A randomised diagnostic imaging trial of [18F]FCH PET/CT vs conventional imaging for primary hyperparathyroidism

We will enrol eligible patients referred to the Endocrine Surgery department at one acute tertiary hospital site, the Royal Brisbane and Women’s Hospital (RBWH) in Brisbane, Australia. After the informed consent process, participants will undergo [18F]fluorocholine (FCH) PET/CT at the RBWH Department of Nuclear Medicine & PET Services. This scan takes approximately 1 hour.. Images will be interpreted by two experienced nuclear medicine specialists in a blinded fashion. Conventional imaging with sestamibi SPECT/CT and 4D CT will be performed unless already completed within the previous six months, and interpreted as per standard care by an experienced nuclear medicine specialist and radiologist respectively. All patients will receive a standard of care neck ultrasound to assist with operative planning. The duration of these imaging procedures will be determined by the local institutional protocol, in general a neck ultrasound takes approximately 1 hour, a 4D CT 1 hour and sestamibi SPECT/CT 4 hours. All imaging techniques will be reviewed at a monthly multidisciplinary meeting, attended by representatives from Endocrinology, Endocrine Surgery, Nuclear Medicine and Radiology. Participants will be randomised 1:1 to the order in which the imaging modality (FCH PET/CT or conventional imaging with sestamibi SPECT/CT and 4DCT) will be reviewed first. The study investigator will record the intended management plan at baseline and following first- and second-line imaging. The intended surgical approach, either minimally invasive parathyroidectomy or bilateral neck exploration, will be documented according to a schema of positive, equivocal and negative results of each imaging technique. As current best practice, it is expected that the majority of participants will proceed to neck surgery within 12 weeks of randomisation, performed by an experienced Endocrine Surgeon. Clinical outcomes of participants will be followed up at one month and six months following definitive surgery. Additional analyses will include accuracy of each imaging modality, inter-observer agreement after a second blind read of all imaging at three months, health economic assessment, comparison of radiation exposure, assessment of environmental impact and measurement of patient satisfaction with imaging techniques.