title: Successful treatment of residual pituitary adenoma in persistent acromegaly following localisation by 11C-methionine PET co-registered with MRI.
abstract: OBJECTIVE
  To determine if functional imaging using11C-methionine positron emission tomography co-registered with 3D gradient echo MRI (Met-PET/MRI), can identify sites of residual active tumour in treated acromegaly, and discriminate these from post-treatment change, to allow further targeted treatment.
  
  
  METHODS
  Twenty-six patients with persistent acromegaly after previous treatment, in whom MRI appearances were considered indeterminate, were referred to our centre for further evaluation over a 4.5-year period. Met-PET/MRI was performed in each case, and findings were used to decide regarding adjunctive therapy. Four patients with clinical and biochemical remission after transsphenoidal surgery (TSS), but in whom residual tumour was suspected on post-operative MRI, were also studied.
  
  
  RESULTS
  Met-PET/MRI demonstrated tracer uptake only within the normal gland in the four patients who had achieved complete remission after primary surgery. In contrast, in 26 patients with active acromegaly, Met-PET/MRI localised sites of abnormal tracer uptake in all but one case. Based on these findings, fourteen subjects underwent endoscopic TSS, leading to a marked improvement in (n = 7), or complete resolution of (n = 7), residual acromegaly. One patient received stereotactic radiosurgery and two patients with cavernous sinus invasion were treated with image-guided fractionated radiotherapy, with good disease control. Three subjects await further intervention. Five patients chose to receive adjunctive medical therapy. Only one patient developed additional pituitary deficits after Met-PET/MRI-guided TSS.
  
  
  CONCLUSIONS
  In patients with persistent acromegaly after primary therapy, Met-PET/MRI can help identify the site(s) of residual pituitary adenoma when MRI appearances are inconclusive and direct further targeted intervention (surgery or radiotherapy).
authors: Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science.
authors: Olympia
authors: O
authors: Koulouri
authors: Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science.
authors: Narayanan
authors: N
authors: Kandasamy
authors: Department of Medical Physics.
authors: Andrew C
authors: AC
authors: Hoole
authors: Department of Nuclear Medicine.
authors: Daniel
authors: D
authors: Gillett
authors: Department of Nuclear Medicine.
authors: Sarah
authors: S
authors: Heard
authors: Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science.
authors: Andrew S
authors: AS
authors: Powlson
authors: Department of Pathology.
authors: Dominic G
authors: DG
authors: O'Donovan
authors: Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science.
authors: Anand K
authors: AK
authors: Annamalai
authors: Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science.
authors: Helen L
authors: HL
authors: Simpson
authors: Department of EndocrinologySt Bartholomew's Hospital, London, UK.
authors: Scott A
authors: SA
authors: Akker
authors: Department of EndocrinologyKing's College Hospital, London, UK.
authors: Simon J B
authors: SJ
authors: Aylwin
authors: Macleod Diabetes and Endocrine CentreRoyal Devon and Exeter Hospital, Exeter, UK.
authors: Antonia
authors: A
authors: Brooke
authors: Department of Diabetes and EndocrinologyNew Cross Hospital, Wolverhampton, UK.
authors: Harit
authors: H
authors: Buch
authors: Department of EndocrinologyLeicester Royal Infirmary, Leicester, UK.
authors: Miles J
authors: MJ
authors: Levy
authors: Department of EndocrinologyImperial College Healthcare NHS Trust, London, UK.
authors: Niamh
authors: N
authors: Martin
authors: Diabetes and Endocrine CentreIpswich Hospital, Ipswich, UK.
authors: Damian
authors: D
authors: Morris
authors: Diabetes and Endocrine CentreIpswich Hospital, Ipswich, UK.
authors: Craig
authors: C
authors: Parkinson
authors: Department of Otolaryngology.
authors: James R
authors: JR
authors: Tysome
authors: Department of Neurosurgery.
authors: Tom
authors: T
authors: Santarius
authors: Department of Otolaryngology.
authors: Neil
authors: N
authors: Donnelly
authors: Department of Nuclear Medicine.
authors: John
authors: J
authors: Buscombe
authors: Wolfson Brain Imaging CentreUniversity of Cambridge and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK.
authors: Istvan
authors: I
authors: Boros
authors: Wolfson Brain Imaging CentreUniversity of Cambridge and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK.
authors: Rob
authors: R
authors: Smith
authors: Wolfson Brain Imaging CentreUniversity of Cambridge and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK.
authors: Franklin
authors: F
authors: Aigbirhio
authors: Department of Neuroradiology.
authors: Nagui M
authors: NM
authors: Antoun
authors: Department of Oncology.
authors: Neil G
authors: NG
authors: Burnet
authors: Department of Nuclear Medicine.
authors: Heok
authors: H
authors: Cheow
authors: Department of Neurosurgery.
authors: Richard J
authors: RJ
authors: Mannion
authors: Department of Neurosurgery Wolfson Brain Imaging CentreUniversity of Cambridge and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK.
authors: John D
authors: JD
authors: Pickard
authors: Metabolic Research LaboratoriesWellcome Trust-MRC Institute of Metabolic Science mg299@medschl.cam.ac.uk.
authors: Mark
authors: M
authors: Gurnell