title: Assessment of Glioma Response to Radiotherapy Using Multiple MRI Biomarkers with Manual and Semiautomated Segmentation Algorithms.
abstract: Multimodality magnetic resonance imaging (MRI) can provide complementary information in the assessment of brain tumors. We aimed to segment tumor in amide proton transfer-weighted (APTw) images and to investigate multiparametric MRI biomarkers for the assessment of glioma response to radiotherapy. For tumor extraction, we evaluated a semiautomated segmentation method based on region of interest (ROI) results by comparing it with the manual segmentation method.
  
  
  
  Thirteen nude rats injected with U87 tumor cells were irradiated by an 8-Gy radiation dose. All MRI scans were performed on a 4.7-T animal scanner preradiation, and at day 1, day 4, and day 8 postradiation. Two experts performed manual and semiautomated methods to extract tumor ROIs on APTw images. Multimodality MRI signals of the tumors, including structural (T2and T1), functional (apparent diffusion coefficient and blood flow), and molecular (APTw and magnetization transfer ratio or MTR), were calculated and compared quantitatively.
  
  
  
  The semiautomated method provided more reliable tumor extraction results on APTw images than the manual segmentation, in less time. A considerable increase in the ADC intensities of the tumor was observed during the postradiation. A steady decrease in the blood flow values and in the APTw signal intensities were found after radiotherapy.
  
  
  
  The semiautomated method of tumor extraction showed greater efficiency and stability than the manual method. Apparent diffusion coefficient, blood flow, and APTw are all useful biomarkers in assessing glioma response to radiotherapy.
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.|Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Shin-Lei
authors.initials: SL
authors.lastname: Peng
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Jiang
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Xuna
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Heo
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.|Department of Radiology, Beijing Hospital, Beijing, China.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Radiology, Beijing Hospital, Beijing, China.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Hanzhang
authors.initials: H
authors.lastname: Lu
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China.
authors.forename: Haiyun
authors.initials: H
authors.lastname: Li
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, MD, China. jzhou@mri.jhu.edu.
authors.forename: Jinyuan
authors.initials: J
authors.lastname: Zhou
mesh_terms: D000465:Algorithms; D000818:Animals; D015415:Biomarkers; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000532:radiotherapy; D008279:Magnetic Resonance Imaging / Q000379:methods*; D064847:Multimodal Imaging; D009368:Neoplasm Transplantation; D051381:Rats; D011923:Rats, Nude; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers
keywords: APT imaging; Brain tumor; image segmentation; multiparametric MRI; response assessment