American journal of nuclear medicine and molecular imaging最新文献

Brain pharmacokinetic parametric imaging based on dynamic positron emission tomography (PET) scan is valuable in the diagnosis of brain tumor and neurodegenerative diseases. For short-axis PET system, standard blood input function (BIF) of the descending aorta is not acquirable during the dynamic brain scan. BIF extracted from the intracerebral vascular is inaccurate, making the brain parametric imaging task challenging. This study introduces a novel technique tailored for brain pharmacokinetic parameter imaging in short-axis PET in which the head BIF (hBIF) is acquired from the cavernous sinus. The proposed method optimizes the hBIF within the Patlak model via data fitting, curve correction and Patlak graphical model rewriting. The proposed method was built and evaluated using dynamic PET datasets of 67 patients acquired by uEXPLORER PET/CT, among which 64 datasets were used for data fitting and model construction, and 3 were used for method testing; using cross-validation, a total of 15 patient datasets were finally used to test the model. The performance of the new method was evaluated via visual inspection, root-mean-square error (RMSE) measurements and VOI-based accuracy analysis using linear regression and Person's correlation coefficients (PCC). Compared to directly using the cavernous sinus BIF directly for parameter imaging, the new method achieves higher accuracy in parametric analysis, including the generation of Patlak plots closer to the standard plots, better visual effects and lower RMSE values in the K_i (P = 0.0012) and V (P = 0.0042) images. VOI-based analysis shows regression lines with slopes closer to 1 (P = 0.0019 for K_i ) and smaller intercepts (P = 0.0085 for V). The proposed method is capable of achieving accurate brain pharmacokinetic parametric imaging using cavernous sinus BIF with short-axis PET scan. This may facilitate the application of this imaging technology in the clinical diagnosis of brain diseases.

Objective: To explore the connection between TGF-β1 expression and the survival of patients with head and neck squamous cell carcinoma (HNSCC), as well as whether non-invasive CT-based Radiomics can predict TGF-β1 expression in HNSCC patients.

Methods: Data on transcriptional profiling and clinical information were acquired from the TCGA database and subsequently categorized based on the TGF-β1 expression cutoff value. Based on the completeness of enhanced arterial phase CT scans, 139 HNSCC patients were selected. The PyRadiomics package was used to extract radiomic features, and the 3D Slicer software was used for image segmentation. Using the mRMR_RFE and Repeat LASSO algorithms, the optimal features for establishing the corresponding gradient enhancement prediction models were identified.

Results: A survival analysis was performed on 483 patients, who were divided into two groups based on the TGF-β1 expression cut-off. The Kaplan-Meier curve indicated that TGF-β1 was a significant independent risk factor that reduced patient survival. To construct gradient enhancement prediction models, we used the mRMR_RFE algorithm and the Repeat_LASSO algorithm to obtain two features (glrlm and ngtdm) and three radiation features (glrlm, first order_10percentile, and gldm). In both the training and validation cohorts, the two established models demonstrated strong predictive potential. Furthermore, there was no statistically significant difference in the calibration curve, DCA diagram, or AUC values between the mRMR_RFE_GBM model and the LASSO_GBM model, suggesting that both models fit well.

Conclusion: Based on these findings, TGF-β1 was shown to be significantly associated with a poor prognosis and to be a potential risk factor for HNSCC. Furthermore, by employing the mRMR_RFE_GBM and Repeat_LASSO_GBM models, we were able to effectively predict TGF-β1 expression levels in HNSCC through non-invasive CT-based Radiomics.

The purpose of this study is to investigate bone SPECT/CT and diffusion-weighted MR imaging (DWI) in medication-related osteonecrosis of the jaw (MRONJ), focusing on the correlation between standardized uptake values (SUVs) and apparent diffusion coefficient (ADC) values. Twenty-nine patients with MRONJ who underwent SPECT/CT and DWI were included in this study. SUVs (maximum and mean) with SPECT/CT, and ADC values (maximum, mean and minimum) with DWI were analyzed on characteristics in MRONJ, such as stage, location, medication and underlying disease, by Mann-Whitney U test. Furthermore, the correlation between SUVs and ADC values for characteristics in MRONJ were assessed by Spearman's rank correlation test for nonparametric data. A p-value lower than 0.05 was considered as statistically significant. SUVs and ADC values have no significant differences for all characteristics in MRONJ. Negative correlations were found in all cases and in stage 2 cases, and no correlations were found in stage 3 cases. In addition, negative correlations were found in maxillary cases, mandibular cases, non-bisphosphonate cases, osteoporosis cases, and malignant tumor cases. In conclusion, this study found multiple correlations between SUVs and ADC values in MRONJ, especially in stage 2. Suggesting that ADC values and SUVs may change with disease progression and the possibility of predicting MRONJ progression by SUVs and ADC values.

