Search Results (227)

18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) could be useful to assess inflammation of the aortic wall, a potential early indicator of aneurysm formation. Nonetheless, its current clinical assessment presents several limitations. The study aimed to develop and validate an innovative technique to obtain thoraco-abdominal aortic wall PET uptake maps. PET/magnetic resonance (MR) was acquired in 82 patients with aortic aneurysms. The thoraco-abdominal aorta was segmented and expanded inward and outward (by 1 to 5 mm) and discretized into 80 standardized wall patches. Standard uptake values (SUV) were calculated for each patch and the thrombus. For inter-observer reproducibility, a second blinded observer analyzed 26 random patients. Validation against manual expert measurements was performed. The feasibility of the patch-wise PET analysis was 98.4%. Inter-observer Dice scores were 0.89 for lumen and 0.82 for thrombus segmentations. SUV mapping presented excellent reproducibility, modestly improving with wall thickness (ICC 0.950 to 0.966), while its agreement with expert measurements improved with thinner walls (ICC 0.848 to 0.755). An optimal balance between reproducibility and accuracy was obtained at 6 mm wall thickness. Reproducible and accurate thoraco-abdominal aortic wall 18F-FDG uptake maps can be obtained from PET/MR, potentially facilitating the exploration of local factors associated with vascular inflammation. Full article

Metabolic imaging is undergoing a fundamental transformation. Traditionally confined to static representations of metabolite distribution through modalities such as PET, MRS, and MSOT, imaging has offered only partial glimpses into the dynamic and systemic nature of metabolism. This Perspective envisions a shift toward dynamic metabolic intelligence—an integrated framework where real-time imaging is fused with physics-informed models, artificial intelligence, and wearable data to create adaptive, predictive representations of metabolic function. We explore how novel technologies like hyperpolarized MRI and time-resolved optoacoustics can serve as dynamic inputs into digital twin systems, enabling closed-loop feedback that not only visualizes but actively guides clinical decisions. From early detection of metabolic drift to in silico therapy simulation, we highlight translational pathways across oncology, cardiology, neurology, and space medicine. Finally, we call for a cross-disciplinary effort to standardize, validate, and ethically implement these systems, marking the emergence of a new paradigm: metabolism as a navigable, model-informed space of precision medicine. Full article

The study assesses the relationship between thalamic proton-MR spectroscopy (¹H-MRS) metabolites and thalamic ¹¹C-ER176 translocator-protein positron emission tomography (TSPO-PET) standardized uptake value ratios (SUVR) to advance our understanding of thalamic involvement in multiple sclerosis (MS)-associated neurodegeneration and disability. In this prospective cross-sectional study, patients with MS (pwMS) and controls underwent 3T-MRI, ¹H-MRS, and ¹¹C-ER176-PET targeting the thalamus. MRI-derived thalamic volume was normalized by intracranial volume. ¹H-MRS metabolites—N-acetylaspartate (NAA), glutamate (Glu), glutamine (Gln), total choline (tCho), and myo-inositol (mIns)—were normalized to total creatine (tCr). Clinical disability was evaluated using MS-specific tests of Expanded Disability Status Scale-EDSS and MS-functional composite-MSFC (including Paced Auditory Serial Addition Test-PASAT). Compared to controls (n = 30), pwMS (n = 21) exhibited smaller thalamic volume, higher thalamic ¹H-MRS mIns/tCr (putative gliosis marker), and higher thalamic ¹¹C-ER176-PET SUVR (glial density marker). In pwMS, higher thalamic mIns/tCr (r = −0.67) and tCho/tCr (r = −0.52) correlated with smaller thalamic volume. In pwMS, higher thalamic mIns/tCr correlated with higher thalamic ¹¹C-ER176-PET SUVR (r = 0.48) and decreased cognitive function (PASAT, rho = −0.48). In controls, decreased thalamic NAA/tCr correlated with increased thalamic ¹¹C-ER176-PET SUVR (r = −0.41). Thalamus, a core central nervous system relay, is affected early in MS disease course. Glial-mediated innate immune activation in the thalamus, evaluated by increased ¹H-MRS mIns/tCr and ¹¹C-ER176-PET SUVR, is associated with loss of thalamic volume and increased disability in pwMS. The multimodal imaging approach with ¹H-MRS mIns/tCr and ¹¹C-ER176-PET SUVR emerges as potential glial biomarkers, to better understand disease mechanisms and evaluate therapeutic interventions targeting glial activity in MS. Full article

