Functional imaging in endocrine disease is now being increasingly used as an aid in the management of challenging cases, where conventional imaging techniques are inadequate/inconclusive. This talk will provide an overview of available nuclide imaging techniques and specifically focus on the use of 11C-Methionine PET in pituitary and 11C-Metomidate PET in adrenal tumours.
11C-Methionine PET in pituitary disease
Although MRI is very useful in pituitary imaging, it can not detect all microadenomas and does not always reliably distinguish between post-operative remodelling and residual tumour. Methionine, as the first amino acid incorporated into all peptides, is an ideal substrate for 11C-labelling to allow identification of sites of increased peptide/protein synthesis. In contrast to 18F-FDG, it is preferentially taken up by the normal pituitary gland compared to surrounding brain. Its potential utility has been explored in the identification of pituitary microadenomas, but also in the detection of residual functioning pituitary adenomas following primary intervention (surgery, radiotherapy).
11C-Metomidate PET in adrenal disease
As primary aldosteronism (PA) is increasingly recognized to be the cause of hypertension in a significant proportion of hypertensive patients, prompt detection and resection of the offending adrenal lesion is crucial. Although adrenal vein sampling remains the gold-standard diagnostic technique in PA, it is technically demanding and not always feasible. Metomidate, a potent inhibitor of CYP11B1 and CYP11B2, can be C11H3-labelled as a PET tracer and has been shown to be taken up avidly by aldosterone producing adenomas (APAs). 11C-metomidate PET-CT has thus been used in a proportion of patients as an alternative to AVS for localising unilateral APAs.
07 Nov 2016 - 09 Nov 2016