Activated macrophages are key effector cells and specific markers in patients with rheumatoid arthritis (RA). Cysteine cathepsin B (CTS-B) is highly expressed in macrophages and positively associated with RA activity and severity. This study aims to evaluate an activity-based multi-modality diagnostic agent, ⁶⁸Ga-BMX2, which targets CTS-B to visualize the arthritis activity and evaluate the treatment efficacy. A CTS-B activity-based probe, BMX2, was labeled efficiently with ⁶⁸Ga to produce ⁶⁸Ga-BMX2 for fluorescent and positron emission tomography (PET) multi-modality imaging. The affinity and specificity of BMX2 binding with the CTS-B enzyme in macrophages were determined by radioactive experiment using RAW 264.7 cell lines, with CA074 and BMX5 as the inhibitors to test the specificity of the binding. Then, PET and fluorescence imaging were acquired on collagen-induced arthritis (CIA) mice. Additionally, the treatment monitoring capability of ⁶⁸Ga-BMX2 PET/CT imaging was tested with methotrexate (MTX). RAW 264.7 macrophage cells showed significant uptake of ⁶⁸Ga-BMX2. The binding of BMX2 with CTS-B in RAW 264.7 macrophage cells is time-dependent and could be blocked by CA074 and BMX5. In vivo optical and PET imaging showed high signals in the right hind arthritis in CIA mice from ⁶⁸Ga-BMX2 and BMX2 accumulated for at least 120 h. Additionally, ⁶⁸Ga-BMX2 signals were significantly reduced in the MTX-treated CIA mice compared to the control group. The ⁶⁸Ga-BMX2, a radioactive and fluorescent dual-modality diagnostic agent targeting CTS-B, demonstrated a practical approach for CIA PET and fluorescence imaging. The ⁶⁸Ga-BMX2 multimodality imaging could significantly monitor the treatment response in the CIA mice.

Fibroblast activation protein (FAP) is a type II transmembrane serine protease overexpressed in cancer-associated fibroblasts (CAFs) and has been associated with poor prognosis. PET/CT imaging with radiolabeled FAP inhibitors (FAPI) is currently being studied for various malignancies. This review identifies the uses and limitations of FAPI PET/CT in malignancies and compares the advantages and disadvantages of FAPI and ¹⁸F-fluorodeoxyglucose ([¹⁸F]FDG). Due to high uptake, rapid clearance from the circulation, and limited uptake in normal tissue, FAPI tumor-to-background contrast ratios are equivalent to or better than [¹⁸F]FDG in most applications. In several settings, FAPI has shown greater uptake specificity than [¹⁸F]FDG and improved sensitivity in detecting lymph node, bone, and visceral tissue metastases. Therefore, FAPI PET/CT may be complementary in distinguishing pathological lesions with conventional imaging, determining the primary site of malignancy, improving tumor staging, and detecting disease recurrence, especially in patients with inconclusive [¹⁸F]FDG PET/CT findings. Nevertheless, FAPI has limitations, including certain settings with non-specific uptake, modified uptake with age and menopause status, challenges with clinical access, and limited clinical evidence.

Multiple myeloma (MM) is a malignant blood disease, but there have been significant improvements in the prognosis due to advancements in quantitative assessment and targeted therapy in recent years. The quantitative assessment of MM bone marrow infiltration and prognosis prediction is influenced by imaging and artificial intelligence (AI) quantitative parameters. At present, the primary imaging methods include computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). These methods are now crucial for diagnosing MM and evaluating myeloma cell infiltration, extramedullary disease, treatment effectiveness, and prognosis. Furthermore, the utilization of AI, specifically incorporating machine learning and radiomics, shows great potential in the field of diagnosing MM and distinguishing between MM and lytic metastases. This review discusses the advancements in imaging methods, including CT, MRI, and PET/CT, as well as AI for quantitatively assessing MM. We have summarized the key concepts, advantages, limitations, and diagnostic performance of each technology. Finally, we discussed the challenges related to clinical implementation and presented our views on advancing this field, with the aim of providing guidance for future research.

Purpose: This study delves into the hemodynamic characteristics of Vertebrobasilar Artery Fenestration (VBAF) combined with Vertebrobasilar Dolichoectasia (VBD) using Magnetic Resonance Angiography (MRA). By summarizing the hemodynamic features and identifying high-risk populations, we aim to provide insights for clinical treatment.

Methods: Utilizing MRA images as a foundation, arterial three-dimensional geometric models were constructed. A total of 22 cases were categorized into control, S, L, U, and Spiral groups, and numerical simulation analysis of the vessels was conducted using computational fluid dynamics methods.

Results: Hemodynamic parameters of the VBAF combined with the VBD model were obtained, including blood flow velocity, oscillatory shear stress (OSI), wall shear stress (WSS), and aneurysm formation indicator (AFI). The V, OSI, and WSS indices of the L, U, and Spiral groups were significantly higher than those of the control group (P < 0.05). High-speed blood flow, elevated WSS, and increased OSI in these groups were concentrated at the fenestration site, with scattered distribution along the tortuous vertebral artery and basilar artery segments, accompanied by significant differences in the parameters of the bilateral vertebral arteries.