Background: It is unclear whether sex or age impacts the prognostic value of a zero coronary artery calcium (CAC) score. Methods: We searched our electronic medical record (eMR) database for primary prevention patients who underwent positron emission tomography/computed tomography (PET/CT) stress testing. We assessed coronary prognosis and all-cause death during 2.2 (SD 1.9) years of follow-up in women vs. men and in those ≥65 vs. <65 years old by CAC = 0 vs. CAC > 0 scores. Results: We identified 40,018 qualifying patients, of which 48.7% were women and 58.9% were ≥65. CAC = 0 was present in 7967 (19.9%), of which 67.8% were women, and 34.9% were aged ≥65. In CAC = 0 patients, 13 coronary events occurred: 7 (0.13%) in women and 6 (0.24%) in men (p = 0.28); and 6 (0.12%) in <65 and 7 (0.25%) in ≥65 years old (p = 0.15). All-cause death rates comparing CAC = 0 to CAC > 0 subjects were 3.1% vs. 9.8% overall: 3.1% vs. 9.5% in women and 3.3% vs. 10.2% in men, 2.4% vs. 6.9% for ages <65, and 4.7% vs. 11.5% for ≥65 years old; all p < 0.001. Conclusions: A zero CAC score predicts an excellent prognosis for not only coronary events but also all-cause mortality, both overall and in women and the elderly. Full article

Purpose or Objective: To evaluate the feasibility and clinical utility of integrating sequential PSMA-PET imaging into an offline–online adaptive workflow for response-based dominant intraprostatic lesion (DIL)-boosting high-risk prostate cancer treated with stereotactic ablative radiotherapy (SABR). Materials and Methods: As part of a prospective trial, patients were treated on MR- or CBCT-guided adaptive radiotherapy (ART) systems with prostate/pelvic node 5-fraction SABR (36.25 Gy/25 Gy) with DIL boost (50 Gy). Whereas traditional DIL boost volumes delineate full pre-therapy imaging-defined disease (GTVinitial), this study serially refined DIL boost volumes based on treatment response defined by PSMA-PET scans after neoadjuvant androgen deprivation therapy (nADT, GTVmb1) and fraction 3 SABR (GTVmb2). DIL delineation employed PET-PSMA fusion to CT/MR simulation and was guided by a rule-based %SUVmax threshold approach. Comparisons of GTV volumes and OAR dosimetry were performed between plans using GTVinitial versus GTVmb1/GTVmb2 for DIL boost, for each of the initial cohorts of five patients from the initially treated cohorts. Results: Five patients treated on MR-Linac (n = 3) or CBCT-based ART (n = 2) were analyzed. Three patients exhibited complete imaging response after nADT, omitting GTVmb boosts. Offline GTVmb refinements based on PSMA-PET were seamlessly integrated into ART workflows without introducing additional treatment time. DIL GTV volumes significantly decreased (p = 0.03) from an initial mean of 11.4 cc (GTVinitial) to 4.1 cc (GTVmb1) and 3.0 cc (GTVmb2). Dosimetric analysis showed meaningful reductions in OAR doses: rectal wall D0.035 cc decreased by up to 12 Gy, while bladder wall D0.035 cc and V18.3 Gy reduced from 52.3 Gy and 52.3 cc (Plan_initial) to 42.9 Gy and 24.9 cc (Plan_mb2), respectively. Urethra doses remained stable, with minor reductions. Sigmoid and femoral head doses remained within acceptable limits. Online adaptation efficiently addressed daily anatomical variations, enabling simulation-free plan re-optimization. Conclusion: PSMA-PET-guided adaptive microboosting for HRPCa SABR is feasible and effective. Standard MR-Linac and CBCT systems offer practical alternatives to BgRT platforms, enabling biology-driven dose personalization and potentially reducing toxicity. Full article

