title: In Vivo DCE-MRI for the Discrimination Between Glioblastoma and Radiation Necrosis in Rats.
abstract: In this study, the potential of semiquantitative and quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) was investigated to differentiate glioblastoma (GB) from radiation necrosis (RN) in rats.
  
  
  
  F98 GB growth was seen on MRI 8-23 days post-inoculation (n = 15). RN lesions developed 6-8 months post-irradiation (n = 10). DCE-MRI was acquired using a fast low-angle shot (FLASH) sequence. Regions of interest (ROIs) encompassed peripheral contrast enhancement in GB (n = 15) and RN (n = 10) as well as central necrosis within these lesions (GB (n = 4), RN (n = 3)). Dynamic contrast-enhanced time series, obtained from the DCE-MRI data, were fitted to determine four function variables (amplitude A, offset from zero C, wash-in rate k, and wash-out rate D) as well as maximal intensity (ImaxF) and time to peak (TTPF). Secondly, maps of semiquantitative and quantitative parameters (extended Tofts model) were created using Olea Sphere (O). Semiquantitative DCE-MRI parameters included wash-inO, wash-outO, area under the curve (AUCO), maximal intensity (ImaxO), and time to peak (TTPO). Quantitative parameters included the rate constant plasma to extravascular-extracellular space (EES) (Ktrans), the rate constant EES to plasma (Kep), plasma volume (Vp), and EES volume (Ve). All (semi)quantitative parameters were compared between GB and RN using the Mann-Whitney U test. ROC analysis was performed.
  
  
  
  Wash-in rate (k) and wash-out rate (D) were significantly higher in GB compared to RN using curve fitting (p = 0.016 and p = 0.014). TTPFand TTPOwere significantly lower in GB compared to RN (p = 0.001 and p = 0.005, respectively). The highest sensitivity (87 %) and specificity (80 %) were obtained for TTPFby applying a threshold of 581 s. Ktrans, Kep, and Vewere not significantly different between GB and RN. A trend towards higher Vpvalues was found in GB compared to RN, indicating angiogenesis in GB (p = 0.075).
  
  
  
  Based on our results, in a rat model of GB and RN, wash-in rate, wash-out rate, and the time to peak extracted from DCE-MRI time series data may be useful to discriminate GB from RN.
authors.affiliation: Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium. Julie.Bolcaen@ugent.be.
authors.forename: Julie
authors.initials: J
authors.lastname: Bolcaen
authors.affiliation: iMinds-IBiTech-MEDISIP, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.
authors.forename: Benedicte
authors.initials: B
authors.lastname: Descamps
authors.affiliation: Department of Radiology and Medical Imaging, Ghent University Hospital, Ghent, Belgium.
authors.forename: Marjan
authors.initials: M
authors.lastname: Acou
authors.affiliation: Department of Radiology and Medical Imaging, Ghent University Hospital, Ghent, Belgium.
authors.forename: Karel
authors.initials: K
authors.lastname: Deblaere
authors.affiliation: Department of Pathology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Caroline Van
authors.initials: CV
authors.lastname: den Broecke
authors.affiliation: Department of Radiation Oncology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Boterberg
authors.affiliation: iMinds-IBiTech-MEDISIP, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.
authors.forename: Christian
authors.initials: C
authors.lastname: Vanhove
authors.affiliation: Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Goethals
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry*; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008954:Models, Biological; D009336:Necrosis; D012372:ROC Curve; D011832:Radiation Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000473:pathology; D011916:Rats, Inbred F344
chemical_list: D003287:Contrast Media
keywords: DCE-MRI; Glioblastoma; Radiation necrosis; Rat model