title: Early-postoperative magnetic resonance imaging in glial tumors: prediction of tumor regrowth and recurrence.
abstract: OBJECTIVE
  This study investigated the value of early-postoperative magnetic resonance (EPMR) imaging in the detection of residual glial tumor and investigated the role of EPMR for the prediction of tumor regrowth and recurrence.
  
  
  METHODS
  We retrospectively analyzed pre- and post-operative magnetic resonance imaging results from 50 adult patients who underwent surgical treatment for supratentorial glial tumor. There were glioblastoma multiforme in 25 patients, astrocytoma (grades II and III) in 11 patients, oligodendroglioma (grades II and III) in 9 patients, and oligoastrocytoma (grades II and III) in 5 patients. EPMR imaging was performed within 24 h after surgery. EPMR findings were compared with the neurosurgeon's intraoperative estimation of gross tumor removal. Patterns of contrast enhancement at the resection site, in residual and developing tumor tissue and blood at the resection site were evaluated on EPMR and in follow-up studies. 'Residual tumor' was defined as contrast enhancing mass at the operative site on EPMR. 'Regrowth' was defined as contrast enhancing mass detected on follow-up in the same location as the primary tumor. 'Recurrence' was defined as appearance of a mass lesion in the brain parenchyma distant from the resection bed during follow-up.
  
  
  RESULTS
  Nineteen patients showed no evidence of residual tumor, regrowth, or recurrence on EPMR or any of the later follow-up radiological examinations. EPMR identified 20 cases of residual tumor. Follow-up showed tumor regrowth in 10 patients, and tumor recurrence in 1 case. EPMR showed contrast enhancement of the resection bed in 45 of the 50 patients. Four of the 20 residual tumors showed a thick linear enhancement pattern, and the other 16 cases exhibited thick linear-nodular enhancement. No thin linear enhancement was observed in the residual tumor group. Nine of the 10-regrowth tumors showed a thick linear-nodular enhancement pattern, and one exhibited thin linear enhancement in EPMR. For predicting regrowth tumor EPMR sensitivity was 91%, specificity was 100%, positive predictive value 1; negative predictive value was 0.9375.
  
  
  CONCLUSIONS
  EPMR, depending on the surgical site enhancement pattern, is a valuable means of demonstrating residual tumors, and can be used to predict possible regrowth after surgery.
authors.affiliation: Marmara University Medical Faculty, Department of Radiology, Istanbul, Turkey.
authors.forename: Gazanfer
authors.initials: G
authors.lastname: Ekinci
authors.forename: Ihsan N
authors.initials: IN
authors.lastname: Akpinar
authors.forename: Feyyaz
authors.initials: F
authors.lastname: Baltacioğlu
authors.forename: Canan
authors.initials: C
authors.lastname: Erzen
authors.forename: Türker
authors.initials: T
authors.lastname: Kiliç
authors.forename: Ilhan
authors.initials: I
authors.lastname: Elmaci
authors.forename: Necmettin
authors.initials: N
authors.lastname: Pamir
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000601:surgery; D003287:Contrast Media; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018365:Neoplasm, Residual / Q000175:diagnosis; D011184:Postoperative Period; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013238:Stereotaxic Techniques
chemical_list: D003287:Contrast Media