title: Usefulness of thallium-201 SPECT in the evaluation of tumor natures in intracranial meningiomas.
abstract: BACKGROUND
  Although intracranial meningiomas are regarded as benign tumors, some of them behave clinically as malignant tumors. Past reports suggest that MIB 1 and vascular endothelial growth factor (VEGF) in postoperative tumor specimens correlate with the aggressive nature of tumors, but preoperative prediction of such a nature is more useful for therapeutic planning for the tumor. The purpose of this study was to assess the usefulness of preoperative thallium-201 chloride single-photon emission computed tomography (Tl SPECT) to evaluate biological behavior in intracranial meningiomas.
  
  
  METHODS
  Tl SPECT was performed on 39 patients with intracranial meningioma and Tl uptake indices were calculated. The difference in the Tl uptake index between atypical meningiomas and other pathological types of meningioma was evaluated. Moreover, correlation of Tl uptake indices with the MIB1 labeling index was estimated. Tl uptake indices were also compared between VEGF strongly positive and weakly positive meningiomas.
  
  
  RESULTS
  The delayed index of atypical meningioma was significantly higher than that of the other pathological types (p = 0.036). Significant correlation was found between the Tl uptake index in the delayed image and MIB1 labeling index (p < 0.0001, R                            (2) = 0.36). Moreover, VEGF strongly positive meningiomas exhibited a significantly higher Tl uptake index compared to VEGF weakly positive meningiomas in both the early image and the delayed image (p = 0.029, 0.023, respectively).
  
  
  CONCLUSIONS
  Tl uptake index may be a possible preoperative surrogate marker of MIB1 and VEGF that is useful in detecting aggressive natures in intracranial meningiomas.
authors.affiliation: Department of Neurosurgery, Hirosaki University Graduate School of Medicine, Zaifucho 5, Hirosaki 036-8562, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Takeda
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakano
authors.forename: Kenichiroh
authors.initials: K
authors.lastname: Asano
authors.forename: Norihito
authors.initials: N
authors.lastname: Shimamura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ohkuma
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008579:Meningioma / Q000000981:diagnostic imaging* / Q000473:pathology; D008875:Middle Aged; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D013794:Thallium Radioisotopes