Imaging techniques such as positron emission tomography/computed tomography (PET/CT) and positron emission tomography/magnetic resonance imaging (PET/MR) have emerged as powerful and versatile tools for the comprehensive assessment of coronary artery disease (CAD). By combining anatomical and functional information in a single examination, these modalities offer complementary insights that significantly enhance diagnostic accuracy and support clinical decision-making. This is particularly relevant in complex clinical scenarios, such as multivessel disease, balanced ischemia, or suspected microvascular dysfunction, where conventional imaging may be inconclusive. This review aims to provide clinicians with an up-to-date summary of the principles, technical considerations, and clinical applications of hybrid PET/CT and PET/MR in CAD. Here, we describe how these techniques can improve the evaluation of myocardial perfusion, coronary plaque characteristics, and ischemic burden. Advantages such as improved sensitivity, spatial resolution, and quantification capabilities are discussed alongside limitations including cost, radiation exposure, availability, and workflow challenges. A dedicated focus is given to the emerging role of artificial intelligence (AI), which is increasingly being integrated to optimize image acquisition, fusion processes, and interpretation. AI has the potential to streamline hybrid imaging and promote a more personalized and efficient management of CAD. Finally, we outline future directions in the field, including novel radiotracers, automated quantitative tools, and the expanding use of hybrid imaging to guide patient selection and therapeutic decisions, particularly in revascularization strategies. Full article

Background: The normal pattern of nipple enhancement on magnetic resonance imaging (MRI) is defined based on healthy individuals, as it correlates with the structural anatomy of the nipple–areola complex (NAC). Understanding the normal range of nipple morphology and enhancement on MRI allows radiologists to better identify abnormalities. Some authors have previously detailed the morphology and characteristics of nipple–areola complex enhancement, both in normal and pathologically infiltrating conditions. Our aim is to present a case series involving a population of women with breast cancer infiltrating the NAC, retrospectively evaluated at our institution. Furthermore, based on previously published literature and our own experience, we intend to propose potential standardized language to describe tumor-infiltrating NAC enhancement on MRI and compare it with CT and PET findings. Methods: Our study included 110 breast cancer patients with NAC infiltration, who were referred to our hospital from August 2023 to July 2024. All patients were candidates for neoadjuvant chemotherapy and therefore underwent MRI and CT; 33 of them also underwent PET/CT. We distinguished the MRI enhancement pattern based on morphology and intensity. There were three types of morphology: SLE (superficial linear enhancement) at the skin level, NEZ (non-enhancing area immediately below the SLE), and INE (nipple enhancement below the NEZ but above the nipple base). In INE, the pattern could be linear or patchy. Depending on the intensity, the enhancement could be minimal, mild, moderate, or marked. The enhancement on CT depended on the distribution of pathological tissue in the infiltrated NAC and could be present or absent; it could involve the nipple base, the nipple body, or both. For quantitative analysis, we used the maximum standardized uptake value (SUV) measured in early-stage PET/CT images, obtained by delineating a three-dimensional volume of interest (VOI) on the NAC. Results: In our population, the most represented enhancement pattern was INE (110), while slightly less than half of the patients showed invasion of the NEZ (49). Approximately one quarter of the patients presented linear ductal INE (36), while the majority presented patchy INE (74). On CT and PET/CT, NAC enhancement was detectable in almost all patients (102), mainly involving the base and the body together. Correlation analysis in the following pairs of variables showed a high association, with a Kendall’s tau value greater than 0.7 (p < 0.001): (1) involvement of the NEZ on ce-MR and pattern of nipple involvement on ce-CT (CT score); (2) morphological pattern of INE on ce-MR (INE score) and intensity of INE enhancement on MR; and (3) pattern of nipple involvement on ce-CT (CT score) and intensity of INE enhancement on MR. The calculated mean SUV of pathological NACs on PET/CT for early-stage images was 3.59, while the mean SUV of contralateral normal NACs was 2.12. The calculated mean NAC-SUV ratio was 1.7. Conclusions: Although pathological involvement of the NAC cannot always be assessed in the final surgical specimen due to the effects of neoadjuvant chemotherapy, so the “gold standard” of histological reference is missing, MRI and CT with morphology and enhancement descriptors, and additionally PET/CT with SUV measurement can, in our opinion, provide valuable information on the infiltrated nipple. Standardized language for describing breast tumors infiltrating the NAC is desirable to ensure consistent interpretation across different radiologists. Full article

