American journal of nuclear medicine and molecular imaging最新文献

The aim was to utilize three segmentation methods on ¹⁸F-FDG PET/CT and PET/MR images of pancreatic neoplasm patients, and further compare the effectiveness in differentiating benign from malignant, TNM-stage and prognosis. We conducted a retrospective analysis of 51 patients with pancreatic neoplasm who had undergone ¹⁸F-FDG PET/CT and PET/MR before treatment. The patients were categorized into malignant and benign groups. For each patient, the lesion was segmented by 3 thresholds and we recorded TNM-stage, treatment strategy, time to death, and the performance status of survivors. We used receiver operating characteristic (ROC) analysis to compare the diagnostic performance of different threshold delineations between benign and malignant, as well as TNM-stage of adenocarcinoma patients. The optimal model of prognostic value was also assessed by Cox proportional hazards regression analysis and Kaplan-Meier survival analysis. For both PET/CT and PET/MR, SUV_max had the best diagnostic efficacy in identifying malignant tumors. The background method of PET/MR exhibited the outstanding performance in M-stage (sensitivity/specificity, 92.90%/88.20%), with the weighted factor being whole-body total lesion glycolysis (WBTLG). In multivariate analysis, WBTLG (Exp [B] = 1.009; P = 0.009), and surgery (Exp [B] = 15.542; P = 0.008) were independent predictive factors associated with prognosis. This study found that SUV_max from PET/CT had the best diagnostic efficacy in identifying malignancy, while PET/MR showed higher specificity and accuracy for M-stage. The treatment strategy and WBTLG were independent prognostic factors in pancreatic neoplasm patients. PET/MR using the background method was identified as the optimal predictive model for prognosis.

Radionuclide antibody conjugate (RAC) is a promising diagnostic and therapeutic tool. It combines radionuclides and antibodies by connecting arms and chelating agents, offering precise targeting and potent killing of tumor cells. However, further development and optimization of this radiopharmaceutical is needed to enhance the ultimate substantive efficacy for clinical translation. In this issue of AJNMMI, Strand et al. evaluated the enhanced permeability effect and different linear energy transfer (LET) of radionuclides in a prostate cancer xenograft model. The results showed that specific targeting might negatively influence normal organ uptake when targeting secreted antigens and different LETs of radionuclides might have diverse effects on receptor expression and cell proliferation in tumors. The findings provide new thinking for the development of antibody-based radiopharmaceuticals.

Primary malignant melanoma most frequently occurs in the skin. Melanoma affecting the gastrointestinal (GI) tract has been substantiated for lesions occurring in the esophagus, stomach, small bowel, and anorectum through multiple published reports, given the presence of melanocytes in these areas. Nevertheless, owing to the exceedingly low incidence of this disease, reports on its clinical features are few, and treatment approaches lack standardization. In this study, we present three cases of GI melanoma with imaging manifestations, emphasizing the pivotal role of ¹⁸F-FDG PET/CT in staging for GI melanoma. Establishing a definitive diagnosis of primary GI melanoma necessitates the exclusion of the possibility of metastasis from more prevalent primary sites. Advancements in molecular imaging technologies and the development of novel tracers provided significant promising methods for enhancing the diagnosis and management of melanoma, contributing to improved patient outcomes and overall disease management.

Giant cell tumor (GCT) is a benign yet locally aggressive bone neoplasm typically situated in the juxta-articular metaphysis of long bones. Although spinal involvement is rare, it is predominantly reported in the axial skeleton, with the sacrum being the primary location. Conversely, GCTs are notably uncommon in the thoracic spine. In this report, we present computed tomography (CT), magnetic resonance imaging (MRI), and 2-Deoxy-2-[fluorine-18]-fluoro-D-glucose (¹⁸F-FDG) positron emission tomography combined with computed tomography (PET/CT) multimodality imaging findings of a 36-year-old woman diagnosed with a GCT of the thoracic spine. CT scans provide a precise evaluation of cortical thinning and penetration. While MRI lacks specific diagnostic indicators for GCT, it remains invaluable for delineating the extent of soft tissue expansion and the tumor's relationship with intraspinal neural elements - critical information for surgical planning. ¹⁸F-FDG PET/CT effectively illustrates the lesion's hypermetabolic and locally aggressive characteristics. It is noteworthy that GCT occasionally exhibits metastatic malignant potential, underscoring the value of FDG PET as a pivotal modality for staging, restaging, or assessing therapy response, and for monitoring the efficacy of radiotherapy. Familiarity with the imaging features of GCT is essential for physicians to avoid misinterpretation. This tumor should be considered in the differential diagnosis of spinal tumors, distinguishing it from bone metastases or neurogenic tumors.

