title: The effect of pulse sequence parameters and contrast agent dose on percentage signal recovery in DSC-MRI: implications for clinical applications.
abstract: OBJECTIVE
  Both technical and pathophysiologic factors affect PSR in DSC-MR imaging. We aimed to determine how TE, flip angle (α), and contrast dose impact PSR in high-grade gliomas.
  
  
  METHODS
  We retrospectively computed PSR maps for 22 patients with high-grade gliomas, comparing 3 DSC-MR imaging methods by using single-dose gadodiamide without preload administration: A (n = 7), α = 35°, TE = 54 ms; B (n = 5), α = 72°, TE = 30 ms; C (n = 10), α = 90°, TE = 30 ms. Methods A-C served as preload for subsequent dynamic imaging using method D (method C parameters but with double-dose contrast). We compared first- and second-injection tumor PSR for methods C and D (paired t test) and tumor PSR for both injections grouped by the first-injection acquisition method (3-group nonparametric 1-way ANOVA). We compared PSR in tumor and normal brain for each first- and second-injection method group (paired t test).
  
  
  RESULTS
  First-injection PSR in tumor and normal brain differed significantly for methods B (P = .01) and C (P = .05), but not A (P = .71). First-injection tumor PSR increased with T1 weighting with a significant main effect of method groupings (P = .0012), but there was no significant main effect for first-injection normal brain (P = .93), or second-injection tumor (P = .95) or normal brain (P = .13). In patients scanned with methods C and D, first-injection PSR significantly exceeded second-injection PSR for tumor (P = .037) and normal brain (P < .001).
  
  
  CONCLUSIONS
  PSR strongly depends on the T1 weighting of DSC-MR imaging, including pulse sequence (TE, α) and contrast agent (dose, preload) parameters, with implications for protocol design and the interpretation and comparison of PSR values across tumor types and imaging centers.
authors: Department of Diagnostic Imaging, Rhode Island Hospital, Providence, RI 02903, USA. jboxerman@lifespan.org
authors: J L
authors: JL
authors: Boxerman
authors: E S
authors: ES
authors: Paulson
authors: M A
authors: MA
authors: Prah
authors: K M
authors: KM
authors: Schmainda
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001254:Astrocytoma / Q000175:diagnosis; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis*; D015331:Cohort Studies; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D005909:Glioblastoma / Q000175:diagnosis; D005910:Glioma / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D009837:Oligodendroglioma / Q000175:diagnosis; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA