title: Quantitative correlational study of microbubble-enhanced ultrasound imaging and magnetic resonance imaging of glioma and early response to radiotherapy in a rat model.
abstract: OBJECTIVE
  Radiotherapy remains a major treatment method for malignant tumors. Magnetic resonance imaging (MRI) is the standard modality for assessing glioma treatment response in the clinic. Compared to MRI, ultrasound imaging is low-cost and portable and can be used during intraoperative procedures. The purpose of this study was to quantitatively compare contrast-enhanced ultrasound (CEUS) imaging and MRI of irradiated gliomas in rats and to determine which quantitative ultrasound imaging parameters can be used for the assessment of early response to radiation in glioma.
  
  
  METHODS
  Thirteen nude rats with U87 glioma were used. A small thinned skull window preparation was performed to facilitate ultrasound imaging and mimic intraoperative procedures. Both CEUS and MRI with structural, functional, and molecular imaging parameters were performed at preradiation and at 1 day and 4 days postradiation. Statistical analysis was performed to determine the correlations between MRI and CEUS parameters and the changes between pre- and postradiation imaging.
  
  
  RESULTS
  Area under the curve (AUC) in CEUS showed significant difference between preradiation and 4 days postradiation, along with four MRI parameters, T2, apparent diffusion coefficient, cerebral blood flow, and amide proton transfer-weighted (APTw) (all p < 0.05). The APTw signal was correlated with three CEUS parameters, rise time (r = - 0.527, p < 0.05), time to peak (r = - 0.501, p < 0.05), and perfusion index (r = 458, p < 0.05). Cerebral blood flow was correlated with rise time (r = - 0.589, p < 0.01) and time to peak (r = - 0.543, p < 0.05).
  
  
  CONCLUSIONS
  MRI can be used for the assessment of radiotherapy treatment response and CEUS with AUC as a new technique and can also be one of the assessment methods for early response to radiation in glioma.
authors.affiliation: Department of Ultrasound, Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310022, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Yang
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287.
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287.
authors.forename: Antonella
authors.initials: A
authors.lastname: Mangraviti
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231.
authors.forename: Lin
authors.initials: L
authors.lastname: Su
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231.
authors.forename: Yin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287.
authors.forename: Wenxiao
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287.
authors.forename: Betty
authors.initials: B
authors.lastname: Tyler
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231.
authors.forename: John
authors.initials: J
authors.lastname: Wong
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231.
authors.forename: Ken Kang-Hsin
authors.initials: KK
authors.lastname: Wang
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231.
authors.forename: Esteban
authors.initials: E
authors.lastname: Velarde
authors.affiliation: Division of MR Research, Department of Radiology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287.
authors.forename: Jinyuan
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21231.
authors.forename: Kai
authors.initials: K
authors.lastname: Ding
mesh_terms: D000818:Animals; D019540:Area Under Curve; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D002560:Cerebrovascular Circulation / Q000502:physiology / Q000528:radiation effects; D003287:Contrast Media; D004453:Echoencephalography / Q000379:methods*; D005910:Glioma / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D045423:Microbubbles; D057054:Molecular Imaging / Q000379:methods; D009368:Neoplasm Transplantation; D011923:Rats, Nude; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media