title: Simultaneous acquisition of T1ρ and T2 quantification in knee cartilage: repeatability and diurnal variation.
abstract: OBJECTIVE
  To develop a robust sequence that combines T1ρ and T2 quantifications and to examine the in vivo repeatability and diurnal variation of T1ρ and T2 quantifications in knee cartilage.
  
  
  METHODS
  Six healthy volunteers were scanned in the morning and afternoon on 2 days using a combined T1ρ and T2 quantification sequence developed in this study. Repeatability of T1ρ and T2 quantification was estimated using root-mean-square coefficients-of-variation (RMS-CV). T1ρ and T2 values from morning scans were compared to those from afternoon scans using paired t-tests.
  
  
  RESULTS
  The overall RMS-CV of in vivo T1ρ and T2 quantification was 5.3% and 5.2%, respectively. The RMS-CV of am scans was 4.2% and 5.0% while the RMS-CV of pm scans was 6.0% and 6.3% for T1ρ and T2 , respectively. No significant difference was found between T1ρ or T2 values in the morning and in the afternoon.
  
  
  CONCLUSIONS
  A sequence that combines T1ρ and T2 quantification with scan time less than 10 minutes and is robust to B0 and B1 inhomogeneity was developed with excellent repeatability. For a cohort with low-level daily activity, although no significant diurnal variation of cartilage MR relaxation times was observed, the afternoon scans had inferior repeatability compared to morning scans.
authors.affiliation: Musculo-skeletal Quantitative Imaging Research (MQIR), Department of Radiology, University of California, San Francisco (UCSF), San Francisco, California, USA.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
authors.forename: Cory
authors.initials: C
authors.lastname: Wyatt
authors.forename: Julien
authors.initials: J
authors.lastname: Rivoire
authors.forename: Eric
authors.initials: E
authors.lastname: Han
authors.forename: Weitian
authors.initials: W
authors.lastname: Chen
authors.forename: Joseph
authors.initials: J
authors.lastname: Schooler
authors.forename: Fei
authors.initials: F
authors.lastname: Liang
authors.forename: Keerthi
authors.initials: K
authors.lastname: Shet
authors.forename: Richard
authors.initials: R
authors.lastname: Souza
authors.forename: Sharmila
authors.initials: S
authors.lastname: Majumdar
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology* / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007719:Knee Joint / Q000033:anatomy & histology* / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: T1ρ; T2; cartilage degeneration; diurnal variation; repeatability
references.citation: Eur J Radiol. 2013 Apr;82(4):647-50
references.pmid: 23333531
references.citation: Magn Reson Imaging. 2011 Apr;29(3):324-34
references.pmid: 21130590
references.citation: Magn Reson Med. 2008 Sep;60(3):640-9
references.pmid: 18727082
references.citation: J Magn Reson. 2003 May;162(1):113-21
references.pmid: 12762988
references.citation: Magn Reson Med. 2009 Jun;61(6):1310-8
references.pmid: 19319904
references.citation: Acad Radiol. 2002 Dec;9(12):1388-94
references.pmid: 12553350
references.citation: Clin Radiol. 2003 May;58(5):389-92
references.pmid: 12727168
references.citation: Magn Reson Imaging. 2008 Nov;26(9):1215-20
references.pmid: 18502073
references.citation: Magn Reson Med. 2000 Jan;43(1):126-32
references.pmid: 10642739
references.citation: Magn Reson Med. 1997 Nov;38(5):759-68
references.pmid: 9358450
references.citation: Magn Reson Med. 1996 Jul;36(1):90-4
references.pmid: 8795026
references.citation: Magn Reson Imaging. 2011 Jun;29(5):608-19
references.pmid: 21524869
references.citation: Magn Reson Med. 2008 Feb;59(2):298-307
references.pmid: 18228578
references.citation: J Biomech. 2013 Feb 1;46(3):541-7
references.pmid: 23102493
references.citation: J Magn Reson Imaging. 2008 Jul;28(1):252-7
references.pmid: 18581387
references.citation: Osteoarthritis Cartilage. 2011 Feb;19(2):171-9
references.pmid: 21112409
references.citation: Magn Reson Med. 2005 Oct;54(4):929-36
references.pmid: 16155867
references.citation: Osteoarthritis Cartilage. 2007 Jul;15(7):789-97
references.pmid: 17307365
references.citation: Radiographics. 2011 Jan-Feb;31(1):37-61
references.pmid: 21257932
references.citation: Med Image Anal. 2008 Apr;12(2):120-35
references.pmid: 17923429