Background/Objectives: Cardiac sarcoidosis (CS) is an inflammatory cardiomyopathy with a strong clinical impact on patients affected by the disease and a challenging diagnosis. Methods: This comprehensive narrative review evaluates the role of [18F]fluorodesoxyglucose ([18F]FDG) positron emission tomography (PET)-based radiomics and machine learning (ML) analyses in the assessment of CS. Results: The value of [18F]FDG PET-based radiomics and ML has been investigated for the clinical settings of diagnosis and prognosis of patients affected by CS. Even though different radiomics features and ML models have proved their clinical role in these settings in different cohorts, the clear superiority and added value of one of them across different studies has not been demonstrated. In particular, textural analysis and ML showed high diagnostic value for the diagnosis of CS in some papers, but had controversial results in other works, and may potentially provide prognostic information and predict adverse clinical events. When comparing these analyses with the classic semiquantitative evaluation, a conclusion about which method best suits the final objective cannot be drawn with the available references. Different methodological issues are present when comparing different papers, such as image segmentation and feature extraction differences that are more evident. Furthermore, the intrinsic limitations of radiomics analysis and ML need to be overcome with future research developed in multicentric settings with protocol harmonization. Conclusions: [18F]FDG PET-based radiomics and ML show preliminary promising results for CS evaluation, but remain investigational tools since the current evidence is insufficient for clinical adoption due to methodological heterogeneity, small sample sizes, and lack of standardization. Full article

Objective: To evaluate the diagnostic performance of fluorine 18 fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (¹⁸F-FDG PET/MR) in the preoperative staging of hypopharyngeal cancer (HPC), compare it with conventional enhanced computed tomography (CT) and MR, and further explore the prognostic value of its metabolic and diffusion metrics for HPC. Methods: This retrospective study included 33 patients with pathologically confirmed HPC. All patients underwent preoperative ¹⁸F-FDG PET/MR, CT, and MR examination. The staging performance of the three modalities was evaluated using pathological staging as a reference. Additionally, metabolic indicators and diffusion-related parameters from PET/MR were collected to investigate their impact on larynx preservation and survival. Results: PET/MR demonstrated accuracies of 90.9% and 71.4% in the preoperative T and N staging, respectively, significantly higher than those of CT (54.5%, p = 0.001; 42.9%, p = 0.021) and MR (66.7%, p = 0.016; 42.9%, p = 0.021). On the whole, significant differences emerged in the maximum standard uptake value (SUVmax), metabolic tumor volume (MTV), minimum apparent diffusion coefficient (ADCmin), and mean ADC (ADCmean) and combined ratios across different T stages, while SUVmax, mean SUV (SUVmean), total lesion glycolysis (TLG), and MTV varied significantly across different N stages. The ADCmin and ADCmean showed good predictive capability for larynx preservation, with AUCs of 0.857 and 0.920 (p < 0.05), respectively. In Cox multivariate analysis of overall survival, high-level ADCmean (p = 0.004) and low-level TLG/ADCmean (p = 0.022) were significantly associated with better survival. Conclusion: In HPC, ¹⁸F-FDG PET/MR imaging significantly surpasses CT and MR in preoperative diagnostic staging. Its diffusion-related parameters have substantial prognostic value, with high ADC values associated with larynx preservation. ADCmean and TLG/ADCmean are potential prognostic indicators for HPC. Full article

