18F-FDG PET/CT and contrast-enhanced CT in the diagnosis of Castleman disease

Castleman Disease-Still More Questions than Answers: A Case Report and Review of the Literature

Background: Idiopathic multicentric Castleman disease (iMCD) is a rare lymphoproliferative disorder with diverse clinical presentations, often posing significant diagnostic challenges. Methods: We report the case of a 20-year-old woman who first presented with fever of unknown origin (FUO) at the age of 14, followed by the development of abdominal lymphadenopathy. We conducted a comprehensive review of her clinical course, diagnostic workup, treatment response, and outcomes. Additionally, we performed a literature review of CD focusing on pathophysiology, classification, diagnostic approaches, and treatment strategies. Results: Extensive investigations performed in the meantime excluded infectious and autoimmune causes. Histopathological analysis of the excised lymph nodes ruled out malignancy and confirmed idiopathic multicentric Castleman disease. Treatment with tocilizumab, an IL-6 receptor antagonist, resulted in rapid resolution of clinical symptoms, normalization of inflammatory markers, and sustained remission. With the final diagnosis established and treatment initiated, she was transitioned at the age of 18 from a pediatric immunology to an adult clinical immunology center. Conclusions: The presented case highlights the importance of considering iMCD in the differential diagnosis of FUO, especially in adolescents, and the efficacy of targeted therapies in managing this challenging disease. A multidisciplinary approach involving clinical, laboratory, imaging, and histopathological evaluation is essential for accurate diagnosis. IL-6 pathway inhibition represents an effective targeted therapy for iMCD, capable of inducing sustained remission in this challenging disease.

MRI and 18F-FDG-PET/CT findings of cervical reactive lymphadenitis: a comparison with nodal lymphoma

Purpose

This study aimed to compare the findings of magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) to differentiate reactive lymphadenitis from nodal lymphoma of the head and neck.

Material and methods

This study included 138 patients with histopathologically confirmed cervical lymphadenopathy, including 35 patients with reactive lymphadenitis and 103 patients with nodal lymphoma, who had neck MRI (n = 63) and/or 18F-FDG-PET/CT (n = 123) before biopsy. The quantitative and qualitative MRI results and maximum standardised uptake value (SUVmax) were retrospectively analysed and compared between the 2 pathologies.

Results

The maximum diameter (22.4 ± 6.9 vs. 33.3 ± 16.0 mm, p < 0.01), minimum diameter (15.8 ± 3.6 vs. 22.3 ± 8.5 mm, p < 0.01), and SUVmax (6.9 ± 2.7 vs. 12.8 ± 8.0, p < 0.01) of the lesion were lower in reactive lymphadenitis than in nodal lymphoma, respectively. T2-hypointense-thickened capsules > 2 mm (46% vs. 14%, p < 0.05) and T2-hypointense areas converging to the periphery (15% vs. 0%, p < 0.05) were more frequently observed in reactive lymphadenitis than in nodal lymphoma, respectively. Hilum of nodes on T2-weighted images (54% vs. 22%, p < 0.05) and diffusion-weighted images (69% vs. 30%, p < 0.05) were more frequently demonstrated in reactive lymphadenitis than in nodal lymphoma, respectively.

Conclusions

Reactive lymphadenitis had a smaller size and lower SUVmax. The presence of T2-hypointense-thickened capsules, T2-hypointense areas converging to the periphery, and hilum of nodes were signs of reactive lymphadenitis.

Imaging of unicentric hyaline-vascular variant of Castleman disease: Emphasis on perilesional fat stranding and fatty proliferation

