250 men (30%), there was a change in management intent, more commonly from palliative to potentially curative intent (255 of 1289 men [20%]). Conclusion Prostate-specific membrane antigen PET helped detect additional sites of disease compared with conventional imaging in approximately 60% of men with biochemical failure and suspected low-volume metastatic disease, resulting in frequent change in management, including a change from palliative to curative or radical intent therapy in 20% of men. Long-term follow-up is needed to determine whether this impacts disease control. Clinical trial registration no. NCT03718260 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Civelek in this issue.
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Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata , Idoso , Humanos , Masculino , Recidiva Local de Neoplasia/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Estudos Prospectivos , Antígeno Prostático Específico , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Neoplasias da Próstata/terapia , Sistema de Registros , Tomografia Computadorizada por Raios XRESUMO
BACKGROUND: Positron emission tomography targeting the prostate specific membrane antigen (PSMA PET/CT) has demonstrated unparalleled performance as a staging examination for prostate cancer resulting in substantial changes in management. However, the impact of altered management on patient outcomes is largely unknown. This study aims to assess the impact of intensified radiotherapy or surgery guided by PSMA PET/CT in patients at risk of advanced prostate cancer. METHODS: This pan-Canadian phase III randomized controlled trial will enroll 776 men with either untreated high risk prostate cancer (CAPRA score 6-10 or stage cN1) or biochemically recurrent prostate cancer post radical prostatectomy (PSA > 0.1 ng/mL). Patients will be randomized 1:1 to either receive conventional imaging or conventional plus PSMA PET imaging, with intensification of radiotherapy or surgery to newly identified disease sites. The primary endpoint is failure free survival at 5 years. Secondary endpoints include rates of adverse events, time to next-line therapy, as well as impact on health-related quality of life and cost effectiveness as measured by incremental cost per Quality Adjusted Life Years gained. DISCUSSION: This study will help create level 1 evidence needed to demonstrate whether or not intensification of radiotherapy or surgery based on PSMA PET findings improves outcomes of patients at risk of advanced prostate cancer in a manner that is cost-effective. TRIAL REGISTRATION: This trial was prospectively registered in ClinicalTrials.gov as NCT04557501 on September 21, 2020.
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Antígenos de Neoplasias/metabolismo , Proteínas de Neoplasias/metabolismo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata/terapia , Radioterapia Guiada por Imagem/métodos , Cirurgia Assistida por Computador/métodos , Adulto , Canadá , Ensaios Clínicos Fase III como Assunto , Estudos de Equivalência como Asunto , Radioisótopos de Flúor , Proteínas Ligadas por GPI/metabolismo , Humanos , Análise de Intenção de Tratamento , Masculino , Recidiva Local de Neoplasia/diagnóstico por imagem , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/terapia , Estadiamento de Neoplasias/métodos , Ensaios Clínicos Pragmáticos como Assunto , Estudos Prospectivos , Prostatectomia/métodos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/metabolismo , Compostos Radiofarmacêuticos , Radioterapia de Intensidade Modulada/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do TratamentoRESUMO
BACKGROUND: Cabozantinib can enhance the effect of abiraterone in preclinical prostate cancer models. This study aimed to define the recommended phase 2 dose (RP2D) and preliminary efficacy of abiraterone + cabozantinib in mCRPC. METHODS: Patients with progressive mCRPC with 0-2 prior chemotherapy regimens but no prior CYP17A1 or MET inhibitor received abiraterone acetate at 1000 mg daily with prednisone 5 mg BID in combination with cabozantinib at 20, 40, or 60 mg daily in a dose-escalation 3 + 3 open-label phase 1 design (Part A). After tolerable doses were defined, cohorts were expanded to better define toxicity and efficacy (Part B). RESULTS: There were no dose-limiting toxicities (DLTs) in the first 4 weeks at any of the three dose levels in Part A. Two of the three patients at the 60 mg dose level required dose reductions beyond cycle 2 due to fatigue. In Part B, nine more patients were accrued to each of the 20 and 40 mg doses. Of the 12 patients treated at the 40 mg dose, only one DLT (grade 3 Lipase elevation) was observed in cycle 1. The median time to radiographic progression was 12.88 months (95% CI:5.42- not estimated [NE]) in the 20 mg cohort and 22.01 months (95% CI:15.44-NE) in the 40 mg cohort. Median overall survival was 23.29 months (95% CI:19.06-NE) in the 20 mg cohort and 39.08 months (95% CI:17.38-NE) in the 40 mg cohort. CONCLUSIONS: Based on tolerability and preliminary efficacy, 40 mg cabozantinib plus 1000 mg abiraterone daily is the RP2D.