This study aimed to evaluate the diagnostic value of uptake ratios in the extraocular muscles (EOMs), lacrimal glands, and optic nerves to detect the inflammation activity of Graves' ophthalmopathy (GO) using quantitative analysis of 99m technetium (^99mTc)-labeled diethylene triamine pentaacetic acid (DTPA) orbital single-photon emission computed tomography/computed tomography (SPECT/CT) images. The patients were categorized into an active stage (clinical activity score ≥ 3/7, n=23) or an inactive stage (clinical activity score < 3/7, n=38), based on their clinical activity score. The uptake ratio was manually determined by placing a region of interest within the area of highest uptake, as agreed upon by consensus, in the EOMs, lacrimal gland, and optic nerve on SPECT images corrected for CT attenuation. Patients with active GO exhibited significantly higher uptake ratios in the EOMs, lacrimal glands, and optic nerves compared to patients with inactive GO (all P < 0.01). These parameters have been proven effective in differentiating between active and inactive disease.

Background: Children and young adults have a vast array of electronics at their fingertips. While it can provide endless hours of entertainment and education, we are also seeing a structural consequence. Children are using these devices with their head tilted down with poor posture resulting in increased stress on the skull from attached structures which can lead to a bone spur (exostosis) at the external occipital protuberance (EOP). While typically painless, it can progress to necessitate surgical intervention.

Objectives: The purpose of this study is to understand the prevalence of exostosis at the EOP and how the finding can affect the nuclear medicine bone scan.

Materials and methods: 43 pediatric patients who underwent a whole-body bone scan over a period of 1 year were included in the study (10-19 years old). Images were reviewed by 2 board-certified Nuclear Medicine physicians to assess for uptake midline in the occipital skull. Suspected cases were followed up with all available clinical and radiographic reports and images.

Results: Bone scan demonstrated an occipital focus of uptake in 7 (16%) of the 43 patients (5 males and 2 females with a mean age of 15 years; range 10-19). Of these, 5/7 (71%) were confirmed by additional imaging.

Conclusion: The rapidly advancing technology is leading to increased screen time in children and young adults. Our study shows that 16% of the pediatric population imaged at our facility between the ages of 10-19 years have signs of exostosis at the EOP. It is particularly important for clinicians to be aware of this entity when reading bone scans to avoid false positive interpretations.

Waldenstrom macroglobulinemia (WM) is a rare inert B lymphocyte lymphoma and the role of FDG PET/CT imaging in WM has not been well established. This study aimed to evaluate the metabolic status of WM by ¹⁸F-FDG PET/CT imaging. We retrospectively analyzed 20 patients who underwent pretherapy ¹⁸F-FDG PET-CT scan. All patients were diagnosed by bone marrow aspiration, laboratory examination and clinical symptoms. Bone marrow involvement was identified with ¹⁸F-FDG PET/CT imaging in 16 of 20, and the mean SUVmax of bone marrow was 4.06±0.85, Lymph nodes were involved in 8 of 20 patients, and the mean SUVmax of Lymph nodes was 4.07±1.27. Liver and spleen were involved in one case respectively, with SUVmax being 3.6 and 3.3. 1 case of extramedullary infiltration and 1 case of lymphomatous transformation. ¹⁸F-FDG PET/CT imaging not only could reveal the metabolic status of lymph nodes, liver, spleen and bone marrow in WM patients, but also evaluate the status of tumor burden which helps to formulate personalized treatment plans.

Background: The aim of this study was to determine the read-out capabilities of the novel C-X-C motif chemokine receptor 4 (CXCR4)-targeting radiotracer [⁶⁸Ga]Ga-PentixaFor compared to the reference radiotracer [¹⁸F]FDG in untreated individuals with head and neck squamous cell carcinoma (HNSCC).

Material and methods: 12 patients with histologically confirmed HNSCC were scheduled for [¹⁸F]FDG and [⁶⁸Ga]Ga-PentixaFor PET/CT. Maximum standardized uptake values (SUV_max) and target-to-background ratios (TBR) were applied with vena cava superior serving as reference. In addition, we compared [⁶⁸Ga]Ga-PentixaFor-PET findings with immunohistochemical (IHC) results of CXCR4 expression.

