the Quarterly Journal of Nuclear Medicine and Molecular Imaging最新文献

Prostate cancer (PCa) is a heterogeneous disease and prevalent malignancy in men, necessitating accurate imaging techniques to facilitate effective diagnosis and management. Recent evidence has demonstrated that [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) and prostate-specific membrane antigen (PSMA)-targeted PET tracers positron emission tomography/computed tomography (PET/CT) imaging can provide complementary biological information, thereby improving diagnostic accuracy and the assessment of lesion heterogeneity in patients with PCa. However, optimal protocols for PSMA/FDG dual-tracer PET/CT and PET/magnetic resonance (PET/MR) imaging remain under investigation. Total-body PET/CT, with its enhanced sensitivity, enables imaging with low tracer activity and facilitates the development of novel dual-tracer PET/CT imaging protocols. PET/MR offers additional valuable information for the diagnosis and local staging of PCa due to its superior soft tissue resolution and multiparametric capabilities. Thanks to the longer MR acquisition time, it is possible to perform low-activity radiotracer PET imaging with the same long-time MR acquisition. Additionally, advancements in time-of-flight technology and the improved sensitivity of PET systems further make low-activity radiotracer PET/MR imaging clinically feasible. Given that expertise in total-body PET/CT imaging technology and access to PET/MR scanners are limited to a relatively small number of institutions worldwide, this review provides clinical exploration to optimize workflows for [⁶⁸Ga]Ga-PSMA-11 and [¹⁸F]FDG dual-tracer PET/CT and PET/MR imaging, with a focus on radiation dose reduction through dual-low-activity-tracer imaging protocols.

Radiopharmaceutical therapy is emerging rapidly as an effective and safe pillar in cancer management. The regulatory approvals for ¹⁷⁷Lu-PSMA-617 radiopharmaceutical therapy in both the pre- and post-chemotherapy metastatic castration resistant prostate cancer clinical space have paved the way for the implementation of this life-prolonging therapy in clinical practice. However, the emergence of resistance to radiopharmaceutical therapy is inevitable, and therefore, combination therapies will be needed to synergize treatment efficacy without untoward collective toxicity. Biologically rational combination therapies across various phases of prostate cancer will lead to more optimal patient outcomes than what can be achieved with monotherapy. This article summarizes select clinical trials on prostate-specific membrane antigen-targeted radiopharmaceutical therapy in combination with other treatments that are either actively accruing or have provided preliminary results.

Targeted alpha therapy (TAT) has shown promise in prostate cancer patients, both hormone-sensitive and castration-resistant, with or without prior treatment. TAT's radiobiological properties explain why it is more potent than other forms of ionizing radiation, such as the clinically approved [¹⁷⁷Lu]Lu-PSMA-617. Although most TAT agents used in compassionate care or clinical trials target the prostate-specific membrane antigen (PSMA), some alternatives are yet to be used clinically, some of which aim to address PSMA-negative prostate cancer. These include [²²³Ra]RaCl2, which is approved for palliative bone pain, and a variety of other non-PSMA antigen or receptor-targeting medicines. Whereas this study focuses on TAT medicines that are currently available for clinical use, it also explores these preclinical agents.

Introduction: This systematic review investigates the potential of artificial intelligence (AI) in improving the accuracy and efficiency of prostate-specific membrane antigen positron emission tomography (PSMA PET) scans for detecting metastatic prostate cancer.

Evidence acquisition: A comprehensive literature search was conducted across Medline, Embase, and Web of Science, adhering to PRISMA guidelines. Key search terms included "artificial intelligence," "machine learning," "deep learning," "prostate cancer," and "PSMA PET." The PICO framework guided the selection of studies focusing on AI's application in evaluating PSMA PET scans for staging lymph node and distant metastasis in prostate cancer patients. Inclusion criteria prioritized original English-language articles published up to October 2024, excluding studies using non-PSMA radiotracers, those analyzing only the CT component of PSMA PET-CT, studies focusing solely on intra-prostatic lesions, and non-original research articles.

Evidence synthesis: The review included 22 studies, with a mix of prospective and retrospective designs. AI algorithms employed included machine learning (ML), deep learning (DL), and convolutional neural networks (CNNs). The studies explored various applications of AI, including improving diagnostic accuracy, sensitivity, differentiation from benign lesions, standardization of reporting, and predicting treatment response. Results showed high sensitivity (62% to 97%) and accuracy (AUC up to 98%) in detecting metastatic disease, but also significant variability in positive predictive value (39.2% to 66.8%).