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OBJECTIVE: In this article, we review the literature on PET/CT in the management of dementia, present evidence for best clinical practices, and discuss recent advances in the field. CONCLUSION: Standard-of-care imaging for dementia includes CT and MRI, primarily for excluding vascular lesions or masses, detecting atrophy, and monitoring disease severity. PET/CT is a powerful functional modality that can differentiate dementia types and influence management. Fluorine-18-FDG PET/CT reveals the spatial pattern of glucose metabolism in the brain. More recently, radiotracers for PET have been developed that bind to amyloid protein, tau protein, and neuroinflammatory markers.
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Demência/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Demência/classificação , Diagnóstico Diferencial , Fluordesoxiglucose F18 , Humanos , Compostos RadiofarmacêuticosRESUMO
BACKGROUND: Bone health is a significant concern in men with prostate cancer. PURPOSE: To evaluate the effectiveness of drug, supplement, and lifestyle interventions aimed at preventing fracture, improving bone mineral density (BMD), or preventing or delaying osteoporosis in men with nonmetastatic prostate cancer. DATA SOURCES: Ovid MEDLINE (1946 to 19 January 2017), EMBASE (1980 to 18 January 2017), and the Cochrane Database of Systematic Reviews (19 January 2017). STUDY SELECTION: Randomized trials and systematic reviews of trials that were published in English; involved men with nonmetastatic prostate cancer; and compared bone-targeted therapies with placebo, usual care, or other active treatments. DATA EXTRACTION: Two reviewers independently extracted study characteristics and assessed study risk of bias for each outcome. DATA SYNTHESIS: Two systematic reviews and 28 reports of 27 trials met inclusion criteria. All trials focused on men with nonmetastatic prostate cancer who were initiating or continuing androgen deprivation therapy (ADT). Bisphosphonates were effective in increasing BMD, but no trial was sufficiently powered to detect reduction in fractures. Denosumab improved BMD and reduced the incidence of new radiographic vertebral fractures in 1 high-quality trial. No trials compared calcium or vitamin D versus placebo. Three lifestyle intervention trials did not show a statistically significant difference in change in BMD between exercise and usual care. LIMITATIONS: Most trials were of moderate quality. Only 2 randomized controlled trials were designed to examine fracture outcomes. Potential harms of treatments were not evaluated. CONCLUSION: Both bisphosphonates and denosumab improve BMD in men with nonmetastatic prostate cancer who are receiving ADT. Denosumab also reduces risk for radiographic vertebral fractures, based on 1 trial. More trials studying fracture outcomes are needed in this population. PRIMARY FUNDING SOURCE: Program in Evidence-Based Care.
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Antagonistas de Androgênios/efeitos adversos , Antineoplásicos Hormonais/efeitos adversos , Conservadores da Densidade Óssea/uso terapêutico , Osteoporose/prevenção & controle , Neoplasias da Próstata/tratamento farmacológico , Antagonistas de Androgênios/uso terapêutico , Antineoplásicos Hormonais/uso terapêutico , Densidade Óssea/efeitos dos fármacos , Denosumab/uso terapêutico , Humanos , Masculino , Osteoporose/induzido quimicamente , Fraturas por Osteoporose/prevenção & controle , Toremifeno/uso terapêuticoRESUMO
PURPOSE: To determine if the minimum administered radiopharmaceutical activity for hepatobiliary scintigraphy can be reduced while preserving diagnostic image quality using enhanced planar processing (EPP). METHODS: A total of 40 infants between 10 and 270 days old (body mass 2.2 - 6.5 kg) had hepatobiliary scintigraphy during the period 2004 - 2010 following the intravenous administration of either (99m)Tc-mebrofenin (18 patients) or (99m)Tc-disofenin (22 patients). Due to the small size of these patients, they all received the minimum administered activity of 18.5 MBq consistent with the North American Consensus Guidelines. Six nuclear medicine physicians subjectively graded the acceptability of the image quality for clinical interpretation using a four-point scale (not acceptable, fair, good, excellent). Each physician independently graded seven image sets including the original study (full activity) and simulated reduced activity studies using binomial subsampling (50% of full activity, 25% of full activity and activity reduced by weight), with and without EPP. RESULTS: For full-activity studies, 98% were deemed acceptable by the six physicians for clinical interpretation. The percentages of acceptable 50% reduced activity studies with and without EPP were not significantly different from the percentage of acceptable full-activity studies (P = 0.193 and P = 0.998, respectively). The percentage of acceptable 25% reduced activity studies without EPP was significantly different from the percentage of acceptable full-activity studies (P < 0.001); however, this difference vanished when EPP was applied (P = 0.482). The activity reduced by weight ranged from 1.85 to 4.81 MBq (10% to 26% of full dose) and the percentages of acceptable studies with and without EPP were significantly different from the percentage of acceptable full-activity studies (P < 0.001 and P = 0.02, respectively). CONCLUSION: Clinically interpretable hepatobiliary scintigraphy images can be obtained in infants when the minimum administered activity is substantially reduced. Without EPP, clinically acceptable images may be produced with a reduction of 50%, and with EPP, a reduction of 75% or more may be possible.