Conclusion: This preliminary investigation identifies the L, U, and Spiral groups as high-risk populations. Abnormal hemodynamics may lead to a vicious cycle in vascular wall pathology, increasing the likelihood of adverse events such as cerebral infarction. Clinical attention should focus on individuals within these groups and their corresponding vascular regions.

Sarcoidosis is a systemic disease with unclear etiology characterized by the accumulation of noncaseating, immune granulomas in affected tissues. In cardiac sarcoidosis (CS), white blood cells build up within the heart muscles, causing cardiac abnormalities. Accurate and early diagnosis of CS proves challenging. However, usage of positron emission tomography (PET) imaging, namely ¹⁸F-FDG-PET, has proven successful in diagnosing inflammatory cardiomyopathy. This review seeks to examine the role of PET in managing ventricular tachycardia in cardiac sarcoidosis. PET, in conjunction with cardiac magnetic resonance imaging (CMR) is also endorsed as the premier method for diagnosis and management of arrhythmias associated with CS by The Heart Rhythm Society. After a CS diagnosis, risk stratification of ventricular arrhythmias is a necessity given the potential for sudden cardiac death. ¹⁸F-FDG-PET has been successful in monitoring disease advancement and treatment responses in CS patients. Early stages of CS are often treated with immunosuppression drugs if there are additional signs of VT. Currently, corticosteroid and anti-arrhythmia compounds: methotrexate, cyclophosphamide, infliximab, amiodarone, and azathioprine are used to suppress inflammation. ¹⁸F-FDG-PET has certainly proven to be an incredibly useful and accurate diagnostic tool of CS. While late gadolinium enhancement by CMR is efficient in detecting myocardial necrosis and/or advanced fibrosis scarring, ¹⁸F-FDG portrays the increased uptake level of glucose metabolism. In combination PET/MRI has proven to be more successful in improving the efficacy of both scans, addressing their drawbacks, and highlighting their advantages. Managing CS patients is highly involved in detecting inflammatory regions of the heart. Early recognition prevents cardiac abnormality, mainly VT and VF in CS patients, and extends lifespan.

Endometriosis is a common cause of infertility, pelvic pain, and dysmenorrhea and there are prior case reports of lesion detection using an 18F-fluoroestradiol (FES) tracer with positron emission tomography (PET). We aimed to further investigate the use of the FES tracer in the context of PET-magnetic resonance (PET-MR) imaging. We administered FES to 6 patients and then imaged them using a Siemens mMR PET-MR scanner. Each patient was taken to surgery within 30 days after imaging, and surgical visualization served as the gold-standard for diagnosis. PET did not prove to be as sensitive as MR (50% per-patient sensitivity versus 67% per-patient and 35% versus 48% per-lesion), and did not show any additional sites over and above MR. When MR was used to localize lesions on PET after imaging, there was insufficient evidence of an association between total tracer uptake and reported pain intensity (P=0.25). FES PET-MR offers no additional value to MR for endometriosis.

HER2 overexpression is associated with various tumor types and prompted the development of targeted therapies. Previously, iso-[²¹¹At]SGMAB-5F7 was developed as a HER2-targeted alpha therapy agent, demonstrating promising therapeutic efficacy in the preclinical stage. Aiming for an ¹⁸F-labeled tracer for companion diagnostics in clinical translation, we employed the Al¹⁸F-RESCA strategy in our current work and investigated whether [¹⁸F]AlF-RESCA-5F7 could visualize HER2 expression in vivo. [¹⁸F]AlF-RESCA-5F7 was attained with high radiochemical purity (> 99%) and molar activity in the range of 16.5 ± 8.8 GBq/μmol (n = 8). Compared to previously reported radiotracers that contained 5F7 as the HER2-targeting carrier and fluorine-18 as the positron-emitting isotope, the radiosynthesis was simplified to one single step within 30 min. The dissociation constant of [¹⁸F]AlF-RESCA-5F7 was determined as 3.3 nM via saturation binding assay using SKOV3 ovarian carcinoma cells. Tumor uptake of the novel tracer in Balb/c nude mice bearing SKOV3 xenografts was 4.69 ± 1.51, 3.34 ± 0.82 and 3.77 ± 0.99 %ID/g at 1, 2, and 4 h post-injection. Even though high retention of radioactivity was seen in the kidneys, micro-PET/CT imaging of [¹⁸F]AlF-RESCA-5F7 delineated the tumor up to 4 h post-injection with minimal activity in the gallbladder, intestines, and bone. This study suggests that [¹⁸F]AlF-RESCA-5F7 is a promising HER2 PET radiotracer with an eased radiolabeling method. Whether [¹⁸F]AlF-RESCA-5F7 could work as a companion diagnostic agent to assist in patient stratification and treatment monitoring of iso-[²¹¹At]SGMAB-5F7 warrants further investigation.