title: Relevance of calcitonin cut-off in the follow-up of medullary thyroid carcinoma for conventional imaging and 18-fluorine-fluorodihydroxyphenylalanine PET.
abstract: OBJECTIVE
  The American thyroid association (ATA) recommends that additional imaging procedures supplement cervical ultrasonography (US) in any patient with a basal calcitonin value above 150 pg/ml in the follow-up of medullary thyroid carcinoma (MTC). The aim of the present study was to reaffirm or challenge this cut-off for 18-Fluorine-Fluorodihydroxyphenylalanine positron emission tomography (18F-DOPA PET) and conventional imaging ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI)).
  
  
  METHODS
  Thirty-nine patients (18 females, 21 males), mean age 62 years, range from 35 to 86, followed-up for MTC were included in the present retrospective study. In our patients 64 18F-DOPA scans, 28 neck US, 28 CT and 8 MRI were performed. For all cases basal calcitonin values were available. Sensitivity and specificity of 18F-DOPA PET and conventional imaging (US, CT, MRI) related to calcitonin values were calculated.
  
  
  RESULTS
  According to the calcitonin cut-off of 150 pg/ml, we found the following sensitivities and specificities: 79% and 80% for 18F-DOPA PET, 75% and 92% for US, 80% and 25% for CT, 50% and 75% for MRI. Taking the level of detectable calcitonin, we calculated the following sensitivities: 52% for 18F-DOPA PET, 46% for US, 79% for CT and 38% for MRI.
  
  
  CONCLUSIONS
  We cannot confirm the calcitonin cut-off proposed by the ATA for the detection of MTC recurrences and contemporaneously we cannot state that 18F-DOPA PET has a very high sensitivity. For the neck region 18F-DOPA PET and US showed similar results. 18F-DOPA PET/CT seems to be the best imaging modality for whole-body tumor detection. Bone metastases are best detected by MRI.
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Alma
authors.initials: A
authors.lastname: Sesti
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Marius
authors.initials: M
authors.lastname: Mayerhoefer
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Philip
authors.initials: P
authors.lastname: Anner
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wadsak
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Robert
authors.initials: R
authors.lastname: Dudczak
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Alexander
authors.initials: A
authors.lastname: Haug
authors.affiliation: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria georgios.karanikas@meduniwien.ac.at.
authors.forename: Georgios
authors.initials: G
authors.lastname: Karanikas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002116:Calcitonin / Q000378:metabolism*; D018276:Carcinoma, Medullary / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014463:Ultrasonography
chemical_list: D019275:Radiopharmaceuticals; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine; D002116:Calcitonin
keywords: 18F-DOPA; Medullary thyroid carcinoma; PET; calcitonin