Conclusions: AI demonstrates significant promise in enhancing PSMA PET scan analysis for metastatic prostate cancer, offering improved efficiency and potentially better diagnostic accuracy. However, the variability in performance and the "black box" nature of some algorithms highlight the need for larger prospective studies, improved model interpretability, and the continued involvement of experienced nuclear medicine physicians in interpreting AI-assisted results. AI should be considered a valuable adjunct, not a replacement, for expert clinical judgment.

Giant cell arteritis (GCA) is the most common of the large vessel vasculitides, with [¹⁸F] fluorodeoxyglucose (FDG) PET/CT indicated for evaluation of suspected large vessel involvement. Advances in PET/CT technology, particularly with digital PET, have significantly improved the assessment of cranial artery involvement in GCA. Recent guidelines have been updated to incorporate [¹⁸F]FDG PET/CT imaging in the diagnosis of GCA. This review article provides a practical guide to the most recent recommendations regarding PET/CT study indications, image acquisition and interpretation criteria for GCA, while discussing potential pitfalls and future research directions in the field.

Diagnosis of spondylodiscitis remains a challenge for clinicians. It results from various causative agents and conditions that can be challenging to identify. Prompt and appropriate treatment are necessary to prevent long-term irreversible complications and sequelae. The diagnosis of spondylodiscitis often constitutes a major challenge for the clinicians, and relies on the combination of clinical, laboratory and imaging findings. Various imaging techniques can be used for the workup of spondylodiscitis, with magnetic resonance imaging and 18-fluoro-deoxy-glucose positron emission tomography, combined with a CT being the most commonly used in daily practice. The aim of this review is to provide general information about indications and protocols for [¹⁸F]FDG PET/CT imaging in spinal infections, focusing on spondylodiscitis, in adults.

¹⁸F fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) has established itself as a critical diagnostic tool in the evaluation of patients with bacteremia and fever of unknown origin (FUO), particularly following futile conventional investigations. These conditions are often challenging due to diverse underlying etiologies, including infections, inflammatory conditions and malignancies. PET/CT has the advantage of being a whole-body imaging technique with high sensitivity for detecting areas of increased metabolism often associated with infection or inflammation. In bacteremia, [¹⁸F]FDG PET/CT can help identify metastatic infections, endocarditis, or abscesses which may be clinically silent and missed on conventional imaging. In FUO, it helps to identify underlying etiologies, directing treatment and management strategies. This review aims to describe the role of PET/CT imaging in these diverse clinical scenarios. Perspectives in the field, including novel equipment and tracers, will be briefly discussed.

Cardiovascular infections have a high mortality rate requiring prompt diagnosis and timely management. [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography/computed tomography (PET/CT) has emerged as a valuable diagnostic imaging modality for various cardiovascular infections, including infective endocarditis (IE) and cardiac implantable electronic device (CIED) infections, particularly when the diagnosis remains challenging. In this article, we provide an overview of the epidemiology and clinical presentation of IE and CIED-related infections, the indications for ¹⁸F-FDG-PET/CT and its incremental role in establishing diagnosis as well as illustrate a variety of clinical cases and discuss interpretation criteria.

Vascular graft infections (VGI) are rare but severe complications following vascular surgery, with significant morbidity and mortality. Diagnosing VGI requires a multidisciplinary approach combining clinical, laboratory, and imaging findings. While CTA remains the first-line imaging modality, its limitations in detecting chronic or low-grade infections highlight the value of advanced nuclear medicine techniques, particularly [¹⁸F]FDG PET/CT. In this review, we discuss the role of [¹⁸F]FDG PET/CT in diagnosing VGI, emphasizing its high sensitivity and negative predictive value, which are critical for ruling out infection. Nevertheless, there are currently no universally accepted criteria for analyzing PET/CT findings in VGI, which poses challenges for consistent interpretation and clinical decision-making. This review aims to provide a comprehensive understanding of FDG PET/CT imaging in the context of VGI by exploring visual grading scales, uptake patterns, and semi-quantitative parameters while highlighting potential pitfalls such as post-surgical inflammation and false-positive results due to graft materials or surgical adhesives. Through a series of illustrative cases, we outline characteristic imaging patterns of infected and non-infected grafts, offering practical guidance for accurate interpretation. Additionally, we discuss the evolving role of FDG PET/CT in assessing treatment response and guiding follow-up in VGI management. This pictorial review seeks to enhance diagnostic accuracy and bridge the gap in standardized PET/CT interpretation criteria, ultimately contributing to improved patient care.