Molecular Imaging and Radionuclide Therapy最新文献

Gliomas are the most common primary malignant brain tumors and are characterized by heterogeneous growth and complex biology, which complicate accurate diagnosis and management. While magnetic resonance imaging (MRI) remains the clinical standard, its limitations in delineating tumor margins and distinguishing recurrence from treatment-induced changes highlight the need for complementary molecular imaging. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) has been extensively studied, providing valuable prognostic information by reflecting tumor glycolytic activity. However, its diagnostic utility is hampered by high cortical background uptake and by poor sensitivity in detecting low-grade gliomas. Conversely, glioma-68 fibroblast activation protein inhibitor (FAPI) PET targets cancer-associated fibroblasts, offering superior tumor-to-background contrast and improved visualization of infiltrative margins. Comparative studies suggest that FAPI PET better discriminates between low- and high-grade gliomas, correlates with tumor stromal activity, and aids in therapy planning by differentiating true progression from post-treatment changes. Despite these advantages, the evidence base for FAPI remains limited, largely derived from small cohorts and pilot studies. Standardized imaging protocols and larger prospective trials are necessary to validate its role. Overall, ¹⁸F-FDG and FAPI PET provide complementary insights into glioma biology, and their integration with MRI and amino acid tracers may refine diagnostic accuracy, therapeutic planning, and prognostic assessment in clinical neuro-oncology.

Tumor-induced osteomalacia, resulting from tumoral overproduction of fibroblast growth factor 23, is a rare paraneoplastic syndrome clinically characterized by muscle weakness, bone pain, and pathological fractures. Fewer than 1,000 cases have been reported in the literature. Laboratory findings typically include hypophosphatemia, normal or decreased levels of 1.25-dihydroxy vitamin D, and normal or elevated levels of FGF23. Functional imaging methods, particularly somatostatin receptor imaging, play an important role in the localization of the tumor. In this case of tumor-induced osteomalacia, we presented the findings from gallium-68 (⁶⁸Ga)-DOTATATE, ⁶⁸Ga-fibroblast, and ¹⁸F-fluorodeoxyglucose positron emission tomography imaging modalities used for tumor localization.

Objective: To investigate whether gallium-68 fibroblast activation protein inhibitor positron emission tomography/computed tomography ⁶⁸Ga-FAPI PET/CT is superior to ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG) PET/CT in the staging of patients with laryngeal cancer (LC).

Methods: A total of 14 patients diagnosed with LC were retrospectively included in the study, of whom 13 were male and 1 female, with a mean age of 65 years. All participants were initially referred to our department for staging with ¹⁸F-FDG PET/CT. Subsequently, each patient underwent a ⁶⁸Ga-FAPI PET/CT scan three days following the ¹⁸F-FDG PET/CT. Both sets of imaging studies were independently evaluated by two experienced nuclear medicine physicians, and the findings were systematicaly compared to assess potential differences in diagnostic performance.

Results: The median maximum standard uptake values (SUV_max) of primary tumors was significantly higher in ⁶⁸Ga-FAPI PET/CT 10.95; range: 3.5-19.2) compared to ¹⁸F-FDG PET/CT (4.85; range: 2.2-10.9). Lymph node involvement was observed on FDG scans in 3 patients, in ipsilateral levels 2 and/or 3, with a median SUV_max of 3.7 (range: 2.4-4.1). FAPI PET/CT also detected lymph node involvement at the same levels in 3 patients, with a notably higher SUV_max of 7.9 (range: 6.8-10.4).

Conclusion: In this study, our results suggest that ⁶⁸Ga-FAPI PET/CT demonstrates superior radiotracer uptake in both primary tumors and lymph nodes, which may enhance detection sensitivity for LC staging compared with ¹⁸F-FDG PET/CT. Nevertheless, further prospective studies with larger patient populations are warranted to validate these preliminary observations and determine the clinical value of this emerging imaging modality.

Spinal cord involvement is a rare manifestation of metastatic ovarian carcinoma. We report a case of high-grade serous ovarian cancer initially diagnosed in 2020. After cytoreductive surgery and multiple chemotherapy regimens, the patient developed brain metastases followed by small hypermetabolic foci along the spinal canal detected on ¹⁸F-fluorodeoxyglucose positron emission tomography/magnetic resonance imaging (¹⁸F-FDG PET/MRI). These lesions, primarily located in the cervical region, were confirmed by contrast-enhanced spinal MRI but were more clearly visualized on ¹⁸F-FDG PET/MRI. Intramedullary spinal cord metastases are extremely rare and often underdiagnosed. While MRI remains the standard for anatomical assessment, ¹⁸F-FDG PET/MRI demonstrated superior lesion detection and definition in this case. This highlights the potential of hybrid imaging for improved diagnostic sensitivity in patients with suspected central nervous system involvement.

