Endocrine Abstracts

Background: Cross-sectional imaging (e.g. CT/MRI) can not always reliably identify the site of ACTH secretion in Cushing’s disease (CD) or the ectopic ACTH syndrome (EAS). We report our experience of localising the source of ACTH-dependent Cushing’s syndrome, using functional imaging with 11C-methionine positron emission tomography (Met-PET).Methods: Forty consecutive patients with: (i) de novo ...

Background: Cross-sectional imaging (e.g. CT/MRI) can not always reliably identify the site of ACTH secretion in Cushing’s disease (CD) or the ectopic ACTH syndrome (EAS). We report our experience of localising the source of ACTH-dependent Cushing’s syndrome, using functional imaging with 11C-methionine positron emission tomography (Met-PET).Methods: Forty consecutive patients with: (i) de novo ...

Background: Existing biomarkers have limited ability to discriminate indolent non-functioning pituitary adenomas (NFPAs) from those with a propensity to recur following primary surgery. Radiomics, the extraction of quantitative data from medical imaging, is increasingly recognised as a tool to augment clinical decision making.Methods: 39 patients who underwent primary trans-sphenoidal surgery for an NFPA between January 2007 and April 2017, were enrolled...

Background: Image reconstruction is a key step for the accurate interpretation of positron emission tomography (PET) scans. Nuclear medicine phantoms play a critical role in this process. However, existing phantoms (based on simple geometric shapes) do not reflect the complexity of sellar/parasellar anatomy. We therefore created a novel pituitary phantom and examined the impact of image optimisation on the detection of microadenomas, using 11C-methionine PET s...

Background: Primary aldosteronism (PA) is an important, potentially curable, cause of hypertension. Distinguishing unilateral and bilateral causes is a critical step in determining who should be considered for adrenalectomy. Adrenal vein sampling (AVS) remains the gold standard for lateralisation. However, AVS is technically challenging with limited availability. To address this, we have introduced molecular imaging using PET/CT with the radiotracer [11C]Metomidate ...

Background: In a sub-group of patients with newly diagnosed pituitary adenomas, conventional MRI will fail to confidently localise the tumour. The role of molecular imaging for these patients is increasingly being recognised, both in terms of confirming diagnosis and in guiding targeted therapy; 11C-Methionine PET co-registered with volumetric MRI (Met-PET/MRCR) can enhance decision making in this group of patients. However, in some cases distinguishing t...

Context: Surgery is the first-line treatment option for thyrotropinomas, but medical therapy with somatostatin receptor ligands (SRL) may be used as neoadjuvant treatment and to facilitate safe surgery.Objectives: To determine the extent to which neoadjuvant SRL (i) corrects clinical, laboratory and tissue hyperthyroidism in thyrotropinomas, (ii) induces tumour shrinkage in macroadenomas, and (iii) aids microadenoma detection by 11C-methionine...

Objective: To determine if an extended lateral approach to trans-sphenoidal surgery (TSS), guided by 11C-Methionine PET/CT co-registered with volumetric MRI (Met-PET/MRCR), can lead to remission in patients with persistent acromegaly due to post-operative lateral/para-sellar tumour remnants.Methods: We identified eight patients with persistent acromegaly following primary intervention [TSS ± medical therapy ± radiotherapy ...

Background: Endocrine Society guidelines classify macroprolactinomas as ‘resistant’ if there is failure to normalise prolactin, or to achieve radiological tumour shrinkage of >50%, on standard doses of dopamine agonist. In this context, escalation of treatment to maximal tolerable doses and/or referral for surgery is advised. However, we have recently observed several ‘discordant responders’, where tumour shrinkage lags significantly (>6 months) beh...

Background: 11C-methionine positron emission tomography (Met-PET) is a potentially important imaging adjunct in the diagnostic workup of pituitary adenomas, including somatotroph tumours. Met-PET can identify residual or occult disease and make definitive therapies accessible for a subgroup of patients who would otherwise require lifelong medical therapy. However, data on its use is still limited to small case series. Here, we report the currently largest sing...