Results: On visual assessment, [¹⁸F]FDG identified more sites of disease, with increased detection rates for both the primary tumor ([¹⁸F]FDG, 12/12 [100%] vs. [⁶⁸Ga]Ga-PentixaFor, 10/12 [83%]) and LN metastases ([¹⁸F]FDG, 9/12 [75%] vs. [⁶⁸Ga]Ga-PentixaFor, 8/12 [67%]). Indicative for improved image contrast using [¹⁸F]FDG, quantification showed a higher TBR for the latter radiotracer, when compared to [⁶⁸Ga]Ga-PentixaFor for all lesions ([¹⁸F]FDG, 11.7 ± 8.5 vs. [⁶⁸Ga]Ga-PentixaFor, 4.3 ± 1.3; P=0.03), primary tumors ([¹⁸F]FDG, 13.6 ± 8.7 vs. [⁶⁸Ga]Ga-PentixaFor, 4.4 ± 1.4; P<0.01), and LN lesions ([¹⁸F]FDG, 9.3 ± 10.6 vs. [⁶⁸Ga]Ga-PentixaFor, 4.7 ± 1.5; P=0.3). IHC showed variable CXCR4 expression in the primary and LN, along with no associations between ex-vivo CXCR4 upregulation and [⁶⁸Ga]Ga-PentixaFor-based TBR (R=0.33, P=0.39) or SUV_max (R=0.44, P=0.2). Of note, IHC also revealed heterogeneous expression of CXCR4 in immune cells in the tumor microenvironment and in germinal centers, indicative for inflammatory reactions.

Conclusions: In HNSCC, [¹⁸F]FDG demonstrated superior diagnostic performance relative to [⁶⁸Ga]Ga-PentixaFor, in particular for assessment of the primary. Based on the IHC analyses, these findings may be explained by CXCR4 upregulation not only by tumor but also by immune cells in the tumor microenvironment.

Radiotracers and medical imaging equipment are the two main keys to molecular imaging. While radiotracers are of great interest to research and industry, medical imaging equipment technology is blossoming everywhere. Total-body PET/CT (TB-PET/CT) has emerged in response to this trend and is rapidly gaining traction in the fields of clinical oncology, cardiovascular medicine, inflammatory/infectious diseases, and pediatric diseases. In addition, the use of a growing number of radiopharmaceuticals in TB-PET/CT systems has shown promising results. Notably, the distinctive features of TB-PET/CT, such as its ultra-long axial field of view (194 cm), ultra-high sensitivity, and capability for low-dose tracer imaging, have enabled enhanced imaging quality while reducing the radiation dose. The envisioned whole-body dynamic imaging, delayed imaging, personalized disease management, and ultrafast acquisition for motion correction, among others, are achieved. This review highlights two key factors affecting molecular imaging, describing the rapid imaging effects of radiotracers allowed at low doses on TB-PET/CT and the improvements offered compared to conventional PET/CT.

A remarkable body of new data establishes that many degenerative brain diseases and some acute injury situations in the brain may be associated with ferroptosis. In recent years, ferroptosis has also attracted great interest in the cancer research community, partly because it is a unique mode of cell death distinct from other forms and thus has great therapeutic potential for brain cancer. Glioblastoma is a highly aggressive and fatal human cancer, accounting for 60% of all primary brain tumors. Despite the development of various pharmacological and surgical modalities, the survival rates of high-grade gliomas have remained poor over the past few decades. Recent evidence has revealed that ferroptosis is involved in tumor initiation, progression, and metastasis, and manipulating ferroptosis could offer a novel strategy for glioma management. Nanoparticles have been exploited as multifunctional platforms that can cross the blood-brain barrier and deliver therapeutic agents to the brain to address the pressing need for accurate visualization of ferroptosis and glioma treatment. To create efficient and durable ferroptosis inducers, many researchers have engineered nanocomposites to induce a more effective ferroptosis for therapy. In this review, we present the mechanism of ferroptosis and outline the current strategies of imaging and nanotherapy of ferroptosis in brain diseases, especially glioma. We aim to provide up-to-date information on ferroptosis and emphasize the potential clinical implications of ferroptosis for glioma diagnosis and treatment. However, regulation of ferroptosis in vivo remains challenging due to a lack of compounds.