title: Detecting gas-induced vasomotor changes via blood oxygenation level-dependent contrast in healthy breast parenchyma and breast carcinoma.
abstract: To evaluate blood oxygenation level-dependent (BOLD) contrast changes in healthy breast parenchyma and breast carcinoma during administration of vasoactive gas stimuli.
  
  
  
  Magnetic resonance imaging (MRI) was performed at 3T in 19 healthy premenopausal female volunteers using a single-shot fast spin echo sequence to acquire dynamic T2 -weighted images. 2% (n = 9) and 5% (n = 10) carbogen gas mixtures were interleaved with either medical air or oxygen in 2-minute blocks, for four complete cycles. A 12-minute medical air breathing period was used to determine background physiological modulation. Pixel-wise correlation analysis was applied to evaluate response to the stimuli in breast parenchyma and these results were compared to the all-air control. The relative BOLD effect size was compared between two groups of volunteers scanned in different phases of the menstrual cycle. The optimal stimulus design was evaluated in five breast cancer patients.
  
  
  
  Of the four stimulus combinations tested, oxygen vs. 5% carbogen produced a response that was significantly stronger (P < 0.05) than air-only breathing in volunteers. Subjects imaged during the follicular phase of their cycle when estrogen levels typically peak exhibited a significantly smaller BOLD response (P = 0.01). Results in malignant tissue were variable, with three out of five lesions exhibiting a diminished response to the gas stimulus.
  
  
  
  Oxygen vs. 5% carbogen is the most robust stimulus for inducing BOLD contrast, consistent with the opposing vasomotor effects of these two gases. Measurements may be confounded by background physiological fluctuations and menstrual cycle changes. J. Magn. Reson. Imaging 2016;44:335-345.
authors.affiliation: Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.|NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK.
authors.forename: Tess E
authors.initials: TE
authors.lastname: Wallace
authors.affiliation: NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK.|Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Patterson
authors.affiliation: Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.|NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK.
authors.forename: Oshaani
authors.initials: O
authors.lastname: Abeyakoon
authors.affiliation: Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.|NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK.
authors.forename: Reem
authors.initials: R
authors.lastname: Bedair
authors.affiliation: Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.|NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK.
authors.forename: Roido
authors.initials: R
authors.lastname: Manavaki
authors.affiliation: Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Mary A
authors.initials: MA
authors.lastname: McLean
authors.affiliation: Institute of Cancer Sciences, University of Manchester, Manchester, UK.
authors.forename: James P B
authors.initials: JP
authors.lastname: O'Connor
authors.affiliation: NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK.|Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Graves
authors.affiliation: Department of Radiology, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.|NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, UK.
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Gilbert
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000000981:diagnostic imaging / Q000378:metabolism*; D001943:Breast Neoplasms / Q000097:blood* / Q000098:blood supply / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000097:blood* / Q000000981:diagnostic imaging; D010092:Oximetry / Q000379:methods*; D010100:Oxygen / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014666:Vasomotor System / Q000000981:diagnostic imaging / Q000378:metabolism
chemical_list: D010100:Oxygen
keywords: BOLD MRI; breast cancer; carbogen; menstrual cycle variation