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Sistema Biliar/diagnóstico por imagem , Iminoácidos/administração & dosagem , Fígado/diagnóstico por imagem , Compostos de Organotecnécio/administração & dosagem , Guias de Prática Clínica como Assunto , Compostos Radiofarmacêuticos/administração & dosagem , Disofenina Tecnécio Tc 99m/administração & dosagem , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Compostos de Anilina , Feminino , Glicina , Humanos , Processamento de Imagem Assistida por Computador/métodos , Lactente , Recém-Nascido , Masculino , Doses de Radiação , Tomografia Computadorizada de Emissão de Fóton Único/normasAssuntos
Densidade Óssea , Neoplasias da Próstata , Antagonistas de Androgênios , Humanos , MasculinoRESUMO
This article focuses on the role of PET/computed tomography in evaluating and managing gastric cancer and colorectal cancer. The authors start with describing the common aspects of imaging with 2-deoxy-2-18F-d-glucose, followed by tumor-specific discussions of gastric and colorectal malignancies. Finally, the authors provide a brief overview of non-FDG tracers including their potential clinical applications, and describe future directions in imaging these malignancies.
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Neoplasias Colorretais , Neoplasias Gástricas , Humanos , Fluordesoxiglucose F18 , Tomografia Computadorizada por Raios X/métodos , Neoplasias Gástricas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Neoplasias Colorretais/diagnóstico por imagem , Neoplasias Colorretais/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodosRESUMO
PURPOSE: This study examines the diagnostic accuracy of brain perfusion SPECT for mild traumatic brain injury (mTBI). PATIENTS AND METHODS: A systematic review and meta-analysis was performed according to PRISMA guidelines (PROSPERO: CRD42023484636). Five databases were searched for studies evaluating brain perfusion SPECT in adult patients with mTBI (GCS 13-15). Study quality was assessed using a modified QUADAS-2 tool. A meta-analysis was performed to pool proportions of hypoperfusion abnormalities across brain lobes. RESULTS: Of 4735 records, 22 studies (5 longitudinal [40% high quality], 17 cross-sectional [24% high quality]) were included totaling 800 patients (mean age, 37.4 ± 12.6 years; 36.4% female). Meta-analysis of proportions indicated that the frontal lobe most frequently showed hypoperfusion on brain perfusion SPECT (pooled proportion 40.1% [95% confidence interval, 31.2% to 49.8%], 99/254, I2 = 54.5%), followed by the temporal lobe (26.1% [95% confidence interval, 19.9% to 33.6%], 68/254, I2 = 30.7%). Several studies found that hypoperfusion abnormalities were associated with neuropsychological findings. Also, brain perfusion SPECT could detect abnormalities not seen on MRI. Abnormalities in perfusion on brain perfusion SPECT may be more readily detected with a quantitative assessment compared with a visual assessment alone, although there appears to be no consensus on the optimal method for image interpretation. Evidence evaluating the sensitivity and specificity of brain perfusion SPECT for mTBI was limited. Using the GRADE framework, the evidence was rated as low. CONCLUSIONS: Although perfusion abnormalities can be seen in patients with mTBI, commonly in the frontal and temporal lobes, the findings are nonspecific and may derive from various factors. Ultimately, brain perfusion SPECT provides additional information for mTBI, but the final added value for the detection of mTBI is unknown.
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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 99mTc carbon particles, 97.1% 81mKr gas, 58.7% 99mTc-DTPA, and 19.4% 133Xe 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.