title: Ga-68-DOTA-TATE PET/CT for discrimination of tumors of the optic pathway.
abstract: OBJECTIVE
  Symptomatic tumors of the optic nerve pathway may endanger vision. They are difficult to classify by imaging alone and biopsy may damage visual function. Tumor pathology influences treatment decision and a diagnostic tool with a high sensitivity and specificity would therefore be invaluable. We hypothesized that Ga-68-DOTA-TATE PET/CT may help in discriminating optic nerve tumors as uptake of somatostatin is elevated in meningiomas.
  
  
  METHODS
  Ga-68-DOTA-TATE PET/CT was used to examine 13 patients with ambiguous, symptomatic lesions of the optic pathway for treatment planning. The presence or absence of meningioma was validated by histopathology or supplementary diagnostic work-up.
  
  
  RESULTS
  Ga-68-DOTA-TATE PET/CT identified 10 meningiomas (en plaque = 1, optic nerve sheath = 4, sphenoidal = 5) correctly via increased SSTR (somatostatin receptor) expression (mean SUVmax (maximum standardized uptake value) = 14.3 ± 15.4). 3 tumors did not show elevated Ga-68-DOTA-TATE uptake (SUVmax = 2.1 ± 1.0). Subsumizing all clinical-radiological follow-up tools available, these lesions were classified as an intracerebral metastasis of an advanced gastric carcinoma, histologically proven inflammatory collagenous connective tissue and presumed leukemic infiltration of a newly diagnosed chronic lymphocytic leukemia. In this case series, Ga-68-DOTA-TATE PET/CT demonstrated both a sensitivity and specificity of 100%. Yet, the golden standard of histopathology was only available in a subset of patients included.
  
  
  CONCLUSIONS
  Ga-68-DOTA-TATE PET/CT proved to be a valuable diagnostic tool for the correct classification of equivocal, symptomatic tumors of the anterior optic pathway requiring therapy. PET/CT results influenced therapy decision essentially in all cases.
authors.affiliation: Department of Ophthalmology , and.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Klingenstein
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Haug
authors.forename: Christina
authors.initials: C
authors.lastname: Miller
authors.forename: Christoph
authors.initials: C
authors.lastname: Hintschich
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008579:Meningioma / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D064847:Multimodal Imaging; D009900:Optic Nerve / Q000000981:diagnostic imaging* / Q000473:pathology; D009942:Organometallic Compounds; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D009942:Organometallic Compounds; C513399:gallium Ga 68 dotatate
keywords: Anterior optic pathway; Ga-68-DOTA-TATE PET/CT; meningioma; tumor