title: Quantitative perfusion- and diffusion-weighted magnetic resonance imaging of gastrointestinal cancers treated with multikinase inhibitors: a pilot study.
abstract: BACKGROUND
  Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) are often used to detect the early response of solid tumors to an effective therapy. The early changes in intratumoral physiological parameters measured by DCE-MRI/DWI have been evaluated as surrogate biomarkers allowing a tailored treatment for the individual patient.
  
  
  METHODS
  Patients with newly diagnosed, biopsy-proven, treatment-naïve gastrointestinal stromal tumor (GIST) or hepatocellular carcinoma (HCC) were enrolled prospectively after institutional review board (IRB)-approved informed consent (5 patients per tumor type). Patients with GIST were treated with sunitinib over 6 weeks. DCE-MRI/DWI was applied before therapy (baseline imaging) and at 2 and 6 weeks after therapy initiation. Patients with HCC were treated with radiation during the first 2 weeks and then with sorafenib for the next 6 weeks. DCE-MRI/DWI was applied in all patients with HCC before and after radiation therapy and at the end of sorafenib therapy. Tumor volume, perfusion parameters (K (trans), the forward volume-transfer constant, and k ep, the reverse reflux-rate constant) and the apparent diffusion coefficient (ADC) were measured.
  
  
  RESULTS
  During 2 weeks of sunitinib therapy, GIST volume, K (trans), and k ep decreased 32 ± 13, 45 ± 24, and 42 ± 15%, respectively, whereas ADC increased 76 ± 24%. After 6 weeks of sunitinib therapy, GIST volume, K (trans), and k ep decreased 56 ± 7, 70 ± 7, and 50 ± 12%, respectively, whereas ADC increased 85 ± 33%. After completion of radiation therapy, HCC volume, K (trans), and k ep decreased 34 ± 14, 35 ± 12, and 4 ± 21%, respectively, but ADC increased 21 ± 9%. During the entire 10-week therapeutic period, HCC volume, K (trans), and k ep decreased 65 ± 15, 40 ± 9, and 26 ± 2%, respectively, whereas ADC increased 28 ± 10%.
  
  
  CONCLUSIONS
  DCE-MRI/DWI can measure the perfusion and diffusion changes in GISTs or HCCs treated with multikinase inhibitors.
authors.affiliation: Department of Radiology.
authors.forename: Hyunki
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology.
authors.forename: Kimberly S
authors.initials: KS
authors.lastname: Keene
authors.affiliation: Department of Radiology University of Arkansas for Medical Sciences Little Rock, AR.
authors.forename: David B
authors.initials: DB
authors.lastname: Sarver
authors.affiliation: Department of Medicine.
authors.forename: S Kyle
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Biostatistics University of Alabama Birmingham, AL.
authors.forename: T Mark
authors.initials: TM
authors.lastname: Beasley
authors.affiliation: Department of Radiology.
authors.forename: Desiree E
authors.initials: DE
authors.lastname: Morgan
authors.affiliation: Department of Medicine.
authors.forename: James A
authors.initials: JA
authors.lastname: Posey