Objectives: Non-small cell lung cancer (NSCLC), the most prevalent type of lung cancer, includes subtypes such as adenocarcinoma (ADC) and squamous cell carcinoma (SCC), which require distinct management approaches. Accurately differentiating NSCLC subtypes based on diagnostic imaging remains challenging. However, the extraction of radiomic features—such as first-order statistics (FOS), second-order statistics (SOS), and fractal dimension texture analysis (FDTA) features—from magnetic resonance (MR) images supports the development of quantitative NSCLC assessments. Methods: This study aims to evaluate whether the integration of FDTA features with FOS and SOS texture features in MR image analysis improves machine learning classification of NSCLC into ADC and SCC subtypes. The study was conducted on 274 MR images, comprising ADC (n = 122) and SCC (n = 152) cases. From the segmented MR images, 93 texture features were extracted. The random forest algorithm was used to identify informative features from both FOS/SOS and combined FOS/SOS/FDTA datasets. Subsequently, the k-nearest neighbors (kNN) algorithm was applied to classify MR images as ADC or SCC. Results: The highest performance (accuracy = 0.78, precision = 0.81, AUC = 0.89) was achieved using 37 texture features selected from the combined FOS/SOS/FDTA dataset. Conclusions: Incorporating fractal descriptors into the texture-based classification of lung MR images enhances the differentiation of NSCLC subtypes. Full article

Objective: This study aimed to compare the diagnostic accuracy of whole-body PET/MR imaging and contrast-enhanced CT for detecting metastatic disease in patients undergoing surgical resection, using pathology as the reference standard. Materials and Methods: Nineteen patients with suspected metastatic involvement (including four who received neoadjuvant therapy before surgery) underwent both FDG PET/MR and contrast-enhanced CT scans. Imaging was reviewed for metastases at defined sites (e.g., perihepatic region, hepatic parenchyma, mesentery, bowel serosa, colon surface, and nodal basins). Findings on each modality were compared to surgical pathology results per site. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated for PET/MR and CT, with pathology as the reference standard. Results: Overall, PET/MR achieved approximately 55.5% sensitivity, 89.5% specificity, 82.5% accuracy, 57.6% positive predictive value (PPV), and 88.6% negative predictive value (NPV). In contrast, CT demonstrated 75.0% sensitivity, 72.3% specificity, 72.9% accuracy, 42% PPV, and 91.5% NPV. No significant correlations were observed between semi-quantitative PET/MR measures, such as SUV or MR ADC values, and patient survival outcomes; therefore, these metrics were excluded from further analysis. Notably, PET/MR imaging findings changed clinical management in 3/6 chemotherapy patients. PET/MR demonstrated greater sensitivity in detecting nodal metastases, 75% compared to CT (25%), and identified small bowel serosal lesions in 1 of 1 case (100% sensitivity) versus none with CT. CT showed slightly higher specificity (81%) for colon serosal involvement than PET/MR (75%). Conclusions: CT demonstrates higher sensitivity, whereas PET/MR offers greater specificity and negative predictive value. When used together, the two modalities may provide a more reliable and comprehensive assessment of metastatic disease. Full article

A novel multimodal super-resolution framework is introduced, combining GAN-based synthesis, perceptual constraints, and joint low-rank sparsity regularization to noticeably enhance MR-PET image quality. The architecture integrates modality-specific ResNet encoders, a transformer-based attention fusion block, and a multi-scale PatchGAN discriminator. Training is guided by a hybrid loss function incorporating adversarial, pixel-wise, perceptual (VGG19), and structured Hankel constraints. The proposed method outperforms all baselines in PSNR, SSIM, LPIPS, and diagnostic confidence metrics. Clinical PET metrics, such as SUV recovery and lesion detectability, show substantial improvement. A thorough analysis of computational complexity, dataset composition, training reproducibility, and motion compensation is provided. These findings are visually supported by processed scan panels and benchmark tables. This framework advances reproducible and interpretable hybrid neuroimaging with strong clinical and technical validation. Full article

