title: BOLD signal in the motor cortex shows a correlation with the blood volume of brain tumors.
abstract: OBJECTIVE
  To investigate whether and how the blood-oxygenation-level-dependent (BOLD) functional MRI (fMRI) signal is modified by brain tumors.
  
  
  METHODS
  The BOLD signal depends on the perfusion, which in turn may be affected in the presence of a tumor. Some studies have demonstrated a reduced BOLD signal in the tumor-bearing hemisphere. The BOLD signal variation in the motor cortex area was studied with finger tapping in a brain tumor group and a control group. An a priori volume-of-interest (VOI)-based method was applied that allows quantification of the mean BOLD signal amplitude and extent of activated volume. BOLD signal amplitude and activated volume were correlated with the extent of edema, a mass effect on the central sulcus, tumor volume, distance of tumor to somatosensory cortex, and tumor blood volume.
  
  
  RESULTS
  In the tumor group the ipsilateral activated volume was reduced by 21% (P = 0.025) and the mean signal amplitude was reduced by 16% (P = 0.004). The mean BOLD signal amplitude shows a significant correlation with the total intratumoral blood volume (P = 0.014).
  
  
  CONCLUSIONS
  We concluded that the peritumoral perfusion was reduced resulting due to a tumor aspirating perfusion (steal phenomenon).
authors.affiliation: Department of Radiology, Nuclear Medicine and Radiooncology, Universitätsklinikum Charité, Berlin, Germany. lutz.luedemann@charite.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Lüdemann
authors.forename: Annette
authors.initials: A
authors.lastname: Förschler
authors.forename: Wolfgünter
authors.initials: W
authors.lastname: Grieger
authors.forename: Claus
authors.initials: C
authors.lastname: Zimmer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001810:Blood Volume; D001931:Brain Mapping / Q000379:methods; D001932:Brain Neoplasms / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D002648:Child; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology*; D010100:Oxygen / Q000097:blood; D015203:Reproducibility of Results; D013003:Somatosensory Cortex / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA; D010100:Oxygen