title: Radial expansion rates and tumor growth kinetics predict malignant transformation in contrast-enhancing low-grade diffuse astrocytoma.
abstract: BACKGROUND
  Contrast-enhancing low-grade diffuse astrocytomas are an understudied, aggressive subtype at increased risk because of few radiographic indications of malignant transformation. In the current study, we tested whether tumor growth kinetics could identify tumors that undergo malignant transformation to higher grades.
  
  
  METHODS
  Thirty patients with untreated diffuse astrocytomas (WHO II) that underwent tumor progression were enrolled. Contrast-enhancing and T2 hyperintense tumor regions were segmented and the radius of tumor at two time points leading to progression was estimated. Radial expansion rates were used to estimate proliferation and invasion rates using a biomathematical model.
  
  
  RESULTS
  Radial expansion rates for both contrast-enhancing (p = 0.0040) and T2 hyperintense regions (p = 0.0016) were significantly higher in WHO II-IV tumors compared with nontransformers. Similarly, model estimates showed a significantly higher proliferation (p = 0.0324) and invasion rate (p = 0.0050) in WHO II-IV tumors compared with nontransformers.
  
  
  CONCLUSIONS
  Tumor growth kinetics can identify contrast-enhancing diffuse astrocytomas undergoing malignant transformation.
authors.affiliation: Harvard Medical School, 25 Shattuck Street, Boston, MA 02115, USA.
authors.forename: Leith
authors.initials: L
authors.lastname: Hathout
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, 924 Westwood Boulevard, Suite 615, Los Angeles, CA 90024, USA.
authors.forename: Whitney B
authors.initials: WB
authors.lastname: Pope
authors.affiliation: UCLA Neuro-Oncology Program, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.|Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
authors.forename: Albert
authors.initials: A
authors.lastname: Lai
authors.affiliation: UCLA Neuro-Oncology Program, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.|Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
authors.forename: Phioanh L
authors.initials: PL
authors.lastname: Nghiemphu
authors.affiliation: UCLA Neuro-Oncology Program, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.|Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Cloughesy
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, 924 Westwood Boulevard, Suite 615, Los Angeles, CA 90024, USA.|UCLA Neuro-Oncology Program, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.|Department of Biomedical Physics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.|Department of Bioengineering, Henry Samueli School of Engineering & Applied Science, University of California Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ellingson
mesh_terms: D001254:Astrocytoma / Q000175:diagnosis* / Q000473:pathology* / Q000503:physiopathology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000473:pathology* / Q000503:physiopathology; D018450:Disease Progression; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008954:Models, Biological; D060787:Neoplasm Grading; D011379:Prognosis; D012189:Retrospective Studies; D047368:Tumor Burden
keywords: MRI; glioma growth model; growth rate; low-grade gliomas; malignant transformation