Molecular Imaging of Pituitary Adenomas
试验速览
- 阶段
- 不适用
- 入组人数
- 20
- 试验地点
- 2
- 主要终点
- PET uptake
研究概览
简要总结
Background: Pituitary adenomas affect 10% of the population. Surgery offers the most cost-effective treatment modality but cure rates are only 40-70%, in part due to the limitations of Magnetic Resonance Imaging (MRI) in visualising small tumours (up to 40% are undetected) and discriminating adenomatous tissue from healthy pituitary or post-surgical change. Positron emission tomography (PET) imaging may improve localisation but current tracers have short half-lives and are unsuitable for routine use. The dopaminergic system regulates pituitary growth and function, as evidenced by the use of dopamine D2 receptor agonists as medical therapy. Dopaminergic PET tracers, including 18F-FDOPA (6-[18F]-L-fluoro-L-3,4-dihydroxyphenylalanine) and 18F (fluorine 18)-Fallypride (which binds to D2/D3 receptors), might thus improve management by enhancing tumour discrimination and quantifying D2 receptor expression.
Aim: To establish whether imaging changes in dopaminergic transmission and receptor function has the potential to improve localisation of pituitary adenomas.
Methods: Subjects with pituitary adenomas will undergo 18F-FDOPA and 18F-Fallypride PET scans in addition to standard pituitary MRI. Quantification of binding potential combined with MRI co-registration to provide enhanced anatomical definition will be applied. In vivo D2 receptor binding will be correlated with ex vivo D2 receptor mRNA (messenger ribonucleic acid) and protein expression from tumour samples removed at surgery.
详细描述
Aim: In this proof-of-concept study, the investigators will seek to establish whether imaging changes in Dopaminergic transmission and receptor function has the potential to improve localisation and management of pituitary adenomas.
Methods:
Patients will be recruited from the general endocrine and pituitary multidisciplinary clinics at the University Hospital of Wales. Patients will comprise those with a confirmed pituitary adenoma for whom pituitary imaging is indicated as part of standard clinical management. Tumour functionality (Cushing's syndrome, Acromegaly, Prolactinoma, TSHoma) and hypopituitarism will be established in accordance with established clinical practice. Detailed surgical, pathological and post-operative data will be collected in each case, in order to facilitate correlation of PET/MRI findings with key clinical outcomes.
Histopathological examination:
Surgical specimens will be fixed in 10% neutral buffered formalin and embedded in paraffin as per standard clinical practice. Histopathological confirmation of the presence and type of pituitary adenoma will be established by typical microscopic appearances of an adenoma supported by immunohistochemical staining for the relevant hormone (Growth hormone, ACTH [Adrenocorticotrophic Hormone], Prolactin, TSH [Thyroid Stimulating Hormone], LH/FSH [Luteinising hormone/Follicle Stimulating Hormone]). Tumour will also be stored snap frozen for subsequent RNA and protein extraction, in order to quantify dopamine D2 short and long isoform receptor expression. This will allow comparison of ex vivo receptor expression levels with in vivo 18F-fallypride uptake.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Diagnostic
- 盲法
- None
入排标准
- 年龄范围
- 16 Years 至 —（Child, Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Confirmed pituitary adenoma for whom pituitary imaging is indicated as part of standard clinical management
排除标准
- •Pregnancy, breastfeeding and any contraindications to MRI or intravenous contrast administration
研究组 & 干预措施
PET imaging
18F-FDOPA and 18F-Fallypride PET imaging
干预措施: PET imaging (Diagnostic Test)
结局指标
主要结局
PET uptake
时间窗: 3 hours
Quantification of tracer binding potential combined with MRI co-registration
次要结局
未报告次要终点