Diffuse hepatic involvement in multiple myeloma is rare and may present a diagnostic challenge ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT). We present the case of a 59-year-old man with a 3-year history of multiple myeloma who developed progressive hepatomegaly and perihepatic ascites. ¹⁸F-FDG PET/CT demonstrated marked diffuse liver enlargement without any focal or diffuse hepatic 18F-FDG uptake, while mild diffuse skeletal uptake suggested a globally ¹⁸F-FDG-low myeloma phenotype. Given the discordance between severe morphological findings and the absence of hepatic metabolic activity, a liver biopsy was performed, which revealed diffuse sinusoidal infiltration by CD138-positive, lambda-restricted plasma cells and excluded hepatic amyloidosis. Following systemic therapy, hepatomegaly and ascites regressed, while hepatic ¹⁸F-FDG uptake remained absent. Written informed consent for publication was obtained from the patient. This case highlights an important limitation of ¹⁸F-FDG PET/CT in detecting diffuse hepatic myeloma and emphasizes the need for multimodal diagnostic integration.

Approximately 0.1% of all prosthetic cardiac valves are affected by fungal endocarditis (bacterial endocarditis being the most common cause), which has a high case fatality rate. Post-treatment clinical improvement and a negative blood culture do not definitively rule out the presence of residual active disease. Among imaging techniques, trans-oesophageal echocardiography has higher sensitivity than transthoracic echocardiography, but has its own limitations. Functional imaging with ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) has shown to have high overall sensitivity, specificity, and accuracy for the diagnosis and follow-up evaluation of prosthetic valve infective endocarditis, thereby significantly influencing clinical management. Here, we report a rare case of a patient with Marfan syndrome and fungal prosthetic valve endocarditis, in which ¹⁸F-FDG-PET/CT played a significant role in management decision.

Truncation artifact during single-photon emission computed tomography occurs when some part of body, such as left ventricle in myocardial perfusion imaging, lies outside the field-of-view during image acquisition. Improper adjustment of axis of rotation of detectors regarding the patient on the scanning table is the main cause. Large or slim patient body habitus is reported as source of this artifact. However, there may be other sources including that in our case, in which the artifact was present in prone position but not in supine imaging. The appearance was one-sided incremental cropping of projections of one of detectors and a wedge-shaped or triangular defect in the corresponding sinogram. This finding may suggest a possible mechanical instability of the gantry during motion over the patient's left side in prone imaging.

Spondyloepiphyseal dysplasia tarda (SEDT) is a rare X-linked skeletal disorder affecting the spine and long bones, leading to short stature, spinal deformities, and joint stiffness. It is caused by genetic mutations, and primarily affects males. Diagnosis is confirmed by imaging and genetic testing. We report the case of a 33 years old patient with a history of X-linked SEDT, who presented with pain in the lower limbs and pelvis, accompanied by limited mobility. Bone scan with ⁹⁹mTc-methylene diphosphonate (MDP) revealed a polyostotic SEDT involvement, periarticular ossifications, and bony bridges in the active phase. The authors highlight the role of bone scan with ⁹⁹mTc-MDP in diagnosing this rare disease.

Objectives: The increasing use of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) imaging has led to the frequent detection of incidentalomas. This study aimed to investigate the prevalence, locations, malignancy rates, and clinical evaluations of incidentalomas detected during preoperative staging with ¹⁸F-FDG PET/CT in patients with surgically relevant primary tumors.

Methods: A total of 251 patients who underwent preoperative ¹⁸F-FDG PET/CT imaging between January 2019 and December 2023 were retrospectively analyzed. Incidental uptake sites were classified into six anatomical regions: thyroid, colon, rectum, prostate, cervix/uterus, and breast. Data regarding maximum standardized uptake value (SUV_max) values, biopsy status, imaging follow-up, and histopathological outcomes were recorded and compared with population-based incidence data from the literature.

Results: The most frequent incidentalomas were detected in the thyroid (11.6%), followed by cervix/uterus (9.6%), colon (7.6%), prostate (4.4%), breast (2.4%), and rectum (2.0%). Malignancy was confirmed in incidentalomas of the thyroid (85.7%), prostate (83.3%), colon (71.4%), rectum (50.0%), and breast (33.3%). Malignancy rates for the thyroid, breast, colorectal, and prostate groups were significantly higher than population-based estimates (p<0.05). No statistically significant correlation was found between SUV_max and malignancy status across localization groups.

Conclusion: Incidental findings on ¹⁸F-FDG PET/CT imaging are common and carry a considerable risk of malignancy, particularly in thyroid, prostate, and colorectal sites. Given the observed diagnostic yield, further clinical evaluation, including tissue diagnosis, should be considered in cases with focal uptake, especially when located in high-risk anatomical regions. Awareness of these findings is essential for timely management and appropriate therapeutic decision-making.

Distant metastases from well-differentiated thyroid carcinoma typically involve the lungs and bones. We report a rare case of metastatic papillary thyroid carcinoma presenting as soft tissue lesion, detected by Iodine-131 whole-body scintigraphy in a 44-year-old asymptomatic male. The patient had previously undergone a total thyroidectomy and bilateral modified radical neck dissection, receiving radioiodine for pT3bN1bMx multifocal classical papillary thyroid carcinoma. Further evaluation with ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography revealed additional sites of soft tissue and muscle metastasis, along with extensive nodal, lung, and skeletal involvement. These findings indicated advanced disease with a poor prognosis, necessitating a change in the treatment plan.