title: Unshielded asymmetric transmit-only and endorectal receive-only radiofrequency coil for (23) Na MRI of the prostate at 3 tesla.
abstract: BACKGROUND
  To develop and optimize radiofrequency (RF) hardware for the detection of endogenous sodium ((23) Na) by 3.0 Tesla (T) MRI in the human prostate.
  
  
  METHODS
  A transmit-only receive-only (TORO) RF system of resonators consisting of an unshielded, asymmetric, quadrature birdcage (transmit), and an endorectal (ER), linear, surface (receive) coil were developed and tested on a 3T MRI scanner. Two different ER receivers were constructed; a single-tuned ((23) Na) and a dual-tuned ((1) H/(23) Na). Both receivers were evaluated by the measurements of signal-to-noise ratio (SNR) and B1 homogeneity. For tissue sodium concentration (TSC) quantification, vials containing known sodium concentrations were incorporated into the ER. The system was used to measure the prostate TSC of three men (age 55 ± 5 years) with biopsy-proven prostate cancer.
  
  
  RESULTS
  B1 field inhomogeneity of the asymmetric transmitter was estimated to be less than 5%. The mean SNR measured in a region of interest within the prostate using the single-tuned ER coil was 54.0 ± 4.6. The mean TSC in the central gland was 60.2 ± 5.7 mmol/L and in the peripheral gland was 70.5 ± 9.0 mmol/L.
  
  
  CONCLUSIONS
  A TORO system was developed and optimized for (23) Na MRI of the human prostate which showed good sensitivity throughout the prostate for quantitative measurement of TSC.
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada, N6A 5B7.
authors.forename: Adam
authors.initials: A
authors.lastname: Farag
authors.affiliation: Department of Medical Biophysics, Western University, London, ON, Canada, N6A 5C1.
authors.forename: Justin Charles
authors.initials: JC
authors.lastname: Peterson
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada, N6A 5B7.
authors.forename: Trevor
authors.initials: T
authors.lastname: Szekeres
authors.affiliation: Department of Medical Biophysics, Western University, London, ON, Canada, N6A 5C1.|London Regional Cancer Program, London, ON, Canada, N6A 4L6.
authors.forename: Glenn
authors.initials: G
authors.lastname: Bauman
authors.affiliation: London Regional Cancer Program, London, ON, Canada, N6A 4L6.
authors.forename: Joseph
authors.initials: J
authors.lastname: Chin
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada, N6A 5B7.
authors.forename: Cesare
authors.initials: C
authors.lastname: Romagnoli
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada, N6A 5B7.|Department of Medical Biophysics, Western University, London, ON, Canada, N6A 5C1.
authors.forename: Robert
authors.initials: R
authors.lastname: Bartha
authors.affiliation: Imaging Research Laboratories, Robarts Research Institute, Western University, London, ON, Canada, N6A 5B7.|Department of Medical Biophysics, Western University, London, ON, Canada, N6A 5C1.|Ontario Institute for Cancer Research, Toronto, ON, Canada, M5G 1L7.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Scholl
mesh_terms: D015415:Biomarkers / Q000032:analysis; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D011467:Prostate / Q000737:chemistry*; D011471:Prostatic Neoplasms / Q000737:chemistry*; D011835:Radiation Protection / Q000295:instrumentation; D011846:Radio Waves; D019275:Radiopharmaceuticals / Q000032:analysis; D012007:Rectum; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012964:Sodium / Q000032:analysis*; D012975:Sodium Isotopes / Q000032:analysis; D014159:Transducers
chemical_list: D015415:Biomarkers; D019275:Radiopharmaceuticals; D012975:Sodium Isotopes; D012964:Sodium
keywords: MRI; asymmetric birdcage; endorectal coil; prostate imaging; radio frequency resonator; sodium (23Na)