In this study, we report the synthesis of Te and Ag₂Te micron-sized rods (MRs) via a controlled hot-injection-based quenching process, enabling the control of rod morphology and enhanced crystallinity. Structural analysis confirmed that the synthesized Te MRs exhibit a trigonal phase, growing along the (110) direction, while Ag₂Te MRs undergo a phase transformation into a monoclinic structure upon Ag doping. A simple and scalable photodetector (PD) was fabricated by drop-casting Te and Ag₂Te MRs onto PET plastic films, followed by the application of Ag paste electrodes. The PD demonstrated room-light-induced photocurrent responses, which increased significantly upon mechanical bending due to the formation of additional conductive pathways between MRs. The Ag₂Te-based bending sensor exhibited a fivefold enhancement in photocurrent compared to its Te counterpart and maintained high stability over 1000 bending cycles. These results highlight the potential of Te and Ag₂Te MRs for use in flexible and wearable motion-sensing technologies, offering a simple yet effective approach for integrating 1D telluride nanostructures into scalable optoelectronic applications. Full article

Positron emission tomography (PET) and liquid biopsy have independently transformed prostate cancer management. This review explores the complementary roles of PET imaging and liquid biopsy in prostate cancer, focusing on their combined diagnostic, monitoring, and prognostic potential. A systematic search of PubMed, Scopus, and Cochrane Library databases was conducted to identify human studies published in English up to January 2025. Seventeen studies met the inclusion criteria and were analyzed according to PRISMA guidelines. Across the included studies, PET-derived imaging metrics, such as metabolic activity and radiotracer uptake, correlated consistently with liquid biopsy biomarkers, including circulating tumor cells and cell-free DNA. Their joint application demonstrated added value in early detection, treatment monitoring, and outcome prediction, particularly in castration-resistant prostate cancer. Independent and synergistic prognostic value was noted for both modalities, including survival outcomes such as overall survival and progression-free survival. Combining PET imaging and liquid biopsy emerges as a promising, non-invasive strategy for improving prostate cancer diagnosis, monitoring, and therapeutic stratification. While preliminary findings are encouraging, large-scale prospective studies are essential to validate their integrated clinical utility. Full article

Objective: Traditional imaging modalities for the planning of Gamma Knife radiosurgery (GKRS) are non-specific and do not accurately delineate intracranial neoplasms. This study aimed to evaluate the utility of positron emission tomography (PET) for the planning of GKRS for intracranial neoplasms (ICNs) and the post-GKRS applications of PET for patient care. Methods: PubMed, Scopus, and ScienceDirect were searched in order to assemble relevant studies regarding the uses of PET in conjunction with GKRS for ICN treatment. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed to identify relevant studies on the use of PET in conjunction with GKRS. Particular emphasis was placed on review articles and medical research investigating tumor delineation and post-operative care. Relevant studies were selected and assessed based on quality measures, including study design, sample size, and significance. Inclusion and exclusion criteria were used to examine the yield of the initial search (n = 105). After a secondary review, the included results were identified (n = 50). Results: This study revealed that PET imaging is highly accurate for the planning of GKRS. In fact, many cases indicate that it is more specific than traditional imaging modalities. PET is also capable of complementing traditional imaging techniques through combination imaging. This showed significant efficacy for the planning of GKRS for ICNs. Conclusions: While PET shows a multitude of applications for the treatment of ICNs with GKRS, further research is necessary to assemble a complete set of clinical guidelines for treatment specifications. Importantly, future studies need a greater standardization of methods and expanded trials with a multitude of radiotracers. Full article