title: Somatostatin receptor scintigraphy in surveillance of pediatric brain malignancies.
abstract: BACKGROUND
  Somatostatin receptor scintigraphy (SRS) has been successfully used in imaging PBTs and, as a functional imaging modality, may be better able to differentiate tumor from scar/necrosis. This retrospective study evaluates the role of SRS in post-treatment surveillance of PBTs.
  
  
  METHODS
  Twenty children (age range: 7 months to 24 years, mean: 9 years) with known brain malignancies underwent serial SRS and MRI. The sensitivity and specificity of SRS and MRI were compared for surveillance scanning using patient outcome as the reference standard. Somatostatin receptors (sstrs) expression was determined by immunohistochemistry (IHC) of available tumor specimens.
  
  
  RESULTS
  SRS was true positive (TP) in 15 of 16 patients with proven disease found post-resection (n = 5) or during follow-up (n = 11). In contrast, MRI was positive in 12 of these 16 patients and equivocal in another two patients where it could not distinguish between radiation necrosis and tumor recurrence. The two patients with false negative (FN) MRI and proven disease were positive by SRS. SRS was negative in all four patients with no evidence of disease by follow-up (mean follow-up = 58 months). The only patient with a FN SRS (TP by MRI) was one without IHC evidence of sstrs. SRS was TP in 7/7 tumors with IHC documented sstrs.
  
  
  CONCLUSIONS
  SRS is a useful adjunct to MRI for post-treatment surveillance of sstr-positive PBTs, particularly when MRI is equivocal.
authors: Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA. geetika-khanna@uiowa.edu
authors: Geetika
authors: G
authors: Khanna
authors: M Sue
authors: MS
authors: O'Dorisio
authors: Yusuf
authors: Y
authors: Menda
authors: Charles
authors: C
authors: Glasier
authors: Barry
authors: B
authors: Deyoung
authors: Brian J
authors: BJ
authors: Smith
authors: Michael
authors: M
authors: Graham
authors: Malik
authors: M
authors: Juweid
mesh_terms: D000293:Adolescent; D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis*; D001932:Brain Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D002648:Child; D002675:Child, Preschool; D016371:Cranial Irradiation / Q000009:adverse effects; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000209:etiology; D017481:Receptors, Somatostatin / Q000032:analysis*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D014408:Biomarkers, Tumor; D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; D013004:Somatostatin; C081788:pentetreotide