title: (18)F-DOPA PET/CT and MRI: description of 12 histologically-verified pheochromocytomas.
abstract: OBJECTIVE
  To describe the (18)F-fluorodihydro-xyphenylalanine ((18)F-DOPA), positron emission tomography (PET) and magnetic resonance imaging (MRI) appearance of pheochromocytomas, with a focus on the presence or absence of typical MRI features.
  
  
  METHODS
  Eleven patients with histologically-verified pheochromocytoma [sporadic (n=9), multiple endocrine neoplasia (MEN) 2A syndrome (n=2)] were enrolled retrospectively. All patients underwent an MRI examination of the upper abdomen. Nine out of 11 patients underwent (18)F-DOPA PET/CT, and the remaining two patients underwent independent PET and computed tomography (CT) examinations. (18)F-DOPA-PET/CT examinations were considered positive when an increased tracer accumulation in the adrenal region, as shown on CT images, was observed. When an adrenal mass was detected on MRI, the T1 and T2 signal intensity and contrast enhancement pattern were recorded. Based on MR characteristics, the lesions were divided into typical and atypical.
  
  
  RESULTS
  Ten out of 11 patients had one lesion, while one patient had two lesions. All pheochromocytomas were detected by both PET/CT and MRI. On (18)F-DOPA scans, all lesions showed an increased tracer accumulation, with a mean maximum standardized uptake value (SUVmax) of 13.7±5.75. Eight out of 12 pheochromocytomas exhibited typical MRI features, with intermediate signal intensity on T1-weighted images in-phase, absence of signal drop on T1-weighted images out-of-phase, high signal intensity on T2-weighted images, and clear contrast enhancement in the arterial phase. The remaining four lesions exhibited atypical MRI features, namely absence of one of the listed criteria.
  
  
  CONCLUSIONS
  In the assessment of pheochromocytoma, the combination of (18)F-DOPA PET with MRI is superior to MRI-alone. (18)F-DOPA PET/MRI may yield a higher diagnostic confidence for the detection of pheochromocytoma than (18)F-DOPA PET/CT.
authors: Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna General Hospital, Waehringer Guertel 18-20, 1090 Vienna, Austria. georgios.karanikas@meduniwien.ac.at.
authors: Silvia
authors: S
authors: Magnaldi
authors: Marius E
authors: ME
authors: Mayerhoefer
authors: Ashkan
authors: A
authors: Khameneh
authors: Matthias
authors: M
authors: Schuetz
authors: Domagoj
authors: D
authors: Javor
authors: Markus
authors: M
authors: Mitterhauser
authors: Robert
authors: R
authors: Dudczak
authors: Marcus
authors: M
authors: Hacker
authors: Georgios
authors: G
authors: Karanikas
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D000328:Adult; D000368:Aged; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D005260:Female; D005462:Fluorine Radioisotopes; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D010673:Pheochromocytoma / Q000000981:diagnostic imaging* / Q000473:pathology*; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; C043437:fluorodopa F 18; D004295:Dihydroxyphenylalanine
keywords: 18F-DOPA; CT; MRI; PET; Pheochromocytoma