title: [Blood volume changes after the radiotherapy of the central nervous system].
abstract: BACKGROUND
  The pathogenesis of late delayed radiation damage in normal brain tissue is most likely due to damage to the vascular endothelium. The mitotic activity of gliomas was shown to correlate with the tumor induced angiogenesis. Dynamic susceptibility contrast MR imaging (DSC MRI) allows the measurement of the cerebral hemodynamics based on the indicator dilution theory. We describe theory and technique of the method and present our experience with blood volume measurements after irradiation of the CNS.
  
  
  METHODS
  We established a double slice technique on a standard 1.5 T MR system without hardware modifications, which allows an absolute quantification of the blood volume in regions of interest (ROI) within the brain. Fifty-five T2* weighted double slice images were acquired before, during and after bolus injection of Gd-DTPA (0.1 mmol/kg in 5 sec.) using a SD FLASH sequence (simultaneous dual fast low angle shot, TR/TE1/TE2 31/16/25, flip angle 10 degrees). Concentration-time curves were calculated from the measured signal-time curves. Blood volume values in tissue were normalised and calculated in absolute values (ml/100 g) based on the knowledge of the arterial input function (AIF), which was measured in the brain supplying arteries. The whole procedure requires only 2 to 3 minutes, the time for post processing is about 15 to 20 minutes.
  
  
  RESULTS
  Blood volume parameter images of representative cases demonstrate the blood volume changes after radiotherapy. A reduction in blood volume could be observed in normal brain tissue and low-grade gliomas, while recurrent tumors were accompanied by a local increase in blood volume.
  
  
  CONCLUSIONS
  Radiation induced blood volume changes in the CNS can be measured using dynamic susceptibility contrast MR imaging. The measurements in normal brain tissue allow a functional in-vivo analysis of late delayed radiation reactions of the CNS. The definite value of intratumoral blood volume measurements for determination of the therapeutic success and for differentiation of recurrences versus radionecroses remains to be clarified in further studies.
authors.affiliation: Radiologische Universitätsklinik Heidelberg.
authors.forename: F
authors.initials: F
authors.lastname: Wenz
authors.forename: M
authors.initials: M
authors.lastname: Fuss
authors.forename: R
authors.initials: R
authors.lastname: Scholdei
authors.forename: M
authors.initials: M
authors.lastname: Essig
authors.forename: F
authors.initials: F
authors.lastname: Lohr
authors.forename: K
authors.initials: K
authors.lastname: Rempp
authors.forename: G
authors.initials: G
authors.lastname: Brix
authors.forename: M V
authors.initials: MV
authors.lastname: Knopp
authors.forename: R
authors.initials: R
authors.lastname: Engenhart
authors.forename: M
authors.initials: M
authors.lastname: Wannenmacher
mesh_terms: D000328:Adult; D001810:Blood Volume / Q000528:radiation effects*; D001921:Brain / Q000473:pathology / Q000528:radiation effects*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000503:physiopathology / Q000532:radiotherapy; D003287:Contrast Media; D005682:Gadolinium; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D004369:Pentetic Acid / Q000031:analogs & derivatives; D013997:Time Factors
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA
vernacular_title: Blutvolumenveränderungen nach Strahlentherapie des zentralen Nervensystems.