title: Bone mineral imaged in vivo by 31P solid state MRI of human wrists.
abstract: OBJECTIVE
  To implement solid state (31)P MRI ((31)P SMRI) in a clinical scanner to visualize bone mineral.
  
  
  METHODS
  Wrists of seven healthy volunteers were scanned. A quadrature wrist (31)P transmit/receive coil provided strong B(1) and good signal-to-noise ratio (SNR). A (1)H-(31)P frequency converter was constructed to enable detection of the (31)P signal by means of the (1)H channel. Data points lost in the receiver dead time were recovered by a second acquisition with longer dwell time and lower gradient strength.
  
  
  RESULTS
  Three-dimensional (31)P images, showing only bone mineral of the wrist, were obtained with a clinical 3 Tesla (T) scanner. In the best overall case an image with isotropic resolution of ∼5.1 mm and SNR of 30 was obtained in 37 min. (31)P NMR properties (resonance line width 2 kHz and T(1) 17-19 s) of in vivo human bone mineral were measured.
  
  
  CONCLUSIONS
  In vivo (31)P SMRI visualization of human wrist bone mineral with a clinical MR scanner is feasible with suitable modifications to circumvent the scanners' limitations in reception of short-T(2) signals. Frequency conversion methodology is useful for implementing (31)P SMRI measurements on scanners which do not have multinuclear capability or for which the multinuclear receiver dead time is excessive.
authors.affiliation: Department of Orthopedic Surgery, Children's Hospital, Boston, Massachusetts 02115, USA. yaotang.wu@childrens.harvard.edu
authors.forename: Yaotang
authors.initials: Y
authors.lastname: Wu
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Reese
authors.forename: Haihui
authors.initials: H
authors.lastname: Cao
authors.forename: Mirko I
authors.initials: MI
authors.lastname: Hrovat
authors.forename: Steven P
authors.initials: SP
authors.lastname: Toddes
authors.forename: Rostislav A
authors.initials: RA
authors.lastname: Lemdiasov
authors.forename: Jerome L
authors.initials: JL
authors.lastname: Ackerman
mesh_terms: D000328:Adult; D000818:Animals; D002113:Calcification, Physiologic / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010758:Phosphorus; D013552:Swine; D014955:Wrist Joint / Q000033:anatomy & histology* / Q000502:physiology*
chemical_list: D010758:Phosphorus