title: The optimal timing for imaging brain tumours and other brain lesions with 18F-labelled fluoromethylcholine:  a dynamic positron emission tomography study.
abstract: OBJECTIVE
  To determine the optimal timing for imaging brain tumours and other brain lesions with 18F-labelled fluoromethylcholine (18F-FCho) PET.
  
  
  METHODS
  Dynamic PET imaging with 18F-FCho (acquisition time of 28 min) was performed in 24 patients with space-occupying lesions in the brain. On the coregistered PET and MRI, lesion-to-normal tissue uptake ratios (LNRs) were calculated. Time-activity curves (TACs) were generated on the basis of the LNRs. Changes in LNR over time were calculated on the basis of the linear part of the TAC (last 22 min of the acquisition).
  
  
  RESULTS
  TACs for 18F-FCho in gliomas of different grading showed that, after a rapid uptake phase, the mean increase in LNR was 1.07 ± 0.93 for glioblastomas, -0.52 ± 1.56 for anaplastic astrocytomas, 0.04 ± 0.13 for grade 2 oligoastrocytomas and 0.37 in a case of a pilocytic astrocytoma. The average increase in LNR was 0.46 for a brain metastasis, 0.41 ± 0.69 for radiation-induced mass lesions and 1.07 for a tumefactive demyelinating lesion. In contrast, TACs for 18F-FCho in meningiomas showed that, after a rapid uptake phase, the average change in LNR was -5.25 ± 4.19 for typical meningiomas and -3.04 in a case of a mixed angiomatous and clear cell meningioma.
  
  
  CONCLUSIONS
  On the basis of the TACs, PET imaging with 18F-FCho starting within minutes after the administration of the tracer is preferred for the detection of brain tumours and other brain lesions. If discrimination between meningioma and other brain tumours is of concern, both 'early' and 'late' PET imaging could be helpful.
authors: Department of aNuclear Medicine, Ghent University, Ghent, Belgium.
authors: Koen
authors: K
authors: Mertens
authors: Julie
authors: J
authors: Bolcaen
authors: Hamphrey
authors: H
authors: Ham
authors: Karel
authors: K
authors: Deblaere
authors: Caroline
authors: C
authors: Van den Broecke
authors: Tom
authors: T
authors: Boterberg
authors: Filip
authors: F
authors: De Vos
authors: Ingeborg
authors: I
authors: Goethals
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D002794:Choline / Q000031:analogs & derivatives*; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D049268:Positron-Emission Tomography / Q000379:methods*; D013997:Time Factors
chemical_list: C516370:fluoromethylcholine; D002794:Choline