The hyaline-vascular variant of Castleman disease (HVCD) is relatively uncommon and demonstrates no specific clinical or laboratory findings; therefore, its preoperative diagnosis warrants a radiological evaluation. This study aimed to review imaging findings of HVCD, focusing on perilesional fat stranding and fatty proliferation. Patients with a pathologically confirmed HVCD diagnosis who had undergone CT were recruited from five hospitals from January 2000 to March 2023. Three experienced radiologists assessed CT findings, including lesion location, lesion size, calcification, enhanced pattern, feeding vessel visualization, and arterial enhancement. Perilesional fat stranding, fatty proliferation, neighboring fascial thickening, and surrounding lymphadenopathy were the primary targets of analysis. Moreover, the intensities and apparent diffusion coefficient (ADC) values on MRI and the maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography (PET) were evaluated. This study enrolled 43 patients (mean age 41.3 years ± 14.6 [standard deviation], 23 women). All lesions were well-defined round masses. Calcification and feeding vessels were detected in 21% (9/43) and 86% (36/43) of the patients, respectively. Perilesional fat stranding and fatty proliferation were observed in 44% (19/43) and 19% (8/43), respectively, with fatty proliferation detected only in retroperitoneal HVCD. Neighboring fascial thickening and surrounding lymphadenopathy were identified in 21% and 60%, respectively. The mean ADC value and SUVmax were 0.884 × 10-3 mm2/s and 5.0, respectively. Retroperitoneal HVCD cases with perilesional fatty proliferation demonstrated a higher visceral fat ratio than those without (p = 0.046). Perilesional fat stranding and fatty proliferation were new characteristics of HVCD, especially in retroperitoneal cases.

Generative AI and large language models in nuclear medicine: current status and future prospects

This review explores the potential applications of Large Language Models (LLMs) in nuclear medicine, especially nuclear medicine examinations such as PET and SPECT, reviewing recent advancements in both fields. Despite the rapid adoption of LLMs in various medical specialties, their integration into nuclear medicine has not yet been sufficiently explored. We first discuss the latest developments in nuclear medicine, including new radiopharmaceuticals, imaging techniques, and clinical applications. We then analyze how LLMs are being utilized in radiology, particularly in report generation, image interpretation, and medical education. We highlight the potential of LLMs to enhance nuclear medicine practices, such as improving report structuring, assisting in diagnosis, and facilitating research. However, challenges remain, including the need for improved reliability, explainability, and bias reduction in LLMs. The review also addresses the ethical considerations and potential limitations of AI in healthcare. In conclusion, LLMs have significant potential to transform existing frameworks in nuclear medicine, making it a critical area for future research and development.

From FDG and beyond: the evolving potential of nuclear medicine

The radiopharmaceutical 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) has been dominantly used in positron emission tomography (PET) scans for over 20 years, and due to its vast utility its applications have expanded and are continuing to expand into oncology, neurology, cardiology, and infectious/inflammatory diseases. More recently, the addition of artificial intelligence (AI) has enhanced nuclear medicine diagnosis and imaging with FDG-PET, and new radiopharmaceuticals such as prostate-specific membrane antigen (PSMA) and fibroblast activation protein inhibitor (FAPI) have emerged. Nuclear medicine therapy using agents such as [177Lu]-dotatate surpasses conventional treatments in terms of efficacy and side effects. This article reviews recently established evidence of FDG and non-FDG drugs and anticipates the future trajectory of nuclear medicine.

A prognostic nomogram based on log odds of positive lymph nodes to predict the overall survival in biliary neuroendocrine neoplasms (NENs) patients after surgery

BACKGROUND

The prognosis of biliary neuroendocrine neoplasms (NENs) patients is affected by the status of metastatic lymph nodes. The purpose of this study was to explore the prognostic value of the log odds of positive lymph nodes (LODDS) and develop a novel nomogram to predict the overall survival (OS) in biliary NENs patients.

METHODS

A total of 125 patients with histologically confirmed biliary NENs were selected from the Surveillance, Epidemiology and End Results (SEER) database and further divided into training and validation cohorts. The discrimination and calibration of the nomogram were evaluated using the concordance index (C-index), the area under the time-dependent receiver operating characteristic curve (time-dependent AUC), and calibration plots. The net benefits and clinical utility of the nomogram were quantified and compared with those of the SEER staging system using decision curve analysis (DCA), net reclassification index (NRI), and integrated discrimination improvement (IDI). The risk stratifications of the nomogram and the SEER staging system were compared.

RESULTS

LODDS showed the highest accuracy in predicting OS for biliary NENs. The C-index (0.789 for the training cohort and 0.890 for the validation cohort) and the time-dependent AUC (> 0.7) indicated the satisfactory discriminative ability of the nomogram. The calibration plots showed a high degree of consistency. The DCA, NRI, and IDI indicated that the nomogram performed significantly better than the SEER staging system.

CONCLUSION

A novel LODDS-incorporated nomogram was developed and validated to assist clinicians in evaluating the prognosis of biliary NENs patients.